Effect of some antioxidants on oxidative DNA damage induced by autoxidation of microquantities of sulfite in the presence of Ni(II)/Gly-Gly-L-His

摘要

Ni~(II)GGH (GGH, glycylglycyl-L-histidine) reacts rapidly with S(IV), in air-saturated solution, to produce Ni~(III)GGH. A mechanism is proposed where Ni~(III) oxidizes SO_3~(2-) to SO_3~(·-), which reacts with dissolved oxygen to produce SO_5~(·-), initiating radical chain reactions. DNA strand breaks and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) formation were observed in air-saturated solutions containing micromolar concentrations of nickel(II) and S(IV). The efficacies of melatonin, (-)-epigallocatechin-gallate (from green tea), resveratrol, tannic, and ascorbic acids in terms of their inhibitory activities of DNA strand breaks and 8-oxodGuo formation were evaluated.