Protective effect of the total flavonoids from Apocynum venetum L. on carbon tetrachloride-induced hepatotoxicity in vitro and in vivo.

Apocynum venetum L., belonging to the family Apocynaceae, is a popular medicinal plant, which is commonly used in the treatment of hypertension, neurasthenia, and hepatitis in China. In the present study, the total flavonoids (TFs) were prepared from the leaves of A. venetum, and its protective effects on carbon tetrachloride (CCl4)-induced hepatotoxicity in a cultured HepG2 cell line and in mice were investigated. Cell exposed to 0.4% CCl4 (v/v) for 6 h led to a significant decrease in cell viability, increased LDH leakage, and intracellular reactive oxygen species (ROS). CCl4 also induced cell marked apoptosis, which was accompanied by the loss of mitochondrial membrane potential (MMP). Pretreatment with TFs at concentrations of 25, 50, and 100 μg/mL effectively relieved CCl4-induced cellular damage in a dose-dependent manner. In vivo, TFs (100, 200, and 400 mg/kg BW) were administered via gavage daily for 14 days before CCl4 treatment. The high serum ALT and AST levels induced by CCl4 were dose-dependently suppressed by pretreatment of TFs (200 and 400 mg/kg BW). Histological analysis also supported the results obtained from serum assays. Furthermore, TFs could prevent CCl4-caused oxidative damage by decreasing the MDA formation and increasing antioxidant enzymes (CAT, SOD, GSH-Px) activities in liver tissues. In summary, both in vitro and in vivo data suggest that TFs, prepared from A. venetum, showed a remarkable hepatoprotective and antioxidant activity against CCl4-induced liver damage.