Caracterização química e avaliação biológica dos extratos hidroetanólicos obtidos do caule, folhas, glomérulo e raízes de Leonotis nepetifolia (L.) R. Br (Lamiaceae)

Abstract

The specie Leonotis nepetifolia is widely distributed in Brazil and worldwide, is a weed treatments used for various purposes by the population, but there are few studies about its chemical composition and biological activity. The purpose of this study is to characterize chemically hydroethanolic extracts of stem, leaves, inflorescences glomerulus and roots of Leonotis nepetifolia and evaluate the biological activity of these. The chemical characterization was performed in HPLC - UV on the chemical profile of the extracts was quantified the level of total phenols and flavonoids. The antioxidant activity was assessed for DPPH˙ and reduce power of the extracts. The microbial activity test was used for broth microdilution methods for bacteria and fungi. We performed screening of the extracts and the activity against promastigotes e amastigotes forms of Leishmania amazonensis. The cytotoxic activity of the extracts was evaluated in murine peritoneal. The chromatograms and UV spectra revealed the presence of polyphenols and flavonoids in greater abundance in extracts of leaves and inflorescences glomerulus, compared with the roots and stem the quantitative analyses showed the same result. The extracts of the stem showed higher activity against Gram positive bacteria, mainly Bacillus cereus, all extracts inhibited the growth of 50% of the bacterial population , all extracts were able to inhibit the growth of 50% and 100% of the extract showed no fungal growth and extracts of the leaves and roots showed greater activity against promastigotes and amastigotes forms of L. amazonensis and the roots extracts showed greater cytotoxic potential in murine macrophages. The crude extracts from Leonotis nepetifolia showed significant activities that relate to the secondary metabolites present in the species mainly polyphenols and flavonoids, performed int this study.