The role of anthocyanins as an antioxidant under oxidative stress in rats.

Cyanidin 3-O-beta-D-glucoside (C3G) is included in anthocyanins, and expected to have a potency to scavenge active oxygen species in vivo. Rats were fed a diet containing C3G (2 g/kg diet) for 14 days, and then subjected to hepatic ischemia-reperfusion (I/R) as an oxidative stress model. I/R treatment elevated the liver thiobarbituric acid-reactive substance concentration and the serum activities of marker enzymes for liver injury, and lowered the liver reduced glutathione concentration. Feeding C3G significantly suppressed these changes caused by hepatic I/R. These results indicate that C3G functions as a potent antioxidant in vivo under oxidative stress. To clarify the mechanism of action of C3G, we investigated the absorption and metabolism of C3G in rats. C3G appeared in the plasma immediately after the oral administration of C3G. Protocatechuic acid, which seems to be produced by the degradation of cyanidin, was also present in the plasma. In the liver and kidneys, C3G was metabolized to methylated form.