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 (CH2Cl2) and dichloromethane/methanol (CH2Cl2/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 (CH2Cl2 and CH2Cl2/MeOH), Lantana camara (CH2Cl2) and Prosopis laevigata (aqueous). These extracts had a median inhibitory concentration (IC50) 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.