The number of publications containing chemical and pharmacotoxicological data is constantly on the increase and the research emphasis in Pharmacognosy is increasingly directed towards pharmacochemistry of natural substances. Among the natural compounds, saponins seem to play a more and more important role because these biologically active compounds benefit from new structural elucidation techniques. The treatment of tropical diseases continues to overwhelm the health care services of developing countries. Although diseases such as malaria affect millions of people of these countries, they are considered as non-profitable by the pharmaceutical industries. A survey of ethnobotanical knowledge in traditional pharmacopoeia was carried out in the areas where malaria is endemic. Volumes of increasing doses of compounds were randomly administered by subcutaneous injections to groups of ten Swiss mice. Analogous biological considerations can be observed with the roots of another Caribbean plant, Sideroxylon cubense, used externally for the treatment of fractures.

Anogeissus leiocarpus DC is an evergreen tree, widely distributed in Asia and Africa. The stem bark is used in traditional medicine, and as chewing sticks and infusion. Nowadays, it is becoming increasingly important to define the phytochemical profile of less studied edible plants. Aim of this research was a first complete characterization of ellagitannins and triterpenoids profiles by HPLC-DAD-MS and 1H NMR and analyses. A total of 59 compounds were identified including 43 ellagitannins and 16 triterpenoids, mainly oleane derivatives and glycosylated forms. Among ellagitannins, roburin, vescalin and castalin were found for the first time. Tannins accounted for 38.9% whereas triterpenoids were 4.8%, both estimated on dry decoction. The decoction was preliminary tested against osteoarthritis in rats. The characterization of the main phytochemicals of Anogeissus leiocarpus DC stem bark decoction is a necessary step to evaluate nutraceutical properties, paving the way for possible food applications of this plant.

From the aerial parts of Tephrosia albifoliolis (Fabaceae). which is endemic of Senegal. six flavonoids were isolated of which, 1 is reported for the first time. Its structure and those of the already known flavonoids 2-6 were established by physical and spectroscopic analysis. Application of 2D NMR techniques was useful for complete characterization of the new compound 1 as well of the others know flavonoids.

Fourteen extracts from seven Cameroon medicinal plants [1, 2], traditionally used to treat malaria and other parasitic diseases were screened for their antiprotozoal activities against Plasmodium falciparum K1 chloroquine resistant strain and Trypanosoma brucei rhodesiense, protozoa responsible for malaria and trypanosomiasis, respectively. The most active extract against P. falciparum was the methanolic extract of Albizia zygia stembark, with an IC50 value of 1.04µg/mL. Three of the tested extract showed IC50 below 7.15µg/mL against T.b. rhodesiense, with Albizia zygia methanolic extract showing again the best activity (IC50 =0.18µg/mL). These results contribute to the validation of the traditional antiprotozoal use of these medicinal species in Cameroon.

Eight extracts from seven selected Cameroonian medicinal plants, traditionally used to treat malaria and other protozoal diseases, were tested in vitro for their antiprotozoal activities against Plasmodium falciparum K1 chloroquine-resistant strain, Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei rhodesiense, protozoa responsible for malaria, visceral leishmaniasis, Chagas disease and African trypanosomiasis, respectively. The most active extract against Plasmodium falciparum K1 strain and Trypanosoma brucei rhodesiense was the methanolic extract of Albizia zygia (Fabaceae) stem bark with IC50 values of 1.0μg/ml and 0.2μg/ml, respectively. Five extracts showed IC50 values below 5μg/ml against Leishmania donovani, with the methanolic seed extract of Harungana madagascarensis showing the highest activity, but only the methanolic extract of Albizia zygia showed activity against Trypanosoma cruzi. Cytotoxicity and selectivity indexes were estimated for the most active extracts. The best ratio of cytotoxicity to antiplasmodial activity (SIa=14) was established for the methanolic leaf extract of Symphonia globulifera (Clusiaceae), while the methanolic stem bark extract of Albizia zygia showed the best ratio of cytotoxicity to antitrypanosomal activity (SIb=22.5).

In the frame work of our research on African species presenting antiparasitic activities, we reported previously the good antiprotozoal activity of Anogeissus leiocarpus (DC.) Guill. & Perr. (Combretaceae) [1]. In continuation of our work, we examined the constituents of the bark of this species.

The antiplasmodial, leishmanicidal and antitrypanosomal activities of eight natural biflavonoids were estimated in vitro on a chloroquine-resistant strain of Plasmodium falciparum, axenically grown Leishmania donovani amastigotes and Trypanosoma cruzi trypomastigotes and Trypanosoma brucei rhodesiense bloodstream forms. Lanaroflavone showed the highest antiplasmodial activity (IC50=0.48μM), isoginkgetin was the most active leishmanicidal compound (IC50=1.9μM), whereas ginkgetin (IC50=11μM) and isoginkgetin (IC50=13μM) showed the best antitrypanosomal activity in our assays. The cytotoxicity and the selectivity indices for the most active compounds were also estimated. Lanaroflavone exhibited a high selectivity index value (SI=159), indicating selective antiplasmodial activity.

Several species of the genus Vochysia (Vochysiaceae) are used by traditional communities in South America to relieve ailments linked to inflammation, such as skin sores, asthma and pulmonary congestion. As the cAMP phosphodiesterase 4 isozyme (PDE4) is currently considered as an intracellular target for new antiinflammatory drugs, several constituents of Vochysia pacifica Cuatrec., an endemic tree from the Western coast of Colombia, were tested for their ability to inhibit PDE4. Purification of the methanol extract of the stem bark of this species led to the isolation of seven known triterpene derivatives: betulinic acid, sericic acid, 24‐hydroxytormentic acid, trachelosperogenin B, 24‐hydroxytormentic acid glucosyl ester, quadranoside I and niga‐ichigoside F1. One triterpene glycoside, quadranoside I, and two triterpenes, betulinic and sericic acids, exhibited mild inhibitory activity on the isolated PDE4 isozyme. Copyright © 2005 John Wiley & Sons, Ltd.

Rutin 1 - quercetine 3-O-alpha-L-rhamnopyrannosyl (1-6) glucopyrannose - and morin 2 - 3,5,7,2',4'-pentahydroxyflavone - have been isolated from two endemic Tephrosia species of Senegal. The structures have been elucidated by comparison with the RMN spectrometric data of the literature. (C) 2004 Academie des sciences. Publie par Elsevier SAS. Tous droits reserves.

Lanaroflavone (1), a biflavonoid isolated from the methanol extract of the aerial part of Campnosperma panamense by bioguided fractionation, has been assessed for in vitro antiprotozoal activity. Lanaroflavone showed both antimalarial and leishmanicidal activities, but was inactive against Chagas disease vector, Trypanosoma cruzi.

Twenty extracts from nine Benin medicinal plants, traditionally used to treat malaria, were screened for in vitro antiplasmodial activity towards Plasmodium falciparum K1 chloroquine resistant and 3D7 chloroquine sensitive strains. All plants showed antiplasmodial activity below 10 microg/ml. Nine extracts exhibited IC50 values below 5 microg/ml towards one or both of the two strains. The most active extract towards the sensitive 3D7 strain was the methanolic extract of Croton lobatus aerial part, with an IC50 value of 0.38 microg/ml. The best inhibition of the growth of Plasmodium falciparum resistant K1 strain was observed with the methylene chloride extract of Hybanthus enneaspermus and with the methanolic extract of Croton lobatus roots (IC50=2.57 and 2.80 microg/ml, respectively).

The activity-guided fractionation of the hydroalcoholic extract of trunk bark of Cedrelopsis grevei led to the isolation of five coumarins, norbraylin (1), methyl-O-cedrelopsin (2), cedrecoumarin A (3), scoparone (4) and braylin (5) as a part of the constituents responsible for the vasorelaxing activity observed for the crude extract.

Eight extracts from four Ivorian medicinal plants, traditionally used to treat malaria, were tested for their antiplasmodial activity in vitro by assessing their ability to inhibit the uptake of [3H]hypoxanthine into the Plasmodium falciparum K1 chloroquine-resistant strain. The most active extract was the methylene chloride extract of Anogeissus leiocarpus which exhibited an IC(50) value of 3.8 micro g/ml. Inhibition of the growth of Plasmodium falciparum was also observed with the methylene chloride extract of Cochlospermum planchonii and Microdesmis keayana as well as with both methylene chloride and methanolic extracts of Hymenocardia acida.