Protection against damaged DNA in the single cell by polyphenols.

The protective properties of seven polyphenols against hydrogen peroxide induced DNA damage in human peripheral blood lymphocytes (PBL) were studied using single cell micro-gel electrophoresis. Hydrogen peroxide causes a concentration-dependent increase in single cell DNA strand breakage in human PBL. Quercetin and 7,8-dihydroxy-4-methyl coumarin exhibited the strongest protection, significantly inhibiting 50 microM H2O2-induced DNA damage at a range of concentrations of 3.1-25 microM. Curcumin, resveratrol and vanillin protected against DNA damage induced by 50 microM H2O2 at a range of concentrations of 6.25-25 microM, but rutin and 7-hydroxy-4-methyl coumarin failed to provide any protection even at concentrations up to 50 microM. Quercetin, 7,8-dihydroxy-4-methyl coumarin, curcumin, resveratrol and vanillin are therefore effective in protection of human single cell DNA from oxidative attack.