r xwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA PHYTOCHEMISTRY PERGAMO Phytochemistry 60 (2002) 315-379 www.elsevier.com/locate/phytochem Flavonoids from dcbaZYXWVUTSRQPONMLKJIHGFEDCBA T e p h r o s ia a e q u ila ta Paul K. Tarus, Alex K. Machocho, Caroline C. Lang'at-Thoruwa, Sumesh C. Chhabra* C h e m is tr y D e p a r tm e n t, Received K e n v a tta U n iv e r s ity , 29 May 200 I: received PO Box 4 3 8 4 4 . N a ir o b i. in revised form 7 February K enya 2002 Abstract From the roots of the plant T e p h r o s ia a e q u ila ta Baker, five flavonoids were isolated of which. 3.4:8,9-dimethylenedioxyptero- carpan is reported for the first time. Its structure and those of the already known flavonoids were established by physical and spectroscopic analysis. Application of 2D NM R techniques was useful for complete characterization of the new pterocarpan as well as the other known flavonoids. K e y w o rd s : 9 2002 Elsevier Science Ltd. All rights reserved.aZYXWVUTSRQPONMLKJIHGFEDCBA T e p lir o s ia a e q u ila ta : Papilionaceae: A : Praecansone B : Z-Praecansone Roots: Parasitic A : Demethylpraecansone protozoa; Antimicrobial activity; 3.4:8.9-Dimethylenedioxypterocarpan: I. Introduction T e p lir o s ia (Papilionaceae) is a large genus of perennial woody shrubs, which are well distributed in the tropical and sub-tropical regions of the world (Gillet et al.. 1971). Between 300 and 400 species are known (Willis. 1973). of which 35 occur in India. 30 are native to South America. 70 are found in South Africa and 50 in equatorial Africa of which 30 are found in Kenya (Chadra. 1976: Allen and Allen. 198 \: Beentje. 1994). Some of the species have been used in herbal remedies. insecticides and rat. fish and human poisons by the various indigenous people of Kenya (Gillet et al.. 1971: Watt and Breyer-Brandwijk. 1962). Phytochemical studies have been carried out on the roots of some species. For example. ~:le roots of T . e m o to id e s A. Rich .. yielded 4".5" -dihydro-5-methoxy-5" -is o phenylfurano-[2".3".7.8]-ftavanone which showed insect antifeedant activity against the larvae of stalk borer. C h i/h ) p a r te llu s (Machocho et al., 1995). The roots of T . h ik le h r a n d tii Vatke yielded a pterocarpan. hildecarpin which exhibited antifeedant activity against the legume pod-borer. M aruca te s tu la lis (Lwande et al .. 1986). T . in te r r u p t a Engl. and T . lin e a r is (Willd.) Pers. both yielded various rotenoids including deguelin and rotenone (Were. 1988). There has been no phytochemical T e p h r o s ia investigation of T . a e q u ila ta . The roots of T . a e q u ila ta are u ed to treat venereal diseases and the leaves to relieve abdominal pains (Kokwaro, 1993: Gillet et al., 1971). In the present investigation. five ftavonoids were isolated from the petrol (bp 40--60 0C) extract of the roots of T . a e u u ila ta . The ptcrocarpan, 3.4:8.9-dimethylenedioxypterocarpan (I) is reported for the first time. The p-oxygena ted chalconcs. praecansone A (2) and praecansone B (3) have been reported earlier from T . p r a e ( '( fI7 .1 ' Brummitt (Camcle et al., 1980), T . p r o c u m b e n s (Venkauuumum et al.. 1987) and T . p u m ila Lam. (Dague ct al., 19X8: Yencsew et al.. 1989). The Z-isomer of praecansonc A (4) is also reported as a plant metabolite while demethylpraecansone A (5) was reported previously from L o n c lio c a r p u s c o s ta r ic e n s is Pittier (Waterman and Mahmoud. 1985). 2. Results and discussion The five flavonoids were isolated from the petrol (bp 40-60 C) extract of the roots by a combination of chromatographic techniques followed by crystallization. The lH NMR spectral data of 1 (Table I) suggested a ptcrocarpan structure due to the splitting pattern of the protons the heterocyclic ring B and the bridging protons or Band C rings (Maximo and Lourenco, 1998; Muchocho ct al .. 1005: Pachler and Underwood. 1967). The shirts appeared at <'\ 5...D d . 4.23 d d . 3.64 t and 3.45 or • Corresponding X 11224. T :- /lllIil l I i / i / I ', . . I . I : .uuhor. scchhuhru Tcl.: "254-2-~1()9()1: " avu.org ( S .c . Chhubra). fax: Praecansone B -2~4-2- P .K . T a r u s 376dcbaZYXWVUTSRQPONMLKJIHGFEDCBA e t a l. I P h y to c h e m is tr y xwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHG 6{) o o o » 375-379 VUTSRQPONMLKJIHGFEDCBA 0 H 0 > H 1 H H H H :2 II OMeO 1 ,,0 7 I' H ~4 # 0 5 6 #8 H 9 OMe 0 OMe OMe 3 2 H I >/~r' ~ 0 OMc o H TY H ::::::...... ::::::...... / H II OMI! OMI! 1/ I 0 O;.,\C 4 0 5 0" k id . which were assigned to H-Ila. l-l-oax. H-6eq and pairs mct hv lcncdioxy protons showed 3-bond corre-1-6a. respectively. The spectrum exhibited lour urolation in the 1-1M BC spectrum with their respective aroprotons in nuuc protons in which the [\\'0 adjacent matic c.uhon .uorns. iositions I and "2 appeared at .5 6.96aZYXWVUTSRQPONMLKJIHGFEDCBA d and 6.55 d . The I 'c '\\1 R spectral data of I (Table I) indicated ·espcctivcly. with ./ values of 8.1 Hz on the tetra-sub17 c.nhon .u oms and was in agreement with the pro.titutcd ring A. The other two !I({m-oriented signal at 8 posed < t ruct urc. The HMQC and HMBC spectra con>.66.1' and 6.37.1' were assigned to protons of positions 7 firmed s tru c tu re 1 1 '0 1 ' the new pterocarpan. The HMQC II1d 10. respectively. on ring D . The assignment or these spectrum prov idcd the assignment of the protonated arom.uic c.ubons a~ follows: .5 123.5 (C-I). /02.1 (C-2). ets of aromatic protons was supported by the R O E S '\' 10-1-.1 ( ( ,- 7 ) and l)3.3 (C-IO). The protonated carbons of pectrum. whereby H-I showed spatial contours with the heterocyclic rings were observed at .5 77.6 (C-Ila). -I-II a and H-2. and H-7 with H-6a.\. H-6eq and H-6a. ()().() (('-il) and .;LJ.()(C -ou). which compared closely with ihese assignments were supported by 3-bond corrc.uion in the HMBC spectrum. The two sets ofuronuuic lircr.uurc v u lu c (\Li.\imo and Lourenco. 1998: Lwandc ct . i l.. /'):--(11. lhc mcihylcncdioxy carbons appeared at8 irot ons suggested the placement of (he two mcihv lcnclil)'\;' groups at S ~.}\-1- (2 1 1 . . / = 1.5 Hz) and 5.lJ.i \ at 1() 1.2 .uid 1(1 (1 . -. The quaternary aromatic carbons \\'CrC Il)~itions -'.-1-and X.LJ.respectively. Additionally. the tw o :1"lgnL'd \\ u h the help of the HMBC spectrum. The I.I\.. llAlt-IJI;.' u:1.!'"}'V ••... ' ••..•••••.•••. ! "''' ,_ _/ _. __ " xwvutsrqponmlkjihgfedcbaZYXWVUTSRQPO proton at position 8 (H .« ) with the methoxyl group at position 9 in 4. The lH NMR spectra of 4 showed the signal of H-8 (H .« ) appearing at a 6.03 which seems to Correlated C-atom have moved upfield compared to a similar proton in 2 IHNMR HMQC HMBC aZYXWVUTSRQPONMLKJIHGFEDCBA 'rolOn while in the l3C NMR, the C-8 signal has moved down ( J in Hz) field to 8 104.8. It therefore appears that 4 is the Z-isoC-lla. C-4a. C-3 1 2 3 .5 d mer of praecansone A (2) when compared to the lH 6 .9 6 d ( 8 .1 ) C-Ilb. C-4 1 0 2 .1 d 6 .5 5 d ( 8 .1 ) NMR and l3C NMR data of the ~-methoxychalcones 143.0 s (C-3) (Kiuchi et aI., 1990). The ElMS spectra of 2 and 4 had 143.3 s (C-4) [M]+ at m ]z 380 for C 23 H 240 S. The base peaks at m ]z 166.8 s (C-4a)VUTSRQPONMLKJIHGFEDCBA 349 represented lose of methoxyl groups. A peak at m ]z 6 6 .0 dcbaZYXWVUTSRQPONMLKJIHGFEDCBA t 4 .2 3 d d i (eq) C-Ila, C-6b. C-4a (10.8. 5.1) 365 in both compounds suggested loses of methyl i (ax) 3.64 I (l0.8) 6 6 .0 t C-lla, C-6b. C-4a groups from the molecular ions. 3 .4 5 d d d 3 9 .6 d C-ll b, C-lOa ia In vitro biological activity tests against parasitic pro(10.8,6.9,5.1) tozoa were performed on the isolated flavonoids. Com117.0 s (C-6b) pounds 3 and 5 showed low activity against T r y p a n o s o m a 1 0 4 .1 d C-IOa. C-9. C-6a 6.66 s 1 4 8 .3 s (C-8) b r u c e i r h o d e n s ie n s e (strain STIB 900, stage trypomasti1 4 8 .3 s (C-9) gotes) with IC so 5.9 and 5.1 11 ml, respectively, and 9 3 .3 d C-8, C-6b 10 6.37 s T rypanosom a c r u z i (strain Tulahuen C4, stage trypo160.0 s (C-I Oa) mastigotes) with IC 7.6 and 6.0 Ilg/ml, respectively. 50 7 7 .6 d 5 .4 3 d ( 6 .9 ) lla C-IOa, C-6b. C-4a The compounds exhibited no cytotoxicity towards L-6 1 1 4 .8 s (C-llb) C-3, C-4 3.4-0CH cO5.S4d(I.5) 100.7 I cells and macrophages but showed considerable activity 101.2 I 3.9-0CH cO5 .9 3 s C-9, C-8 against L e is h m a n ia donovani (strain MHOM-ET-67, stage amastigotes) with at IC so values 17.2 and 9.0 The carbon multiplicities were determined by DEPT data. 2 and 4 exhibited no Ilg/ml. respectively. Compounds activity against any of the parasitic protozoa or against P la s m o d iu m [ a lc ip a r u m (strain K I and NF54, stages mass spectrum of 1 showed an [M]+ at m ] : 312 for IEF). C'7H'206 thus confirming the above deductions based on NMR data analysis. Compounds 1-3 exhibited low activity against gramThe 'H NMR and I3C NMR spectra of 2 are similar positive bacteria. B a c illu s s u b tilis and M ic r o c o c c u s lu te a and 4 and 5 even less activity (~8 mm). Compound 3 to those of praecansone A which had earlier been reported from T . p r a e c a n s as praecansone A (Camele et showed an inhibition zone of II and 13 mm against B . aI., 1980), and later the structure was revised by Oagne s u b tilis and M . h i/e a . respectively. The crude petrol (bp et al. (1988). Compounds 2 and 4 had different physical 40-60 C) extract was inactive against the gram-negaand chromatographic properties but had closely related tive bacteria. E s c h e r ic h ia c o li and P s e u d o m o n a s a u r UV and NM R spectral data. The' H NM R spectra of 2 e g in o s a when tested at I00 ~lg/disk while 5 showed some and 4 were similar with minor variations. Each comactivity (inhibition zone = 10 mm) against these bacpound had three sets of methoxyl groups, two isolated teria. The other compounds showed slight or no activity protons, and unsubstituted benzene ring and a dimethyl against the gram-negative bacteria. The compounds chromene ring as the prenyl substitution. In the 'H were not active against the fungus, A s p e r g illu s n ig e r and the yeast. S a c c h a r o m v c e s c e r e v is ia e . The antibacterial NM R of 2 the olefinic signal at 8 6.44 for H-8 (H-cx) activities of these tlavonoids were much lower than showed ROESY contours with H-2 or H-6 of the those observed for . he standard antibiotics especially unsubstituted benzene ring and one of the methoxyl cotrimoxazolc. streptomycin. kanamycin, gentamycin groups at 8 3.86. which was assigned to position 9. This and chloramphenicol. implied that this particular methoxyl group was in the tr a n s -o r ie n ta tio n with respect to the hydrogen. One of the other methoxyl groups at 8 3.72 showed a spatial correlation with H-4" signal at 8 6.50 and this was 3. Experimental assigned to position 6'. The remaining methoxyl group at 83.66 was assigned to position 2' based on the spatial 3 .1 . G e n e r a l c x p c r im c n ta l p r o c e d u r e s correlation with the lone aromatic proton of position 3' at 8 6.19. The ,-'c I M R spectrum of 2 is identical to VIps were uncorrected I R spectra: Perkin-Elmer 598 that of Praecansone A occurring as the E-isomer espeFTI R series spectrometer in KBr pellet. UV: Perkincially the 13C NMR peak at 8 101.2 (C-8) as reported by Elmer lambda 16 u v .,« spectrometer in MeOH. Kiuchi et al. (1990). No spatial correlation in the EI M S: Hewlett Packard 5989 A mass spectrometer at ROESY spectra wus observed between the olefinic 70 cY with direct probe insert at 120-140 "C. NMR: ~ablc I "he I H NMR. HMQC and HMBC spectral data for compound I P .K . T a r u s e t a l., 378 dcbaZYXWVUTSRQPONMLKJIHGFEDCBA P liy to c h e m is tr y 6 0 (2 0 0 2 ) 3 7 5 -3 7 9 Varian VXR 500; CDCI) at 500 MHz for 'H NMR and 209. 239, 304. IH NMR spectral data (500 MH 75 MHz for 13C MR with TMS as int. standard and CDCI) and DC NMR spectral data (75 MHz, CDCI the chemical shifts reported in [) (ppm) units relative to s 7.83 (2H, m , H-2, H-6), 7.42 (I H, m , H-4), 7.37 (21 TMS signal and coupling constantsVUTSRQPONMLKJIHGFEDCBA (1 ) in Hz. Silica gel m . H-3, H-5), 6.50 (1H, d , J = 10 Hz, H-4"), 6.44 (lH. SDS chromagel 60 A CC (6-35 urn) was used for VLC, H-8), 6.19 (IH.s, H-3'), 5.43 (IH, d , J = 1 0 Hz, H-3' and silica gel 60 F 254 (Machereyagel) for analyt. (0.25 3.86 (31-1, s , 9-0Me), 3.72 (3H, s, 6'-OMe), 3.66 (3H. mm) and prep. (0.25 mm) TLC. Spots on chromato2'-OMe), 1.42 (61-1,s , 2"-Me}). DC xNMR spectral da gram were detected under UV light (254 and 365 nm) (75 MHz, CDCl3 ): 190.2 (C-7), 166.1 (C-9), 157.7 (C-4 and by spraying with 25% aqueous H 2 S0 4. 154.5 (C-6'), 155.6 (C-2'), 139.7 (C-I) 131.6 (C-4), 128 (C-2, C-6), 127.7 (C-3, C-5), 127.0 (C-4"), 116.8 (C-3' 3 .2 . P la n t m a te r ia l 111.9 (C-5'), 101.2 (C-8), 96.0 (C-3'), 76.5 (C-2"), 62 (2'-OMe), 56.2 (9-0Me), 55.8 (6'-OMe), 28.0 (2"-Me The roots of T . a e q u ila ta Baker were collected at the ElMS (probe) 70 eV, m ] : (reI. int.): 380 [MjT (6). 31 (20), 349 (100), 335 (8), 319 (18), 245 (5), 217 (4), II summit of zaui Hills in Makueni District, Kenya in (14), 105 (22), 77 (17). December, 1999. The sample was authenticated by Mr. Simon Mathenge, Botany Department, University of Nairobi, Kenya. A voucher specimen (SMjPKTj02,99) 3 .6 . P r a e c a n s o n e B (3) has been deposited in the herbarium, Nairobi University, Nairobi. Yellow oil (17. . g), IR v~ ~ ;cm-': 2980 and 30e 1670, 1610, 1560 ~80, 1370, 1200, 1150, 1130. L 3 .3 . E x tr a c tio n a n d is o la tio n i.~ ;? H nm: 274, 'OlJ. 'H NMR spectral data (500 MH CDCI3) and I3C NMR spectral data (75 MHz, CDCI [) 7.90 (2H. 1 1 1 . H-2, H-6), 7.50 (I H, 117, H-4), 7.40 (21 Air-dried roots (1.64 kg) were extracted with petrol 17l. H-3. H-5), 6.~0 (IH. d , J = 10 Hz, H-4"), 6.47 (11 (bp 40-60 °C). After evaporation of solvents. a yellow s, H-8), 6.23 (IH, 5, H-3'), 5.50 (11-1, d , J = 10 Hz. I paste (11.3 g) was obtained and the dried extract was 3"). 3.78 (3H. s , 6'-OMe), 3.76 (3H, s , 2'-OMe), l. chromatographed on a silica gel by VLC and eluted (6H. s . 2"-Me2)' 13C MR spectral data (75 MIwith n-hexane-EtOAc mixtures from the ratio of 9: I to CDCI.1): 188.0 (C-9), 182.0 (C-7), 158.2 (C-4'). 151 I: I to obtain fractions A to D. When fraction A was (C-2'). 155.0 (C-6'), [34.0 (C-I). 132.1 (C-4), 128.5 ( repeatedly recrystalized in Me2CO, 5 (30.0 mg) was obtained as yellow needle-like crystals. fraction B was 2. C-6). 127.7 (C-4"), 127.0 (C-3. C-5), 116.5 (C-3 114.0 (C-5'). 100.5 (C-8), 96.2 (C-3'), 76.4 (C-2"), 6~ rechromatographed on silica gel and eluted with petrol (6'-OMe), 56.1 (_'-OMe), 28.0 (2"-Me}). ElMS (prol (bp 60-80 C): EtOAc (9: I) which on recrystallization in Me2CO yielded) (19.1 mg). Fraction C from the VLC 70 eY. 1 1 1 z (rel. int.): 366 [Mj (16). 351 (100). 3 column was twice subjected to silica gel prep. TLC (95).321 (4).305 (It). 247 (16), 231 (9),217 (17). 2 (52.) .190 (7).175 (7).160 (7). 105 (25), 91 (6).77 (2' eluting with CHCI3:EtOAc (1:1) and CHCI) (100%). respectively. to yield 3 (11.7 mg). Fraction 0 was 69 (14).51 (6). rechromatographed on silica gel by VLC with petrol (bp J .7 . c is- P I '( ( ( 'U I I I . w lle A (4 ) 60-80 C):EtOAc (4: I) as eluant and was later subjected to silica gel prep. TLC with CHCI3 : EIOAc (I: I) as eluant to yield 2 (22.7 mg) and 4 (17.2 mg).aZYXWVUTSRQPONMLKJIHGFEDCBA Y cllow oil (17.9 rng). Found [Mj + 380.1 s: C:,H:.jO" Calc. for 380.1624. [R v ~ ;~ ~ em-I: 1660. L 3 . 4 . 3 . 4 - D illl( 't lir / l'lI l'd io x , r p t C 'r o c ( [ r p ( f l1 (J ) i,;~,'.~~)11 rim: 2X4. IH MR spectral data (500 MICDCId: 8 7.X9 (2H. n t, H-2. H-6), 7.43 (I H. 1 1 1 . HWhite crystals. mp 154-156 C.IR crn r': 2940. 7.38 (2H. 1 1 1 . H-3. H-5). 6.50 (I H. d , J = 10 Hz. H--+ 1610.1480.1460.1360.1150.1050.1030.1010.930.830. 6.22 (I H . .1'. H-3'). 6.03 (I H. s . H-8). 5.52 (I H. UY i.~ ; ~ ~ ) ll nm: 209.239.304. 'H MR spectral data J = 10 Hz. 1-1-3").3.78 (3H. s . 9-0Me). 3.70 (3H. s. (500 MHz. CDCl;) and '3C MR spectral data ( r OMe). 3.65 (3H. s . 2'-OMe). 1.44 (6H. s. 2"-Me2)' I MHz. CDCI1): cr. Table I. E[MS (probe) 70 eY.111 ~ (rel. 189.0 (CMR spectral data (75 MHz. CDCI3): int.): 312 [M]' (100).295 (1 3 ).2 2 5 (6).175 (16).165 (10). 16-+.0 (C -LJ). 158.3 (C-· +'). 156.0 (C-6'), 155.0 (C-: 162 (26).1-+9 (21).139 (11).125 (8). III (13).97 (18). 85 I-+O.D(C-I). 13l.5 C4). 128.1 (C-2. C-6), 127.8 (C C-5). 127.6 ( C A lf) . 116.1 (C-3"), 110.0 (C-5'), 104.8 ( (17).83 (20). 81 (15). 71 (28).69 (31). 57 (46). 55 (31). (). 95.7 ( -3'). 76.4 (C-2"). 62.2 (2'-OMe). 57.3 3 .5 . P m l'c { ( I I . I '! I I I l' A ( 2 ) OMe). 55.LJ (6'-OMe). 28.1 (2"-Me2)' E[MS (probe) .::V. I I I ~ (rei. int.): 380 [Mj- (11).365 (19). 349 (10 335 (X). 319 (16).2-15 (4). 217 (3),167 (9).105 (12). Yellow oil (17.9 mg), [R I'I~~I!~ cm "': 2940.1610.1-+80. 11m: I-+(]O.1360. 1150. 1050. IOJO. 1010. 930.830. i'I~,'.~~)ll (9 ). v~~:~ P .K . 3 .8 . T o r u s e t 0 1 ./ P h y to c h e m is tr y 6 0 12(02) 375-379 379 Baltz, T., Baltz, D., Goroud. c ., Crocket, 1., 1985. Cultivation B xwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (5) D e m e tliy lp r a e c a n s o n e semi-defined medium b r u c e i, T . e q u ip e r d u m , of animal T. in a infective forms of T ry p a n o so m a T . r h o d e n s ie n s e . T . g a m b ie n se . e v a n s i, Yellow needle-like crystals from n-hexane-EtOAc EMRO Journal 4, 1273-1277. (9:1), (17.9 mg), mp 126-129 VUTSRQPONMLKJIHGFEDCBA -c , lit. (Waterman and c ., Gerlach. E.H .. HawkinBarry, A.L. Coyle. M.B., Thornsberry, Mahmoud, 1985). Found [M]+ 352.1317; C21H200S son. R.W .. 1979. Methods of measuring zones of inhibition with the. Bauer-Kirby disk susceptibility test. Journal of Clinical. Calc. for 352.1311. v ~ ~ ~ em:": 1640, 1580, 1280. UV aZYXWVUTSRQPONMLKJIHGFEDCBA Microbiology 10,885-889. i.~ :? H nm: 279, 369. IH NMR spectral data (500 MHz, Beentje, HJ .. 1994. Kenya trees shrubs and ianas. National Museums CDCl3 ): 1> 7.86-7.91 (2H, m , H-2, H-6), 7.45-7.50 (3H, of Kenya. Nairobi, pp. 311-312. I ll. H-3, H-4, H-5), 7.32 (lH, s , H-8), 6.69 (IH, d , J = 10 Camele. G., Monache, F.D., Monache, G.D., Marini-Betolo. G.B .. Hz, H-4"), 5.95 (IH, s , H-3'), 5.47 (IH, d , J = 10 Hz, H1980. Three new flavonoids from T e p h r o s ia p ra e c a n s. Phytochem3"), 3.92 (3H, s , 2'-OMe), 1.46 (6H, s , 2"-Me2). I3C istry 19. 07-709. Chadra. M . (E d .). 1976. The Wealth of India. Publications and InforNMR spectral data (75 MHz, CDCI3 ): 194.0 (C-9), mation Directorate. CSIR. New Delhi, pp. 151-157. 175.8 (C-7), 162.0 (C-4'), 160.5 (C-2'), 159.9 (C-6'), Dagne. E .. Dinku. B .. Gray, C.D., Waterman. P., 1988. Pumilaiso133.5 (C-I), 131.6 (C-4), 128.7 (C-2, C-6), 128.1 (C-3, Cflavones A . B from the seedpods of T e p h r o s ia p u m ila . Phytochem5), 126.6 (C-4"), 116.1 (C-3"), 104.0 (C-3'), 103.0 (C-1'), istry 27.1503-1505. 98.2 (C-8), 91.8 (C-5'), 76.4 (C-2"), 55.9 (2'-OMe), 28.4 Gillet. 1.B._ Polhill. R.M .. Verdcourt, B., 1971. Flora of tropical East Africa. The Government Printers, Nairobi, pp. 501. (2"-Me2). ElMS (probe) 70 eV, m ] : (reI. int.): 352 [M]+ Kiuchi. F .. Chen. X ., Tsuda, Y.Z.-E., 1990. Isomerization of ~-meth(17),337 (40), 319 (3), 232 (3), 217 (100), 202 (6),191 oxychatcones: preferred existence of E -iso m e rs in naturally occur(24), 105 (20), 77 (25),69 (5), 51(4). ring I\--methoxychalcones. 1862-18 I. 3 .9 . P a r a s itic assay Kokwaro.10 .. 1993. Medicinal Literature The assays to determine activity of the ftavonoids for T . b r u c e i r lio d e n s ie n s e , T . c r u z i and L e is h m a n ia d o n o v a n i were carried out according to the method of Raz et al. (1997) and Baltz et al. (1985). The antiplasmodium activity was determined as described by Ridley et al. (1996). Lwande. Chemical Bureau. Nairobi. W .. Bentley. hildecarpin. M.D., rOOI: of T e p h r o s ia nali. A .. f99· . A n tim ic r o b ia l 1986. The structure W .. Jondiko. Insect. L.V.c.. Hassa- the roots of T e p h r o s ia activity against Swinhoe. Science. Application 1.1.. Moreka. from of from the the larvae of the spot led Journal of Pharmacognosy 33. 222 227. Maximo. The bioassay for antimicrobial activity was carried out by agar diffusion assay method as described by Barry et al. (1979). P .. Ll>UrCIH;o.A .. 1998. A pterocarpan Phytochemist Pachter, K.G.R .. Underwood. lated d.ua hcdron from C !( !.\' p a r v iflo r u s . rv ~X. 359-362. W.G.E .. 1967. NMR the heterocyclic I 'll! ' protons spectrum calcu- of (- )-pterocarpin. Tetra- ~ 3 . I X 17. Riiz. B.. hen. vl., Grether-Buhler, Y .. Kaminsky. R .. Brun. R .. 1997. The .vl.unar .md Blue assay to determine drug sensitivity of African trypano-omcs ( T . h . r lu u le n s ie n s « , T . h . g a m b ie n s ie u s c i in vitro. Acta Tropica (r.i_ 1 .;< ) I~7. Acknowledgements The authors are grateful to Dr. C. Codina and the staff at Department of Natural Products. Faculty of Pharmacy, University of Barcelona. Spain for running the NMR and MS spectra. P.K.T. thanks German Academic Exchange services (DAAD) for financial support for this research. Thanks are also due to Reto Brun of the Swiss Tropical Institute. Basel. Switzerland .or carrying out the parasitic assays and finally to Mr. Simon Mathenge. Botany Department. University of \lairobi. Kenya for the authentication and collection of .he plant material. Ridley. R.G .. Hofhcinz. Mascindri. M.A .. Lrwylcr, G .. Rao. procum bcns formation " I" Pr.icc.msonc I. 272.' B. Journal 01" for praecansone of A con- of the Chemical Society Perkin E.N .. 1985. Flavonoids Poi-ouou-, Pl.uu-, 1,1" Southern from the seeds of and Eastern Africa. and l st ed. Living- stone. Lorulon. p p . (,53 663. 0 .. I lJ:S. lsol.uion and "I" '\,dir"bi. Chemical Ycncsc« .. \ .. J)agne. and lin c a r is . of Flavovl Sc thesis. of Flowering Plant and Ferns. Uni- 1135 pp. E .. Waterman. -ccd PI Is I,r T c p h r o -ia Characterization T c p h r o s ia : airobi. Dictionary vcrxit , P I',,'> " Cambridge. The Univcrsuy W .. 1996. ~727. P .. \Iahmoud. Uni\ cr-itv The Lcuurninoscac. pp. 6~5 (,~9. A .. o r l'lI\ c o v t a r ir v n s is . Willis . . I . c . . I 'r . '. I. S .. Peters. C; 1987. Flavonoids structure noid-, from F c p h r o v i« in tc r r u p ta ~eferences Dorn. 40. 1846-185~. E.V .. Vilain. revised c.. Phytochemistry 24. 571-57~. \1..1.. Brcvcr-Br.mdwijk. M.G .. 1962. The Medicinal L ( lIIC h f" Watl. W .. Thaitong. 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