Isolation of anthocyanin from black rice (Heugjinjubyeo) and screening of its antioxidant activities

Abstract

Colored rices are a hulled grains having red or purple pigments in bran. Especially black rice (Heugjinjubyeo) is considered to be a healthy food in Asia. Black rice is of great interesting because of the possible biological activity with their anthocyanins. Anthocyanins are water-soluble plant pigments and representatives of flavonoids. The anthocyanins in black rice include cyanidin 3-O-glucoside, peonidin 3-O-glucoside, malvidin 3-O-glucoside, pelagonidin 3-O-glucoside and delphinidin 3-O-glucoside. In this study, anthocyanins in a black rice were analyzed quantitatively and qualitatively with HPLC and UV-Vis spectrophotometer. The anthocyanins contained approximately 95% of cyanidin -3-O-glucoside and 5% of peonidin -3-O-glucoside. Antioxidant activities of the anthocyanin extract were investigated by using various in vitro methods. The 100g/ml concentration of the anthocyanin extracted exhibited 88.83% inhibition on the peroxidation of linoleic acid, 55.20% DPPH free radical scavenging activity, 54.96% superoxide anion radical scavenging activity, and 72.67%) hydrogen peroxide scavenging activity. And it also showed high ferrous ion reducing capability. These results suggest that the anthocyanin extracted from black rice may be utilized as a possible antioxdiant agent against ROS.