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Electrocatalytic evaluation of DNA damage by superoxide radical for antioxidant capacity assessment
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Orientador(es)
Resumo(s)
The integrity of DNA purine bases was herein used to evaluate the antioxidant capacity. Unlike other
DNA-based antioxidant sensors reported so far, the damaging agent chosen was the O
2 radical enzymatically
generated by the xanthine/xanthine oxidase system. An adenine-rich oligonucleotide was adsorbed
on carbon paste electrodes and subjected to radical damage in the presence/absence of several antioxidant
compounds. As a result, partial damage on DNA was observed. A minor product of the radical oxidation
was identified by cyclic voltammetry as a diimine adenine derivative also formed during the
electrochemical oxidation of adenine/guanine bases. The protective efficiency of several antioxidant compounds
was evaluated after electrochemical oxidation of the remaining unoxidized adenine bases, by
measuring the electrocatalytic current of NADH mediated by the adsorbed catalyst species generated.
A comparison between O
2 and OH radicals as a source of DNA lesions and the scavenging efficiency
of various antioxidant compounds against both of them is discussed. Finally, the antioxidant capacity
of beverages was evaluated and compared with the results obtained with an optical method.
Descrição
Palavras-chave
NADH electrocatalysis DNA damage Antioxidant capacity Ascorbic acid Reactive oxygen species Superoxide radical
Contexto Educativo
Citação
Editora
Elsevier