Protective effect of alcohol extract of Yulangsan leaf on chemically-induced liver injury in mice

Purpose: To investigate the protective effect of Millettia pulchra Kurz var. Laxior (Dunn) Z. Wei (Yulangsan) leaf (YLSL) on chemically-induced liver injury in mice. Methods: Models of carbon tetrachloride (CCl4) and D-galactosamine (D-GalN)-induced liver injury in Kunming mice were prepared by intraperitoneal injection. Sixty mice were randomly divided into normal saline (NS) group, liver-injury group, low-, medium- and high-dose YLSL groups (7.5, 15 and 30 g/kg dose, respectively), and biphenyldicarboxylate (BPDC) group, with 10 animals per group. Indices for liver, spleen and thymus were assessed. Serum aspartate transaminase (AST) and alanine aminotransferase (ALT) activities, levels of malondialdehyde (MDA) in liver tissues and reduced glutathione (GSH) as well as activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in liver tissue were assayed. Liver tissue damage was assessed histologically. Results: YLSL could significantly decrease the elevation of AST or ALT in liver injuries induced by CCl4 or D-GalN in mice, which showed a dose-effect relationship obviously. The high dose YLSL significantly decreased thymus weight relative to CCl4 and D-GalN (CCL4 CCL4+YLSL: 4.4213 +/- 1.0544 vs 3.7120 +/- 0.8534; D-GalN vs YLSL + D-GalN: 3.7272 +/- 1.1655 vs 1.9548 +/- 1.2996, p < 0.01). However, SOD activity was significantly increased (p < 0.01, p < 0.05). In treatment groups exposed to CCl4, GSH-Px activity was significantly increased (p < 0.01) and GSH levels decreased (middle dose group and positive control group). In treatment groups with D-GalN, GSH content was significantly increased (p < 0.01 or p < 0.05), while GSH-Px activity decreased (p < 0.01). Conclusion: YLSL has protective effect against chemically-induced liver injury in mice. The mechanism may be related to attenuation of free radical-induced lipid peroxidation.