Antioxidant features of red wine pyranoanthocyanins: experimental and theoretical approaches

This work is focused on the study of the antioxidant properties of red wine anthocyanin derivatives (carboxypyranoanthocyanins, methylpyranoanthocyanins, oxovitisins, and pyranoanthocyanin-phenolics) derived from malvidin-3-glucoside. Some antioxidant features were determined using the DPPH assay and the ability to delay lipid peroxidation in a liposome membrane system by monitoring oxygen consumption. The pyranoanthocyanin-phenolics have higher antioxidant potential than that of malvidin-3-glucoside, suggesting that the addition of a catechol or flavanol moiety increases the antioxidant capacity. The only derivatives that showed lower antioxidant features than malvidin-3-glucoside were oxovitisins and methylpyranomalvidin-3-glucoside. Also, the radical scavenging capacity of these pyranoanthocyanins was computationally explored using DFT methods. All pyranoanthocyanins were suggested as good candidates as antioxidant compounds because they easily donate an H atom to the free radicals, originating stable species. Altogether, these results support the fact that the antioxidant potential arising from anthocyanins is not impaired by some of their transformations during red wine aging.