Abstract

Therapeutic alternatives are being searched for trichomoniasis as a result of the increased prevalence of metronidazole-resistant infections. Mangifera indica L. (Anacardiaceae) is one of the most important tropical trees since ancient times. Traditionally, it has been used as an anti-diarrheal and anti-diabetic, and recently its gallotannin-rich leaves and stem bark extracts have shown antiparasitic activities against various parasites. Aiming at exploring the anti-Trichomonas vaginalis activity of Mango’s gallotannins, an aqueous ethanol extract of fresh kernels of M. indica was phytochemically investigated. Based on simple gel chromatographic procedure, ethyl gallate (2), a group of five isomeric tetragalloyl-glucoses (3–7), and a pentagalloyl-glucose (8) were simultaneously isolated from single fraction by a preparative RP-HPLC. The isolates were identified based on spectroscopic analyses and comparison with reported data. They showed structural-dependent inhibitory effects on the growth of T. vaginalis trophozoites in an in vitro investigation. Ethyl gallate and 1,2,4,6-tetra-O-galloyl-â-D-glucose (7) exhibited elevated anti-T. vaginalis activity (IC50 = 1.3, 2.4 ìg/mL, respectively). This is the first report exploring the potential of gallotannins as trichomonacidal agents.

Key words: Anacardiaceae, Mangifera indica, kernels, simultaneous isolation, gallotannins, Trichomonas vaginalis