Anti-apoptotic effects of novel phenolic antioxidant isolated from the Pacific oyster (Crassostrea gigas) on cultured human hepatocytes under oxidative stress.

The antioxidant, and hepatoprotective properties of 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA), a natural phenolic antioxidant isolated from the Pacific oyster, were defined using cultured human hepatocyte-derived cells (C3A). DHMBA showed no cytotoxicity at 62.5-500μM, as well as chlorogenic acid (CGA), vitamin C, and vitamin E. However, butylated hydroxytoluene, eicosapentaenoic acid, docosahexaenoic acid and catechin reduced cell viability. In the presence of the prooxidant 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), DHMBA at 125-500μM improved cell viability, whereas CGA had no effect. DNA ladder formation and flow-cytometric studies indicated that DHMBA inhibited AAPH-induced apoptosis and necrosis. CGA was ineffective. Thus, DHMBA is a novel, potent antioxidant, effectively protecting cultured hepatocytes from apoptosis and necrosis caused by oxidative stress. Additionally, the concentration of DHMBA was determined by mass spectrometry to be 24.4μmol/kg wet oyster meat, and three polyphenols (gentisic acid, daidzein, and matairesinol) were newly identified in the oyster extracts.