In vitro antileishmanial activity of Mexican medicinal plants

AIM OF THE STUDY: To evaluate the anti-leishmanial activity and cytotoxicity of aqueous and organic extracts of ten plants used in Mexican traditional medicine as anti-parasitics. MATERIALS AND METHODS: For the organic extracts, plant material was macerated in dichloromethane (CH(2)Cl(2)) and dichloromethane/methanol (CH(2)Cl(2)/MeOH) (1:1) during two weeks; the aqueous extracts were prepared by infusion. The extracts were tested against promastigotes and intracellular amastigotes of Leishmania amazonensis. The cytotoxicity was assayed in parallel on peritoneal macrophages of BALB/c mice. RESULTS: Four of the thirty extracts tested were active and selective against L. amazonensis promastigotes: Schinus molle (CH(2)Cl(2) and CH(2)Cl(2)/MeOH), Lantana camara (CH(2)Cl(2)) and Prosopis laevigata (aqueous). These extracts had a median inhibitory concentration (IC(50)) against intracellular amastigotes under 50 μg/mL and a selectivity index (SI) higher than 5, which indicates that they constitute valuable candidates to obtain secondary metabolites with leishmanicidal activity. CONCLUSIONS: The results derived from this study indicate that L. camara, P. laevigata, and S. molle might provide interesting new leads for the development of antileishmanial drugs.