Caracterização química, atividade antioxidante e antigenotóxica de extrato de brácteas de Araucaria angustifolia (Bert) O. Kuntze

Abstract

Araucaria angustifolia (Bert.) O. Kuntze is a dioecious species, with male and female flowers found on separate trees. The A. angustifolia female cone consists of fully developed edible seeds and non-developed seeds called bracts. These bracts have high concentration of phenolic compounds, which have the potential to prevent oxidative damage to lipids, proteins and nucleic acids, and decreasing the incidence of diseases related to oxidative stress, such as cardiovascular and neurological diseases, and cancer. The aim of the present study was to evaluate the chemical characterization and antioxidant and antigenotoxic activities of the extract of A. angustifolia bracts. In this work the polyphenols total of A. angustifolia extract was determinate by Folin-Ciocalteu reagent and its chemical composition was confirmed by high performance liquid chromatography (HPLC). The extract potential to neutralize reactive species was evaluated by 2,2- diphenyl 1-picrylhydrazyl (DPPH●) method and by the ability to mimic the activities of superoxide antioxidants like dismutase (SOD) and catalase (CAT). In human cell line of lung fibroblast (MRC5), we evaluated the protective effect of the extract on cell viability by reduction of 3 - (4,5 dimethylthiazol - 2 - yl ) -2,5 diphenyl tetrazolina bromide (MTT), in the activity of SOD and CAT enzymes in oxidative damage to lipids, proteins and the deoxyribonucleic acid (DNA) (enzymatic and alkaline comet assay) induced by hydrogen peroxide (H2O2). The total phenolic content of the A. angustifolia extract was 670.93 ± 17.79 mg catechin / 100 g bracts, and catechin, epicatechin, quercetin and apigenin the main polyphenol found. The A. angustifolia extract was able to reduce DPPH● and presented like activity of SOD and CAT enzymes. Furthermore, the A. angustifolia extract at the concentrations studied (25 and 50 mg/mL) reduced cell death , oxidative damage to lipids, proteins and DNA, and decreased depletion of antioxidant enzymes SOD and CAT induced by H2O2 in MRC5 cells . Although, no correlation between polyphenols and bookmarks of oxidative injury have been observed. There was a negative correlation between damage to lipids, proteins and DNA with enzymes SOD and CAT, suggesting that these enzymes play a role in the regulation of cellular redox metabolism. These results showed that the A. angustifolia has potential as a source of phytochemical compounds with relevant bioactivities.