Leishmaniasis is the second-largest parasitic killer in the world (after malaria).Currently, there are no effective vaccines or therapeutic interventions thus creating a gap for new alternative remedies in the management of the disease. Medicinal plants offer this attractive option as antileishmanial agents since they are relatively safe, locally available and affordable. The study assessed antileishmanial activity of methanol, hexane, dichloromethane and ethyl acetate extracts, in addition to the aqueous phase of Bidens pilosa, Tithonia diversifolia and Sonchus oleraceus on Leishmania major parasites as well as their phytochemical composition. The phytochemical screening of the plants showed presence of alkaloids, saponins, terpenoids, anthraquinones, glycosides, tannins and flavonoids. Cytotoxicity studies on Vero cells showed a low toxicity with IC50 more than 0.12 mg/ml. L. major viability was determined at various concentrations of the extracts and standard (Pentostam) using MTT reagent and results displayed as IC50. The extracts from S. oleraceus, B. pilosa, and T. diversifolia displayed IC50 values from 0.03 mg/ml to 4.89 mg/ml on Leishmania parasites. Among the three plants extracts, dichloromethane extract had the highest activity with IC50 0.03 mg/ml. As indicated, all the extracts demonstrated a great potential in inhibiting the growth of Leishmania promatigotes with low toxicity making them good candidates for compound isolation and drug manufacture.
Keywords: Vero cells, MTT, cytotoxicity, promastigotes, Sonchus oleraceus, Bidens pilosa, Tithonia diversifolia