Abstract: This study was focused on the antioxidant mechanisms of four anthocyanins from purple sweet potato.DPPH assay and lipid peroxidation assay were used to determine the antioxidant activities of the anthocyanins.And the geometrical features,bond dissociation energy (BDE) and ionization potential (IP) parameters were computationally explored using DFT (density functional theory) study.The results showed that the phenolic hydroxyl with OH-4′ were the most active,and the BDE were lower than that of resveratrol.The theoretical calculation results were consistent with the experimental conclusions.Thus,the anthocyanins could have good antioxidant activities.The DFT method could be potential for the development of antioxidant activity of anthocyanin.

Key words: anthocyanin, antioxidant activity, density functional theory, bond dissociation energy