Abstract: Objective: This study aimed to optimize the extraction of polysaccharides from mixed Fructus Schisandrae and Radix Astragali (SAP) and to examine their protective effects on alcohol-induced acute liver injury in mice. Methods: An orthogonal array design was applied to optimize SAP extraction by water extraction and alcohol precipitation. A total of 40 mice were randomly divided equally into normal control (CON) group, CON + SAP group, liver injury model (MOD) group and MOD + SAP group. The mice in the SAP-treated groups were intragastrically administered with 100 mg/kg SAP, and those in the CON and MOD groups were administered with an equal volume of distilled water for 30 days in the same way. Fifty percent ethanol (12 mL/kg) was orally given to the mice in the MOD and MOD + SAP groups at 1 hour after the last administration, and those in the CON and CON+SAP group were given an equal volume of distilled water intragastrically. Sixteen hours later, blood and liver samples were collected for the calculation of liver indexes of the mice in each group and the detection of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in serum as well as the contents of reduced glutathione (GSH), malondialdehyde (MDA) and triglyceride (TG) in liver tissues. Hematoxylin-eosin staining (HE) was performed to observe pathological changes of liver tissues. Results: The optimum conditions for SAP extraction were determined as follows: solid-to-liquid ratio, 1:45; extraction time, 3 h; and temperature, 100 ℃. Compared with the alcohol-induced liver injury model, SAP significantly reduced the liver index in mice (P < 0.05) and the levels of ALT and AST in serum (P < 0.05), elevated the content of GSH (P < 0.01), significantly reduced the contents of TG and MDA in liver tissues (P < 0.05), and improved the pathological changes of liver tissues. Conclusions: SAP could have a protective effect on alcohol-induced acute liver injury in mice.

Key words: Fructus Schisandrae, Radix Astragali, polysaccharide, alcohol-induced acute liver injury