Anti-Toxoplasma activity of vegetal extracts used in West African traditional medicine

Both Toxoplasma gondii and Plasmodium are Apicomplexan protozoa that share common metabolic pathways and potential drug targets. The objective of this study was to examine the anti-Toxoplasma activity of nine West African pla nts with known activity against P. falciparum. The extracts were obtained f rom parts of plant commonly used, by most traditional healers, in the form of infusion or as water decoction. The in vitro activity of plant extracts on T. gondii was assessed on MRCS tissue cultures and was quantified by enz yme-linked immunoassay, Aqueous extracts from Vernonia colorata were found to be inhibitory for Toxoplasma growth at concentrations > 10 mg/L, with on IC50 of 16.3 mg/L. A ten-fold gain in activity was obtained when organic s olvents such as dichloromethane, acetone or ethanol were used to extract V. colorota's active principles. These extracts were inhibitory at concentrat ions as low as 1 mg/L, with ICS, of 1.7, 2.6 and 2.9 mg/L for dichlorometha ne, acetone and ethanol extracts respectively. These results indicate a pro mising source of new anti-Toxoplasma drugs from V. colorata and African med icinal plants.