Phenolics from the Patagonian currants Ribes spp.: Isolation, characterization and cytoprotective effect in human AGS cells

The South American currants (Ribes spp.) are native species occurring in southern Chile and Argentina. Ripe fruits from Ribes cucullatum, Ribes magellanicum, Ribes punctatum and Ribes trilobum were investigated for antioxidant activity and phenolic constituents. The fruit extracts were submitted to membrane chromatography to separate the anthocyanins and copigments. Individual anthocyanins were isolated by high-performance counter-current chromatography and were identified as cyanidin-3-rutinoside, cyanidin-3-glucoside, delphinidin-3-glucoside and delphinidin-3-rutinoside. The main compound in the copigment fraction was 3-caffeoylquinic acid. Around 60 compounds were tentatively identified by HPLC-DAD-MS/MSn. The fruit phenolics comprise 23 anthocyanins, 13 hydroxycinnamic acids (HCA) and 23 flavonols. From the polymeric fraction, (epi)-gallocatechin and (epi)catechin tetramers were identified after thiolytic depolimerization. Significant cytoprotection was exhibited by the extracts, anthocyanins and copigments against oxidative and dicarbonyl-induced stress in human gastric AGS cells. This study provides evidence on the potential of native Chilean currants as functional foods. (C) 2016 Elsevier Ltd. All rights reserved.