Mechanism of Resveratrol Dimers Isolated from Grape Inhibiting O Induced DNA Damage by UHPLC-QTOF-MS and UHPLC-QQQ-MS Analyses.

Resveratrol dimers have been extensively reported on due to their antioxidative activity. Previous studies revealed that resveratrol dimer has been shown to selectively quench singlet oxygen (O), and could protect DNA from oxidative damage. The mechanism of resveratrol dimers protecting DNA against oxidative damage is still not clear. Therefore, in this project, the reactants and products of resveratrol dimers protecting guanine from oxidative damage were qualitatively monitored and quantitatively analyzed by UHPLC-QTOF-MS and UHPLC-QQQ-MS. Results showed that when guanine and resveratrol dimers were attacked by O, mostly resveratrol dimers were oxidized, which protected guanine from oxidation. Resveratrol dimers' oxidation products were identified and quantified at 467.1134 [M-H] and 467.1118 [M-H], respectively. The resorcinol of resveratrol dimers reacted with singlet oxygen to produce p-benzoquinone, protecting guanine from O damage. Therefore, it is hereby reported for the first time that the resorcinol ring is the characteristic structure in stilbenes inhibiting O induced-DNA damage, which provides a theoretical basis for preventing and treating DNA damage-mediated diseases.