Abstract
Bergenin is a C-glucoside of 4-O-methyl gallic acid that has been isolated from the cortex of Mallotus japonicus (Euphorbiaceae). Acetylbergenin was synthesized by acetylation from bergenin to increase lipophilic and physiological activities. The therapeutic effects of bergenin and acetylbergenin were evaluated against carbon tetrachloride ($CCl_4$)-induced hepatotoxicity in rats. Bergenin and acetylbergenin were administered orally once daily for successive 5 days, after the intraperitoneal injection of a mixture 0.5 m1/kg of $CCl_4$ in olive oil (1:1). The substantially elevated serum enzymatic activities of alanine/aspartate aminotransferase, sorbitol dehydrogenase and ${\gamma}$-glutamyltransferase induced by $CCl_4$ were restored towards normalization by posttreatment with bergenin and acetylbergenin. Bergenin and acetylbergenin also significantly prevented the elevation of hepatic malondialdehyde formation and depletion of glutathione content induced by $CCl_4$ in a dose dependent fashion. In addition, the decreased activities of glutathione S-transferase and glutathione reductase were restored towards normalization. These results suggest that therapeutic effects of bergenin and acetylbergenin may be related complex mechanisms that involve prevention of lipid peroxidation and preservation of hepatic GSH. The results of this study clearly indicate that bergenin and acetylbergenin have potent hepatothrapeutic action against $CCl_4$-induced hepatotoxicity in rats. In addition, acetylbergenin 50 mgHg showed almost the same levels of hepatoprotective activity as those of bergenin 100 mgAg, indicating the fact that lipophilic acetylbergenin is more effective in the hepatoprotective action against $CCl_4$ than bergenin.
