Abstract: Proanthocyanidins, which are the predominant compounds of the bark extracts of Myrica esculenta,Phyllantus emblica and Larix gmelini, were separated and purified in the present study. Three different systems, i.e., the DPPH radical scavenging assay,FRAP and lipid peroxidation inhibitory activity were used to investigate the antioxidant activity of the extracts. The results showed that all three extracts had high antioxidant activity. The bark extracts of M. esculenta had a stronger antioxidant ability than those of P. emblica and L. gmelini. The structure-activity relationship of proanthocyanidins was confirmed on the basis of the results obtained. The more hydroxyl groups (—OH) of these compounds might contribute to the higher antioxidant activity.

Key words: proanthocyanidins, antioxidant activity, Myrica esculenta, Phyllanthus emblica, Larix gmelinii