Electrochemical Study on DNA Damage Based on the Direct Oxidation of 8‐Hydroxydeoxyguanosine at an Electrochemically Modified Glassy Carbon Electrode

Abstract

AbstractThe study of DNA damage induced by Fenton reaction (Fe2+/H2O2) in vitro was performed based on the direct electrochemical oxidation of 8‐hydroxydeoxyguanosine (8‐OH‐dG), the biomarker of DNA oxidative damage, at an electrochemically modified glassy carbon electrode (GCE). The effects of antioxidants, such as ascorbic acid, and hydroxyl‐radical scavenger (mannitol) on the DNA damage were also investigated. 8‐OH‐dG, the oxidation product of guanine residues in DNA, has shown significantly oxidative peak on the electrochemically modified GCE. The oxidative peak current of 8‐OH‐dG was linear with the damaged DNA concentration in the range of 10–200 mg/L. The experimental results demonstrate that ascorbic acid has ambivalent effect on DNA oxidative stress. It can promote DNA oxidative damage when ascorbic acid concentration is below 1.5 mM and protect DNA from damage in the range of 1.5–2.5 mM. As a hydroxyl‐radical scavenger, mannitol inhibits significantly DNA oxidative damage. The influence of Fe2+, as reactant, and EDTA as iron chelator in the system were also studied. The proposed electrochemical method can be used for the estimation of DNA oxidative damage from new point of view.