Antileishmanial Potential and Chemical Characterization of the Hydroalcoholic Extract Obtained from Lantana caatingensis Moldenke (Verbenaceae) Leaves and Its Polar Fractions

Lantana caatingensis Moldenke (Verbenaceae) is an endemic plant from northeastern Brazil. However, its chemical composition is almost unknown. This study aimed to characterize the chemical compounds found in L. caatingensis and investigate the antileishmanial potential of its hydroalcoholic extract and polar fractions. Compounds present in the hydroalcoholic extract obtained from L. caatingensis leaves and its polar fractions (ethyl acetate and methanolic) were analyzed by liquid chromatography with a photodiode-array detector coupled to electrospray ionization quadrupole time-of-flight mass spectrometry. An antileishmanial assay was performed in a 96-well plate against Leishmania major promastigotes using resazurin on a plate spectrophotometer and the results were expressed as percentage of growth inhibition. Nine compounds were determined in the investigated extract and fractions, classified as flavonoids, flavonoid C-glycosides and phenylethanoid glycosides. The antileishmanial activity revealed that the hydroalcoholic extract and the ethyl acetate fraction were active against L. major promastigotes with inhibitory concentration of 71.78 and 26.86 µg mL^-1, respectively, while the methanolic fraction was inactive (478.40 µg mL^-1). This is the first report on the chemical composition and antileishmanial activity of L. caatingensis extracts. These results contribute to further knowledge of species belonging to the Lantana genus.

Keywords:
flavonoids; phenylethanoids; mass spectrometry; promastigotes; natural products