SHORT REPORT Rec. Nat. Prod. 3:3 (2009) 165-169 Chemical Constituents of Klainedoxa gabonenses and Paullinia pinnata Etienne Dongo*1, Hidayat Hussain*2, Renadin S. Miemanang 1, Dagobert Tazoo1, Barbara Schulz3, Karsten Krohn*2 1 Department of Organic Chemistry, Faculty of Science, Yaounde I University, P. O Box 812, Yaounde, Cameroon. 2 Department of Chemistry, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany 3 Institut für Mikrobiologie, Technische Universität Braunschweig, Spielmannstraße 7, 31806 Braunschweig, Germany (Received March 4, 2009; Revised April 2, 2009; Accepted April 5, 2009) Abstract: From the whole plant of Klainedoxa gabonenses betulinic acid (1), lupeol (2), ß-sitosterol (3), amyran-3-one (4) and 3,3',4'-tri-O-methylellagic acid (5) were isolated. Similarly paullinomide A (6), -amyrin (7), 2-(4-hydroxy-3,5-dimethoxyphenyl)-3-hydroxymethyl-2,3-dihydro-1,4,5-trioxaphenanthren-6-one (8), 5 poriferastane-3ß,6 -diol (9), -sitosterol (3), l-quebrachitol (10), and ß-sitosterol glucopyranoside (11) were isolated from roots of Paullinia pinnata. Preliminary studies showed that 2-(4-hydroxy-3,5-dimethoxyphenyl)-3hydroxymethyl-2,3-dihydro-1,4,5-trioxaphenanthren-6-one (8) showed moderate algicidal activity against the alga Chlorella fusca Keywords: Paullinia pinnata; Klainedoxa gabonenses; algicidal activity. 1. Plant Source The African continent is endowed with one of the richest biodiversity in the world, with an avalanche of many food plants used as herbs, health foods and for therapeutic purposes. Over 5,000 different species of plant substances have been recognized to occur in these areas, and many of them have been found to be useful in traditional medicine for prophylaxis and cure of diseases [1]. As part of our systematic search for new bioactive lead structures from African medicinal plants, Klainedoxa gabonenses and Paullinia pinnata L. were selected for chemical and biological investigations. * Corresponding authors: E- Mail:Hidayat110@gmail.com (H.Hussain), Phone +49-5251-602185 and E- Mail: k.krohn@upb.de (K. Krohn) The article was published by Academy of Chemistry of Globe Publications www.acgpubs.org/RNP © Published 06/07/2009 EISSN: 1307-6167 Constituents of K. gabonenses and P. pinnata 166 The plant K. gabonenses (Irvingiaceae) was collected (November 2005) from Eloundem, while roots of P. pinnata L. (Sapindaceae) were collected (April 2004) at Obala, Central province of the Republic of Cameroon. The two African plants were identified by Dr. Louis Zapfack and voucher specimens of P. pinnata L. (No 44641) and K. gabonenses (N° 35206/HNC) have been deposited at the National Herbarium, Yaounde, Cameroon. 2. Previous Studies Early studies regarding the chemical constituents of K. gabonenses revealed the presence of one tannin, methyl gallate [2]. Later, two flavonol glycosides [3], one cerebroside and a ceramide from P. pinnata L. were isolated by our group [4]. 3. Present Study The air-dried stem barks (8 kg) of K. gabonenses (Irvingiaceae) were exhaustively extracted with methanol at room temperature. The extract was evaporated to dryness yielding 510 g of residue. The whole extract was extracted with n-hexane, chloroform, ethyl acetate, and n-butanol. The nhexane and EtOAc extract were combined (158 g) and the combined extract was subjected to column chromatography (silica gel, n-hexane, n-hexane-EtOAc and EtOAc, in order of increasing polarity) yielding 8 fractions. Fraction 1 was further separated by silica gel column chromatography and eluted with n-hexane-EtOAc (9:1) to give betulinic acid (1, 13.2 mg). Similarly, lupeol (2, 11.1 mg) was isolated from fraction no. 6, after elution with a mixture of n-hexane–EtOAc (8.5:1.5) and ß-sitosterol (3, 10 mg) was isolated from fraction 7 with n-hexane–EtOAc (8:2). Repeated column chromatography of fraction 3 using n-hexane–acetone (9.5:0.5) as the eluent afforded -amyran-3-one (4, 6.5 mg). Repeated CC of fraction 5, eluted with a mixture of petroleum ether-EtOAc (7.5:2.5), gave 3,3',4'-tri-O-methylellagic acid (5, 5.3 mg). The air-dried leaves (7 kg) of P. pinnata L. (Sapindaceae) were exhaustively extracted with methanol at room temperature. The extract was evaporated to dryness yielding 520 g of residue. The whole extract was extracted with n-hexane, chloroform, ethyl acetate, and n-butanol. The EtOAc extract (80 g) was then subjected to column chromatography (silica gel, n-hexane, n-hexane-EtOAc and EtOAc, in order of increasing polarity) yielding 21 fractions. Fraction no. 15 was subjected to column chromatography and eluted with a mixture of n-hexane-EtOAc (4:6) to yield paullinomide A (6, 6.1 mg) (Miemanang et al., 2006), while fraction no. 3 gave -amyrin (7, 8.0 mg) upon elution with n-hexane–EtOAc (9:1). Similarly, fraction 4 gave -sitosterol (3, 11.1 mg) after elution with nhexane–EtOAc (9:1). Fraction no. 13 was subjected to column chromatography and eluted with a mixture of n-hexane-EtOAc (6:4) to afford 5 -poriferastane-3ß,6 -diol (9, 6.5 mg) and impure lquebrachitol (10). l-Quebrachitol (10, 13.5 mg) was purified by CC after elution with EtOAc-MeOH (9:1). Column fraction no. 14 was eluted with n-hexane–EtOAc (5:5) to afford 2-(4-hydroxy-3,5dimethoxyphenyl)-3-hydroxymethyl-2,3-dihydro-1,4,5-trioxaphenanthren-6-one (8, 6.5 mg) and fraction 17 gave ß-sitosterol glucopyranoside (11, 10 mg) with n-hexane–EtOAc (2.5:7.5). The whole plant extract of the stem of K. gabonenses was fractionated by silica gel column chromatography to give several fractions, which were further chromatographed on silica gel to give three triterpenes (1, 2, and 4), one steroid (3), and compound 5 (Figure 1). These five compounds were identified as betulinic acid (1) [5], lupeol (2) [6], ß-sitosterol (3) [7], -amyran-3-one (4) [8], 3,3',4'tri-O-methylellagic acid (5) [9] by comparison of 1D and 2D NMR data with reported data. Similarly, paullinomide A (6) [4], -amyrin (7) [10], 2-(4-hydroxy-3,5-dimethoxyphenyl)-3-hydroxymethyl-2,3dihydro-1,4,5-trioxaphenanthren-6-one (8) [11], 5 -poriferastane-3ß,6 -diol (9) [12], -sitosterol (3) [7], l-quebrachitol (10) [13], and ß-sitosterol glucopyranoside (11) [14] were isolated from roots of P. pinnata and their structures were determined by comparison of 1D and 2D NMR data with reported values. Preliminary studies showed that 2-(4-hydroxy-3,5-dimethoxyphenyl)-3-hydroxymethyl-2,3- 167 Dongo et al., Rec. Nat. Prod. (2009) 3:3 165-169 dihydro-1,4,5-trioxaphenanthren-6-one (8) showed moderate algicidal activity against the alga Chlorella fusca. R HO O HO 1 R = CO2H 2 R = CH3 3 4 O OCH3 O H3CO OCH3 O HO O 5 Compounds (1-5) isolated from Klainedoxa gabonenses O HN OH HO OH HO 6 7 OMe O O H3CO O HO OH O HO HO OH OCH3 OH OH HO OH 8 10 9 OH O HO 3 O HO HO OH 11 Compounds (3, 6-11) isolated from Paullinia pinnata Figure 1. Compounds 1–11 isolated from K. gabonenses and P. pinnata. Constituents of K. gabonenses and P. pinnata 168 Antibacterial, Antialgal, and Antifungal activities. Compounds 8-10 were tested for antibacterial, antialgal and antifungal activities. Only compound 8 showed activity against the alga Chlorella fusca, while compounds 9 and 10 were inactive in these tests. Chemotaxonomic significance: The small family of Irvingiaceae, also frequently subordinated within the Simaroubaceae, consists of the genera Desbordesia, Irvingia, and Klainedoxa. Whereas Desbordesia and Klainedoxa are native to tropical Africa, Irvingia occurs in addition in Cochinchina and Malaysia [15]. Recent treatments of the genus, variously treated as belonging to Irvingiaceae or to Simaroubaceae, have recognized two species, K. gabonenses Pierre ex Engl. and K. busgenii [16]. Early chemical studies of genus Klainedoxa revealed the presence of one tannin from K. gabonenses [2]. Continuing chemotaxonomic studies on the genus Klainedoxa, we report here on the results obtained for K. gaoneneses. Interestingly, compounds 1 and 5 were characterized for the first time from the genus Klainedoxa and have been isolated from genus Irvingia of same family [9]. This finding is evidence that the genera Klainedoxa and Irvingia are closely related taxonomically. On the other hand, compound 2–4 were characterized for the first time from the Irvingiaceae family, and thus isolation of compounds 2–4 in the present investigation is a major contribution to chemotaxonomic studies of the Irvingiaceae family. The ceramide, paullinomide A (6) and -amyrin (7), and two steroids (3 and 11) have been isolated previously from P. pinnata L. by our group [4]. The other fact which should be commented on is the isolation of a ceramide from P. pinnata L. This is the first time that a ceramide has been isolated from the genus Paullinia. On the other hand, coumarinolignoid (8) has been reported from genus Daphne of the Thymelaeaceae family [11, 17], and 5 -poriferastane-3ß,6 -diol (9) has been reported from the marine red alga Garcilaria edulis [12]. Similarly, l-quebrachitol (10) has been reported from the Asteraceae [18] and Elaeagnaceae families [19]. 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