Polyphenolics enhance red blood cell resistance to oxidative stress: in vitro and in vivo

In this study we investigated the potential antioxidant properties of blueb erry polyphenolics in vitro and vivo, using red blood cell (RBC) resistance to reactive oxygen species (ROS) as the model. In vitro incubation with an thocyanins or hydroxycinnamic acids (HCA) (0.5 and 0.05 mg/ml) was found to enhance significantly RBC resistance to H2O2 (100 mu M) induced ROS produc tion. This protection was also observed in vivo following oral supplementat ion to rats at 100 mg/ml. However, only anthocyanins were found to afford p rotection at a significant level, this at 6 and 24 h post supplementation. This protection was not consistent with the measured plasma levels of antho cyanins. Indeed, plasma polyphenolic concentrations were highest after 1 h, declining considerably after 6 h and not detected after 24 h. The differen ce in absorption between anthocyanins and HCA is likely to have contributed to the observed difference in their abilities to afford protection to RBC. This protection represents a positive role following dietary consumption o f polyphenolics from blueberries, against ROS formation within RBC in vivo. (C) 2000 Elsevier Science B.V. All rights reserved.