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BillburttiaSales & Hedge is a new genus endemic to Madagascar, which belongs to the Apiaceae family and comprises of two species, namelyBillburttia capensoidesandB. vaginoides.The present work was undertaken in a view to explore secondary metabolites from the leaves ofB. capensoides, contributing to have more knowledge on the chemical profile of this species. Liquid-liquid partition followed by chromatographic separation of its ethanolic extract led to the isolation of two new prenylated chromones, 2'R-hydroxy-7-O-methylallopeucenin and the known coumarins imperatorin and xanthotoxin. Their chemical structures were established on the basis of spectroscopic methods including nuclear magnetic resonance (NMR) and high resolution mass spectrometry, and by comparison with the reported data in the literature. The structure of the compound 3 was confirmed by single-crystal X-ray diffraction. This is the first report on the nonvolatile constituents ofB. capensoides. The presence of imperatorin and xanthotoxin supported that the new endemic genusBillburttiabelongs to the Apiaceae family. All these data may induce further research on this species in order to find new chemical entities with biological and chemotaxonomic interests.

During an ethnobotanical survey conducted among the Zafimaniry clan in the Amoron'i Mania region of Madagascar, 164 medicinal plants species from 138 genera and 73 families are recorded to be used by local people to treat 65 different types of human diseases. The most prescribed species belong to Asteraceae (30 species), Fabaceae (8 species), Rubiaceae (7 species) Poaceae (6 species) and Solanaceae (7 species) botanical families. Helichrysum was the most cited genus with 6 species. The main pathologies treated with medicinal plants are abdominal colic (10.5%) using 25 species, cough (7.2%, 23 species), intestinal parasites (6.3%, 20 species) and diarrhea (5.8%, 25 species). The vernacular names and the recipes of used plants are also reported. Data are collected by interviewing 191 informants aged between 16 and 100 using standardized questionnaires. The present study shows that the Zafimaniry people use a large number of medicinal plants for their primary health care. Some of the recorded plants are new in the Malagasy ethnopharmacopoeia.

The essential oils of six endemic Malagasy Helichrysum species were investigated by GC (RI), GC&ndash, MS and 13C NMR spectrometry. In total, 153 compounds were identified accounting for 90.8% to 99.9% of the total composition. The main constituents were &alpha, pinene for H. benthamii, 1,8-cineole for H. dubardii, (E)-&beta, caryophyllene for H. indutum, and H. bojerianum. H. diotoides essential oil was characterized by the presence of two lilac alcohols and four lilac acetates whereas H. hirtum essential oil exhibited an atypical composition with 7&beta, H-silphiperfol-5-ene, 7-epi-subergorgiol, and 7-epi-silphiperfol-5-en-13-oic acid as major components.

Background : Madagascar, a big island in the Indian Ocean is one of the countries of hotspot biodiversity in the world. Among this biological richness, medicinal plants hold an important place in the everyday life of Malagasy people. However, the documentation on the uses of medicinal plants is still scarce and the synthesis of related works dated back to 1990. Methodes : This study was conducted by referring to 99 publications. The most cited taxa are determined according to the values of their frequency of citation. The fidelity level of species related to each disease is calculated using the formula of Friedmann et al . Results: The medicinal plants inventoried in Madagascar consist of 3245 species, of which 60% are endemic. Croton L. (98 species) , Helichrysum Mill. (46 species) Noronhia Stadtm. ex Thouars, (39 species) et Psychotria L. (29 species) are the most represented genera. Albizia Durazz. (23,5%) , Aloe A. Rich. (22,7 %) and Aphloia (DC.) Benn. (22,7%) are the most cited ones. The first three most diversified families are the same as those the mostly cited, namely Fabaceae (279 species), Asteraceae (238 species), and Rubiaceae (218 species). Psiadia altissima (DC.) Drake and Cinnamosma macrocarpa H. Perrier are the two first endemic autochthon species which are the most frequently cited. Harungana madagascariensis Lam. ex Poir. for the non endemic autochthon species and Lantana camara L. for the introduced species. The digestive and genito-urinary disorders, traumatic affections, poisoning and other consequences of external origins are the most predominant diseases treated with plants. The fidelity levels of the first five species used to treat these groups of diseases range between 50 and 95.5%. These diseases also belong to the most morbid ones in Madagascar. Conclusions: The present study highlight the actual state of Madagascan medicinal plants and the corresponding ailments. These data are useful to direct the future projects of biodiversity conservation in Madagascar and pharmacological and ethnobotanical investigations of medicinal plants. Key words: Madagascar, medicinal plants, actual state, most diversified and cited species

International audience; Methanolic extracts of 14 plant species used in traditional medicine in Madagascar were investigated for their antibacterial activities. Several extracts showed high inhibitory activities (Maytenus polyacantha, Mystroxylon aethiopicum, Psychotria bridsoniae, Dombeya tsaratananensis, Psychotria oreotrephes, Razafimandimbisonia sambiranensis) against Listeria monocytogenes, Staphylococcus aureus and Streptococcus pyogenes strains, some of which reached a MIC value lower than 0.1 mg/ml. The extract of P. oreotrephes was the most active against Clostridium perfringens, Proteus mirabilis and Yersinia enterocolitica. Escherichia coli and Salmonella Enteritidis were resistant to all tested extracts. This study demonstrates that plant extracts from species belonging to the Lauraceae, Proteaceae, Celastraceae, Malvaceae and Rubiaceae families have high antibacterial activity, some of which are bactericidal, against Gram-positive pathogenic bacteria that are known to cause infectious diseases.

Des enquêtes ethnobotaniques ont été menées dans les formations forestières de la baie de Rigny-Antsiranana à Madagas- car. Ces formations forestières sont des zones clés de la biodiversité malgache et constituent la principale source d’appro- visionnement des populations locales en plantes utiles. Trente-huit informateurs d’âge compris entre 15 et 80 ans, tradipra- ticiens, mères et pères de famille et connaissant bien les plantes médicinales, ont été enquêtés en les amenant en forêt ou bien en leur montrant des spécimens d’herbier. La méthode d’enquête indivi- duelle retenue était l’entretien semi-struc- turé. Cinquante-trois espèces de plantes médicinales réparties dans 50 genres et 28 familles ont été recensées. Trente-huit espèces (68,6 %) sont endémiques de Madagascar. Les dix premières espèces les plus utilisées ont des indices de fidéli- té élevés pour les maladies indiquées. Dix-neuf espèces ont des indices de fidéli- té élevés (> 60 %) pour diverses maladies. Les maladies auxquelles les informateurs rattachent le plus grand nombre de plantes médicinales sont les affections du système digestif (maux de ventre et diarrhée), les maladies générales (les plaies et la fatigue), les infections et infestations (le paludisme), tout comme la grossesse, la naissance et la puerpéralité. Les indices de fidélité de Adansonia madagascariensis et Senna alata destinées respectivement à la lutte contre la perte de poids et l’hyperten- sion artérielle sont également élevés. Toutes ces maladies sont fréquentes à Madagascar. Les formations végétales de la baie de Rigny-Antsiranana constituent un réservoir de plantes médicinales pour la région Nord de Madagascar. Les connais- sances locales relatives à ces plantes n’ont pas été transcrites mais restent orales et risquent d’être perdues. La végétation naturelle y est menacée par la pression anthropique et l’absence de plan de conservation. Des recherches chimiques et pharmacologiques sur les espèces endémiques, et des mesures de conser- vation de la végétation, sont nécessaires pour leur valorisation et leur protection.

Melicope madagascariensis (Rutaceae) is an endemic plant species of Madagascar that was first classified as a member of the genus Euodia J. R. & G. Forst (Rutaceae) under the scientific name Euodia madagascariensis Baker. Based on morphological characteristics, Thomas Gordon Hartley taxonomically revised E. madagascariensis Baker to be M. madagascariensis (Baker) T.G. Hartley. Chemotaxonomical studies have long been used to help the identification and confirmation of taxonomical classification of plant species and botanicals. Aiming to find more evidences to support the taxonomical revision performed on E. madagascariensis, we carried out phytochemical investigation of two samples of the plant. Fractionation of the ethanol extracts prepared from two stem bark samples of M. madagascariensis (Baker) T.G. Hartley led to the isolation of seven known furoquinoline alkaloids 1–7 and two known methoxyflavones 8 and 9. The presence of furoquinoline alkaloids and methoxyflavones in the title species is in agreement with its taxonomic transfer from Euodia to Melicope. Antiprotozoal evaluation of the isolated compounds showed that 6-methoxy-7-hydroxydictamnine (heliparvifoline, 3) showed weak antimalarial activity (IC50 = 35 µM) against the chloroquine-resistant strain Dd2 of Plasmodium falciparum. Skimmianine (4) displayed moderate cytotoxicity with IC50 value of 1.5 µM against HT-29 colon cancer cell line whereas 3,5-dihydroxy-3′,4′,7-trimethoxyflavone (9) was weakly active in the same assay (IC50 = 13.9 µM). Graphical Abstract

The chemical composition of twenty-five essential oil samples from the aerial parts of two Malagasy endemic species Billburttia capensoides Sales & Hedge and B. vaginoides Sales & Hedge, were investigated for the first time. Based on chromatographic profiles, three selected samples were investigated using GC(RI), GC-MS and 13C NMR. The content of the main components varied drastically from sample to sample: p-mentha-1,3,8-triene (0.2–52.7%), terpinolene (2.8–40.7%) and dill apiole (0.0–22.2%). Statistical analysis of the 25 oil compositions allowed the distinction of two well-differentiated groups. Samples of group I contained mainly p-mentha-1,3,8-triene while the Group II was dominated by terpinolene and dill apiole.

Bioassay screening of plant extracts can identify unique lead compounds for drug development, but the "hit rate" from random screening is very low. Targeted screening of medicinal plants has been repeatedly reported to increase the percentage of samples displaying bioactivity. Contrarily, Maranz (2012) suggested that African antimalarial plants were unsuitable sources of antimalarial drugs because high prevalence of malaria would result in rapid evolution of resistance to active compounds that directly targeted the parasite. As malaria is highly prevalent in much of Madagascar, it was of interest to determine whether Malagasy antimalarial plants would outperform randomly selected plants in conventional antimalarial assays being conducted as part of a discovery program. Of 1294 plant samples screened for antimalarial activity, 39.6% had an IC50

Antiplasmodial bioassay guided fractionation of a Madagascar collection of Crinum firmifolium led to the isolation of seven compounds. Five of the seven compounds were determined to be 2-alkylquinolin-4(1H)-ones with varying side chains. Compounds 1 and 4 were determined to be known compounds with reported antiplasmodial activities, while 5 was believed to be a new branched 2-alkylquinolin-4(1H)-one, however, it was isolated in limited quantities and in admixture and therefore was synthesized to confirm its structure as a new antiplasmodial compound. Along with 5, two other new and branched compounds 6 and 7 were synthesized as well. Accompanying the five quinolones were two known compounds 2 and 3 which are inactive against Plasmodium falciparum. The isolation, structure elucidation, total synthesis, and biological evaluation of these compounds are discussed in this article.

In our continuing search for biologically active natural products from tropical forests as part of an International Cooperative Biodiversity Group (ICBG) program, we obtained an EtOH extract from the roots of a plant identified as Ambavia gerrardii (Baill.) Le Thomas (Annonaceae) from Madagascar. The extract exhibited good antiproliferative activity against the A2780 human ovarian cancer cell line with an IC50 value of 10 µg/mL. The genus Ambavia (Annonaceae) consists of only two species, A. capuronii and A. gerrardii, both of which are endemic to Madagascar, and no phytochemical work has been reported on either species. Previous phytochemical studies of plant species in the Annonaceae family have revealed the presence of cytotoxic acetogenins,2, 3 miliusanes,4 styrylpyrones,5 polyacetylenes,6 diterpenoids,7, 8 flavanones,9 and alkaloids.6,10 The extract was selected for bioassay-directed fractionation to isolate its active components on the basis of its activity and the absence of previous phytochemical studies.

Investigation of the endemic Malagasy plant Bussea sakalava for antiproliferative activity against the A2780 ovarian cancer cell line led to the isolation of the four new diphenylpropanes 1-4 and the new cycloheptadibenzofuran 5; compound 5 has a previously unreported natural product skeleton. The structure elucidation of these compounds was based on the analysis of their 1D and 2D NMR and mass spectroscopic data. Compounds 1-5 were tested for antiproliferative activity against the A2780 human ovarian cancer cell line.

Bioassay-guided fractionation of an ethanol extract of a Madagascar collection of Elaeodendron alluaudianum led to the isolation of two new cardenolide glycosides ( 1 and 2 ). The 1 H and 13 C NMR spectra of both compounds were fully assigned using a combination of 2D NMR experiments, including 1 H– 1 H COSY, HSQC, HMBC, and ROESY sequences. Both compounds 1 and 2 were tested against the A2780 human ovarian cancer cell line and the U937 human histiocytic lymphoma cell line assays, and showed significant antiproliferative activity with IC 50 values of 0.12 and 0.07 μM against the A2780 human ovarian cancer cell line, and 0.15 and 0.08 μM against the U937 human histiocytic lymphoma cell line, respectively.

Two new flavanones, remangiflavanones D and E (1 and 2), were isolated from an extract of the twigs, leaves, and flowers of Physena madagascariensis together with three known flavanones, remangiflavanones A–C (3–5), and (E)-N-feruloyltyramine (6). The structures of the new compounds 1 and 2 were established on the basis of one-dimensional and two-dimensional NMR spectroscopic data interpretation. All compounds were evaluated for their cytotoxicity in the A2780 human ovarian cancer cell line. Compound 5 was the most active with an IC50 value of 2.5 µg mL−1. ¶Biodiversity Conservation and Drug Discovery in Madagascar, Part 22. For part 21, see reference 1.

An analysis of the taxonomic composition of 6,496 samples of plants collected for the National Cancer Institute is conducted and the results are presented. The results show that collecting has been highly biased towards woody plant families, as these species are often abundant, they yield samples of multiple parts, and it is often easy to collect sufficient material for isolation of chemicals present in low concentration. Conversely, herbaceous plants that are small or grow in sparse populations are underrepresented in collections. Three of the ten generically most diverse families in Madagascar have not been sampled, and of these ten families, only Rubiaceae and Euphorbiaceae have had greater numbers of samples collected than predicted if collecting was random. The causes of this bias are discussed, and solutions to ensure that bioprospecting efforts gather samples reflective of the diversity present are presented.

Investigation of the endemic Madagascan plant Uvaria sp. for antiproliferative activity against the A2780 ovarian cancer cell line led to the isolation of two new acetogenins. The structures of these two compounds were elucidated on the basis of analysis of their 1D and 2D NMR spectra, circular dichroism, and mass spectrometric data, together with chemical modification. The two acetogenins display weak antiproliferative activity against the A2780 ovarian cancer, the A2058 melanoma, and the H522 lung cancer cell lines.

Fractionation of an antiplasmodial ethanolic extract from the aerial parts of Vitex cauliflora led to the isolation of the new labdane diterpene 1 together with the known triterpene uvaol. The structure of the new compound 1 was established as 3-oxo,15,17,18-triacetoxy-labda-7,13E-diene on the basis of spectroscopic data (1D and 2D NMR, MS).

Bioassay-guided fractionation of the EtOH extracts obtained from a plant identified as Didymochlaena truncatula led to the isolation of two cytotoxic alkaloids, camptothecin and 9-methoxycamptothecin. A second plant collection yielded three lignan derivatives, didymochlaenone A (1), didymochlaenone B (2), and (-)-wikstromol, one stilbene, (E)-3-methoxy-5-hydroxystilbene, and two stigmasterol derivatives, stigmast-4-en-3beta-ol and stigmast-4-en-3-one, but no camptothecins, and it is probable that a coding error led to a mistaken identification of the original extract. The structures of the new compounds 1 and 2 were established on the basis of extensive interpretation of one- and two-dimensional NMR spectroscopic data.

Bioassay guided fractionation of the ethanol extract of a new endemic species of the genus Astrotrichilia led to the isolation of the new antiproliferative 3-(4′-hydroxy-2′,3′-dihydroprenyl)-4,6-dimethoxy-5-methylcoumarin, named astrotricoumarin (8) with an IC50 value of 6.8 μM against the A2780 cell line. The structure of compound 8 was elucidated on the basis of its physical and spectroscopic data, including extensive 1D- and 2D-NMR analysis.