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
