Antioxidant and protective effect of an oleanolic acid-enriched extract of A. deliciosa root on carbon tetrachloride induced rat liver injury.

The ethanol-water extract of A. deliciosa root (EEAD) was fractionated into n-hexane (EEAD-He), ethyl acetate (EEAD-Ea), n-butanol (EEAD-Bu) and aqueous (EEAD-Aq) fractions according to their different polarity and solubility. Among the four extracts, it was found that EEAD-Bu was enriched with oleanolic acid (OLA). The antioxidant and hepatoprotective activities of various EEAD fractions and OLA were carefully investigated by the methods of ferric thiocyanate (FTC) and thiobarbituric acid (TBA), as well as the model of CCL4-induced liver toxicity in rats. The results showed that the EEAD-Bu had higher in vitro antioxidant and in vivo hepatoprotective activities than those of the other types of extracts (p< 0.05). When the CCL4-induced rats were treatment with 120 mg/kg EEAD-Bu, the activities of alanine transaminase (ALT) and aspartate transanimase (AST) in rat serum decreased 90 % and 81 %, respectively, as compared with those of the CCL4 control rats. Furthermore, the lipid peroxidation (MDA) decreased 42 % and glutathione (GSH) increased 114 % in the rats liver homogenate, as compared with those of the control. The results also indicated that the hepatoprotective activity of the EEAD-Bu (at the dose of 120 mg/kg) was higher than that of the reference drug silymarin (at the dose of 60 mg/kg), and OLA acted as an important role in dose-dependent protection against CCL4 hepatotoxicity. The findings indicate that the OLA-enriched EEAD-Bu extract had significant and concentration dependent hepatoprotective effect for the carbon tetrachloride induced rat liver injury.