Repair Activity Of Trans-Resveratrol Toward 2’-Deoxyguanosine Radicals

trans-Resveratrol plays great roles in preventing and controlling some disease such as cancer,Alzheimer’s disease and heart disease induced by DNA radicals because of its high oxidation activity.Therefore,it is important to study the repair activity of trans-resveratrol toward DNA radicals.In this work,the repair activity of 2′-deoxyguanosine（dGuo）radicals by neutral（ROH）and anionic（RO^-）forms of trans-resveratrol in polar and non-polar solvents have been studied using density functional theory.The hydrogen transfer（HT）/the proton coupled electron transfer（PCET）and the single electron transfer（SET）mechanisms have been considered.Both HT and SET mechanisms are contribute to the reactions between ROH and dGuo-radicals in polar solvent.However,RO^-was found to repair dGuo-radicals preferentially through SET mechanism.When molar fraction of ROH and RO^-are considered,the total rate constants k^ROHOH_totaland k^RO-_totalare 6.31×10⁶ and 9.88×10⁸ dm³ mol^-1s^-1,respectively,the repair activity of RO^-is better than that of ROH.The overall rate constants k_overallof repairing dGuo-radicals by trans-resveratrol are 9.94×10⁸ and 2.01×10⁹dm³ mol^-1s^-1in polar and non-polar solvents,respectively,which indicates that the repair activity of trans-resveratrol in non-polar solvent is better than that in polar solvent.Unfortunately,trans-resveratrol can repair base radicals of dGuo rather than 2′-deoxyribose radicals regardless of the polarity of the environment.The repairing 2′-deoxyguanosine cation radical（dGuo·⁺）by ROH and RO^-through SET mechanism is also considered in polar solvent.When molar fraction of ROH and RO^-are considered,the total rate constants k^ROHOH_totaland k^RO-_totalare 7.17×10⁹ and 9.35×10⁵ dm³ mol^-1s^-1,respectively,the repair activity of ROH is better than that of RO^-.The overall rate constants k_overallof repairing dGuo·⁺by trans-resveratrol is 7.17×10⁹ dm³ mol^-1s^-1.It can be concluded that trans-resveratrol is an effective antioxidant to repair base radicals of dGuo and dGuo·⁺.The overall rate constants k_overallin our study is well in agreement with experiments which the rate constants are about 10⁸¹0⁹ dm³ mol^-1s^-11 for the repairing dGuo-radicals by polyphenols.The study could help us to understand the repair activity of trans-resveratrol toward dGuo-radicals.