Estudo fitoquímico e avaliação da atividade biológica de Tibouchina pereirae Aubl. (Melastomataceae)

Abstract

The Melastomataceae family comprises 4,570 species in approximately 180 genera present in all tropical and subtropical regions of the planet. This family, in Brazil, is the sixth largest family of Angiosperms, with over 1500 species. The genus Tibouchina presents, approximately, 350 species, however, are poorly studied. The Tibouchina pereirae Aubl., a shrub, is popularly used for the treatment of kidney diseases. In this study, we show the antioxidant and antinociceptive effects of T. pereirae. The hexane (EHTP), ethanol (EETP) and aqueous (EATP) extracts were obtained by maceration from the aerial parts of T. pereirae. The flavonoid rich fraction (FFTP) was obtained from fractionation of EHTP. The analysis of FFTP by HPLC-DAD and HPLC-MS/MS led to characterization of these flavonoids. The antioxidant activity of extracts was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay system and the in vivo experiments were conducted on Swiss mice using the acetic acid-induced writhing test and the formalin-induced pain test. Results showed that extracts (EHTP, EETP and EATP) and FFTP present antioxidant activity, when compared to standard butylated hydroxytoluene (BHT) and ascorbic acid (AA). The EHTP and FFTP (i.p., 100mg/Kg) reduced the nociception produced by acetic acid by 90,36% and 94,74%, respectively. The FFTP reduced the formalin effects in both phases by 54, 35% and 92,05%, while the EHTP only protected the second phase by 83,39%.