Effect of complex polyphenols and tannins from red wine on DNA oxidative damage of rat colon mucosa in vivo

Background: Dietary polyphenols have been reported to have a variety of bio logical actions, including anti-carcinogenic, antioxidant and anti-inflamma tory activities. Aim of the study: In the present study we have evaluated the effect of an o ral treatment with complex polyphenols and tannins from red wine and tea on DNA oxidative damage in the rat colon mucosa. Methods: Isolated colonocytes were prepared from the colon mucosa of rats t reated for ten days with either wine complex polyphenols (57.2 mg/kg/d) or theartbigin (40 mg/kg/d) by oral gavage. Colonocyte oxidative DNA damage wa s analysed at the single cell level using a modification of the comet assay technique. Results: The results show that wine complex polyphenols and tannins induce a significant decrease (-62 % for pyrimidine and -57 % for purine oxidation ) in basal DNA oxidative damage in colon mucosal cells without affecting th e basal level of single-strand breaks. On the other hand, tea polyphenols, namely a crude extract of thearubigin, did not affect either strand breaks or pyrimidine oxidation in colon mucosal cells. Conclusions Our experiments are the first demonstration that dietary polyph enols can modulate in vivo oxidative damage in the gastrointestinal tract o f rodents. These data support the hypothesis that dietary polyphenols might have both a protective and a therapeutic potential in oxidative damage-rel ated pathologies.