Thierry Sevenet

Novel Antimalarial Compounds Isolated in a Survey of Self-Medicative Behavior of Wild Chimpanzees in Uganda

ABSTRACT Following a veterinary and behavioral survey of chimpanzees from a natural population in Uganda, leaf samples of Trichilia rubescens were collected because of the unusual method of ingestion observed. The methanolic crude extract of T. rubescens leaves exhibited significant antimalarial activity in vitro. Bioassay-directed fractionation provided two new limonoids, trichirubines A and B. A greater understanding of the role of secondary compounds in the primate diet may be helpful in recovering naturally occurring compounds of medicinal significance for human medicine.

Alkaloids of Alstonia angustifolia

Abstract Thirty-one alkaloids have been isolated from the leaves and from the stem bark of Alstonia angustifolia from Malaysia. Twenty of them were known compounds: yohimbine, O -acetyl yohimbine, pleiocarpamine, fluorocarpamine, cathafoline, cabucraline, N -1 desmethylquaternine, vincamajine, normacusine B, lochnerine, affinisine, akuammicine, 11-methoxyakuammicine, antirhine, alstonisine, alstonerine, alstophylline, macralstonine, villalstonine and tetrahydrocantleyine. Among the 11 novel alkaloids, three were monomers: 19,20-dehydro-10-methoxytalcarpine, 19,20-dehydro- O -acetyl yohimbine and hydroxystrictamine, and eight were dimers: villalstonine N -4′-oxide, 10-methoxy villalstonine, 10-methoxyvillalstonine N-4′-oxide, 10-methoxymacrocarpamine, 10-methoxymacrocarpamine N -4′-oxide, angusticraline, alstocraline and foliacraline. Structural elucidation of the new alkaloids was based on spectral data analysis including high field 1 H and 13 CNMR.

Cytotoxic polyisoprenes and glycosides of long-chain fatty alcohols from Dimocarpus fumatus

The ethanolic extract from the stem bark of Dimocarpus fumatus, showed in vitro cytotoxic activity against KB cells. Fractionation of the extract gave compounds belonging to different classes. The two major components have been identified as a benzoquinone, sargaquinone, and a chromene, sargaol. One sphingolipid, soyacerebroside I, two glycosides of sitosterol, and fatty acids were also identified. Besides these known compounds, two new glycosides of long-chain fatty alcohols have been identified as 1-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->6)-beta-D- glucopyranosyl]hexadecanol and 1-O-[[alpha-L-arabinopyranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1 -->2)- beta-D-glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->6)-beta-D- glucopyranosyl] hexadecanol, and a mixture of three new diacylglycerylglucosides has been isolated. These structures were elucidated by analysis of 2D-NMR and mass spectra.

Noninvasive Monitoring of the Health of Pan troglodytes schweinfurthii in the Kibale National Park, Uganda

We assessed the health status of chimpanzees (Pan troglodytes schweinfurthii) of the Kanyawara group in the Kibale National Park in Western Uganda via noninvasive methods. We conducted visual veterinary inspection, parasitological and urine analysis in association with behavioral observations, causing minimal disturbance or stress to individually recognized chimpanzees. We applied multiple parasitological techniques to 252 stool samples to compare their efficacy in detecting parasitic infection and to increase the power of detecting a wide range of parasites at a more sensitive level. We examined 76 urine samples via a quick detection method to evaluate multiple parameters of urine that indicate organ dysfunction. Results of the different analyses are mutually supportive and provided useful information for monitoring bodily condition and diseases. The multifaceted health evaluation system is a beneficial tool for monitoring long-term and short-term changes in health status due to environmental stress, seasonal dietary change, and disease in wild chimpanzee populations. Use of this method to detect changes in health, when employed together with behavioral observations, may also provide important insights into the potential effects of self-medicative behaviors.

New nitrogenous and aromatic derivatives from Aglaia argentea and A. forbesii

Seeds and leaves of Aglaia argentea and bark of A. forbesii were extracted. The known cyclopentatetrahydrobenzofuran derivative rocaglaol (1) and the aminopyrrolidine odorine (5), were isolated together with nine new compounds: didesmethylrocaglamide (6), aglains A (7), B (8) and C (9), aglaforbesins A (10) and B (11), ethylrocaglaol (12) and forbaglins A (13) and B (14). Compounds 7–11 and 13,14 possess a new cyclopentatetrahydrobenzopyran and benzoxepine skeleton, respectively, linked to an odorine type moiety. All the structures were elucidated notably by 2D NMR spectroscopy. In addition, the structure of forbaglin A was established by X-Ray crystallographic analysis. Didesmethylrocaglamide revealed strong cytotoxic activity against KB cells (IC50 0.006 μg/ml).

Lapidilectine A and lapidilectine B, two new alkaloids from Kopsia lapidilecta

Abstract Bark and leaves of Kopsia lapidilecta Van der Sleesen were extracted. Two new indole alkaloids were afforded: lapidilectine A 1 (bark) and lapidilectine B 2 (leaves). Both possess a novel skeleton with a five membered unsaturated ring. The structures of these alkaloids were elucidated especially by 2D NMR analysis.

Alkaloids from leaves and root bark ofErvatamia hirta

Abstract During chemical investigation of the leaves and root bark of Ervatamia hirta , 33 alkaloids were isolated. Seven are new: six are the ‘monomeric’ alkaloids ( E ) 16- epi -normacusine B , ( E ) 16- epi -affinisine, O -acetyl-16- epi -affinisine, affinisine- N (4)-oxide, dehydro-16- epi -affinisine, norfluorocurarine- N (4)-oxide, and the seventh is the bisindole 16-decarbomethoxyvoacamine-pseudoindoxyl. The known alkaloids are: ( E ) 16- epi -isositsirikine, β-yohimbine, yohimbine, 19,20-dehydro-β-yohimbine, β-yohimbine-pseudoindoxyl, isositsirikine, 19,20-dihydroisositsirikine, β-yohimbine-oxindole, normacusine B , affinisine, vobasine, dregamine, tabernaemontanine, norfluorocurarine, 12-hydroxynorfluorocurarine, apparicine, 3,14-dihydroellipticine, antirhine, voacristine, ibogaine, i☐ygaine, i☐ygaine-hydroxyindolenine, iboluteine, 4′,17,(17β)-dihydrotchibangensine, 16-decarbomethoxyvoacamine and 19,20-dihydro-16-decarbomethoxyvoacamine. Structural elucidation of the new alkaloids is based on spectral data and chemical correlations.

Hemisynthesis of rhazinilam analogues: structure - activity relationships on tubulin-microtubule system

Abstract Semi-synthesis of derivatives of rhazinilam, an antitubulin compound, delineated some molecular features necessary for biological activity. In the course of this study, the formation of rhazinilam from 1,2-didehydroaspidospermidine is reexamined and a new mechanism is proposed.

A PRELIMINARY CHEMOTAXONOMIC REVIEW OF KOPSIA (APOCYNACEAE)

The present paper is the result of a botanical and chemical study of the Indo-Pacific genus Kopsia (Plumerioideae-Rauvolfieae) Apocynaceae. Some of the species of this genus possess medicinal uses. A survey of the accepted taxa and their synonymy, based on the study of types, is presented. Studies on alkaloids provides chemotaxonomic information. Indeed, in some cases, chemical relationships occur between species belonging to the same botanical group.

A new phytochemical survey of Malaysia. V: Preliminary screening and plant chemical studies

A large phytochemical survey of the flora of the Malaysian Peninsula and Sabah is described, covering the systematic search for alkaloids, and partly, for saponins and flavonoids. Details of some chemical studies are reported. This emphasizes the great interest of such a study.