Red cabbage anthocyanins: Profile, isolation, identification, and antioxidant activity

Red cabbage is rich in a number of bioactive substances, including anthocyanins. The anthocyanin profile of red cabbage consisting of twenty derivatives of cyanidin glucosides was described by means of HPLC-DAD-MS/MS. The base structure of anthocyanins identified was cyanidin-3-diglucoside-5-glucoside. Their glucoside residues were nonacylated, monoacylated and diacylated. Sinapic, ferulic, caffeic and p-coumaric acids were recognized as main phenolic adds in this structure. The predominant anthocyanin in red cabbage was nonacylated form of cyanidin-3-diglucoside-5-glucoside, followed by cyanidin-3-(sinapoyl)(sinapoyl)-diglucoside-5-glucoside and cyanidin-3-(p-coumaroyl)-diglucoside-5-glucoside. Anthocyanins were isolated and purified by Amberlite XAD-16 column chromatography and by HPLC on C18 semi-preparative column. Among the seven isolated and purified red cabbage anthocyanins, cyanidin-3-diglucoside-5-glucoside diacylated with sinapic add showed the highest radical-scavenging activities toward both 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation and superoxide anion radical. The relative contribution of anthocyanins to the antioxidant capacity of red cabbage extract was low. The results obtained indicated that red cabbage has its own characteristic anthocyanin pattern as well as a kind of acylation that affects the antioxidant activity of acylated anthocyanins. (C) 2012 Elsevier Ltd. All rights reserved.