A Theoretical Elucidation on Radical-Scavenging Activity of Three Anthocyanins in Black Rice

To investigate the difference in the radical-scavenging-activity of three anthocyanins,i.e.Cyaniding-3-glucoside,Cyaniding-3,5-diglucoside and Pelargonidin-3,5-diglucoside,the O-H bond dissociation enthalpy (BDE) and ionization potential (IP) were calculated by a combined density functional theory (DFT) method B3LYP/6-31G(d)//AM1.It was found that there is a high linear coefficient between IP and total antioxidant capacities (TAC),implying that proton-coupled electron-transfer mechanism is preferred in the radical-scavenging process.