ANTI-PLASMODIAL AND IMMUNOMODULATORY ACTIVITY OF MEDICINAL PLANTS USED IN BURKINA FASO AGAINST MALARIA

Plasmodium falciparum malaria is the most common cause of death in Burkina Faso. The persistence of drug resistance parasites makes the disease difficult to control. Moreover, the recent reports of emergence of resistance to artemisinin derivatives, which are the most effective antimalarial presently available, confirm that new drugs are greatly needed. The reliability of indigenous herbal drugs may be helpful. In Burkina Faso, the decoctions of Canthium henriquesianum Schum, Gardenia sokotensis Hutch. and Vernonia colorata Willd. are used to treat malaria. The study objective was to evaluate the antiplasmodial properties of these plant extracts and to check the relevance of their use. The plants aerial parts were soxhlet-extracted with water and different solvents and then screened for antiplasmodial activity through the pLDH method on P. falciparum sensitive (D10) and resistant (W2) strains. The aqueous extract from C. henriquesianum was the most active with IC50 of 80,02± 26,83 and 66.8±21.6 μg/ml on D10 and W2, respectively. The ethyl acetate extract was even more potent with IC50 24.0±7.4 μg/ml. No toxicity was observed against mammalian cells, suggesting a good therapeutic index. The decoction of C. henriquesianum contains hydrolysable tannins, flavonoids, saponins and no alkaloids. Extracts of C. henriquesianum also induced a dose-dependent inhibition of the production of IL-1b by human monocytes, thus confirming its traditional use as antipyretic. Attempts to identify the active principle for antiplasmodial and anti-inflammatory activities are ongoing.