Estudo fitoquímico e avaliação da atividade citotóxica de espécies do gênero Baccharis

Abstract

With the growing number of cancer cases in recent decades, this disease has become an alarming worldwide problem. The pharmacological treatments available lack specificity and induce serious adverse effects, demanding research for new therapeutic options. A promising source of compounds with anti-cancer activity are plants, whether medicinal or not, which increasingly contribute to the development of antineoplastic drugs. In this context, a cytotoxic screening with 14 ethanol extracts of species of the genus Baccharis was performed against human tumor cells, since some substances already isolated, such as phenolic acids, flavonoids and terpenes, showed the pharmacological potential of species of this genus. The extracts of B. imbricata and B. megapotamica showed promising cytotoxic activity and were selected for biomonitored fractionation. The preliminary evaluation of the chemical composition of the extracts and fractions of these two species was carried out by UPLC-ESI-MS/MS and allowed the characterization of the phytochemical profile of these plants, composed mainly of derivatives of chlorogenic acid and flavonoids. The evaluation of the cytotoxic activity of the fractions was performed in lung cancer cells (A549), prostate carcinoma cells (DU145) and hepatocellular carcinoma cells (HepG2) and in healthy cell culture (human gingival fibroblasts). The dichloromethane fraction of B. imbricata was selected to continue the studies and was again divided into DCM 1 and DCM 2. Refraction of DCM 2 by HPLC-RF on a preparative scale allowed the isolation and elucidation unambiguous of betuletol, a dimethoxylated flavonol, which has already been described in the literature. This substance has already been identified in shoots of B. dracunculifolia, but it has not yet been described in B. imbricata.