In vitro antiplasmodial activity and cytotoxicity of nine plants traditionally used in Gabon.

Abstract Aim of the study As part of a project to identify new compounds active on malarial parasites, we tested the in vitro antiplasmodial activity of nine plants traditionally used to treat malaria symptoms in Haut-Ogooue Province, South-East Gabon. Materials and methods Dichloromethane and methanolic extracts of each plant were tested for their antiplasmodial activity on two chloroquine-resistant strains of Plasmodium falciparum (FCB and W2), based on lactate dehydrogenase activity. Cytotoxicity was assessed with the MTT test on MRC-5 human diploid embryonic lung cells. Results The methanolic extract of Staudtia gabonensis and the dichloromethane extract of Adhatoda latibracteata showed high antiplasmodial activity (IC 50 Monodora myristica and the dichloromethane extract of Afromomum giganteum also showed promising activity (1  50 Monodora myristica and Leonotis Africana showed moderate activity (10  50 Culcasia lancifolia had IC 50 values of 10–40 μg/ml but high cytotoxicity (selectivity indexes Dorstenia klaineana had moderate antiplasmodial activity (IC 50 around 17 μg/ml) but strong cytotoxicity (0.43 μg/ml), giving a selectivity index of about 0.03. Conclusions Most extracts of nine selected plants traditionally used to treat malaria in Gabon had interesting antiplasmodial activity in vitro . This supports continued investigations of traditional medicines in the search for new antimalarial agents. The compounds responsible for the observed antiplasmodial effects are under investigation.