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

Abstract

Ni^IIGGH (GGH, glycylglycyl-L-histidine) reacts rapidly with S(IV), in air-saturated solution, to produce Ni^IIIGGH. A mechanism is proposed where Ni^III oxidizes to , which reacts with dissolved oxygen to produce , 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.

Keywords:

• DNA
• Sulfite
• Nickel
• Gly–Gly–His
• Antioxidants

Acknowledgments

We gratefully acknowledge the financial support from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Conselho Nacional de Pesquisa e Desenvolvimento Tecnológico (CNPq) and Núcleo de Ensino, Pesquisa e Assessoria a Saúde (Nepas, FMABC).