Electrochemical and Antioxidant Properties of Anthocyanins and Anthocyanidins

Electrochemical properties of delphinidin, cyanidin, pelargonidin, kuromanin and callistephin were investigated by cyclic and differential pulse voltammetries at different pH values and also in methanol. On the basis of oxidation potentials, the order of antioxidant activity for anthocyanidins is delphinidin > cyanidin > pelargonidin. Oxidation peaks for anthocyanins (kuromanin and callistephin) are shifted to more positive potentials compared to anthocyanidins (delphinidin, cyanidin and pelargonidin). Oxidation peak currents are linearly dependent on the square root of the scan rate, which is typical of a diffusion controlled electrochemical process. Antioxidant activities of the compounds were evaluated using the 1,1 -diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method and they are directly related to their redox potential values. The order of the antioxidant activity is delphinidin > cyanidin > pelargonidin > kuromanin > callistephin.