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

Abstract

The study of DNA damage induced by Fenton reaction (Fe 2þ /H 2 O 2 ) 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 Fe 2þ , 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.

On‐Line Electrochemistry/Electrospray Ionization Mass Spectrometry (EC/ESI‐MS) for the Generation and Identification of Nucleotide Oxidation Products

“…For dGMP and dCMP, good conversion rates were achieved, allowing advanced structure elucidation of dGMP oxidation products by ESI-MS/MS. Further developments in the electrochemical technique, for example the combination of the direct electrochemical oxidation with Fenton reactions [14], have the potential to further increase the oxidative conversion of nucleotides. The comparison of the presents results with oxidative DNA damage occurring in the organism shows that the formation of mutagenic DNA lesions like 8-oxo-dGMP, 2'-deoxy-5-hydroxycytidine 5'-monophosphate, 2'-deoxycytidine glycol 5'-monophosphate as well as hydroxylated dUMP and dTMP species was successfully achieved in the EC-MS setup.…”

“…Besides bare electrode surfaces, modified glassy carbon electrodes have been implemented for studying DNA oxidation processes. [13,14]. Electrochemical DNA sensors, generally consisting of single stranded DNA, immobilized on glassy carbon electrode surfaces, can bind highly specific to target DNA strands [15].…”

DNA-based biosensor for the electrocatalytic determination of antioxidant capacity in beverages

“…The RSD was 3.2% at 1 µmol l −1 . Zhang et al (2008) reported the study of DNA damage induced by Fenton system on a glassy carbon electrode (GCE) and its pro-tection with the antioxidant ascorbic acid. These authors verified that ascorbic acid promoted protective effect on the DNA in a nar-row concentration range (from 1.5 to 2.5 mmol l −1 ) while at lower concentrations, a prooxidant role was observed.…”

Electrochemical evaluation of total antioxidant capacity of beverages using a purine-biosensor

“…Zhang et al (2008) reported the study of DNA damage induced by Fenton system on a GCE and its protection with the antioxidant ascorbic acid. Ascorbic acid promoted protective effect on the DNA in a narrow concentration range (from 1.5 to 2.5 mmol l -1 ) (Zhang et al, 2008). Nobushi and Uchikura (2010) reported the protective effects on the DNA by applying ascorbic acid as a scavenging antioxidant.…”