EFFECT OF FLAVAN-3-OL TANNINS PURIFIED FROM CAMELLIA-SINENSIS ON LIPID-PEROXIDATION OF RAT-HEART MITOCHONDRIA

We induced lipid peroxidation in rat heart mitochondria with FeSO4 and compared the inhibitory effect of various flavan-3-ol tannins on it. These tannins were purified from Chinese tea (Camellia sinensis). Oxygen consumption and malondialdehyde formation were used to quantitate the amount of lipid peroxidation. The free radical scavenger activity of tannins was then measured with a diphenyl-p-picrylhydrazyl method. These tannins significantly inhibited lipid peroxidation at micromolar concentration. Their potencies were higher than that of Trolox, a water soluble analogue of vitamin E. Since epicatechin-3-O-gallate, epigallocatechin-3-O-gallate and gallocatechin-3-O-gallate were more potent than other flavan-3-ol tannins in these assays, we considered that a galloyl group in 3-O-position increased the scavenger activity of flavan-3-ol tannins as well as their potency in inhibiting lipid peroxidation.