AVALIAÇÃO QUÍMICA E BIOLÓGICA DE ESPÉCIES DE Baccharis (ASTERACEAE)

Abstract

Baccharis is a genus widely distributed in the Americas, comprising 442 species, 40% of which occur in Brazil. Baccharis species are known in folk medicine as “carquejas” and “vassouras”, being used especially in tea form as anti-inflammatory, digestive and diuretic. The wide use of species of this genus in traditional medicine can be attributed to the main chemical groups, flavonoids and terpenoids, especially essential oils. The substances present in the species have great commercial and industrial importance; however, the species still lacks studies on the chemical composition, biological activities and safety in use. Therefore, this study aims to investigate the chemical composition and biological activities of B. albilanosa, B. coridifolia, B. dracunculifolia, B. erigeroides, B. microdonta, B. napaea, B. ochracea, B. pauciflosculosa, B. pluricapitulata, B. punctulata, B. reticularioides e B. sphenophylla. Through microchemical analysis it was possible to locate the structures responsible for the compartmentalization of the main secondary metabolites of Baccharis species, being essential oils and oleoresins found in the secretory ducts and glandular trichomes, and the phenolic compounds in the mesophyll, stem cortex and vascular systems. By means of GC-MS, the chemical profile of the essential oils from B. albilanosa, B. coridifolia, B. erigeroides, B. napaea, B. ochracea and B. pluricapitulata were investigated, in which spathulenol (7.48-38.56%) and caryophyllene oxide (11.04-11.11%) presented as major components. The cytotoxic potential of the essential oils from B. albilanosa, B. coridifolia, B. erigeroides, B. napaea, B. ochracea and B. pluricapitulata were also investigated, and almost all of which showed cytotoxicity against the four cancer strains SK-MEL, KB, BT-549 and SK-OV-3, except the essential oil of B. erigeroides. Regarding normal kidney cells, most samples were cytotoxic against both LLC-PK1 and Vero, with the exception of B. erigeroides, for which there was no cytotoxicity in the Vero cell line. Repellent and insecticidal bioassays of the essential oils of B. microdonta, B. punctulata, B. reticularioides, B. sphenophylla and B. pauciflosculosa were carried out, in which the repellent activities of essential oils of B. microdonta and B. punctulata (a 10 μg/cm2

), and the isolated

compounds spathulenol and kongol were similar to DEET (25 nmol/cm2

). Baccharis punctulata showed the highest insecticidal action (DL50 = 20.4 ppm) among the five species evaluated. Acute toxicity assay was performed on B. dracunculifolia and the aqueous extract and essential oil showed no toxicity up to the dose of 2.000 mg/kg in rats. This is the first study to investigate the chemical composition and biological activities of B. albilanosa, B. erigeroides, B. napaea e B. pluricapitulata. Finally, this work brings unprecedented information to the genus Baccharis, adding even more industrial and commercial value and the therapeutic potential of the species.