Effect of polyphenols from wild Chilean currants (Ribes spp.) on the activity of intracellular antioxidant enzymes in human gastric AGS cells

The protective effect of polyphenols from Chilean currants (Ribes spp.) in human epithelial gastric cells (AGS) against oxidative induced-stress has been recently reported. The aim of the present study was to assess the ability of polyphenol-enriched extracts (PEE) from three Chilean Ribes species to modify the activities of the intracellular antioxidant enzymes: catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GSH-R) and superoxide dismutase (SOD) in AGS cells. The PEE of each species was fractionated using membrane chromatography to give an anthocyanin-enriched fraction (AF) and a copigment fraction (CF). A significant increase in the SOD activity was observed with a dose-response effect after an overnight incubation of AGS cells with the PEE, AF and CF from the selected species. The activity of CAT was enhanced by the CF of Ribes magellanicum and R. cucullatum, and by the AF of R. punctatum. For the GSH-R, a dose-response effect was observed in the extracts of R. magellanicum, while for the GSH-Px activity, only the AF of R. magellanicum and R. cucullatum had a significant increase. The studied samples were not able to increase the intracellular GSH content. Only the R. magellanicum samples raised the intracellular total antioxidant activity. These results suggested that the increase in the activity of the antioxidant response enzymes is associated with the cytoprotective effect of these native currants.