In vivo non-enzymatic repair of DNA oxidative damage by polyphenols.
The non-enzymatic repair of DNA oxidative damage can occur in a purely chemical system, but data show that it might also occur in cells. Human hepatoma cells (SMMC-7721) and human hepatocyte cells (LO2) were treated with 200microM H(2)O(2) for 30min to induce oxidative DNA damage quantified by amount of 8-OHdG and degree of DNA strand breaks, without inducing enzymatic repair. The dynamics of enzymatic repair activity quantified by unscheduled DNA synthesis, within 30min after removal of H(2)O(2) enzymatic repair mechanism has not been initiated. However, pre-incubation with low micromolar level polyphenols, quercetin or rutin can significantly attenuate DNA damage in both cell lines, indicating that the polyphenols did not work through an enzymatic mechanism. Unscheduled DNA synthesis after removal of H(2)O(2) was also markedly decreased by quercetin and rutin. Combined with our previous studies of fast reaction chemistry, the inhibitory effect of polyphenols have to be assigned to non-enzymatic repair mechanism rather than to enzymatic repair mechanism or antioxidant mechanism.
Tan
Xiaorong
X
School of Bioengineering, Henan University of Technology, Zhengzhou, People's Republic of China.
Zhao
Chenyang
C
Pan
Jing
J
Shi
Yimin
Y
Liu
Guoan
G
Zhou
Bo
B
Zheng
Rongliang
R
D000080242:8-Hydroxy-2'-Deoxyguanosine; D002460:Cell Line; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects / Q000502:physiology*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D010636:Phenols / Q000378:metabolism*; D059808:Polyphenols; D011794:Quercetin / Q000378:metabolism; D012431:Rutin / Q000378:metabolism
D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D012431:Rutin; D000080242:8-Hydroxy-2'-Deoxyguanosine; D011794:Quercetin; D006861:Hydrogen Peroxide; D003849:Deoxyguanosine