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THE 13 th SYMPOSIUM OF THE NATURAL 

PRODUCTS RESEARCH NETWORK FOR EASTERN 

AND CENTRAL AFRICA (NAPRECA) 

Theme “DRUG DISCOVERY FROM AFRICAN 

RAINFOREST” 

August 10-14, 2009 

Tel: 00243999942710 

Kinshasa/Gombe, DR Congo 

BOOK OF ABSTRACTS

13th NAPRECA SYMPOSIUM BOOK OF ABSTRACTS August 10-14, 2009 

>>>> SCOPE OF THE SYMPOSIUM >>>> 

Role of ethnopharmacology in drug discovery 

Target identification and validation for diseases 

of concern to African countries 

Screening of extracts for bioactivity 

Herbal remedies 

Vector control agents and repellents 

Monitoring the isolation of active constituents 

Structure elucidation of bioactive compounds 

Ethics of Drug development 

Bringing active compounds into drug development 

Green Chemistry 


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Local Organizing Committee 

Prof. Dr. Dibungi T. Kalenda - Chairman 

Prof. Dr. Mudogo Virima - Secretary and 

Vice Chairman 

Prof. Dr. Kokengo Bokolo - Treasurer 

Members 

Prof. Dr. Kambu Kabangu, 

Prof. Dr. Tona Lutete, 

Prof. Dr. Takaisi Kikuni, 

Prof. Dr. Mpuza Kapundu, 

Prof. Dr. Kasende Okuma, 

Prof. Dr. Yav Gushimana, 

Prof. Dr. Taba Kalulu, 

Prof. Dr. Molisho Ngongo, 

Prof. Dr. Kunyima Badibanga, 

Prof. Dr. Mpiana Tshimakinda, 

Dr. Ndjoko Karine et Pn Manga Opondjo 

Fernand. 

Prof. Dr. Dr. h.c. G. Bringmann 

Prof. B. Abegaz (Botswana) 

Prof. E. Dagne (Ethiopia) 

Prof. Philippe Rasoanaivo 

(Madagascar) 

Prof. J. Midiwo (Kenya) 

Prof. R. T. Majinda (Botswana) 

Prof. Joseph Moswa (DR Congo) 

NAPRECA Advisory Panel 

Contact Person 

Regional Coordinating Office Committee 

Professor Dr. J.O. Midiwo (Executive 

Secretary, NAPRECA) 

Professor Dr. C. Thoruwa (Assistant 

Secretary/Treasurer) 

Professor Dr. Abiy Yenesew (Programme 

Officer, NAPRECA) 

Dr Solomon Derese (Member) 

Dr. Joseph Mwaniki (Member) 

Prof. Dibungi Kalenda (DR Congo) 

Dr. Maud K. Mugisha (Uganda) 

Dr. J. Magadula (Tanzania) 

Prof. Sami Khalid (Sudan) 

Prof. Joseph Mbafor (Cameroon) 

Prof. Dr. Abiy Yenesew (Programme Officer, NAPRECA) 

ayenesew@uonbi.ac.ke 


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SPONSORS OF THE THIRTEENTH NAPRECA 

SYMPOSIUM 

Université de Kinshasa 


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FOREWORD 

We take this opportunity to welcome delegates to the 13 th NAPRECA Symposium to 

the Democratic Republic of Congo. The theme of the Symposium “Drug discovery 

from African rain forest” could not have been better used; the African biodiversity 

still offers great opportunity for doing what the them says. The amount of research 

that has been done on African medicinal plants and their development to 

phytomedicines or phytopharmaceuticals is still quite limited. The Congo basin is 

also the centre of the “African Rain Forest” by all consideration and has a 

bewildering array of biodiversity which needs to be tapped by us for the benefit of 

mankind. 

There is a large rapporteur of topics to be covered during this Symposium as 

indicated by the titles. We also have some luminary leading researchers and people 

of different disciplines in the field amongst us and we should seize the opportunity 

to explore collaboration for more effective and productive research activity as we 

usually endevour to carry out. It is clear to all of us that while the resolution and 

identification of active ingredients is gaining momentum in our institutions, we are 

not moving quickly enough to what should be our ultimate goal which should be 

getting the “product”. We should spend time at this Symposium reflecting the 

difficulties of doing this amongst ourselves. 

Finally, many of you, we are sure, are eagerly awaiting their first social experiences 

in the Congo. We wish that you will cease the opportunity to see as much as possible 

and leave with a positive impression. 

Enjoy your stay in Kinshasa. Seize your chance. 

Pascal Dibungi Kalenda- President, NAPRECA - Congo 

Jacob Ogweno Midiwo- Executive Secretary, NAPRECA. 


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PROGRAMME FOR THE 13 TH NAPRECA SYMPOSIUM 

16:00 – 18:00 COCKTAIL 

SUNDAY, AUGUST 9 TH 2009 

ARRIVAL 

REGISTRATION, CERCLE ELAEÏS 

MONDAY, AUGUST 10 TH 2009 

SESSION I 

Chairperson: Prof. Dr. Virima Mudogo (Secretary and Vice Chairman, Organizing 

Committee) 

08:00 – 09:00 

09:00 – 09:10 

09:10 – 09:20 

09:20 – 09:30 

09:30 – 09:35 

09:35 – 09:45 

09:45 – 10:00 

10:00 – 10:45 

Registration Continues 

Welcome and Introductory Remark by Prof. Dr. Dibungi Kalenda 

Remark by Prof. J.O.Midiwo (Executive Secretary, NAPRECA) 

Remarks by sponsors 

Official of UNIKIN 

Rector, UNIKIN 

Government Official from DRC 

Keynote address by Prof. Dr. Dibungi Kalenda 

10:45 – 11:00 TEA BREAK 

SESSION II 

PLENARY LECTURES (PL) 

Chairperson: Prof. Dr. Dibungi Kalenda (Chairman, Organizing Committee) 

PL 1 

PL 2 

PL 3 

11:00 – 11:40 

11:40 – 12:20 

12:20 – 13:00 

Prof. Dr. Berhanu Abegaz 

Novel metabolites from Rhus pyroides from 

Botswana and Morus mesozyga from Cameroon 

Prof. Kurt Hostettmann 

The potential of African medicinal plants as source of 

new drugs. 

Dr. Karine Ndjoko 

Application of LC-MS and LC-NMR Techniques to 

the Identification of Bioactive Natural Products 


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13:00 – 14:00 LUNCH 

SESSION III 

Chairperson: Prof. Dr. Abiy Yenesew 

PL 4 14:00 – 14:40 Prof. Dr. Dr. h.c. G. Bringmann 

Anthraquinones and alkaloids –acetogenic, antiinfective, 

and axially chiral! 

SL 1 

SL 2 

SL 3 

14:40 – 15:00 

15:00 – 15:20 

15:20 – 16:00 

Steinert, C. 

Isolation of bioactive compounds from the tropical 

liana Ancistrocladus congolensis 

Irmer, A. 

The biosynthetic origin of naphthylisoquinoline 

alkaloids 

Ngombe, N.K. 

Vasoconstrictor and inotropic effects induced by 

the root bark extracts of Anthocleista 

schweinfurthii (Gilg) (Gentianaceae) 

16:00 – 16:30 TEA BREAK 

SESSION IV 

Chairperson: Prof. Dr. Ermias Dagne 

PL 5 16:30 – 17:10 Prof. Dr. P. Okinda Owuor 

Optimising yields and quality of tea in different 

locations 

************End of day one************** 


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TUESDAY, AUGUST 11 TH 2009 

SESSION V 

Chairperson: Prof. Dr. Berhanu Abegaz 

PL 6 08:30 – 09:10 Prof. Philippe Rasoanaivo 

Drug discovery at IMRA: Recent results and way 

forward 

PL 7 

SL 4 

SL 5 

09:10 – 09:50 

09:50 – 10:10 

10:10 – 10:30 

Prof. Dulcie A Mulholland 

Terpenoids from African Medicinal Plants 

Mpiana, P.T. 

Antisickling activity of Justicia secunda Vahl 

Merhatibeb, B. 

HPLC analysis and NMR identification of homoisoflavonoids 

and stilbenoids from the inter-bulb 

surface of Scilla nervosa. 

10:30 – 11:00 TEA BREAK 

SESSION VI 

Chairperson: Prof. Dr. Dr. h.c. G. Bringmann 

SL 6 11:00 – 11:20 Bwire, R.N. 

Radical scavenging principles from Cassia abbreviata 

beareana holmes and Vangueria parvifolia sond & a facile 

palladium catalysed transfer hydrogenation protocol of 

prochiral alkenes. 

SL 7 

SL 8 

SL 9 

11:20 – 11:40 

11:40 – 12:00 

12:00 – 12:20 

Yagi, S. 

Phytochemical and biological studies of Gegeria alata 

Kabera, J.N. 

Phytomedicine development from plants of Rwanda 

Namutebi, A. 

The role of nutraceutical-implied empirical grades of plant 

foods in eliciting plant biodiversity on women small 

holder farms 


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SL 10 

SL 11 

12:20 – 12:40 

12:40 – 13:00 

Chairperson: Dr. Karine Ndjoko 

PL 8 14:00 – 14:40 

SL 12 

SL 13 

SL 14 

SL 15 

14:40 – 15:00 

15:00 – 15:20 

15:20 – 15:40 

15:40 – 16:00 

Mapitse, R. 

Synthesis of methoxystilbenes 

Shetonde, O.M. 

Total synthesis of biarylchalcones: Rhuschalcone VI and its 

analogues 

13:00 – 14:00 LUNCH 

SESSION VII 

Prof. Abiy Yenesew 

Red hot compounds from the red hot poker plants, 

Kniphofia species 

Magadula, J.J. 

Bioactive extracts and compounds from some 

Garcinia species growing in Tanzania 

Byamukama, R. 

Anthocyanins from selected plant species in 

Uganda 

Sivakumar, T. 

An application of mass spectra in natural products 

Ngombe, N.K. 

Screening of antibacterial and antifungal activities 

of fifteen extracts from Anthocleista schweinfurthii 

(Gilg.) (Gentianaceae) 

16:00 - 16:30 TEA BREAK 

Chairperson: Prof. Dr. Dibungi Kalenda 

PL 9 16:30 – 17:10 Prof. Dr. Joe Conolly 

Lifetime of Natural Products 

************End of day two************** 


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Chairperson: 

PL 10 08:30 – 09:10 

PL 11 

PL 12 

09:10 – 09:50 

09:50 – 10:30 

Chairperson: 

SL 16 11:00 – 11:20 

SL 17 

SL 18 

SL 19 

SL 20 

11:20 – 11:40 

11:40 – 12:00 

12:00 – 12:20 

12:20 – 12:40 

WEDNESDAY, AUGUST 12 TH 2009 

SESSION VIII 

Prof. Ermias Dagne 

Quality control of Natural Products 

Prof. Sabrina Krief 

From plants to bioactive compounds - through the 

study of great apes- ecology, chemistry and 

conservation of Tropical forest 

Prof. J. Quetin-Leclercq 

Croton zambesicu: isolation and quantification of 

active diterpenes and structure-activity 

relationships 

10:30 – 11:00 TEA BREAK 

SESSION IX 

Derese, S. 

Antiplasmodial -hydroxydihydrochalcone from 

seedpods of Tephrosia elata 

Kerubo, L. 

Phytochemical investigation of surface exudates of 

Dodonaea angustifoliafor in vitro antiplasmodial 

and mosquito larvicidal activity 

Mukanganyama, S. 

The role of natural products as modulators of drug 

efflux in pathogenic microbes 

Kamatenesi-Mugisha Maud 

Nutri-medicinal plants usage in the management of 

immuno-compromised ailments in Uganda 

Ngadjui, B.T. 

Chemistry and biological evaluation of Morus 


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SL 21 

12:40 – 13:00 

mesozygia and Dorstenia spp (Moraceae) 

Chiteva, R. 

Phytochemical investigation of resins from 

Commiphora holtziana in Kenya 

13:00 – 14:00 LUNCH 

SESSION X 

Chairperson: Prof. Dr. Tana Lutete 

SL 22 14:00 – 14:20 Nindi, M.M. 

Phytochemistry, analytical chemistry and medicinal 

plants: challenges in Africa 

SL 23 

SL 24 

14:20 – 14:40 

14:40 – 15:00 

K. B. Kubata 

Trypanosomiasis and African indigenous 

knowledge 

Ngombe, N.K. 

A n t i b a c t e r i a l a n d a n t i f u n g a l a c t i v i t i e s 

o f c a r d i a c g l y c o s i d e s e x t r a c t o f 

S n t h o c l e i s t a s c h w e i n f u r t h i i ( G i l g ) 

( G e n t i a n a c e a e ) 

15:00 – 16:00 POSTER SESSION 

16:00 – 16:30 TEA BREAK 

Chairperson: Prof. Dr. Kokengo Bokolo 

16:30 – 17:30 ROUND TABLE DISCUSSION 

************End of day three************** 


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THURSDAY, AUGUST 13 TH 2009 

SESSION XI 

Chairperson: 

08:30 – 10:30 GREEN CHEMISTRY WORK 

SHOP 

10:30 – 10:45 TEA BREAK 

10:45 – 13:00 GREEN CHEMISTRY WORK 

SHOP CONTINUES 

13:00 – 14:00 LUNCH 

Chairperson: 

14:00 – 14:45 

14:45 – 15:30 

Chairperson: 

16:00 – 17:30 

SESSION XII 

15:30 – 16:00 TEA BREAK 

19:00 DINNER 

Medicinal Plants in the Congolese Art 

(DRC) 

Prof. Dr. Dr. h.c. G. Bringmann 

Our Congolese-German partnership – a 

model case for other universities? 

Round Table Discussion 

************End of day four************** 

FRIDAY, AUGUST 14 TH 2009 

EXCURSION 


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PLENARY LECTURES 


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[PL -1] NOVEL METABOLITES FROM RHUS PYROIDES FROM 

BOTSWANA AND MORUS MESOZYGA FROM CAMEROON 

Berhanu M. Abegaz a , O. M. Shetonde a , G.D.W.E.Kapche b , W. Mammo c , and K. 

Marobela d 

a Department of Chemistry, d Department of Biological Sciences, University of 

Botswana, Gaborone, Botswana; b Department of Chemistry, Higher Teachers’ 

Training College, University of Yaounde1, P.O. Box 47, Yaounde Cameroon; 

c Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, 

Ethiopia. 

abeazb@mopipi.ub.bw 

We have recently completed a phytochemical investigation of the medicinal plant 

known as Rhus pyroides as well as the total synthesis of the major constituents [1, 2, 

3]. Our studies have resulted in the isolation of two kinds of unique bichalcones: one 

set containing an oxygen bridge between the chalcone moieties (1-4); and the 

second set (5, 6) consisting of two directly linked chalcones. The plant has 

demonstrated fairly strong biological activities and these properties appear to be 

attributed to these novel metabolites. We have therefore undertaken and 

successfully achieved the total synthesis of these compounds and their derivatives. A 

full investigation of the biological activities of these compounds is currently 

underway. We have also completed the investigation of the Moraceous plant, 

Morus mesozyga from Cameroon which yielded 13 metabolites of which five were 

found to be novel 2-aryl benzofuran derivatives [4]. The structural features of these 

metabolites and their significance will be discussed. 

References 

1. B. Masesane, S. O. Yeboah, J. Liebscher, C. Muegge and B. M. Abegaz. 1999. A 

Bichalcone from the twigs of Rhus pyroidesPhytochemistry, 53, 1005-1008. 


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2. Ladislaus K. Mdee, Samuel O. Yeboah, and Berhanu M. Abegaz 2003. 

Rhuschalcones II-VI, Five New Bichalcones from the Root Bark of Rhus pyroides, J. 

Nat. Prod. 66(5) pp 599 – 604. 

3. O. M. Shetonde, W. Mammo, M. Bezabih, K. Marobela, d and B. M. Abegaz, Total 

Synthesis and anti-protozoal activities of Rhuschalcone VI and derivatives, 2009 

manuscript under to be submitted. 

4. G.D.W.E.Kapche, C.D. Fozin, J.H. Donfack, G.W. Fotso, D. Amadou, A>k. Tchana, 

M. Bezabih, P.F. Moundipa, B.T. Nadjui, B.M. Abeaz, Prenylated arylbenzofuran 

derivatives from Morus mesozyia, Phytochemistry, 2009, 70, 216-221. 

[PL -2] THE POTENTIAL OF AFRICAN MEDICINAL PLANTS AS 

SOURCE OF NEW DRUGS 

Kurt Hostetmann 

Laboratory of Pharmacognosy and Phytochemistry, School of Pharmaceutical 

Sciences, University of Geneva, University of Lausanne, CH-1211 Geneva 4, 

Switzerland 

Kurt.Hostettman@pharm.unige.ch 

The African continent with tropical forests, coastal regions, desertic regions and high 

mountains has a very wide biodiversity which is not yet fully exploited. The most 

famous plant issued from Africa is without any doubt coffee (various species of the 

genus Coffea, Rubiaceae) which is now well-implanted in South America. A couple of 

African plants have provided important molecules such as the alkaloids of 

Catharanthus roseus (Apocynaceae) used worldwide for the treatment of leukaemia 

and various cancers. To fight arthritic pains, extracts of devil’s claw (Harpagophytum 

procumbens, Pedaliaceae) are widely used in Europe and are now recognized as 

registered drugs and not as food supplements anymore. The same applies for 

Umckaloabo (Pelargonium sidoides, Geraniaceae), a plant used in the Zulu traditional 

medicine. Extracts of this plant have been introduced with great success in the 

Western medicine for the efficient treatment of acute bronchitis and other problems 

of the respiratory tract. Hoodia gordonii (Apocynaceae) is used as food supplement 

to inhibit appetite. Many other exemples could be cited. 

The approach to find new bioactive compounds from higher plants will be described 

and illustrated with the search for new antifungal compounds from various African 

plants. The potential of these plants is important in the fight against neglected 

diseases such as parasitic diseases which still affect millions of people in Africa. In 


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Mali, a plant introduced long times ago from Central America, Argemone mexicana 

(Papaveraceae) is now used by traditional healers to treat malaria. The 

phytochemical investigation of this plant will also be presented. 

[PL -3] APPLICATION OF LC-MS AND LC-NMR TECHNIQUES TO THE 

IDENTIFICATION OF BIOACTIVE NATURAL PRODUCTS 

Karine Ndjoko 

[PL -4] ANTHRAQUINONES AND ALKALOIDS –ACETOGENIC, ANTI- 

INFECTIVE, AND AXIALLY CHIRAL! 

Gerhard Bringmann et al. 

Institute of Organic Chemistry, University of Würzburg, Germany 

bringman@chemie.uni-wuerzburg.de 

Natural products chemistry is a stimulating and future-oriented field of research, 

providing new chemical and biological challenges and inspirations, but also new drug 

candidates and, thus, new chances to overcome diseases and suffering of mankind. 

We pursue natural products chemistry in a broad, multi-disciplinary way, with 

analytical, synthetic, biosynthetic, computational, and pharmaceutical facets. This 

high degree of interdisciplinarity is, exemplarily, depicted for different classes of 

compounds that possess unusual, stereochemically intriguing structures, new or 

even unprecedented biosynthetic origins and, in particular, promising bioactivities. 

Our strategy to find novel-type compounds is spectroscopy-assisted, rather than 

bioactivity-guided, with the structural novelty as the primary search criterion. The 

lecture describes the strategy for such an online search for novel-type structures by 

HPLC-MS/MS-NMR-CD (in combination with quantum chemical CD calculations), 1,2 

exemplarily for different classes of metabolites (see Figure). These involve 

acetogenic alkaloids and anthraquinones from plant or marine sources, possessing 

unprecedented biosynthetic origins and/or stereochemically intriguing C,C- or C,Naxes 

(sp 2 -sp 2 or sp 2 -sp 3 ), which are configurationally stable or semi-stable. 3-5 


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The work shows the synergy of these interdisciplinary facets of natural products 

research in the isolation, structural elucidation (online or offline), biosynthesis, 

synthesis, and bioactivity discovery and optimization of natural products. 

1. G. Bringmann, T. Bruhn, K. Maksimenka, Y. Hemberger; The Assignment of 

Absolute Stereostructures by Quantum Chemical Circular Dichroism 

Calculations; Eur. J. Org. Chem. 2009, 17, 2717-2727. 

2. G. Bringmann, T.A.M. Gulder, M. Reichert, T. Gulder; The Online Assignment 

of the Absolute Configuration of Natural Products: HPLC-CD in Combination 

with Quantum Chemical CD Calculations; Chirality 2008, 20, 628- 642. 

3. G. Bringmann, B. Abegaz, M. Knauer, J. Mutanyatta; Knipholone and related 

4-phenylanthraquinones: structurally, pharmacologically, and biosynthetically 

remarkable natural products; Nat. Prod. Rep. 2008, 25, 696-718. 

4. G. Bringmann, J. Mutanyatta-Comar, K. Maksimenka, J. M. Wanjohi, M. 

Heydenreich, R. Brun, W.E.G. Müller, M.G. Peter, J. O. Midiwo, A. Yenesew; 

Joziknipholones A and B, the First Dimeric Phenylanthraquinones, from the 

Roots of Bulbine frutescens; Chem. Eur. J. 2008, 14, 1420-1429. 

5. G. Bringmann, I. Kajahn, M. Reichert, S.E.H. Pedersen, J.H. Faber, T. Gulder, R. 

Brun, S.B. Christensen, A. Ponte- Sucre, H. Moll, G. Heubl, V. Mudogo; 

Ancistrocladinium A and B, the First N,C-Coupled 

Naphthyldihydroisoquinoline Alkaloids, from a Congolese Ancistrocladus 

Species; J. Org. Chem. 2006, 71, 9348-9356. 

Keywords: Naphthylisoquinoline alkaloids; anthraquinones; atropisomerism; 

synthesis; biosynthesis; anti-infective activity 

Schrott: 

G. Bringmann, A. Irmer; Acetogenic Anthraquinones: Biosynthetic Convergence and 

Chemical Evidence of Enzymatic Cooperation in Nature; Phytochem. Rev. 2008, 7, 

499-511. 


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[PL -5] OPTIMISING YIELDS AND QUALITY OF TEA IN DIFFERENT 

LOCATIONS 

P. Okinda Owuor 

Department of Chemistry, Maseno University, 

Private Bag, Maseno 40105, Kenya 

owuorpo@africaonline.co.ke 

Tea (Camellia sinensis (L)) is grown under tropical and sub-tropical environments 

with large variations in climatic conditions resulting in yields and quality differences. 

These differences are attributed changes to soil types, altitudes, solar radiation, 

rainfall, seasonal conditions and agronomic in-puts. Further away from the equator, 

the seasonal variations are much larger than close to the equator. Consequently, 

seasonal yield distributions and quality become more variable as distance from the 

equator increases. Close to the equator, growth is more uniform, and it was assumed 

growth and leaf chemical composition which control yields and quality, respectively, 

do not vary much. As a result, agronomic inputs and processing technology 

recommendations have been uniform to a large extent. But recent research have 

demonstrated large variations in quality and yields in the different environments 

within East and Central African tea growing areas implying need for region specific 

agronomic recommendations and processing technologies. This report reviews 

results of studies to establish the variations in yields and quality of black tea in 

different locations within the region due to agronomic inputs and processing 

technologies. For same cultivars grown in different locations, there were differences 

in yields and quality suggesting variations in growth pattern and differences in the 

chemical composition of the same cultivar in the different regions. Growth and green 

leaf chemical composition resulting in differences in yields and black tea quality were 

observed in the same cultivars grown at different altitudes even within a 10 km 

radius at different altitudes. Yields declined but quality improved with rise in 

altitude. When the same cultivar was subjected to different rates on nitrogenous 

fertiliser and plucking intervals, response depended on the location of growth. 

Indeed, the optimal yields and quality were obtained at different nitrogenous 

fertiliser rates and plucking intervals demonstrating the growth and green leaf 

chemical composition varied with location of production. Fermentation is a critical 

stage in black tea processing as most noticeable chemical transformations occur at 

this stage. Using same cultivar grown in Kenya and Malawi, and processed under 

identical conditions, large differences in the resultant black tea chemical 

composition hence quality were recorded, at the same fermentation duration. 

Indeed, optimal fermentation durations in the same cultivars were arrived at after 

same fermentation duration in the two countries. Generally, optimal fermentation 

durations were much shorter in Malawi than in Kenya under identical fermentation 


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conditions. The data suggest that the there is need to develop region specific 

agronomic inputs, cultivars and processing technologies. Adoption of agronomic 

inputs and processing technologies recommendations develop away from the 

farming area may be subjecting some tea growers to perpetual low production 

and/or production of low quality black tea. This subjects the producers to continuous 

poverty. 

Keywords 

Black tea, Camellia sinensis, environment, genotypes, cultural and agronomic 

practices, processing technologies, yields, quality. 

[PL -6] DRUG DISCOVERY AT IMRA: RECENT RESULTS AND WAY 

FORWARD 

Philippe Rasoanaivo 1 , Solofoniaina Razafimahefa 1 , Benoît Rasolondratovo 2 , Jarl 

Wikberg 3 

1 

Institut Malgache de Recherches Appliquées, BP 3833; 101-Antananarivo, 

Madagascar, rafita@moov.mg 

2 

Département de Chimie, Faculté des Sciences, Université de Toliara, BP 304, 601 

Toliara, Madagascar ; rasolobe@moov.mg 

3 

Department of Pharmaceutical Biosciences, Uppsala University, Box 591, 

Biomedicum, SE 751 24 Uppsala, Sweden; jarl.wikberg@farmbio.uu.se 

One of main activities of the Institut Malgache de Recherches Appliquées (acronym 

IMRA) is drug discovery which is focussed on tropical diseases (malaria and 

chikungunya) and diseases of ageing (diabetes of ageing, erectile dysfunction in old 

men, and memory and cognitive dysfunction). The presentation will be focussed on 

erectile dysfunction. The work has been carried out in collaboration with Uppsala 

University. The arrival of the synthetic drug Sildenafil citrate and its chemical 

analogues has captivated the public imagination, and has drawn tremendous 

medical attention to the concept of sex male dysfunction. A search of PubMed, using 

the search term erectile dysfunction (ED) and comparing the results for the period 

1961-1997 with that of 1998-2009, 1997 being the year when sildenafil was 

launched, reveals a dramatic 15-fold steep increase in frequency of papers, and this 

includes papers in ‘‘high impact factor’’ peer-reviewed journals. In response to 

recent advances in synthetic medication, there has been a recent growing interest 

towards the search of traditionally herbs, which are being constantly claimed for the 

treatment of erectile and libido dysfunction. At this point, Neobegua mahafalensis 

(Meliaceae) is used in the South and West parts of Madagascar for the treatment of 

erectile dysfunction in old men. We used the physiology-based approach to 


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demonstrate activities, and the mating behaviour test to assess the efficacy of 

different extracts from the species. Bioassay-guided fractionation led to the isolation 

of three pharmaco-active constituents as limonoids with unprecedented structures 

[1]. They were active even at very low doses, i.e. 0.4 down to 0.04mg/kg, and had 

long lasting effects after three days consecutive treatment. Preliminary 

investigations suggest that the lippophilic bioactive compounds probably act in the 

brain, which precludes any direct vascular effects. Acute and sub-acute toxicological 

studies in rodents demonstrated the safety of the active constituents. A 

phytomedicine under the trade name Dangitsyl ® was formulated with the active 

constituents. Under the regulations regarding the clinical evaluation of traditional 

medicine preparations in Madagascar, the clinical efficacy of Dangitsyl was verified 

at daily dosages ranging from 10mg to 60mg in preliminary trials. The effect of 

Dangitsyl is delayed; most subjects experience a pronounced improvement of sexual 

performance on the 4 th or 5 th day following the start of the treatment, and the effect 

may persist for several weeks. This corroborates the effects observed in animal 

models. The duration of the effect of Dangitsyl is therefore very long (several weeks 

to even months), and may vary with patient, and as well as over time with repeated 

treatment for the same patient. Several pharmacological studies are underway to 

further clarify the mechanism of action of the active limonoids. 

References 

1. J.E.S. Wikberg, P. Rasoanaivo, S. A. Razafimahefa, B. Rasolondratovo 

(4/12/2008) Novel compounds and pharmaceutical preparations. PCT patent 

WO 2008/145996 A2. 

[PL -7] TERPENOIDS FROM AFRICAN MEDICINAL PLANTS 

Dulcie A Mulholland 

Division of Chemical Sciences, Faculty of Health and Medical Sciences, University of Surrey, 

Guildford, GU27XH, Surrey, United Kingdom 

D.Mulholland@surrey.ac.uk 

Phytochemical investigations of the genus Croton (Euphorbiaceae) and Phyllanthus 

(Phyllanthaceae) have yielded a range of di- and tri-terpenoids. Of particular interest is the 

range of novel cembranoids isolated from Croton gratissimus, as shown below, which 

include the first example of a cembrane-derived diterpenoid with a C-2, C-12 bond. Croton 

sylvaticus has yielded clerodane diterpenoids including a novel lactonized clerodane 

furanoditerpenoid and Croton pseudopulchellus has yielded ent-kaurane diterpenoids 


8


including two novel ent-kaur-16-en-19-oic acid derivatives. The variation in diterpenoid 

classes isolated from the different Croton species investigated will be discussed. 

Cembranoids from Croton gratissimus. 

H O 

O 

H O 

H O 

O 

H 

O 

O 

H 

[PL -8] RED HOT COMPOUNDS FROM THE RED HOT POKER 

PLANTS, KNIPHOFIA SPECIES 

Abiy Yenesew, a Immaculate Achieng a , Meron Gebru, a Matthias Heydenreich, b Martin 

G. Peter, b Ermias Dagne, c Michael Knauer d , Gerhard Bringmann d 

a 

Department of Chemistry, University of Nairobi, PO Box 30197, Nairobi, Kenya 

b 

Institut für Chemie, Universität Potsdam, PO Box 60 15 53, D-14415 Potsdam, 

Germany 

c 

Department of Chemistry, Addis Ababa University, PO Box 30270, Addis Ababa, 

Ethiopia 

d 

Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 

Würzburg,Germany 

ayenesew@uonbi.ac.ke 

Knipholone, the first 4-arylanthraquinone was discovered from the stem of Kniphofia 

foliosa (Asphodelaceae) in 1984 [1]. Since then a number of 4-arylanthraquinones 

including knipholone anthrone have been isolated from this plant [2, 3] and other 

members of the Asphodelaceae, namely from Bulbine [4] and from Bulbinela species 

[5]. Compounds belonging to this new class of anthraquinones have rotationally 

hindered biaryl linkages. The absolute configuration of knipholone and the other 

members was established by the use of advanced quantum chemical CD calculations 

[6]. Recently the first dimeric arylanthraquinones, named joziknipholones A and B, 

have been discovered from the roots of Bulbine frutescens [7]. We have now 

reinvestigated Kniphofia foliosa and identified joziknipholone A and other 

anthraquinones. More significantly, we have discovered an unprecedented 

tetrameric phenylanthraquinone, named jozi-joziknipholone. The structures and 

antiprotozoal activities of these compounds will be discussed. 

H 

HO 

O 

H 

H 

HO 

HO 

O 


OH 

9


References 

1. Dagne, E.; Steglich, W. Phytochemistry 1984, 23, 1729-1731. 

2. Dagne, E.; Yenesew, A. Phytochemistry 1993, 34, 1440-1441. 

3. Yenesew, A.; Dagne, E.; Müller, M.; Steglich, W. Phytochemistry 1994, 37, 525- 

528. 

4. Kuroda, M.; Mimaki, Y.; Sakagami, H.; Sashida, Y. J. Nat. Prod. 2003, 66, 895-897. 

5. Mutanyatta, J.; Bezabih, M.; Abegaz, B. M.; Dreyer, M.; Brun, R., Kocher, N.; 

Bringmann, G. Tetrahedron 2005, 61, 8575-8484. 

6. Bringmann, G.; Maksimenka, K.; Mutanyatta-Comar, J.; Knauer, M.; Bruhn, T. 

Tetrahedron 2007, 63, 9810-9824. 

7. Bringmann, G.; Mutanyatta-Comar, J.; Maksimenka, K.; Wanjohi, J.M.; 

Heydenreich, M.; Brun, R.; Müller, W.E.G.; Peter, M.G.; Midiwo, J.O.; Yenesew, 

A. Chem. Eur. J. 2008, 14, 1420-1429. 

[PL -9] LIFETIME OF NATURAL PRODUCTS 

Joe Conolly 

Scotland, UK 

joec@chem.gla.ac.uk 

In almost fifty years of natural product research I have met a lot of very nice people 

and a lot of very nice compounds. In my talk I want to look back and to highlight 

some of the major changes I have seen over the years. Then I shall discuss some of 

the compounds isolated by my Cameroon colleagues in their quest for anti-malarial 

activity. Finally I shall mention some of my favorite compounds from other parts of 

the world. 


10


[PL -10] QUALITY CONTROL OF NATURAL PRODUCTS 

Ermias Dagne 

African Laboratory for Natural Products (ALNAP), Department of Chemistry, 

Addis Ababa University, P.O. Box 30270, Addis Ababa Ethiopia. Fax: 251 111 

239468. 

edagne@ethionet.et 

The worldwide demand for high quality, safe, effective, and clean natural plant 

products has grown significantly in recent years. Although there is rich heritage in 

the use of medicinal plants in Africa, not much economic benefit has been derived 

from this area despite the rapidly expanding international market. 

In the past, herbs and essential oil bearing plants were largely harvested from the 

wild and brought to the market without questions being asked about their origin, 

botanical identity, methods of cultivation, safety, efficacy, sustainable harvesting, 

loss of genetic diversity resulting from extensive wild harvesting etc. Botanical 

misidentification, inappropriate methods of collection and processing and presence 

of pesticide and microbial residues have all negatively contributed to the marketing 

of African natural products. 

The export of raw plant materials requires product-tracking system for the 

cultivation and sustainable harvesting. Processed products, which usually give better 

returns, need to be backed by quality control data, which usually require trained 

manpower and sophisticated technology, both not readily available in Africa. The 

role local and regional universities could play in alleviating the problem of quality 

control of natural products cannot be overemphasized. 

The main purpose of this talk is to present recent results in quality control of natural 

products achieved in our laboratory. 


11


[PL -11] FROM PLANTS TO BIOACTIVE COMPOUNDS 

THROUGH THE STUDY OF GREAT APES- ECOLOGY, CHEMISTRY AND 

CONSERVATION OF TROPICAL FOREST 

Sabrina Krief 

Departement Hommes Natures, Sociétés, UMR 7206- Muséum National d’Histoire Naturelle, 

57 rue Buffon, 75005 Paris, France- tel: +33 1 40 79 53 37- 

krief@mnhn.fr 

Tropical forests are being threatened by accelerating rate of forest conversion and 

degradation. They contain however 50 to 90 % of the animal and vegetal species and 

remain the main source for medicinal products. Of all the primates, 90% live in 

tropical forests and one in five is endangered or critically endangered. The unique 

habitat of six species of great apes is tropical forests. In the framework of the 

partnership between French and Ugandan institutions (Museum National d’Histoire 

Naturelle, France- Institut de Chimie des Substances Naturelles, France- Makerere 

University, Uganda- Uganda Wildlife University, Uganda) we aim at implementing 

the knowledge on phytochemistry and biodiversity of Ugandan plants using 

chimpanzees as “guides”. In Kibale National Park, Uganda, we monitor the 

chimpanzee (Pan troglodytes schweinfurthii) diet since 1999. Of the 250 plant parts, 

some are rarely consumed and have a low nutritive value. We thus explore the 

relationship between health and plant selection to target plants and to isolate 

bioactive compounds. Several bioactive extracts of plants species eaten by 

chimpanzees were investigated some of them leading to novel molecules. Bioguided 

fractionation of the leaves’ extract of Trichilia rubescens (Meliaceae) provided new 

antiplasmodial limonoids, novel cytotoxic oleanane-type triterpene saponins were 

isolated from extract of leaves and bark of Albizia grandibracteata (Fabaceae) and 

ten novel cycloartanes triterpenoids from Markhamia platycalyx (Bignoniaceae) 

exhibiting antitrypanosomal activities were elucidated. In addition, there is a large 

overlap between the ingested plant parts by chimpanzees and those used in 

traditional medicine. Studying and preserving the interactions between humans, 

animals and flora is of major interest for the human health and the planet welfare in 

the future. For this reason, the Association ‘Projet pour la Conservation des Grands 

Singes’ in partnership with UNESCO, and MAEE currently conduct a sensitization 

programme using kits with 120kg of educative tools in African countries which are 

home range of great apes. In Gabon and Uganda, 15 000 kids from 120 schools in 

remote areas participated in 2008 to sessions where Apes are ambassadors for 

tropical forests. DRC, Congo as well as Cameroun will be soon partners of the 

programme through ECOFAC partnership. The motivation of participants for 

preserving forests for a sustainable use of their resources as well as Apes survival 

greatly increased following the programme. It is the challenge of the seventh species 


12


of Great Apes, present worldwide and threatening the others, human beings, to save 

their closest parents, umbrella and keystone species in tropical forests. 

[PL -12] CROTON ZAMBESICUS : ISOLATION AND QUANTIFICATION 

OF ACTIVE DITERPENES AND STRUCTURE-ACTIVITY RELATIONSHIPS 

J. Quetin-Leclercq 

UCL- Belgium 

Croton zambezicus Muell. Arg. (Euphorbiaceae) (Syn.C. amabilis Muell. Arg., C. 

gratissimus Burch.) is a shrub or small tree reaching 10 m in height. It is a Guineo- 

Congolese species widespread in Tropical Africa. The leaf decoction is used in Benin 

as anti-hypertensive, anti-microbial (urinary infections) and to treat fever associated 

with malaria. 

The genus Croton is well known for its diterpenoid content and a lot of different 

types of diterpenes (phorbol esters, clerodane, labdane, kaurane, trachylobane, 

pimarane, etc.) have been isolated from this genus. 

There was very little literature concerning the phytochemical content of Croton 

zambesicus although this plant is widely used in African traditional medicine. 

Labdane, clerodane and trachylobane diterpenes have been identified in its stem 

bark. 

During our research, we isolated from the leaves three new trachylobanes, one 

isopimarane together with trans- -amyrin and sterols, as well as a mixture of 

two diterpenes that inhibits the KCl-induced contraction of male Wistar rat aorta in a 

concentration-dependent manner with an IC50 of 1 μg/mL. As the dichloromethane 

fraction of the aqueous extract of the leaves show some antihypertensive properties 

on mice, we decided to test the diterpenes isolated from the leaves of Croton 

zambesicus to evaluate their vasorelaxant activity on Wistar rat aorta. Their 

vasorelaxant effect was compared to a series of synthetic trachylobanes on 

KCl-induced contractions in order to evaluate the structure-activity relationships. 

The cytotoxicity of all these compounds has also been evaluated on HeLa cells as 

some trachylobanes were shown to be cytotoxic ant pro-apoptotic. 

We showed for the first time the vasorelaxant properties of some pure trachylobane 

diterpenes at low concentration (IC50 < 5 µg/mL) on KCl-induced contractions but 

none of them have an effect on noradrenaline-induced contractions. We also 

observed that a carbonyl group at C-14 associated to a hydroxyl or ketonic function 


13


at C-15 or a carbonyl at C-3 associated to a hydroxymethyl group at C-4 plays an 

important role on the vasorelaxant activity of trachylobane diterpenes. We did not 

observe a marked effect of the absolute configuration nor of the cleavage of the 

C13-C16 cyclopropane bond. Our work also shows that cytotoxic activities of these 

diterpenes were not correlated to their vasorelaxant properties. 

To quantify these compounds in plants and extracts, a sensitive and accurate 

method, combining Soxhlet extraction, solid-phase extraction and capillary gas 

chromatography was developed and fully validated for the quantitative 

determination of four diterpenes (ent-trachyloban-3β -ol, ent-18-hydroxytrachyloban-3-one, 

ent-trachyloban-3-one and isopimara-7,15-dien-3β-ol) in the 

leaves of Croton zambesicus. 

These results indicate that C. zambesicus leaves contain vasorelaxant diterpenes 

which could account, at least partially, for their use to treat hypertension. 

Nevertheless, as some of these compounds are cytotoxic, this plant has to be used 

with caution and in vivo toxicity studies are needed before this plant could be 

recommended in medicine 

Schematic SAR model for the vasorelaxant activity of synthetic trachylobane 

diterpenes. 

References 

1. Adjanohoun, E.J et al. Contribution aux Etudes Ethnobotaniques et 

Floristiques en République Populaire du Bénin, Vol. 1 (1989). 

2. Baccelli C et al., Journal of Naturals Products (2007) 70:910-917 

3. Baccelli C et al. Planta Medica (2005) 71:1036-1039 

4. Block S et al. Phytochemical Analysis (2005) 16:342-348 


14


5. Block S et al. Anticancer Research (2005) 25:363-368 

6. Block S et al. Phytochemistry (2004) 65:1165-1171 

7. Block S et al. Planta Medica (2002) 68:647-649 

8. Ngadjui, B.T. et al. Phytochemistry (2002) 60: 345–349. 

[PL 13] OUR CONGOLESE-GERMAN PARTNERSHIP – A MODEL CASE 

FOR OTHER UNIVERSITIES? 

Gerhard Bringmann 1 , Virima Mudogo 2 , Dibungi Kalenda 2 

1 

Institute of Organic Chemistry, University of Würzburg, Germany, 

bringman@chemie.uni-wuerzburg.de 

2 

Université de Kinshasa, mudogov@yahoo.fr, dibungikalenda@daad-alumni.de 

The University of Kinshasa (UNIKIN), once a leading university in Subsaharan Africa, 

presently suffers from difficult conditions concerning staff age and replacement, 

shortage of scientific instrumentation, and insufficient infrastructure in general. 

Starting with an intense cooperation on the biodiversity of Congolese plants and the 

resulting chemical diversity, and guided by our personal dreams to find solutions to 

these difficult problems, we have, together with our friends, built up a multi-faceted 

joint program, which consists of essentially 9 'columns': 

1. The scientific cooperation as such, 

since 1994. 

2. A joint university-university 

agreement since 2003. 

3. Joint lecture courses, seminars, and 

excursions. 

4. The organization of scientific 

symposia, starting with the first 

chemistry and pharmacy 

symposium in 2005, and, in 2009, 

hosting the 13th NAPRECA 

symposium. 

5. The collection and donation of 

scientific books (30 tons, more than 

10 further tons en route). 

6. A first German-Congolese joint 

highschool-highschool project. 

7. Likewise just starting: a joint bee 


15


project near the UNIKIN campus. 

8. Intense public relations work (i.a., 

at the European Parliament). 

9. An excellence-scholarship system (BEBUK), a probably unique, privately financed 

program, which will enable young outstanding Congolese students to study 

rapidly and efficiently and then to go abroad and come back for an academic 

career in Africa. After a first pilot phase I (students of chemistry and pharmacy), 

and encouraged by the excellent results of the first 4 scholars, the scholarship 

system has been extended to presently 10 students of chemistry, pharmacy, 

medicine, laws, and letters, and will be enlarged to all other subjects and 

disciplines of the UNIKIN. 

In Würzburg (Germany), the joint program is paralleled by the foundation of the 

Africa Circle at the University of Würzburg (www.afrikakreis.uni-wuerzburg.de), 

which involves scientists from all 10 faculties, by an own NGO ("Support for the 

UNIKIN", see logo), and by a research network SFB 630 "Agents against Infectious 

Diseases" (www.sfb-630.uni-wuerzburg.de); coordinator of all these institutions is G. 

Bringmann. 

Keywords: Partnership UNIKIN-UNIWUE; BEBUK; excellence scholarship; 

biodiversity; agents against infectious diseases 

Speaker: Prof. Dr. Dr. h.c. Gerhard Bringmann, Institut für Organische Chemie, Am 

Hubland, 97074 Würzburg, Germany, bringman@chemie.uni-wuerzburg.de 


16


SHORT LECTURES 


17


[SL - 1] ISOLATION OF BIOACTIVE COMPOUNDS FROM THE 

TROPICAL LIANA ANCISTROCLADUS CONGOLENSIS 

C. Steinert, Asfaw Debella + , K. Messer, G. Bringmann* 

Institute of Organic Chemistry, University of Würzburg, Am Hubland, D-97074 

Würzburg 

+ present address: Ethiopian Health and Nutrition Research Institute, P.O. Box 1242, 

Addis Ababa, Ethiopia 

The small plant family of the Ancistrocladaceae comprises approximately 18 species 

in the palaeotropic regions and, up to now, one single genus named 

Ancistrocladus.[1] These lianas feature hooked branches as climbing implements, 

and are closely related to the Dioncophyllaceae, tropical lianas with hooked leaves. 

The two plant families are used in traditional African and Asian medicine against 

dysentery, malaria, African sleeping sickness and leishmaniasis.[2] The bioactivity 

results from naphthylisoquinoline alkaloids, an extraordinary class of biaryls, only 

found in Ancistrocladaceae and Dioncophyllaceae species. The naphthylisoquinolines 

consist of a naphthalene and an isoquinoline moiety, coupled via a biaryl axis. The 

axis joins the two molecule halves at various positions and usually is rotationally 

hindered. Several naphthylisoquinolines, C,C-coupled ones, like dioncophylline A and 

C and ancistrolikokine B, and N,C-coupled ones, like ancistrocladinium B, have shown 

in vitro and in vivo activities against pathogens of tropical diseases. 

Previous work in our research group on Ancistrocladus congolensis showed the 

presence of numerous interesting naphthylisoquinolines and also 

naphthylisoquinoline dimers, which are known for their anti-HIV activity. Recently, 

the structures of two new compounds, a 7,8’- coupled naphthylisoquinoline and a 

dimer, were elucidated, three more are in progress. In addition, the naphthoquinone 

malvone A was isolated from plant material for the first time. 


18


References 

1. C. M. Taylor, R. E. Gereau, G. M. Walters; Ann. Missouri Bot. Gard. 2005, 92, 

360-399. 

2. G. François, G. Timperman, W. Eling, L. Aké Assi, J. Holenz, G. Bringmann; 

Antimicrob. Agents Chemother. 1997, 41(11), 2533-2539. 

[SL - 2] THE BIOSYNTHETIC ORIGIN OF NAPHTHYLISOQUINOLINE 

ALKALOIDS 

A. Irmer , S. Rüdenauer, J. Mutanyatta-Comar, T. F. Noll, G. Bringmann* 

Institute of Organic Chemistry, University of Würzburg, Am Hubland, D-97074 

Würzburg 

The small palaeotropical plant families Dioncophyllaceae and Ancistrocladaceae 

comprise most peculiar lianas. They are the only plants known to produce 

naphthylisoquinoline alkaloids, like, e.g., dioncophylline A. These remarkable natural 

products are characterized by their unprecedented structures, usually with 

rotationally hindered and thus stereogenic biaryl axes, by their promising 

antiprotozoal bioactivities (e.g., against Plasmodium, Leishmania, and Trypanosoma 

species), and by the unique biosynthetic origin of both, the isoquinoline and the 

naphthalene portions, each from six acetate units .[1] 

To evidence this acetogenic origin by biosynthetic experiments was possible only by 

the establishment of cell cultures of these sensitive tropical lianas, thus providing a 

sterile in vitro system that reliably produces the alkaloids. More detailed insight into 

the biosynthetic pathway was now gained by the synthesis and incorporation of two 

advanced 13C2-labeled isoquinoline precursors .[2] The unambiguous incorporation of 

these precursors into dioncophylline A and two other naphthylisoquinolines was 

achieved by spectroscopic methods ( 1 H NMR, 13 C NMR, and INADEQUATE 

experiments). 


19


The results thus obtained suggest that the initially formed dihydroisoquinoline is 

efficiently and highly stereoselectively reduced to the corresponding transconfigured 

tetrahydroisoquinoline, which is then further coupled oxidatively with the 

naphthalene moiety to form the complete naphthylisoquinoline alkaloids. 

1. G. Bringmann, M. Wohlfarth, H. Rischer, M. Grüne, J. Schlauer, Angew. Chem. 

Int. Ed. 2000, 39, 1464-1466. 

2. G. Bringmann, J. Mutanyatta-Comar, M. Greb, S. Rüdenauer, T. F. Noll, A. 

Irmer, Tetrahedron 2007, 63, 1755-1761. 

[SL – 3] VASOCONSTRICTOR AND INOTROPIC EFFECTS INDUCED BY 

THE ROOT BARK EXTRACTS OF ANTHOCLEISTA SCHWEINFURTHII (GILG) 

(GENTIANACEAE) 

Nadege Kabamba Ngombe a,b , Dibungi T. Kalenda b , Joelle Quetin-Leclercq a , Nicole 

Morel c, 

a 

Laboratoire de pharmacognosie, Louvain Drug Research Institute, Université 

catholique de Louvain, Av.E. Mounier 72, 1200 Bruxelles, Belgium 

b 

Centre d’Etudes des Substances Naturelles d’Origine Végétale, Université de 

Kinshasa 

BP202 KIN IX, Kinshasa, Democratic Republic of Congo. 

c Laboratoire de physiologie cellulaire, Université catholique de Louvain, 

Av.Hipppocrate 55, 1200 Bruxelles, Belgium. 

The present study was performed to evaluate the cardiovascular effects of three 

extracts from the root bark of A. schweinfurthii (Gilg) positive to kedde reagent 

considered as specific for cardiac glycosides. Plant extracts which contains “digital 

like” compounds present a possible cardiotoxicity due to inhibition of the Na + ,K + 

ATPase pump. Nowadays, there is no evidence of cardio-vascular activity of the 

extracts of A. schweinfurthii (Gilg.). This big tree of tropical regions are eaten by 

bonobo (Pan paniscus), an endemic pigmee chimpanzee of the Democratic Republic 

of Congo and also used in folk medicine to treat several disorders (malaria, tumors, 

cancers, venereal diseases, bacterial diseases…). The effects of dichloromethane 

soluble fraction of the ethanolic extract (DCMR), cardiac glycoside-rich fraction 

(CARDAN) and aqueous extract (AE ) on the vascular responses of isolated rat aorta 

and the cardiac functions in isolated frog heart were evaluated. In isolated rat aortic 

preparations, the contraction evoked by AE was completely reversed by 

phentolamine (1µM), whereas the contractile response to CARDAN was inhibited by 

the addition of verapamil (1µM). Effect of DCMR was transient and contraction 

relaxed spontaneously. In frog isolated heart, A.schweinfurthii extracts exhibited 


20


positive inotropic effect in isolated frog heart. The effect of AE and DCMR was 

depressed in the presence of propranolol. The inotropic effect of CARDAN was 

unaffected by the beta blocker. The present results showed for the first time the 

cardiovascular effect of three extracts isolated from A. schweinfurthii (Gilg) 

containing cardiac glycosides type compounds as indicated by a positive reaction 

with Kedde reagent. 

KEY WORDS: Anthocleista schweinfurthii- cardiac glycosides extracts- asoconstrictor 

effect-inotropic effect. 

[SL - 4] ANTISICKLING ACTIVITY OF JUSTICIA SECUNDA VAHL 

P.T. Mpiana, K.N. Ngbolua, M.T. Bokota, T.K. Kasonga, E.K. Atibu, and V. Mudogo 

Anthocyanins extracts from some Congolese plants used in traditional medicine 

against sickle cell anemia had recently showed antisickling activity in vitro 1,2 Justicia 

secunda is one of them. Its use is even advised by some religions congregation to 

bypass blood transfusions. 

SS erythrocytes treated using anthocyanins extracts of J. secunda indicated the reappearance 

of the biconcave shape of erythrocytes with a mean radius value of 

3.3±0.3µm similar to that of normal ones. The solubility of Deoxyhemoglobin S 

erythrocytes and their osmotic fragility increased upon treatment with anthocyanins 

extracts. 

These findings suggest that anthocyanins extract play a role in both stabilizing 

erythrocyte membrane and inhibiting polymerization of hemoglobin S. This provides 

a possible molecular basis for earlier reports on the antisickling properties of 

anthocyanins and their use in the management of sickle cell disease. 

Key words: Justicia secunda, Antisickling activity, Anthocyanins extracts. 

REFERENCES 

1. Mpiana PT, Mudogo V, Tshibangu DST, Ngbolua KN, Atibu EK, Kitwa EK, 

Kanangila AB, Makelele LK; Activité antifalcémiante et thermodégradation 

d’une fraction d’anthocyanes extraits de Zizyphus mucronata; Annales 

Africaines de Médecine 2009, 2, N°2, 91-97. 


21


2. Mpiana PT, Tshibangu DST, Shetonde OM and Ngbolua KN; In vitro 

antidrepanocytary activity (anti-sickle cell anaemia) of some Congolese 

plants; Phytomed 2007, 14, 192-195. 

[SL - 5] HPLC ANALYSIS AND NMR IDENTIFICATION OF HOMOISO- 

FLAVONOIDS AND STILBENOIDS FROM THE INTER-BULB SURFACE OF 

SCILLA NERVOSA 

Merhatibeb Bezabih, Samson O. Famuyiwa and Berhanu M. Abegaz 

Department of Chemistry, University of Botswana, P. Bag UB00704, Gaborone, 

Botswana 

Scilla nervosa (Burch.) Jessop [syn. Scilla regidifolia (Kunth), Schizocarphus nervosus 

(Burch.) Van der Merwe] (Hyacinthaceae) is an important traditional medicinal plant 

in Southern Africa where it is native to Botswana, Namibia, South Africa and 

Swaziland. It is used to treat infections and rheumatic fever. On the other hand it is 

also recognized to be poisonous to livestock [1-3]. 

In Botswana the bulbs of S. nervosa are claimed to enhance female fertility. One will 

find the bulbs offered for sale in open markets at bus stations and other public 

places in Botswana. Our earlier investigation of the dried and powdered bulbs of S. 

nervosa purchased at the Gaborone bus station in Botswana yielded 13 

homoisoflavonoids and 3 stilbinoids [4]. Additionally two homoisoflavonoids and 

two stilbenoids were reported from whole bulbs of S. nervosa collected in South 

Africa [5]. Twenty one isoflavonoids are reported from the genus Scilla. 

The yellow inter-bulb deposits from Scilla nervosa were anaylsed by HPLC and found 

to contain 19 components. Twelve of the 19 were identified by comparison of Rt 

values with those of authentic homoisoflavonoids and stilbenoids, co-elution and by 


22


preparative isolation followed by NMR and MS. Two new homoisoflavonoids, 3-(4hydroxyoxybenzyl)-5,7-dimethoxy-6-hydroxychroman-4-one 

and 3-(4methoxybenzyl)-6,7-dimethoxy-5-hydroxychroman-4-one 

were also identified. 

References 

1. Abegaz BM (2002)Novel phenylanthraquinones, isofuranonaphthoquinones, 

homoisoflavonoids, and biflavonoids from African plants in the genera 

Bulbine, Scilla, Ledebouria, and Rhus, Phytochemistry Reviews 1, 299–310. 

2. Kellerman TS, Coetzer JAW, Naude TW (1988). In Plant poisonings and 

mycotoxicoses of livestock in Southern Africa (p. 96). Cape Town: Oxford 

University Press. 

3. Watt J M, Breyer-Brandwijk M G (1962). In Medicinal and poisonous plants of 

Southern and Eastern Africa (2nd ed.) (p. 713). Edinburgh: E and S Livingstone 

Ltd. 

4. Silayo A, Ngadjui BT, Abegaz BM (1999) Homoisoflavonoids and stilbenes from 

the bulbs Scilla nervosa subsp. rigigitolla. Phythochemistry, 52, 947-955. 

5. Bangani B, Crouch NR, Mulholland DA (1999) Homoisoisoflavanones and 

stilbenoids from Scilla nervosa. Phytochemistry, 51, 947-951. 

[SL - 6] RADICAL SCAVENGING PRINCIPLES FROM CASSIA 

ABBREVIATA BEAREANA HOLMES AND VANGUERIA PARVIFOLIA SOND 

& A FACILE PALLADIUM CATALYSED TRANSFER HYDROGENATION 

PROTOCOL OF PROCHIRAL ALKENES 

Regina N. Bwire 1 Majinda R.T. Runner 2 and Masesane B Ishmael 2 

1 

Department of Physical Science, Masinde Muliro University of Science and 

Technology(MMUST), Box 190, Kakamega – Kenya. 

2 

Chemistry Department, University of Botswana, Private bag, 00704, Gaborone – 

Botswana. 

Corresponding Author: Email: nabwire2002@yahoo.com 

The extracts and compounds isolated from two medicinal plants in use in Eastern 

and Southern Africa were assayed for antioxidant activity. They showed very good to 

appreciable activity and this is reported here. Both the rapid TLC analysis and the UV 

spectrophotometric method were used to assay these compounds for radical 

scavenging activity. A facile stereoselective palladium catalysed transfer 

hydrogenation protocol of prochiral alkenes was also developed 


23


Key word index: Cassia abbreviata Beareana Holmes, Vangueria parvifolia Sond, 

Radical scavenging, Antioxidants, Stereoselective. 

[SL - 7] PHYTOCHEMICAL AND BIOLOGICAL STUDIES OF GEGERIA 

ALATA 

Randa Babiker a , Rostand Manfouo b , Sakina Yagi a,c , Igbal Choudhary b , Françoise 

Chrétien c , Yves Chapleur c , Dominique Laurain-Mattar c 

a Department of Botany, Faculty of Science, University of Khartoum, P.O. Box 321, 

Sudan. b International Center for Chemical Sciences, HEJ Research Institute of 

Chemistry, University of Karachi, Karachi, Pakistan, c Groupe S.U.C.R.E.S., UMR 7565 

CNRS-Nancy-Université, BP 70239,54506 Nancy-Vandoeuvre, France 

Plants form the main ingredients of medicines in traditional systems of healing and 

have been the source of inspiration for several major pharmaceutical drugs. Gegeria 

alata (DC), Oliv & Hiern (Asteraceae) has been used as traditional medicine for many 

applications such as epilepsy, spasms, pneumonia and rheumatism 1 . Also, the whole 

plant is used as insecticidal and in food as spices. Repeated column chromatography 

of the chloroform extract of the roots of G. alata yielded two new sesquiterpene 

lactones [1&2] together with the known Geigerane (sesquiterpene lactone) and 

Flavonol: 7-O- methylkaempferol. Six components were detected in the oil of G. 

alata roots representing 99% of the total oil. 

Extracts from the leaves and roots were screened for different biological activities 

such as antibacterial, antifungal, cytotoxicity, and insecticidal activities. All extracts 

of the roots and the ethanol extract of the leaves showed significant activity against 

S. aureus and K. pneumonia. The former bacterium was also susceptible to 

chloroform extract of leaves. Also the ethanol extract of the roots displayed 

significant activity against E. coli. The hexane and ethanol extracts of leaves showed 

moderate antifungal activity against C. albicans. 

The chloroform extract of the roots showed significant insecticidal activity against 

Tribolium castaneum and Callosbruchus analis while the volatile oil exhibited only a 

significant activity against C. analis. The brine shrimp lethality assay showed absence 

of any measurable cytotoxicity of the hexane and chloroform extracts of the leaves 

whereas, both extracts as well as volatile oil obtained from roots showed significant 

cytotoxicity. Thus G. alata, as shown by in-vitro assays, could be a potential source 

for natural antibacterial, insecticidal and anticancer agents. 


24


Keywords: Gegeria alata, sesquiterpene lactones, flavonol, biological activity. 

Reference 

El Ghazali, G.E.B., El Tohami, M.S. & El Egami, A.A.B. 1997. Medicinal plants of Sudan, 

Part III, Medicinal plants of the eastern Nuba Mountains. Khartoum Univrsity 

Press. 

[SL - 8] PHYTOMEDICINE DEVELOPMENT FROM PLANTS OF 

RWANDA 

Justin N. KABERA, Polycarpe NYETERA 

IRST/Research centre in Phytomedicines and Life sciences, Butare- RWANDA 

kajust68@yahoo.fr, jkabera@irst.ac.rw 

In Rwanda, the first scientific work on the pharmacopoeia and traditional medicine 

started in the year 1972, at the National University of Rwanda (UNR), more precisely 

within the Faculty of Medicine by a small group of researchers-teachers. In 1975, this 

group is reinforced by a few teachers of the Faculty of Science, in particular those 

from the Department of Chemistry. In the years 1980, these researchers put in place 

the University Research Centre on the Pharmacopoeia and Traditional Medicine 

known as CURPHAMETRA. In 1989, this centre became the centre Pharmacopoeia of 

the Institute of scientific and technological research (IRST) by law Nr 06/1989 of 

March 15, 1989. Very recently, this centre was named “Research Center in 

Phytomedicines and Life sciences” (CRP&SV). 

Since 1989, several drugs containing plant extracts were developed, components 

with new structures were isolated and were given names inspired by the vernacular 

names of the plants; such as for example: Idomaïn de Gutenbergia coridifolia 

(vernacular name :Idoma). 


25


The studies undertaken on the medicinal plants are mainly based on information 

provided by traditional healers during ethno-botanic investigations. First, these 

plants are the subject of a botanical study for the exact scientific identification. Then, 

the extracts of these plants prepared using various solvents are subjected to a series 

of biological and pharmacological tests in order to detect a biological activity. The 

plants having revealed a particularly interesting activity are the subject of a chemical 

study including isolation, purification and structural identification of active 

ingredients having the initially detected biological activity. The isolation of the active 

ingredients is generally carried out using various methods of extraction, column and 

thin layer chromatography, preparative chromatography and purification by 

crystallization. The determination of chemical structures is carried out, in 

collaboration with foreign laboratories better equipped than ours, by various 

techniques of spectrometry: infra-red (IR), ultraviolet (UV), gas chromatography 

coupled with mass spectrometry (GC-MS) and by nuclear magnetic resonance 

(NMR). The biological and pharmacological tests are mainly carried out on laboratory 

mice, in our “Research Centre in Phytomedicines and Life sciences” (CRP&SV). 

Essential oils are extracted by the method of steam distillation. Their chemical 

composition is established by gas chromatography coupled with mass spectroscopy. 

The antimicrobial activity is tested by the traditional biological methods. The results 

of this research led to the manufacture of drugs containing the local plants extracts 

and also aroused the interest to continue research because the potentialities are 

enormous. 

[SL - 9] THE ROLE OF NUTRACEUTICAL-IMPLIED EMPIRICAL 

GRADES OF PLANT FOODS IN ELICITING PLANT BIODIVERSITY ON 

WOMEN SMALL HOLDER FARMS 

AGNES NAMUTEBI*, LEVI. S. M. AKUNDABWENI 1 and JUDITIH KIMIYWE 2 

Department of Food Science & Technology, Makerere University, PO Box 7062, 

Kampala, Uganda; asnamutebi@agric.mak.ac.ug, asnamutebi@yahoo.co.uk 

1 Department of Plant Science and Crop Protection-University of Nairobi, P.O. Box 

30197-00100 Nairobi; proflevi@uonbi.ac.ke 

2 Department of Food Nutrition and Dietetics, Kenyatta University, P.O. Box 43844, 

Nairobi; email: jokimiywe@yahoo.com: 

A range of plant biodiversity species, produced for household food and nutrition 

security, characterize women small-holder farms of the Lake Victoria Basin. The 


26


usefulness of nutraceutical-implied grades computed from micro-nutrient mineral 

concentrations of plant germplasm in eliciting plant biodiversity is presented. Plant 

foods were sampled from women small-holder farms in Iganga (Uganda) and Vihiga 

(Kenya) districts. Mineral concentrations were measured using Energy dispersive Xray 

fluorescence spectroscopy (XRF), converted to nutrametric scores (1-10) and 

grades (low, medium and high). Six minerals were consistently found in a decreasing 

concentration order (p>0.05) viz.: potassium, calcium, iron, Zinc, manganese and 

strontium and used to elicit plant biodiversity variation on the farms. The 

nutrametric grades computed using the If logic function have been coined as units of 

biodiversity. A single mineral exhibited a wide plant biodiversity on the farms. 

Similarly, a combination of the six minerals exhibited wide plant biodiversity. Plant 

foods were from Acanthaceae, Amaranthaceae, Asteraceae, Basellaccae, 

Cucurbitaceae, Dioscoreaccae, Moraceae, Musaceae and Solanacea families. The 

plant foods captured on these farms with medium to high nutraceutical grades have 

been identified for phyto-chemical profiling to further qualify their nutraceutical 

value to in order to conserve the seed and share among farmers. 

Key words: Biodiversity, Nutraceutical, Small-holder, Mineral 

[SL - 10] SYNTHESIS OF METHOXYSTILBENES 

Mapitse, R.; Chacha, M.; Home, P.; Masesane, I. B.; Majinda, R. R. T. and Mutisya, D. 

Department of Chemistry, University of Botswana, P/Bag UB 00704, Gaborone, 

Botswana. 

gabaitsr@mopipi.ub.bw 

Polyhydroxystilbenes are among the naturally occurring bioactive compounds often 

isolated from plant materials. Examples include resveratrol 1 and its analogues. The 

observed biological activities range from antibacterial, antifungal and anticancer 

properties, to name just a few. Some methoxystilbenes have been found to possess 

superior biological activities compared to the polyhydroxy analogues. In some cases 

the introduction of the methoxy groups has led to a 100-fold improvement 2 in 

biological activity. This paper describes the synthesis of methoxystilbenes using the 

Wittig reaction. It was found that the substitution pattern of both the ylide and 

aldehyde affected the cis/trans ratio of the stilbene product. Biological activity of the 

compounds is currently being investigated. 


27


MeO 

CH 2PPh 3 CHO 

Br 

+ 

OMe 

NaOH 

H 2O, rt 

References 

1. Gosslau, A.; Chen, M.; Ho, Ci-T.; Chen, K. Y., British Journal of Cancer, (2005), 

92(3), 513-521. 

2. Park, E-U.; Min, H-Y.; Ahn, Y-H.; Bae, C-M.; Pyee, J-H.; Lee, S. K., Bioorganic 

and Medicinal Chemistry Letters, (2004), 14, 5895-5898. 

[SL - 11] TOTAL SYNTHESIS OF BIARYLCHALCONES: RHUSCHALCONE 

VI AND ITS ANALOGUES 

MeO 

MeO 

MeO 

Oscar M. Shetonde, a,b Merhatibeb Bezabih, b Wendimagegn Mammo, c Kerstin 

Marobela, d and Berhanu M. Abegaz b,* 

a On study leave from Department of Chemistry, Universite′ de Kinshasa, P.O.Box: 

119, Kinshasa XI, DR Congo, b Department of Chemistry, University of Botswana, 

P/B 00704, Gaborone, Botswana. c Department of Chemistry, Addis-Ababa University, 

P.O.Box: 1176, Addis-Ababa, Ethiopia. d Department of Biological Sciences, University 

of Botswana, P/B 00704, Gaborone, Botswana. 

Rhus pyroides Burch. (Anacardiaceae) is a shrub to a medium-sized tree widely 

distributed in the eastern part of Botswana and South Africa, and is used against 

epilepsy in traditional medicine. 1,2 R. pyroides is an exceptionally rich source of 

bioactive bichalcones with novel structural characteristics. 1 Rhuschalcone VI (1) is a 

naturally occurring biarylchalcone composed of two molecules of isoliquiritigenin (2). 

The natural material was reported for the first time by Mdee et al. 1 from the root 

bark of R. pyroides and was shown to have a strong anti-plasmodial activity and a 

moderate antiproliferative activity against two colorectal cancer cells. 1 However, the 

quantities obtained from natural sources were limited, and it is remarkable that 

+ 


OMe 

28


whereas a number of flavonoids have been employed in Suzuki reactions, 3 the use of 

chalcones and the synthesis of any biaryl-type Rhuschalcones has not yet been 

reported. In order to provide ready access to sufficient quantities of material for 

more complete biological studies, as well as a general route for the preparation of 

Rhuschalcone VI and its structural analogues, the total synthesis of Rhuschalcone VI 

has been achieved starting from simple and available resorcinol and 4hydroxybenzaldehyde. 

Since a previous report 1 on Rhuschalcone VI has shown that it possesses interesting 

biological activities, unnatural Rhuschalcone VI analogues may show similar and/or 

other pharmacological activities, which would warrant additional investigation. 

Within this context, and in order to demonstrate the applicability of our strategy, we 

undertook and successfully completed the preparation of a few such Rhuschalcone 

VI analogues that would be of value in SAR studies. The first total syntheses of eight 

Rhuschalcone VI-type bichalcones were achieved, indicating that the general 

methodology developed by our group is of practical use in the syntheses of more 

congeners carrying the same carbon-framework and the creation of biologically 

more potent substances. The lecture will describe our strategy, which involves the 

solvent-free Aldol syntheses of chalcones, and the first time use of the Suzuki- 

Miyaura coupling reaction in the synthesis of bichalcones. 

Key words: Synthesis, Rhuschalcone VI, Biarylchalcones, Suzuki-Miyaura reaction. 

1. Mdee, L.K.; Yeboah, S.O.; Abegaz, B.M. J. Nat. Prod. 2003, 66, 599-604. 

2. Svenningsen, A.B.; Madsen, K.D.; Liljefors, T.; Stafford, G.I.; Staden, J.V.; 

Jäger, A.K. J. Ethnopharmacology. 2006, 103, 276-280. 

3. Chen, J.; Chang, H.W.; Kim, H.P.; Park, H. Bioorg. Med. Chem. Lett. 2006, 16, 

2373-2375. 


29


[SL - 12] BIOACTIVE EXTRACTS AND COMPOUNDS FROM SOME 

GARCINIA SPECIES GROWING IN TANZANIA 

Joseph J. Magadula a *, Ester Innocent a , Supinya Tewtrakul b , Kuo-Hsiung Lee c 

a 

Institute of Traditional Medicine, Muhimbili University of Health and Allied Sciences, 

P.O. Box 65001, Dar es salaam, Tanzania 

b 

Department of Pharmacognosy and Pharmaceutical Botany, Faculty of 

Pharmaceutical Sciences, Prince of Songkla University, Hat-Yai, Songkhla, 90112, 

Thailand 

c 

Natural Products Laboratory, School of Pharmacy, University of North Carolina, 

Chapel Hill, North Carolina 27599, USA 

The genus Garcinia is a member of the Clusiaceae (Gutiferae) family that comprises 

of plant species growing mainly in tropical Africa and Southeast Asia 1 . Trees or 

shrubs of this genus usually produce yellow resin of medicinal importance while 

fruits of most species of the genus Garcinia are edible. Phytochemically, the genus is 

well known to contain prenylated xanthones 2 , flavonoids 3 , isoprenylated 

benzophenones 4 and triterpenoids 5 . 

In our continued efforts to search for novel and bioactive compounds from the 

genus Garcinia, we recently investigated 17 crude extracts from 9 Garcinia species 

growing in Tanzania for their potential against 4 human cancer cell lines, HIV-1 

protease inhibitors, antioxidants and antimicrobial activities. Furthermore, 

phytochemical studies on the stem bark of Garcinia semseii gave three novel 

isoprenylated benzophenones (1-3) while from the root barks of Garcinia edulis and 

Garcinia volkensis, three bioactive prenylated xanthones (4-6) were isolated. The 

results for biological activities exhibited by crude extracts and compounds together 

with structure elucidation of new compounds will be presented and discussed. 

References 

1. Perry, LM, Metzger, J (Eds.), 1980. Medicinal Plants of East and South-East 

Asia. MIT Press, London, p. 175. 

2. Yang, NY, Han, QB, Cao, XW, Qiao, CF, Song, JZ, Chen, SL, Yang, DJ, H, Xu, HX, 

2007. Two new xanthones isolated from the stem bark of Garcinia lancilimba. 

Chem. Pharm. Bull. 55, 950–952. 

3. Babu, V, Ali, SM, Sultana, S, Ilyas, M, 1988. A biflavonoid from Garcinia 

nervosa. Phytochemistry 27, 3332–3335. 

4. Oliveira, CMA, Porto, ALM, Biurich, V, Marsaioli, AJ, 1999. Two prenylated 

benzophenones from the floral resins of three Clusia species. Phytochemistry 

50, 1073–1079. 


30


5. Nyemba, AM, Mpondo, TN, Connolly, JD, Rycroft, DS, 1990. Cycloartane 

derivatives from Garcinia lucida. Phytochemistry 29, 994–997. 

[SL - 13] ANTHOCYANINS FROM SELECTED PLANT SPECIES IN 

UGANDA 

Robert Byamukama a , Monica Jordheim b , Bernard Kiremire a and Oyvind Andersen b . 

a Chemistry Department, Makerere University, P.O. Box 7062, Kampala, Uganda 

b Department of Chemistry, University of Bergen, Allegt. 41, 5007, Bergen, Norway 

rbyamukama@chemistry.mak.ac.ug 

Anthocyanins comprise a diverse group of intensely coloured pigments responsible 

for the appealing and often spectacular orange, red purple and blue colours of many 

fruits, vegetables, cereal grains, flowers, leaves, roots and other plant storage 

organs. The most common food colorants that have been used worldwide are 

synthetic ones some of which are deemed to be carcinogenic. Because of this, the 

safety of synthetic colorants has been questioned in the past years, and this has 

significantly increased the interest in natural colorants as food colour additives such 

as anthocyanins. Today, interest in anthocyanin pigments has also intensified 

because of their possible health benefits. Anthocyanins are potent antioxidants and 

may be chemoprotective. 

This presentation will give the results of anthocyanin analysis (isolation and structure 

elucidation) from a number of plants plant species in Uganda including the novel 

compounds whose structure has been elucidated (Hippeastrum cultivars, Castor- 

Ricinus communis, Acalypha hispida, Rubus Pinnatus, R. Rigidus) from Uganda. The 

presentation summarise the following Publications 

1. Robert Byamukama, Monica Jordheim, Bernard Kiremire and Øyvind M. 

Andersen (2008). New anthocyanins from the stem bark of Castor, Ricinus 

communis. Natural Product Communications , 3 (9), 1497-1500. 

2. Robert Byamukama, Jane Namukobe and Bernard Kiremire (2009). 

Anthocyanins from leaf stalks of cassava (Manihot esculenta Crantz). African 

Journal of Pure and Applied Chemistry Vol. 3 (2), 020-025. 

3. Robert Byamukama, Bernard T. Kiremire, Øyvind M. Andersen and Andreas 

Steigen (2005). Anthocyanins from fruits of Rubus pinnatus and Rubus rigidus. 

Journal of Food Composition and Analysis, 18, 599–605. 

4. Robert Byamukama, Monica Jordheim, Bernard Kiremire, Jane Namukobe 

and Øyvind M. Andersen (2006). Anthocyanins from flowers of Hippeastrum 

cultivars. Scientia Horticulturae, 109, 262–266. 


31


5. Bergitte Reiersen, Bernard T. Kiremire, Robert Byamukama and Øyvind M. 

Andersen (2003). Anthocyanins acylated with gallic acid from chenille plant, 

Acalypha hispida.. Phytochemistry , 64, 867–871. 

[SL - 14] AN APPLICATION OF MASS SPECTRA IN NATURAL 

PRODUCTS 

T. Sivakumar, R.Rajavel, K.Srinivasan,Jagadeeswaran M, Saravanan.R 

Nandha college of pharmacy, Perundurai main road, Erode, Tamilnadu, India - 

638052 

Natural flavonoids, alkaloids, saponins and sesquiterpenoids have been extensively 

investigated because of their biological and physiological significances, as well as 

their promising clinical uses. It is designed to improve the productivity and quality of 

results to facilitate wise decisions for use of MS data. Interpretation of mass 

spectrometry (MS) data can help to solve the problems. The successful hyphenation 

of LC and MS, which was thought as "the bird wants to marry with fish", has been 

conducted widely in natural product sample analysis. The application of mass 

spectrometry in the natural health products industry is, however, sparse. Given the 

complexity of the chemical composition of these products, the use of mass 

spectrometry as a chromatographic detector is essential for the proper identification 

and quantification of their bioactive components. It is also important to monitor the 

fate of the bioactive components of natural health products during processing, as 

processing conditions may modify their structure and activity. Mass spectrometric 

evaluations of commercial health food products show that most products are lacking 

in quality, indicates that the methods presently used for quality control and 

quantitative analysis are not adequate. This paper examines the use of biomolecular 

mass spectrometry for analysis of the bioactive components in functional foods, 

neutraceuticals, and herbal health products. With the health and safety of 

consumers at stake, mass spectrometry should be made mandatory for analysis of 

those products. 

Keywords: alkaloids, mass spectrometry, natural products 


32


[SL – 15] SCREENING OF ANTIBACTERIAL AND 

ANTIFUNGAL ACTIVITIES OF FIFTEEN EXTRACTS FROM ANTHOCLEISTA 

SCHWEINFURTHII (GILG.) (GENTIANACEAE) 

Nadege Kabamba Ngombe a,b , Erick Francisco Rakotoniriana a , Dibungi T. Kalenda b 

and Joelle Quetin-Leclercq a 

a 

Unité CHAM, Louvain drug research institute, Université catholique de Louvain, 

Av.E.Mounier 72, Bruxelles 1200, Belgium 

b 

Centre d’Etudes des Substances Naturelles d’Origine Végétale,Université de 

Kinshasa BP 202 KIN IX, Kinshasa, Democratic Republic of Congo. 

Anthocleista schweinfurtii (Gilg) is a common plant of tropical regions, whose 

leaves, stem bark and root bark are eaten by bonobo (Pan paniscus), an endemic 

pigmee chimpanzee of the Democratic Republic of Congo and also used in folk 

medicine to treat several disorders (malaria, tumors, cancers, venereal diseases, 

bacterial diseases…). Only few studies on the chemical and biological activities of this 

plant have been performed. The development of multiple resistances in human 

pathogenic microorganisms to the indiscriminate use of antibiotic drugs commonly 

employed in the treatment of infectious diseases, have conducted scientists into 

looking for new antimicrobial substances from various sources like medicinal plants. 

The screening of plant extracts for antimicrobial activity has shown that higher plants 

represent a potential source of new anti-microbial agents. The present study was 

conducted to investigate antibacterial and antifungal activities of fifteen extracts 

from A.schweinfurtii (Gilg). Inhibition of bacterial growth and fungal growth was 

investigated using agar diffusion methods (paper disc method). The microorganisms 

used in this study consisted of reference strains of Staphylococcus aureus, 

Escherichia coli, Pseudomonas aeruginosa, Klebsilla pneumonie , Klebsiella 

oxytocica, Yercinia enterolytica, Enterobacter aerugines and Candida albicans. Most 

extracts of Anthocleista Schweinfuthii showed antimicrobial activity against S.aureus 

and E.coli and antifungal activity against C. albicans at the concentrations tested. The 

least effective were the most polar fractions (EtOAc extracts and aqueous residues) 

indicating that most active molecules were lipophilic. 

KEY WORDS: Anthocleista schweinfurthii- antifungal activity-antibacterial activity 


33


[SL - 16] ANTIPLASMODIAL -HYDROXYDIHYDROCHALCONE FROM 

SEEDPODS OF TEPHROSIA ELATA 

Lois M. Muiva a,b , Abiy Yenesew a , Solomon Derese a , Matthias Heydenreich c , Martin G. Peter c , 

Hosea M. Akala d , Norman C. Waters d , Charles Mutai e , Joseph M. Keriko b , Douglas Walsh d 

a 

Department of Chemistry, University of Nairobi, P. O. Box 30197-00100, Nairobi, 

Kenya 

b 

Department of Chemistry, Jomo Kenyatta University of Agriculture and Technology, 

P.O. Box 62000, Nairobi, Kenya 

c 

Institut für Chemie, Universität Potsdam, PO Box 60 15 53, D-14415 Potsdam, 

Germany 

d 

United States Army Medical Research Unit-Kenya, Walter Reed Project), Kisumu, 

MRU 64109, APO, AE 09831-4109, USA 

e 

Centre of Traditional Medicine, Kenya Medical Research Institute, P.O. Box 54840- 

00200, Nairobi, Kenya 

sderese@uonbi.ac.ke 

Tephrosia species (Leguminosae) in East Africa are used in traditional medicinal 

practice to treat infectious diseases. It is estimated that there are between 300 and 

400 Tephrosia species, of which some 30 are found in Kenya. The genus Tephrosia is 

rich in flavonoids and isoflavonoids including rotenoids. Previous phytochemical 

investigation of the roots of T. elata yielded flavanones, a flavone, pterocarpans and 

rotenoids. 

In this study from the seedpods of Tephrosia elata, a new -hydroxydihydrochalcone 

named (S)-elatadihydrochalcone (1) was isolated. In addition, the known flavonoids 

obovatachalcone, obovatin, obovatin methyl ether and deguelin were identified. The 

structures were determined on the basis of spectroscopic evidence. The crude 

extract and the flavonoids obtained from the seedpods of this plant showed 

antiplasmodial activities. The literature NMR data on -hydroxydihydrochalcones is 

reviewed and the identity of some of the compounds assigned - 

hydroxydihydrochalcone skeleton is questioned. These results will be discussed during 

the short lecture. 


34


Key Words: Tephrosia elata; Leguminosae; seedpods; (S)-elatadihydrochalcone; βhydroxydihydrochalcone; 

Antiplasmodial Activity. 

[SL - 17] PHYTOCHEMICAL INVESTIGATION OF SURFACE EXUDATES 

OF DODONAEA ANGUSTIFOLIAFOR IN VITRO ANTIPLASMODIAL AND 

MOSQUITO LARVICIDAL ACTIVITY 

Kerubo, L. O a , Midiwo, J. O a , Derese, S a , Yenesew, A a , Matthias, H b , Peter, M. G b , 

Akala, H. M. c , Eyase, F c , Waters, N. C. c , Kabaru, J d 

a Department of Chemistry, Nairobi University, Box 30197-00100, Nairobi, Kenya 

b Institut für Chemie, Potsdam Universitat, P Bag 60 15 53, D-14415 Potsdam, 

Germany 

c 

United States Army Medical Research Unit-Kenya, Walter Reed Project, Kisumu, 

MRU 

64109, APO, AE 09831-4109, USA 

d 

Department of Zoology, Nairobi University, P Bag 30197-00100, Nairobi, Kenya. 

lkerubo@uonbi.ac.ke 

Dodonaea angustifolia in study belongs to the family sapindaceae distributed in the 

tropical and subtropical regions of the world. Traditionally this plant is used as an 

analgesic, laxative, antipyretic, in rheumatism, eczema, and skin ulcers. The most 

common secondary metabolites of these plants are terpenoids and flavonoids 

usually deposited on the surface of the leaves, and are known to have antioxidant, 

antibacterial and antiviral activities. The surface exudes of Dodonaea angustifolia is 

up to 12% surface exudates and has yielded seven methylated flavonoids and two 

clerodane terpenoids. The surface exudates showed anti-plasmodial activity with 

IC50 values of 41.5 3.9 g/ml against chloroquine-sensitive (D6) strain of the P. 

falciparum. The crude extract did not show good larvicidal activity, against the larvae 

of Aedes aegypti, as its LC50 value was > 60 μg/ml after 24 hours. Most of the 

isolated compounds showed moderate anti-plasmodial activity against the D6 strain 

of Plasmodium falciparum (Table 1.0). Among the compounds tested for larvicidal 

activity against Aedes aegypti; rhamnocitrin (5) and santin (4) showed good dose 

dependent activity with an LC50 value of 1.75 and 5.1 g/ml (Table 1.0), respectively, 

after 24 hours. 

In this presentation the chemistry, antiplasmodial and mosquito larvicidal activity of 

some isolated compounds will be discussed. 


35


Keywords: Dodonaea angustifolia, surface exudates, in vitro antiplasmodial, 

mosquito larvicide. 


36


[SL - 18] THE ROLE OF NATURAL PLANT PROD UCTS AS 

MOD ULATORS OF DRUG EFFLUX IN PATHOGENIC 

MICROBES 

Rumbidzai Mangoyi, Sungai Mazando, Tariro Chitemerere, Elaine Chirisa, Theresa 

Chimponda and Stanley Mukanganyama 

Biomolecular Interactions Analyses, Department of Biochemistry, University of 

Zimbabwe, Box MP 167, Mount Pleasant, Harare, Zimbabwe. Email: 

smukanganyama@medic.uz.ac.zw 

The success of infectious disease chemotherapy has been dimmed ever since the 

dawn of the antimicrobial drug era because of the anti-infective resistance. 

Numerous diseases caused by microorganisms have become difficult to treat 

including microorganisms responsible for severe infections in hospitalized patients, 

food borne pathogens, and sexually transmitted pathogens are resistant to most 

available antimicrobial drugs. Among the mechanisms of drug resistance observed 

clinically, enhanced drug efflux from the pathogenic organisms has been noted to 

play a significant role. Among these drug efflux pumps are ATP-binding cassette 

(ABC) family which is found in most microorganisms. Several studies now show a 

common cause of high-level drug efflux in clinical isolates of pathogenic organisms 

and this is correlated to the over-expression of drug efflux proteins. Efflux pumps 

can be specific for a class of antibiotics or responsible for multidrug resistance. They 

are attractive antibacterial targets and co-administration of an efflux pump inhibitor 

(EPI) with an antibiotic can potentially be used to modulate or enhance the effects of 

the antibiotic. The existence of every class of the five existing families of efflux 

pumps has been demonstrated in Mycobacterium tuberculosis, Candida albicans, 

Escherichia coli and other bacterial species. Using Mycobacterium aurum, Candida 

albicans and several bacterial species, we have investigated the role of plant extracts 

in the efflux of ciprofloxacin (CIP) or Rhodamine 6G (R6G) from these cells. The 

study was performed to set up both ciprofloxacin efflux assay and Rhodamine 6G 

efflux assay in Mycobacterium aurum, Candida albicans, E. coli for testing plant 

natural compounds as efflux pump inhibitors (EPIs). After determining the MICs and 

MBCs for the putative EPIs, they were tested for their effects as inhibitors of the 

efflux pumps. Our results show the both compounds (CIP and R6G) are pumped out 

from these cells via an ATP-dependent pathway. The efflux of ciprofloxacin from C. 

albicans was inhibited by standard efflux inhibitors such as reserpine, cccp and 

verapamil. Several plant extracts (Syzigium cordatum, Cussonia natalensis, and 

Combretum zeyhrii) were shown to modulate the effects of these pumps in Candida 

albicans. Further work is being carried out on to assess the effects of plant extracts 

on the efflux of drugs from the other model organisms such as S. aureus, E. coli, C. 


37


glutamicum, P. aeruginosa, M. aurum and Bacillus species. This study provides 

evidence for the role of plant compounds not just as inhibitors of growth but also as 

modulators of drug efflux from the cells and this may provide an additional 

mechanism for the action of natural plant compounds as anti-infective agents. 

[SL - 19] NUTRI-MEDICINAL PLANTS USAGE IN THE MANAGEMENT 

OF IMMUNO-COMPROMISED AILMENTS IN UGANDA 

Kamatenesi-Mugisha Maud, Acipa Annabel & Oryem-Origa Hannington 

Department of Botany, Makerere University. P.O. Box 7062, Kampala, Uganda. 

Tel: 256-772-438905 

mkamatenesi@botany.mak.ac.ug 

To regard food as medicine is part of cultural heritage. Today, more advanced 

scientific research reveals that human health is directly connected to nutrition 

(Johns, 2003, Lentini et al., 2007). There is no definitive resource available containing 

this information for African food plants. FAO, (2003) observed that wild food plants 

have a potential in the mitigation of HIV/AIDS impact, especially among the rural 

poor. In Uganda, 80% of mothers use traditional medicine to provide health care for 

themselves and children (Kamatenesi et al, 2005, Kamatenesi and Oryem-Origa 

2006). For instance, in the treatment of ailments that women suffer especially in 

rural areas, herbal medicines are the first line treatment unless the condition 

deteriorates then they seek modern health facilities. This study inventoried 

nutritional medicinal plants and performed the nutritional analysis of some nutrimedicinal 

plants used in most parts of Uganda. The research findings revealed that 

vegetables such as Amaranthus graecizans Auct.Non L, Solanum nigrum Acerb. ex. 

Dunal, Cleome gynandra L., are rich in nutrients and micronutrients such as iron, 

calcium, phosphorus, potassium, beta carotene and vitamin C, proteins and dietary 

fibre. These plants were found to be favoured by immuno-compromised people 

including pregnant women for immune boosting and restoration of appetite. This 

paper will present the value of food plants that double as medicinal plants in health 

care delivery in Uganda. 

Key words: Nutri-medicinal plants; immune boosting; nutritional analysis; Uganda. 


38


[SL – 20] CHEMISTRY AND BIOLOGICAL EVALUATION OF MORUS 

MESOZYGIA AND DORSTENIA SPP (MORACEAE) 

B. T. Ngadjui a G.D.W.F. Kapche b , M. –T. Bezabih c and B. M. Abegaz c 

a 

Department of Organic Chemistry, Faculty of Science, University of Yaounde 1 

BP 812, Yaounde, Cameroon, 

b 

Department of Chemistry, Higher Teachers’ training College, University of Yaoundé 

1, P.O Box 47, Yaoundé, Cameroon 

c 

Department of Chemistry, Faculty of Science, University of Botswana, Private Bag, 

0022, Gaborone, Botswana 

ngadjuibt@yahoo.fr 

The study of natural products is an important area of scientific activity in Cameroon. 

This study embraces the disciplines of Taxonomic botany, pharmacology, 

pharmacognosy and chemistry. The selection of the plant material for investigation 

has been guided by its uses in the traditional medicine. We have been able to isolate 

and identified many novel structures and biological properties such as anti-malarial, 

anti- inflammatory, antimicrobial. Summary of the recent work on Morus mesozygia, 

and Dorstenia ssp (Moraceae) will be presented. 

Morus mesozygia 

Morus or Mulberry (Moraceae) is a genus of 10-16 species of deciduous trees native 

to Warm, Temperate and Subtropical regions of Asia, Africa and the America. Leaves 

of Morus species, especially, of M. alba have been an indispensable food source for 

silk-worms. Morus mesozygia is a small to medium sized forest tree of Tropical 

Africa; its leaves and fruit provide food for Monkey and Chimpanzee[1]. M. 

mesozygia is used to cure venereal diseases stomach troubles [1]. Repeated column 

chromatography of the trunk bark organic extract yielded several prenylated 

arylbensofuran derivatives such as 5-(2,3-dihydroxy-3-methylbuthyl)-2-(3,5dihydroxyphenyl)benzofuran-6-ol 

[1]. 

Dorstenia spp 

The genus Dorstenia(Moraceae), represented by about 170 species worldwide, 

contains many plants that are used as anti-snakebite, anti-infection and antirheumatism 

remedies in the medicinal plant therapy of many countries in Africa, 

Central and South America. The genus is now recognized as a rich source of prenyl 

and geranyl-substituted coumarins and flavonoids [2]. There is now increasing 

interest in the genus Dorstenia; during the last decade close to 40 papers have 

appeared dealing with investigations of over 29 Dorstenia species. We have so far 

investigated 16 species out of 23 identified in Cameroon. The results of our studies 


39


yielded: triterpenoids, styrenes, coumarins and mainly flavonoids [2]. Eleven 

diprenylated flavonoids have so far been isolated from Dorstenia and all of them are 

reported from the twigs the twigs of D. mannii. The pharmacological data of this 

genus are scanty. Extracts of D. multiradiata show antileishmanial activity. 

1. G.W.F. Kapche, C.D. Fozing, J.H. Donfack, G.W. Fotso, D. Amadou, 

A.N.Tchana, M.-T. Bezabih, P. moundipa, B.T. Ngadjui, B.M. Abegaz; 

Phytochemistry;70,216-221 (2009). 

2. Ngadjui, B. T. Abegaz, B.M. “The chemistry and pharmacology of the genus 

Dorstenia (Moraceae)” in studies in Natural Products Chemistry (ed. Atta-Ur- 

Rahman, Elsevier, vol 29 Bioactive Natural Products (Part J), pp. 761-805 

(2003) 

[SL – 21] PHYTOCHEMICAL INVESTIGATION OF RESINS FROM 

COMMIPHORA HOLTZIANA IN KENYA 

Rose Chiteva a,b , Abiy Yenesew b , John Wanjohi b and Ben Chikamai c 

a Forest Products Research Center, Karura, Kenya Forestry Research Institute (KEFRI), P. 

O. Box 64636, 00620, Nairobi, Kenya ; 

b Department of Chemistry, University of Nairobi, P. O Box 30197, Nairobi, Kenya; 

c Kenya Forestry Research Institute (KEFRI), P. O. Box 20142, 00200, Nairobi, Kenya 

In the antimicrobial analysis, the crude extracts of Commiphora holtziana showed an 

appreciable activity against Gram positive (Bacillus pumilis, Bacillus subtilis and 

Staphylococcus aureus) and Gram negative (E. coli) bacteria, and the fungus 

Sacharamyces cervisiae. A new compound, 11–hydroxyl-γ-muurolene (1) was 

isolated and characterized from the hexane extract. In addition, two known 

compounds, (1E)-3-methoxy-8,12-epoxygermacra-1,7,10,11-tetraen-6-one (2) and 

(1E)-3-methoxy-8,12-epoxygermacra-1,7,10,11-tetraen-6-one (3) were also 

identified. Furthermore, a total of 174 compounds were detected by GC – MS 

analysis, and some 14 of these were identified by the comparison of their mass 

spectra with data available in the GC – MS library. The details of these results will be 

presented. 


40


1 

OH 

CH 3 O 

O 

2 

O 

CH 3 O 

[SL - 22] PHYTOCHEMISTRY, ANALYTICAL CHEMISTRY AND 

MEDICINAL PLANTS: CHALLENGES IN AFRICA 

Mathew Muzi Nindi 

Department of Chemistry, University of South Africa, P. Box 392, Pretoria, 0003, RSA 

Medicinal plants have for a long time played an essential role to a variety of 

communities in Africa. It is not surprising that tremendous research on medicinal 

plants have been studied extensively by African researchers as well as other 

scientists worldwide. The pharmaceutical industry in developed countries has 

invested heavily in the development of novel drug entities for the treatment of 

disease from large supply banks of compounds for new screens. However, drug 

development through natural product research is challenging and requires a multidisciplinary 

approach that would include expertise in phytochemistry and analytical 

chemistry. There is a need for analytical chemists to play a role in the isolation, 

sample pre-treatment, characterization and quantification of isolated compounds. 

Elimination of problematic common natural products such as saponins, tannins, from 

plant extracts prior to characterization, quantification and testing using biological 

screening procedures require an analytical approach. The partnership of analytical 

chemistry and phytochemistry should lead to providing the missing analytical data 

such as percentage composition of active metabolites present in plants. Such 

information is invaluable especially in biologically active extracts that have 

demonstrated reduced activities when tested as pure components. 

The presentation would review the currently available technology that could be used 

in the phytochemistry research of natural products. Examples will be given of some 

of the work that we have already done. The challenges faced by African scientists in 

this area of research will also be reviewed. 

3 


O 

41


[SL - 23] TRYPANOSOMIASIS AND AFRICAN INDIGENOUS 

KNOWLEDGE 

K. B. Kubata 

NEPAD/Biosciences eastern and central Africa, Nairobi, Kenya 

b.kubata@africabiosciences.org 

Lipid mediators (Prostaglandins, Thromboxane A2, etc.) comprise a family of 

structurally related biologically active compounds involved in various symptoms 

associated with parasitic diseases. The molecular mechanisms of Lipid mediators 

Lipid mediators’ biosynthesis in animals have been studied extensively. Currently, 

several lines of evidence link their production with parasitic infections. The author 

will discuss Prostaglandins (PGs) production in parasitic protozoa and their roles in 

pathogenesis and parasite physiology as well as the recent advances in our 

understanding of the enzymology of PG production in various parasites. The author 

will also discuss the role of some African tropical plants in the control of parasitic 

infections such as trypanosomiasis and malaria. 

[SL – 24] ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES OF CARDIAC 

GLYCOSIDES EXTRACT OF ANTHOCLEISTA SCHWEINFURTHII (GILG) 

(GENTIANACEAE) 

Nadege Kabamba Ngombe a,b , Erick Francisco Rakotoniriana a , Dibungi T. Kalenda b 

and Joelle Quetin-Leclercq a * 

a 

Unité CHAM, Louvain drug research institute, Université catholique de Louvain, 

Av.E.Mounier 72, Bruxelles 1200, Belgium 

b 

Centre d’Etudes des Substances Naturelles d’Origine Végétale,Université de 

Kinshasa BP 202 KIN IX, Kinshasa, Democratic Republic of Congo. 

Anthocleista schweinfurthii (Gilg) is one of the food plants of Bonobo(Pan paniscus), 

an endemic chimpanzee pygmee of the Democratic Republic of Congo. In folk 

medicine, this plant is used to treat several disorders (malaria, tumors, cancers, 

venereal diseases, bacterial diseases. Little is known about the chemical 

compositions or biological activities of Anthocleista schweinfurthii (Gilg). 

Phytochemical screening showed that some extracts of this plant were positive to 

Kedde reagent, so were likely to contain cardiac glycosides. Cardiac glycosides could 

derive from plants, skins and parotid gland of amphibians. They are used as cardiac 

stimulant. Few studies on the antibacterial and antifungal activities of cardiac 

glycosides have been performed. The present investigation was carried out to 


42


evaluate antibacterial and antifungal activities of cardiac glycoside type compounds 

rich-extract (CARDAN) from the root bark of Anthocleista schweinfurthii (Gilg) against 

two strains of bacteria (Bacillus substilis and Escherichia coli), the pathogenic fungus 

Cladosporium cucumerinum and the pathogenic yeasts Candida albicans. Inhibition 

of bacterial and fungal growth was assessed in semi quantitative fashion by 

bioautography on TLC plates. CARDAN showed interesting antibacterial activity 

against both bacteria when tested at concentration of 50 and 100µg. We observed 

no activity of this extract against fungi at the same concentration. 

KEY WORDS: Anthocleista schweinfurthii- cardiac glycosides extract- antifungal 

activity-antibacterial activity-bioautography 


43


YOUNG SCIENTIS 


44


[YS 1] THE ANTI-PROLIFERATIVE EFFECTS OF PLANT PRODUCTS 

ON HUMAN LEUKEMIA CELL LINES JURKAT AND WIL2 

Simbiso C.Dumbura 1 , Lesilane. Mampuru 2 and Stanley Mukanganyama 1 

1 

Biomolecular Interactions Analyses Group ,Department of Biochemistry, University 

of Zimbabwe, P.O.MP167 Mount Pleasant, Harare, Zimbabwe 

2 

Medicinal Plant Research Group, Department of Biochemistry ,Microbiology, and 

Biotechnology ,University of Limpopo, Private Bag X1106,Sovenga 0727,South Africa, 

sdumbura@science.uz.ac.zw 

Background Cancer is a worldwide problem with treatment being undermined by 

drug resistance and drug toxicity in patients. With most therapeutic drugs being 

derived from plant sources researchers have turned to plants for discovery of less 

expensive and less toxic chemotherapeutic compounds that alone or used with 

conventional drugs induce apoptosis, inhibit proliferation or increase drug sensitivity 

of cancer cells. Plants that are used as traditional medicines are under investigation 

to validate claims of disease treatment and test them on other diseases. 

Objectives To screen for plant extracts that inhibit proliferation of leukaemia cell 

lines Jurkat and Wil 2 

Methodology Medicinal plants used in Zimbabwe were screened for their ability to 

inhibit cell proliferation as compared to anticancer drug doxorubicin. Methanolic 

extracts from 14 plants were screened for ability to inhibit Wil2 and Jurkat cell 

growth at concentrations 0, 50,100,250,500 and 1000 µg/mL. Trypan blue assay was 

used for cell counting and cell viability determination. Doxorubicin was used as the 

positive control at a concetration of 10 µg/ml. 

Results and Discussion The 5 most active of the extracts were found to be potent in 

this order: Parinari curatellifolia>Aloe forex >Croton >Vernonia adoensis >Euphobia 

traculli >Cajanus cajan. The extract from Parinari curatellifolia reduced cell 

proliferation by half at a concetration of 50 µg/ml after 3 hours as compared to the 

anticancer drug doxorubicin that halved cell proliferation after 5 hours of incubation 

in comparison to the control. The extract from Parinari curatellifolia was the most 

potent at reducing proliferation of the cell lines. The leaves of this plant are used by 

locals for treating stomach ailments and fever. Aloe forex the second most potent is 

used locally for treating skin ailments, coughs, liver and spleen diseases 

Conclusion. The extracts from Parinari curatellifolia and the other four plants 

exhibited anticancer activity and could, therefore, serve as source of active chemical 

species that can potentially be used as anti-cancer drug leads. 


45


Key words: Leukemia cell lines, anti-proliferative, medicinal plants, plant extracts, 

doxorubicin 

[YS -2] ANTIBACTERIAL ACTIVITY OF SELECTED PLANTS FROM 

ZIMBABWE 

Tariro Chitemerere and Stanley Mukanganyama 

Biomolecular Interactions Analyses Laboratory, Department of Biochemistry, 

University of Zimbabwe, P.O.MP 167, Mount Pleasant, Harare, Zimbabwe 

alisonsiyaz@gmail.com 

Background The indiscriminate use of antibiotics has led to the emergence of drug 

resistant pathogens. For instance, 90-95 % of methicillin-resistant Staphylococcus 

aureus (MRSA) have been reported. The emergence of drug and multidrug resistance 

means that bacterial infections that were once easy to treat have now become 

difficult to treat as well as expensive because patients stay longer in hospitals. The 

search for new antibacterial agents is a matter of urgency to successfully manage 

and contr ause of the diversity of chemicals found in plants. Furthermore, ethnomedicinal 

use ol bacterial infections and pathogens. Nature is a source of new 

antibacterial agents bec of plants has been practiced by many cultural divides the 

world over since ancient times. These practices could give leads for the development 

of new antibacterials. However, only a small fraction of these chemicals have been 

discovered yet with the majority of them still to be exploited. 

Objectives The aims of the study were to screen for plant extracts exhibiting 

antibacterial activity and to determine extract concentrations that are bactericidal to 

five bacterial species: Escherichia coli ATCC 11229, Pseudomonas aeruginosa ATCC 

27853, Staphylococcus aureus ATCC 9144, Bacillus subtilis ATCC 6633 and Bacillus 

cereus ATCC 11778. 

Methodology Seventeen plant extracts selected from Zimbabwe were screened for 

antibacterial activity using the disc diffusion assay. Minimum inhibitory 

concentrations (MICs) and minimum bactericidal concentrations (MBCs) of top five 

potent extracts were determined using the microdilution and agar dilution methods 

respectively. Ampicillin was used as a reference antibiotic in all experiments. Serial 

two-fold dilution of plant extracts ranged from a concentration of 1000 µg/ml to 

1.95 µg/ml. 

Results Initial screening by the disc diffusion assay, showed the following to be the 

top five most potent plant extracts. 


46


E. Coli ; Callistemon sp > Vernonia adoensis > Parinari curatellifolia > Parinari 

curatellifolia> Mangifera indica. 

P. aeruginosa; Vernonia adoensis >Callistemon sp > Parinari curatellifolia > Parinari 

curatellifolia> Mangifera indica. 

S. aureus; Vernonia adoensis >Callistemon sp > Parinari curatellifolia > Parinari 

curatellifolia> Faurea sp 

B. subtilis; Callistemon sp > Asteraceae family > Vernonia adoensis > Parinari 

curatellifolia > Faurea sp> Mangifera indica. 

B. cereus; Vernonia adoensis >Callistemon sp > Parinari curatellifolia > Xeroderris 

stuhlmannii > Parinari curatellifolia. 

These extracts were then used to determine the MIC and MBC. 

MIC and MBC results showed that Mangifera indica and Callistemon sp were the 

most potent extracts for P. aeruginosa, E. coli and B. subtilis. Callistemon sp and 

Vernonia adoensis were the most potent for S. aureus and B. cereus. 

Conclusion The most potent extracts among all species of bacteria were Callistemon 

sp, Mangifera indica and Vernonia adoensis. The active antibacterial compounds in 

these plant species will be isolated using bio-guided fractionation assays. The 

extracts from the three species will also be used to determine their effects on the 

efflux of ciprofloxacin from the bacterial cells. 

Key words: natural plant products, ethnomedicinal, antibacterial, screening, 

bioassay 


47


POSTERS 


48


[PS – 1] ABIETANE DITERPENOIDS FROM CLERODENDRUM 

ERIOPHYLLUM 

Francis Machumi, Abiy Yenesew and Jacob O. Midiwo 

Department of Chemistry, University of Nairobi, P.O. Box 30197 (00100), Nairobi, 

Kenya 

francis.machumi@gmail.com 

Clerodendrum eriophyllum is a tree/shrub that grows to a height of about 8m high. It 

is widely used in Kenya’s traditional medicine for treatment of fever and malaria. Invitro 

anti-plasmodial tests on methanol/dichloromethane (1:1) extract of the roots of 

this plant showed activities against chloroquine sensitive (D6) and chloroquine 

resistant (W2) clones of Plasmodium falciparum parasites. 

Chromatographic separation on the extract, aimed at isolating the anti-plasmodial 

constituents, led to isolation of eight abietane diterpenoids, whose structures were 

elucidated using spectroscopic methods. 

[PS – 2] PURIFICATION OF 2-ARYLBENZOFURANS FROM AFRICAN 

MULBERRY MORUS MESOZYGIA (MORACEAE) BY CENTRIFUGAL 

PARTITION CHROMATOGRAPHY 

Gilbert Deccaux Kapche a , Pierre Waffo-Teguo b , Victor Kuete c , Bonaventure Ngadjui d 

and Jean-Michel Mérillon b 

a 

Department of Chemistry, Higher Teachers’ Training College (ENS), University of 

Yaounde I, P.O. Box 47, Yaounde, Cameroon 

b 

GESVAB, EA 3675, ISVV, UFR des Sciences Pharmaceutiques, Université Victor 

Segalen Bordeaux 2, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France 

c 

Department of Biochemistry, University of Dschang, P.O. Box 67 Dschang, 

Cameroon 

d 

Department of Organic Chemistry, Faculty of Science, University of Yaounde I, P.O. 

Box 812, Yaounde, Cameroon 

Six 2-aryl benzofurans derivatives were isolated from the twigs of a Cameroonian 

medicinal plant Morus mesozygia (Moraceae) in a preparative-scale using centrifugal 

partition chromatography (CPC). In this study, we have successfully used the 

quaternary Arizona solvent systems (n-heptane-EtOAc-MeOH-water) for the 


49


purification of moracin C (1), moracin M (2), moracin Q (3), moracin R (4), moracin T 

(5) and moracin U (6). Their structure was elucidated using MS, 1D and 2D NMR. 

Their antimicrobial activity was evaluated, and all non cyclised prenylated 

compounds (1, 4, and 5) were found to be active on at least 60 % of the tested 

microbial strains. 

Key words: Antimicrobial activity, 2-arylbenzofurans, centrifugal partition 

chromatography, Moraceae, moracin, Morus mesozygia. 

KINETIC STUDY OF THE ANTI-DIABETIC PROPERTIES OF BRYOPHYLLUM 

PINNATUM LEAVES 

*ARANSIOLA Elizabeth Funmilayo 1 , IWALEWA Ezekiel Olugbenga 2 , DARAMOLA 

Michael Olawale 1 , SELUWA Aanuoluwapo Mary 1 and OLUFOWOBI Olugbenga 

Oluwaseun 1 

1 Department of Chemical Engineering, O.A.U., Ile-Ife. Nigeria 

2 Department of Pharmacology, O.A.U., Ile-Ife. Nigeria 

Tel: +2348039537535 

aransiola4@yahoo.com & earansi@oauife.edu.ng 

Diabetes is one of the major degenerative diseases in the world today. Conventional 

drugs used for its treatment are expensive and unaffordable by the rural populace. 

This work was aimed at studying the anti-diabetic properties of Bryophyllum 

pinnatum leaves using animal models. Since albino rats have similar blood to 

humans, they were used as model. 

The rats were made diabetic by injecting them with glucose to raise their blood 

glucose level. Aqueous extract of the leaf was administered on several rats with 

dosages of different concentrations. 

The measurement of the rats’ blood glucose level after administering the extract 

showed significant drop in glucose level to a value close to normal in about 120mins. 

These results were competitive with results obtained when a mixture of the extract 

and Glibenclamide was administered. 

This study revealed that when 200mg/Kg concentration of the extract was used, it 

gave a better reduction in the glucose level than the higher concentrations of the 

extract. The results also obtained from a combination of Glibenclamide and extract 

sample showed large drop in the blood glucose level. This now concludes how the 


50


extract and its combination with existing diabetes drug can lead to better 

normalization of the glucose level. 

Key words: Anti-diabetics, Bryophyllum pinnatum, Blood glucose level, albino rats 

ANIMAL SELF-MEDICATION: A BIO-RATIONAL FOR DRUG DISCOVERY 

Michael A. Huffman, Primate Research Institute, Kyoto University 

Plant secondary metabolites (PSM) are traditionally viewed as the means by which 

plants inhibit or limit damage done to them by herbivores. This stimulated research 

into how animals are sometimes able to detoxify PSM in order to utilize the plant’s 

nutritional properties. Some herbivorous species also exploit PSM for their curative 

value, as humans traditionally do around the world. A growing body of research 

shows that primates ingest PSM for positive benefits, in particular for their 

therapeutic and passive preventative properties. A growing body of evidence for this 

comes from the emerging field of animal self-medication, particularly from the study 

of primates. Self-medication primarily take on three forms, ingestion of plants for 

their structural barriers to digestion (e.g. silicate) or bioactive / toxic properties and / 

or external application of PSMs. African great apes, and chimpanzees in particular, 

practice the first two forms in response to parasite infections. A substantial number 

of such plant species have been recorded and are also known to be traditionally 

utilized by some African cultures for the treatment of similar symptoms / diseases. 

New PSM have also been discovered which may have potential use for humans. 

Thirteen novel compounds and their biological activities have been discovered from 

the investigation of one species alone; Vernonia amygdalina. Other examples exist 

from research on a variety of wild and domestic animals species. Traditionally 

humans around the world have looked to animals as a source of medicinal wisdom. 

In this two pronged approach, natural products chemistry has much to benefit from 

the study of animal self-medication. 

PHYTOCHEMICAL PROFILE AND MOSQUITO LARVICIDAL ACTIVITIES OF 

THREE KOTSCHYA SPECIES. 

Innocent E, a* Kaale EA b , Mgeniwaho B b and Mbwambo ZK c 

a Department of Biological and Pre-clinical Studies, Institute of Traditional Medicine, 

Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es salaam 


51


b 

Department of Medicinal Chemistry, School of Pharmacy, Muhimbili University of 

Health and Allied Sciences, P.O. Box 65001, Dar es salaam 

c 

Department of Natural Products Development and Formulation, Institute of 

Traditional Medicine, Muhimbili University of Health and Allied Sciences, P.O. Box 

65001, Dar es salaam 

Due to resistance of mosquito vectors to chemical insecticides previously used, it is 

becoming necessary to identify safe, eco-friendly and effective alternative sources of 

larvicides in order to reduce mosquito menace. Previous studies have shown that 

polar extracts of Kotschya uguenensis show larvicidal & growth disruption 

activities of immature stages of Anopheles. In this study, it was hypothesized that, 

other Kotschya species may contain the responsible bioactive compounds in varying 

amounts. Hence need to compare the chemical profiles of the ethanolic root extracts 

of Kotschya uguenensis, K. speciosa and K. strigosa and conduct further studies on 

their mosquito larviciding properties. Reverse phase plates (Uniplate-HPTLC-RP8F uv 

254) were used for qualitative analysis of the crude extracts. The plates were 

developed and placed under a CAMAG TLC scanner 3 controlled by an external 

computer equipped with WINCAT software and scanned at UV 360 nm. 

Larvicidal assay against Culex quinquefascintus was done according to WHO 1996 

protocol. Higher activity was shown for the root extract of K. uguenensis attaining 

100% mortality on 4 th day at 500 and 250 g/ml. K. speciosa attained greater effect 

(≥ 45%) on 8 th day compared to K. strigosa ( ≤ 35%) especially at 250 g/ml. 

Densitometric evaluation revealed a presence of a common peak at RF 0.28 whose 

composition in Kotschya uguenensis, K. speciosa, and K. strigosa agreed with the 

trend of larvicidal results for the three plant species. This confirmed presence of 

similar bioactive compound responsible for larvicidal activity in the three extracts. 

However, further studies should be done to isolate, characterize and quantify this 

compound to know whether it works alone or in synergism with other compounds 

present in the extract. 

Key words: Kotshya uguenensis, K. strigosa, K. speciosa, Verbenaceae, Mosquito 

Larvicidal activities, HPLTC 


52


ANTI-PARASITIC ACTIVITY AND CYTOTOXICITY OF SELECTED MEDICINAL 

PLANTS FROM KENYA 

Elizabeth V.M. Kigondu a,b , Geoffrey M. Rukunga b , Joseph M. Keriko c , Willy K. Tonui d , 

Jeremiah W. Gathirwa b , Peter G. Kirira b , Beatrice Irungu b , Johnstone M. Ingonga d , 

Isaiah O. Ndiege e . 

a 

Institute of Tropical Medicine and Infectious Diseases (ITROMID), P.O. Box 54840, 

Nairobi 00200, Kenya 

b 

Center for Traditional Medicine and Drug Research, Kenya Medical Research 

Institute (KEMRI), P.O. Box 54840, Nairobi 00200, Kenya 

c 

Department of Chemistry, Jomo Kenyatta University of Agriculture and Technology 

(JKUAT), P.O. Box 62000, Nairobi 00200, Kenya 

d 

Center for Biotechnology Research and Development, Kenya Medical Research 

Institute, P.O. Box 54840, Nairobi 00200, Kenya 

e 

Department of Chemistry, Kenyatta University, P.O. Box 43844, Nairobi 00100, 

Kenya 

Extracts from 6 selected plant species, used as medicinal plants by indigenous local 

communities in Kenya, were screened for in vitro anti-plasmodial and antileishmanial 

activity, against 2 laboratory-adapted Plasmodium falciparum isolates 

(D6, CQ-sensitive and W2, CQ-resistant) and Leishmania major (IDU/KE/83 = NLB-144 

strain), respectively. The methanol extract of Suregada zanzibariensis leaves 

exhibited good anti-plasmodial activity (IC50 4.66 0.22 and 1.82 0.07µg/ml for D6 

and W2, respectively). Similarly, the methanol extracts of Albizia coriaria (IC50 

37.83 2.11µg/ml for D6) and Asparagus racemosus (32.63 2.68 and 

33.95 2.05µg/ml for D6 and W2, respectively) had moderate anti-plasmodial 

activity. Although the leishmanicidal activity of extracts were lower than for 

pentostam (80%), reasonable activity was observed for Aloe nyeriensis methanol 

(68.4 6.3%), Albizia coriara water (66.7 5.0%), Maytenus putterlickoides methanol 

(60.0 6.23%), Asparagus racemosus methanol and water (58.3 8.22 and 

56.8 6.58%, respectively), Aloe nyeriensis water (53.3 5.1%) and Acacia tortilis 

water (52.9 6.55%) extracts at 1000µg/ml. Leishmania major infected macrophages 

treated with methanol extracts of Suregada zanzibariensis and Aloe nyeriensis var 

kedongensis and Pentostam ® had infection rates of 28 2.11, 30 1.22 and 40 3.69%, 

respectively at 1000µg/ml, indicating better anti-leishmanial activity for the extracts. 

Multiplication indices for Leishmania major amastigotes treated with methanol 

extracts of Albizia coriaria, Suregada zanzibariensis and Aloe nyeriensis var 

kedongensis, aqueous extract of Acacia tortilis and pentosam were 28.5 1.43, 

29.4 2.15, 31.1 2.22, 35.9 3.49 and 44.0 3.27%, respectively, at 1000µg/ml, 


53


confirming better anti-leishmanial activity for the extracts. All extracts exhibited very 

low cytotoxicity (CC50 >500µg/ml) against human embryonic lung fibroblast (HELF) 

cells. The investigations demonstrated the efficacy and safety of some extracts of 

plants that are used by rural indigenous communities for the treatment of parasitic 

diseases. 

EVALUATION OF SOME TANZANIAN PLANT SPECIES AS SOURCES OF 

BOTANICAL LARVICIDAL FOR ANOPHELES GAMBIAE GILES S.S 

Charles Kihampa 1 , Cosam C. Joseph 2 , Mayunga H.H. Nkunya 2 , Stephen Magesa 3 , 

Ahmed Hassanali 4 , Matthias Heydenreich 5 and Erich Kleinpeter 5 

1 

School of Environmental Science and Technology, Ardhi University, Tanzania 

2 Department of Chemistry, University of Dar es Salaam, Tanzania 

3 

Amani Research Centre, National Institute for Medical Research, Tanzania 

4 

International Centre of Insect Physiology and Ecology (ICIPE), Kenya 

5 Institut für Chemie, Universität Potsdam, Germany 

In many isolated areas of the world indigenous people have historically relied on 

locally sourced natural plant-based remedies to kill, repel or prevent biting insects 

entering their homes. Although synthetic insecticides ruled the plant protection 

scene, their replacement either partially or totally is now considered a necessity 

because of the adverse effects associated with their use. This presentation will give 

detailed mosquitocidal properties of some Tanzanian plant species. Extracts from 

those plant species and different fractions thereof were compared for their 

immediate toxicity and longer-term effects on Anopheles gambiae Giles sensu stricto 

(Diptera: Culicidae). Larvicidal effects of the extracts appeared to be associated with 

components of low polarity extracted by pet ether and chloroform than those of 

high polarity extracted by methanol. Farther investigations that are needed and 

possible use of the results in terms of development of larval control strategies for 

malaria vectors are discussed. 

Keywords: Botanical mosquitocides; Anopheles gambiae s.s.; igr activity 


54


UNUSUAL SESQUITERPENE KETONE FOUND IN THE ESSENTIAL OIL OF 

CYPERUS DISTANS L. (CYPERACEAE) FROM SOUTH AFRICA 

Oladipupo A. Lawal 1 , Adebola O. Oyedeji 1 and Andy R. Opoku 2 

1 

Department of Chemistry, University of Zululand, KwaDlangezwa 3886, South 

Africa 

2 

Department of Biochemistry & Microbiology, University of Zululand, KwaDlangezwa 

3886, South Africa 

ladilawal@hotmail.com 

The essential oil from the rhizomes of Cyperus distans growing wild in KwaZulu-Natal 

Province, South Africa was obtained by hydrodistillation and analyzed by GC and 

GC/MS for the first time. Twenty-three constituents were identified, representing 

88.4% of the oil composition. The chemical profile of the oil was very different from 

the essential oils of several species of the genus Cyperus, with little amount of 

cyperene (3.1%) detected. The most interesting feature of the oil was the presence 

of an unusual and rarely occurring sesquiterpene ketone, zierone (33.9%). 

Keywords: Cyperus distans, Cyperaceae, essential oil composition, zierone. 

ANTI-PROTOZOAL CONSTITUENTS OF ACRIDOCARPUS CHLOROPTERUS 

OLIVER 

Hamisi M. Malebo 1,2,4,5 , Wenzler Tanja 2 , Monical Cal 2 , Sauda M. Swaleh 1 , Maurice O. 

Omolo 3 , Ahmed Hassanali 4 , , Urs Séquin 5 , Daniel Häussinger 5 , Petur Dalsgaard 6 , 

Matthias Hamburger 6 , Reto Brun 1 , Isaiah O. Ndiege 1 

1 

Department of Chemistry, Kenyatta University, P.O. Box 43844, Nairobi, Kenya. 

2 

Medical Parasitology and Infection Biology, Parasite Chemotherapy Unit, Swiss 

Tropical Institute, University of Basel, Socinstrasse 57, CH-4002, Basel, Switzerland. 

3 

Department of Physical Sciences. Masinde Muliro University of Science & Technology, 

P. O. Box 190, Kakamega, Kenya 

4 

International Centre for Insect Physiology and Ecology, P.O. Box 30772, Nairobi, 

Kenya. 

5 

Institute of Organic Chemistry, University of Basel, St Johanns Ring 19 , CH-4052, 

Basel, Switzerland. 

6 

Institute of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50 , CH- 

4056, Basel, Switzerland. 


55


Protozoal diseases like malaria, trypanosomiasis and leishmaniasis caused by 

Plasmodium, Trypanosoma and Leishmania, respectively, have overwhelming impact 

on public health in developing regions. Due to their prevalence, virulence and drug 

resistance, they are the most serious and widespread parasitic diseases encountered 

by mankind. The inadequate armory of drugs, high cost and lack of new drugs are 

the major limiting factors in the fight against the 3 diseases. Consequently, there is 

continuing need of research on the discovery and development of new effective and 

safe anti-protozoal drugs. In this work, extract from Acridocarpus chloropterus was 

tested for its anti-protozoal activity. Anti-protozoal bioassays revealed inactivity. 

Chromatography of A. chloropterus extract led to the isolation and identification of 5 

triterpenes: β-sitosterol (1), stigmasterol (2), friedelin (3), oleanolic acid (4), ursolic 

acid (5); and 5 flavonoids: apigenin (6), luteolin (7), vitexin (8), kaempferol (9) and 

quercetin (10). Quercetin (10) exhibited moderate in vitro anti-plasmodial activity 

(IC50 2.6+0.05 μg/ml) while the rest of compounds were inactive. Mild to weak in 

vitro anti-trypanosomal activity was observed in quercetin (10) (IC50 3.60+0.00001 

μg/ml), ursolic acid (5) (IC50 7.80+0.0001 μg/ml) and apigenin (6) (IC50 9.0+0.00001 

μg/ml). Good in vitro anti-leishmanial activity (IC50 0.80+0.00001, 2.10+0.00001, 

2.20+0.00001, 5.90+ 0.0001 and 3.5+0.00002 μg/ml) and favourable selectivity were 

observed in ursolic acid (5), quercetin (10), kaempferol (9), apigenin (6) and oleanolic 

acid (4), respectively. SAR comparisons in the isolated triterpenoids confirmed that, 

the OH at C-3 with, 23-CH3, 25-CH3, 26-CH3, C-12/C-13 double bond, 28-CO2H, H-20 

and 30-CH3 in the molecular framework of ursolic acid (5) are the structural motifs 

responsible for the strong anti-leishmanial activity whereas in the isolated 

flavonoids, the 3-OH and 3′-OH in the apigenin (6) molecular framework are the 

structural motifs responsible for the observed strong anti-protozoal activity. The 

strong to moderate anti-leishmanial activity of the isolated triterpenes and 

flavonoids render them good candidates as molecular templates for SAR studies 

which could lead to new drug development. 


56


IN VIVO EFFICACY OF ORAL AND INTRAPERITONEAL ADMINISTRATION 

OF EXTRACTS OF WARBURGIA UGANDENSIS (CANELLACEAE) IN 

EXPERIMENTAL TREATMENT OF OLD WORLD CUTANEOUS 

LEISHMANIASIS CAUSED BY LEISHMANIA MAJOR 

Peter Kamau 1 , Zipporah Ng’ang’a 3 , Johnstone Ingonga 2 and Geoffrey Rukunga 2 and 

Willy Kiprotich Tonui 2 

1 Daystar University, Science department, P.O. Box 44400, 00100, Nairobi. 2 Kenya 

Medical Research Institute. 

3 Jomo Kenyatta University of Agriculture and Technology. 

*E-mail: ngure2001us@yahoo.com 

The antileishmanial activity of extracts of Warburgia ugandensis Spraque 

(Canellaceae), a known traditional therapy in Kenya was evaluated in vivo. Treatment 

of infected BALB/c mice with W. ugandensis extracts orally resulted in a reduction of 

the size of lesions compared to the untreated control. The lesion sizes differed 

significantly for the four extracts (p=0.039) compared to the untreated control. For 

mice treated by intraperitoneal injection, the lesion sizes increased initially for the 

hexane, dichloromethane and ethyl acetate extracts and healed by day 42. The 

lesion sizes for mice treated with methanol extract increased steadily from 2.47mm 

to 3.57mm. The parasitic burden was significantly higher (p


ANALYSIS OF NUTRITIONAL AND PHARMACOLOGICAL STATUS OF 

SELECTED PLANTS USED FOR TREATING HIV/AIDS AND OPPORTUNISTIC 

INFECTIONS IN EASTERN UGANDA 

Cyprian Osinde, Maud Kamatenesi Mugisha and Hannington Oryem-Origa 

DEPARTMENT OF BOTANY MAKERERE UNIVERSITY. P.O.BOX 7062, KAMPALA 

UGANDA. 

osindecyprian@yahoo.co.uk 

This paper presents an inventory of medicinal and nutritional plants used in 

treatment of opportunistic infections for HIV/AIDS patients and their mode of use, 

parts of plants used and the management status of these plants. People use herbs 

as food to treat opportunistic infections and this is reflected by the number of herbs 

mentioned. Sixty five species of plants belonging to sixty three genera and forty 

three families were mentioned. Plants used as medicine are in the categories of wild, 

indigenous, shrubs, cultivated, introduced, herbs, trees and lianas. The plant parts 

most frequently used for treating opportunistic infections due to HIV/AIDS are 

leaves, bark, and roots. Medications are mostly prepared as infusions, decoctions 

and topical applications. Some selected plants were analyzed for nutrients and they 

showed a variety of nutrients ranging from proteins, fibers and minerals. A 

comparative study on the antibacterial activities of the extracts was also done on 

Escherichia coli (ATCC 25922), Pseudomonas auriginosa (ATCC 27853) and 

Staphylococcus aureus (ATCC 25923). All the plant extracts were found to have 

considerable activities against the test organisms by use of the agar well diffusion 

assay. They showed inhibition zones ranging from 3.5mm to 20.1mm. Their MIC 

values were determined by use of serial dilution method and it ranged from 

0.0009g/ml to 0.125g/ml. 


58


IN VIVO ANTIVIRAL AND LARVICIDAL POTENCY OF URSANE 

TRITERPENOIDS AND A GARLIC ACID DERIVATIVE FROM TOUSSAINTIA 

PATRICIAE 

*Samwel, S., Nkunya M.H.H., Joseph, C.C., Innocent E. and Msoffe, P.L.M 

Department of Chemistry, University of Dar es Salaam, P.O.Box 35061, Dar es 

Salaam, Tanzania. 

Tel: +255 22 2410038 

Mobile +255 754 206 560 or +255 718 944 724 

Fax: +255 22 2410038 

E-mail: samwel@chem.udsm.ac.tz or samnyandoro@yahoo.com 

Ursolic acid, its two hydroxylated derivatives as well as garlic acid derivative (ethyl 

3,4,5-trihydroxybenzoate) isolated from the leaves of Toussaintia patriciae 

(Annonaceae) exhibited in ovo antiviral potency against Newcastle Disease Virus 

(NDV) and (IBDV) at 360μg/mL. The three ursane triterpenoids also exhibited 

larvicidal activity against Anophelese gambiae mosquito larvae at their late 3 rd and 

early 4 th instar whereas the garlic acid derivative was inactive up to 50μg/mL. The 

larvicidal LC50 values will be presented in the results and discussion section. The 

structural determination was achieved based on the spectroscopic data. 

Key words: Ursane triterpenoids, garlic acid derivative, antiviral, larvicidal, 

Toussaintia patriciae. 

IN VITRO ANTILEISHMANIAL ACTIVITY OF EXTRACTS OF WARBURGIA 

UGANDENSIS (CANELLACEAE), A KENYAN MEDICINAL PLANT 

*Willy Kiprotich Tonui 1 , Peter Kamau Ngure 2 , Johnstone Ingonga 1 , Charles Mutai 1 , 

Elizabeth Kigondu 1 , Zipporah Ng’ang’a 3 ,Geoffrey Rukunga 1 and Albert Kimutai 1 . 

1 

Center for Biotechnology Research and Development, Kenya Medical Research 

Institute, Nairobi, Kenya 

2 

Daystar University, Science department, P.O. Box 44400, 00100, Nairobi, Kenya 

3 

Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya 

*Email: wtonui@kemri.org 

The antileishmanial activity of extracts of W. ugandensis (Family Canellaceae), a 

known traditional therapy and one of the commonly used medicinal plants in Kenya 

was evaluated. We tested extracts of this plant for possible antileishmanial activity in 

vitro. Different doses of hexane, dichloromethane, ethyl acetate and methanol 


59


extracts of W. ugandensis were tested against Leishmania major and Leishmania 

donovani promastigotes and amastigotes. The hexane extract had the best activity 

against L. major promastigotes and amastigotes with IC50 value of 9.95 for 

promastigotes and 8.65 for amastigotes and minimum inhibition concentrations of 

62.5 µg/ml. The activity of the hexane extract on amastigotes was comparable 

(p>0.05) to that of pentostam and amphotericin B. Similar results were obtained for 

L. donovani with IC50 values of 8.67 for promastigotes and 100-fold reduction of 

amastigotes in macrophage cultures. Warburgia ugandensis had lower levels of 

toxicities compared to pentostam and amphotericin B. This study scientifically 

demonstrates the potential of W. ugandensis in the treatment of leishmaniasis. 

Key words: Warburgia ugandensis; Leishmaniasis; Promastigote; Amastigote 

INNOVATION SYSTEMS AND CLUSTER APPROACHES FOR 

EXPLOITATION OF THE INDIGENOUS AND EXOTIC EDIBLE AND 

MEDICINAL MUSHROOMS OF THE LAKE VICTORIA BASIN 

Olila, D., Kabasa, JD., Kisovi, L., Engola, A. and Munishi, PKT 

* Department of Veterinary Physiological Sciences, 

Makerere University, 

P.O. Box 7062, Kampala 

olilad@vetmed.mak.ac.ug 

Mushrooms are used as food and medicine in many societies. They are also of 

considerable biotechnological value and important nutraceuticals, particularly in 

immuno-compromised patients (e.g. HIV cases). However, the nutritional, ecological, 

medicinal and biotechnological importance of indigenous Ugandan mushrooms are 

not adequately studied and documented. 

Faced with poor and rapidly growing population in Uganda, the competition for 

natural resources by different producer groups is increasing. Expansion of crop and 

animal production has adverse effects on the environment. There is increasing 

pressure on land, leading to loss of indigenous mushroom bio-diversity without 

understanding their contribution to present and future generations. 

This paper will present some data on characterisation of indigenous mushroom 

ecology, their cultivation, indigenous knowledge, domestication and assessment of 

their potential as sources of nutrients, novel antibiotics and metabolites for 


60


improved health and socio-economic benefits. The information was gathered 

through reconnaissance surveys, participatory appraisals and standard laboratory 

techniques involving assessment of nutritional and pharmacological potential. 

Innovation systems and cluster approaches are presented as a way forward to 

maximise exploitation of the indigenous African mushroom biodiversity. This is 

because today, economic development policies that target individual firms or 

industries are no longer the most viable option for regions. Cluster development has 

gained considerable attention over the past decade, as an operational means to 

systematically enhance the competitiveness of regions. The new economy of clusters 

has to do with speed, quality, flexibility, innovation, networks, and building critical 

mass. This new style demands a team approach at local level, a clustering approach. 

This clusters approach is the missing link in the indigenous mushroom industry in 

Africa. It is only through developing of viable clustering that even small firms are able 

to gain the necessary critical mass to service world markets. 

PHYTOCHEMICAL ANALYSIS OF COMMIPHORA HOLTZIANA OLEO-GUM 

RESIN 

Sylvia A. Opiyo 1 , Lawrence O. A. Manguro 1 , Peter Lemmen 2 and Eberhardt Herdweck 3 

1 

Maseno University, Department of Chemistry, P. O. Box 333, Maseno, Kenya 

2 

Technical University Munich, Institute of Organic Chemistry and Biochemistry, 

Lichtenbergstrasse 4, 85747- Garching, Germany 

3 

Technical University Munich, Institute of Inorganic Chemistry, Lichtenbergstrasse 4, 85747- 

Garching, Germany 

sylvopiyo@yahoo.com 

An investigation on the acetone extract of Commiphora holtziana gum resin yielded eleven 

known compounds namely cabraleadiol monoacetate, mansumbinol, 3β-acetylamyrin, 3αacetylboswellic 

acid, 2-methoxy-8,12-epoxygermacra-1(10),trine-6-one, 2-methoxy-5acetylfuranogermacra-1(10),7,11-trien-6-one, 

furadienone, 2-methoxy-5-acetyt-4furanogermacra-(10) 

Z-en-6-one, α-amyrin, sitosterol and stigmasterol together with four 

new triterpenes characterized as methyl 3-oxo-1α,19α,28-trihydroxyurs-12-en-24-oate (1), 

methyl 3β-acetyl-2α,11α,19α,28-tetrahydroxyurs-12-en-24-oate (2), methyl 3β,11α-diacetyl- 

1α,2α,28-trihydroxyurs-12-en-24-oate (3) and 3β,28-diacetyl-1α,2α,25-trihydroxydammar- 

23-ene (4).The structures were determined using spectroscopic and physical methods as 

well as by comparison with data from the literature. 

Keywords: Commiphora holtziana; Burseraceae; triterpenes; gum-oleo-resin exudates. 


61


INTERSPECIFIC CHEMICAL SIGNALS INFLUENCING OVIPOSITION BY THE 

MALARIA MOSQUITO, ANOPHELES GAMBIAE 

Sabina W. Wachira 1,2 , Mary Ndung'u 3 , P.G. N. Njagi 1 and Ahmed Hassanali 1,4 

1 

International Centre of Insect Physiology and Ecology (ICIPE), PO Box 30772-00100, 

Nairobi, Kenya: 

2 

Kenya Medical Research Institute (KEMRI), PO Box 54840-00200, Nairobi, Kenya 

3 

Department of Chemistry, Jomo Kenyatta University of Agriculture and Technology, 

PO Box 62000, Nairobi, Kenya 

4 

Chemistry Department, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya. 

Email: swachira@kemri.org 

Gravid Anopheles gambiae Giles makes a choice of an appropriate oviposition site. The 

presence of Culex quinquifasciatus in an oviposition site influences gravid An. gambiae 

decision to oviposit at a specific site or not. The effect of volatiles emanating from varying 

numbers of egg rafts and/or larvae of C. quinquifasciatus in relation to oviposition by An. 

gambiae was evaluated using double cup oviposition assay. The oviposition response had 

various patterns depending on the number of egg rafts and/or larvae used in test water. 

Oviposition was observed to increase in the presence of C. quinquifasciatus egg rafts at low 

density. At increased density the oviposition activity index decreased to negative value. The 

presence of C. quinquifasciatus larvae deterred the oviposition by gravid An. gambiae even 

at low density. However when both Culex quinquifasciatus larvae and egg rafts were used 

with varying density of egg rafts and constant number of larvae the deterrent was more than 

when the two were used separately. 

Key words: Anopheles gambiae, Culex quinquifasciatus, oviposition, egg rafts, larvae, 

deterrence. 

LEAF-SURFACE DEPOSITED COMPOUNDS AS ALTERNATIVE ANIMAL 

FEED PRESERVATIVES 

*Onemus M. Wanjau a , Simon M. Mahungu b , and Richard W. Mwangi c 

a Department of Chemistry, Egerton University 

b Department of Dairy and Food Science, Egerton University 

c Department of Zoology, University of Nairobi. 

owanjau@yahoo.com 


62


The presence of an array of secondary metabolites in the leaf-surface exudates has 

elicited phytochemical screening. The constituent compounds, supposedly, serve a 

protective role on the plant lipids against autoxidation occasioned by UV radiation. 

Some flavonoids, Polsen 1, Polsen 3 and Polsen 5, isolated from the leaf-surface 

exudate of Polygonum senegalense were investigated for antioxidant effect on 

edible oils, heated to about 200 0 C. Polsen 1 enhanced the induction period and thus 

could be used as an animal feed additive for the purpose of retarding oxidative 

destruction of the naturally occurring carotenes and vitamin E in animal feeds. 

One compound (Polsen 5) showed a cytotoxic effect against a mammarian cell-line, 

Chine Hamster Ovarian (CHO), using the 3-(4,5-dimethylthiazol-2yl)-2,5diphenyltetrazoliumbromide. 


63


GREEN CHEMISTRY WORKSHOP 

SPONSORED BY THE PAN AFRICAN CHEMISTRY 

NETWORK (PACN) 


64


GREEN CHEMISTRY AND METAL COMPLEXES/MATERIALS 

Neil Coville 

University of Witwatersrand, Johannesburg 

Neil.Coville@wits.ac.za 

Green Chemistry is a philosophy at how to approach a chemical problem. It is 

possible to use the ‘12 Principles of Green Chemistry’ (and also Green Engineering) 

to evaluate whether a reaction is more ‘green’ than other approaches. In this talk 

two aspects relating to the synthesis of, mainly inorganic compounds, will be 

discussed. The one issue will relate to the topic of solventless/solvent-free 

chemistry; the other to the use of ‘green’ principles in making nanomaterials. 

GREEN CHEMISTRY: A TOOL FOR ENVIRONMENTAL POLLUTION 

PREVENTION CAUSED BY CHEMICAL MANUFACTURING 

PROCESSES 

Joseph M. Keriko 

Jomo Kenyatta University of Agriculture and Technology,Nairobi, Kenya 

kerikojm@yahoo.co.uk 

Green chemistry is a particular type of pollution prevention that has solutions to 

the current global warming problems. It is an approach that provides a fundamental 

methodology for changing the intrinsic nature of a chemical product or process so 

that it is inherently of less risk to human health and the environment. 

Green chemistry involves the design and redesign of chemical syntheses and 

chemical products to prevent pollution and thereby solve environmental problems. 

It is therefore, a particular type of pollution prevention. 

Synthetic chemists, those who design new chemicals and their manufacturing 

processes, have not been particularly environmentally conscious. This is primarily 

due to the fact that they are at the beginning of the process, identifying ways to 

make chemicals, while the problems have traditionally been identified with the end 

of the process, the waste stream. Thus, the role of synthetic chemists has 

historically been to design synthetic pathways to produce target molecules for the 

least cost in the greatest yield. However, synthetic chemists should play a more 

central role in developing Green chemical methods for pollution prevention rather 

than end-of-pipe control. 


65


In this paper therefore, I will discuss the current global ecological footprint 

situations, introduction to green chemistry, tools and the principles of green 

chemistry. The role that chemists need to play in preventing environmental 

pollution based on the Green chemistry methods will also be mentioned. 

THE SEARCH FOR GREEN CATALYSTS 

Egid B. Mubofu 

University of Dar es Salaam, Chemistry Department, P. O. Box 35061, Dar es Salaam, 

Tanzania 

mubofu@chem.udsm.ac.tz or ebmubofu@yahoo.co.uk 

The importance of catalysis makes it one of the most intensely studied and pursued 

field in both chemical engineering and applied chemistry. The development and 

advancement of catalysis holds the key for improvement of economic, 

environmental and for the sustainability of the world. The use of principles of Green 

Chemistry on the design of chemical products and processes puts catalysis as one of 

the cornerstone of pollution prevention by design. This presentation gives a brief 

description of green chemistry in relation to design of products and sustainability. 

The clean technology pool and the green chemical technologies and hot spots are 

briefly introduced. This is followed by examples of various catalysts that have been 

designed based on green chemical technologies and hot spots. These catalysts are 

mostly chemically anchored onto the surface of micelle templated silica (MTS) 

support. Some examples of atom economy and green chemistry matrix drawn from 

other workers are given so as to illustrate the concept. The supported catalysts have 

been tested on Heck, Suzuki, epoxidation of norbonene, oxidation of maleic acid and 

enzyme catalysed reactions. The paper concludes by giving the key messages about 

the importance of green chemistry for sustainable development. 


66


GREEN CHEMISTRY PARADIGM: THE ROLE OF NATURAL PRODUCTS 

Jacob O Midiwo, Joe Mwaniki, Isaac Chogii, Leonidah Kerubo, Bernard Juma 

Department of Chemistry, University of Nairobi, P. O. Box 30197, Nairobi. 

jmidiwo@uonbi.ac.ke 

The world is going green and chemists are being asked to ‘shift’ their thinking to 

Green Chemistry for sustainable development- design processes that ‘--- meet the 

needs of the present without compromising the ability of the future generations to 

meet their own needs’. To give guidelines on sustainability, the 12 principles have 

been enunciated by Paul Anastas and John Warner; the seventh principle says - “a 

raw material should be renewable rather than depleting whenever technically and 

economically practicable”. Certain natural products provided in large amounts by 

higher plants and fungi secondary metabolism should be highlighted as raw 

materials for synthesis (structural modification) of fine chemicals such as drugs and 

other biologically active products to propagate green. 

Many plant species scattered amongst different plant families produce in large 

amounts what may be referred to as surface exudates- non polymeric organic 

molecules that seem to have protective function to the plants. These exudates in the 

aerial parts have functionality that make them attractive to be considered as green 

synthons. Examples of surface exudates plants studied (Polygonum senegalense, 

Psiadia punctulata, Dodonaea angustifolia, Senecio roseiflorus) for quantities of 

exudates and structural diversity will be given in this lecture; structural derivatisation 

of the natural compounds for activity optimization, in certain cases, under green 

conditions will be alluded to. Other examples of plants with high yielding potential 

sources of starter compounds will also be mentioned. 


67

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