3-O-Acyl Triterpenoids and Antileishmanial Effect of the Ethanolic Extract from Mimosa caesalpiniifolia Inflorescences

Abstract

Background: Mimosa caesalpiniifolia Benth. (Mimosaceae) is a native plant from Brazilian Caatinga/Cerrado used in the traditional medicine. The aim of this work was to investigate the chemical composition and the antileishmanial activity of the inflorescences from M. caesalpiniifolia. Methods: The ethanolic extract from M. caesalpiniifolia inflorescences was submitted to fractionation in silica gel chromatography column, and the known structures were elucidated using spectroscopic methods. The antileishmanial activity of the EtOH extract and pure compounds was evaluated against the promastigote forms of Leishmania amazonensis. Results: In this study, the EtOH extract from M. caesalpiniifolia inflorescences (IC50= 74.52 μg mL-1) and lupeol (IC50 = 15.40 μg mL-1) demonstrated significant inhibition of the growth at 48 h for promastigote forms of L. amazonensis when compared with Glucantime® (IC50 = 1190.21 μg mL-1), a reference drug. Moreover, the cytotoxicity evaluation of EtOH extract of M. caesalpiniifolia inflorescences against murine peritoneal macrophages was also determined. Then, the selectivity index shows that the EtOH extract of M. caesalpiniifolia inflorescences is more toxic to the parasite than mammalian host cells. The chemical characterization of the ethanolic extract from M. caesalpiniifolia inflorescences resulted in the identification of fatty acids and isoprenoids as lupeol acetate, lupeol, β-amyrin, a mixture of steroids and a mixture of fatty acid triterpenyl esters. 3-O-Acyl triterpenoids are being reported for the first time in M. caesalpiniifolia. Conclusion: The EtOH extract of M. caesalpiniifolia inflorescences is a rich source of triterpenoids and a promising natural product against leishmaniasis.