Grape waste extract obtained by Supercritical Fluid Extractioncontains bioactive antioxidant molecules and inducesantiproliferative effects in human colon adenocarcinoma cells

Grape waste management is one of the main problems of winery industries, but, conversely, grape waste contains an high amount of polyphenols that might protect against human diseases related to oxidative stress, such as colorectal cancer. Therefore, the aim of this work was to investigate the antioxidant and antiproliferative activities of a grape waste extract obtained by Supercritical Fluid Extraction (SFE). Since the beneficial effect of grape is related to its content of polyphenolic molecules, the extract was chemically characterized by HPLC in order to assess its major bioactive components. The antioxidant activity of the grape extract was determined. The results showed that the grape extract presents a strong antiradical activity in the in vitro DPPH assay and protects against ROS production in human colon adenocarcinoma cells (Caco-2). In contrast, the extract doesn’t protect in the citronellal thermooxidation system and shows a weak protective action against lipid peroxidation in Caco-2 cells. The clonogenic assay and the cell cycle distribution analysis show that the grape extract has a significant antiproliferative effect in a tumour cell line. These data indicate that grape extract is a promising product to be used as an anti free radicals agent and could exert a chemopreventive action.