Evaluation of resveratrol oxidation in vitro and the crucial role of bicarbonate ions

Polyphenols can oxidize in culture medium and produce artifacts in cell culture studies. However, the extent and mechanism of the oxidation of resveratrol, a polyphenol abundant in red wine, is unclear. We investigated the oxidation of resveratrol in vitro and the effects of various components of the culture medium on the degradation of resveratrol and the production of H 2O2. We found that 96% of resveratrol at a concentration of 200 μM was degraded in Base Modified Eagle Medium after 24 h of incubation at 37 °C, producing about 90 μm of H2O2. Including sodium bicarbonate in the medium markedly stimulated resveratrol degradation and H2O2 production. In sum, we found that bicarbonate ions played a crucial role in the oxidative degradation of resveratrol in vitro, and that the degradation of resveratrol can be avoided by withdrawing sodium bicarbonate from the medium. A mechanism for the oxidation of resveratrol is proposed.