Atividade antioxidante do extrato do caroço do açaí: aspectos moleculares em células endoteliais humanas

Abstract

The discard of açai seed (Euterpe oleracea Mart.) has a significant environmental impact. Thus the development of by-products that facilitate the use of them is extremely relevant. An hydro-alcoholic extract of acai seed has been shown as a possible medicinal plant extract with pharmacological properties useful for therapeutic use in the treatment of cardiometabolic diseases. The endothelium is an important component in the pathogenesis of various vascular diseases, and endothelial dysfunction is the initial event in the development of atherosclerotic disease. However, there is no enough knowledge about the antioxidant activity, the content and profile of phenolic compounds and molecular aspects involved in the biological activity of ASE in human endothelial cells, which are the objectives of this study. Endothelial cells from human umbilical cord (HUVEC) were used in the presence of an oxidative insult induced by hydrogen peroxide (H2O2) concomitantly or not with ASE. The antioxidant activity of the extract was measured by Folin-Ciocalteu, ferric reducing ability power (FRAP), trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) and quantification, as well as the profile of phenolic compounds were assessed using high performance liquid chromatography (HPLC). Analyzes of generation of reactive species oxygen and protein carbonylation, and the activity of antioxidant enzymes, migratory potential of the cells and expression of proteins involved in the pathway of the transcription factor Nrf2 were performed. The outcomes show that ASE has high antioxidant capacity compared to other extracts. Seven phenolics compounds were quantified most of them belong to the class of phenolic acids: syringic acid (4.0 mg /100 g of dry extract), 2-hydroxy cinnamic acid (9.9 mg /100 g of dry extract), acid gallic (19.0 mg /100 g of dry extract), 3,4-dihydroxybenzoic acid (22.6 mg /100 g of dry extract), benzoic acid (26.7 mg /100 g extract dry), 3,4-dihydroxyphenylacetic acid (65.7 mg /100 g of dry extract) and 4-hydroxyphenylacetic acid (93,7 mg phenol/100 g of dry extract). Groups that were exposed to H2O2 showed less migratory potential greater ROS and increased the protein carbonylation, with the treatment and pretreatment with ASE able to attenuate these parameters. There was a tendency to higher expression of Nrf2 in the groups treated with ASE, requiring more work compared signaling pathways and regulate this transcription factor. Thus, ASE, that is rich in phenolic compounds, was able to revert the above oxidative stress induced by H2O2 and there is a tendency that this effect is attributable to upregulation of Nrf2 signaling pathway in human endothelial cells