Resveratrol affects in a different way primary versus fixed DNA damage induced by H2O2 in mammalian cells in vitro.

Resveratrol (3,5,4'-trihydroxystilbene) is a natural occurring molecule, synthesized by plants in response to different stresses. Recent literature data seem to converge in indicating Resveratrol as an agent possessing protective effects against oxidative stresses through different mechanisms. Furthermore conflicting data are present in relation to its activity of free radical scavenger. Here we studied the antioxidant activity actually exerted by the agent against reactive oxygen species induced by H(2)O(2) treatments in CHO cells. Our attention has been focused on two major potential mechanisms: scavenging activity and interference with oxidative metabolism, by the analysis of three important targets: intracellular oxidation (Dichlorofluorescein Test), primary DNA damage (Comet Assay) and fixed DNA damage (chromosomal aberrations). Cells were treated with a single H(2)O(2) dose (2x10(-4) M) in order to induce Reactive Oxygen Species and than challenged with Resveratrol to test its ability in modulating damage. Two experimental protocols have been applied: (i) simultaneous treatment and (ii) a 3 h Resveratrol pre-treatment. In our experimental conditions Resveratrol does not appear able, 'per se', to induce primary DNA damage whereas a slight increase in endogenous oxidation and chromosomal aberrations at the highest dose have to be noticed. In combined treatments the molecule appears to differently affect primary and fixed DNA damage.