Abstract: Myrica esculenta Buch. -Ham. is a species of perennial tree distributing widely in Southern China. Major components of extracts from M. esculenta bark are partially galloylated polymeric prodelphinidins. Based on the feature of chemical structure, anti-oxidation activities of prodelphinidins are stronger compared with procyanidins. Extracts from the bark were obtained by intensified extraction with water followed by separation and purification. The extracts are proanthocyanidins identified by anthocyanidin reaction and IR-spectra. Number-average molecular weight(M_n) of the extracts are respectively 1705 (95%) and 798 (5%) determined by GPC and VPO. Galloylation degree at C-3 of the molecule were determined as 38%. Bio-activity deter-mination showed that the extracts could evidently inhibit lipid peroxidation, complex metal ions (e.g., Fe²⁺, 181 mg/g) and scavenge free radical (e.g., DPPH, scavenging speed 0.23 mg/min for 1 mg target extracts; scavenging rate 92%, while mass ratio of extract to DPPH 1:1.8). Results indicated that the extracts would be hopefully developed as a new type of natural antioxidant and radical-scavenging agent.

Key words: Myrica esculenta Buch. -Ham., proanthocyanidins, prodelphinidins, antioxidation, free radical-scavenging