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