| Schisandra chinensis (Turcz.) Baill, mainly distributed in the Northeast Asian region, is widely used in the area of functional food and medicine for its rich in bioactive components, such as lignans and triterpenoids. In this study, total triterpenoid and lignan from S. chinensis (TLS) was extracted from the stems and analysed its chemical composition. The effect and mechanism of intervention on acute and chronic alcohol-induced liver injury by TLS was indepth studied to lay the foundation for industrialization development of S. chinensis. The main results are as follows:1. A method for preparative purification of lignans from S. chinensis was established using a combination of high-speed counter-current chromatography (HSCCC) and preparative high-performance liquid chromatography (HPLC). The crude extracts obtained from stems powder of S. chinensis by using70%ethanol were separated in an AB-8macroporous resin column and then eluted with a graded ethanol series. A two-phase solvent system consisting of n-hexane-ethyl acetate-methanol-water (1:1:1:1, V/V) was used for HSCCC, and a mobile phase of acetonitrile-water (50:50, V/V) was used for preparative HPLC. The results obtained using HSCCC were compared with those obtained using preparative HPLC, and their advantages were further integrated to improve the separation efficiency. Six known lignans were identified by electrospray ionization mass spectrometry and1H nuclear magnetic resonance (NMR) and13C NMR analyses, and the purities of all the compounds were above91%. Based on the previous research of our group, we considered the resin-purified sample as total triterpenoid and lignan from TLS.2. The hepatoprotective effects of TLS in a mouse model of acute alcohol-induced liver injury were evaluated based on biochemical indicators and antioxidative capacity of serum and liver in21d. Severe liver damage caused by50%ethanol intake with increasing activation of hepatic markers was decreased in the group of mice fed TLS, and the results were confirmed through hematoxylin and eosin staining. Serum biochemical indicators and antioxidative capacity were abnormal by intragastric administration of50%ethanol, but recovered by TLS. Furthermore, TLS increased the activity of antioxidant enzymes and reduced inflammatory reactions in liver. The experimental results indicate that TLS has preventive and therapeutic effects against acute alcohol-induced liver injury because it could get down the levels of ALT, AST, ALP, TC, TG, LDL-C, MDA, and make up the levels of HDL-C, SOD, GSH, T-AOC.3. Rat was used to establish the model of chronic alcohol-induced liver injury. The body showed obvious dose effect relationship after intake of alcohol through liver function, lipid levels and dynamic changes of antioxidant capacity in oxidation of serum in30d,60d and90d. After intake of30%ethanol, the levels of TC, TG and MDA increased significantly, while the levels of HDL-C, SOD, GSH, GSH-Px and CAT decreased significantly. Over time, lipid peroxidation induced by intake of alcohol gradually increased. After intake of TLS, levels of serum biochemical indices showed a significant recovery. Compared with30%ethanol control group, the levels of TC, TG and MDA decreased significantly, while the levels of HDL-C, SOD, GSH, GSH-Px and CAT increased significantly in high dose intervention group by TLC.4. Rat was intragastric administration with different concentrations of ethanol for90d.30%ethanol control group showed significant fatty degeneration, morphological changes of liver cells, increase of serum ALT and AST levels, increase of liver homogenate MDA and ROS levels, decrease of SOD, GSH, GSH-Px and CAT levels, enhanced expression and activity of CYP2E1in liver microsomes, inhibited expression and activity of HO-1. After intake of different doses, especially high dose of TLS, the fatty degeneration significantly reduced and resolved. Liver function was significantly recovered, and the abnormal activation of CYP2E1was inhibited. The activity and expression levels on RNA and protein of HO-1increased significantly.All the results indicated that there was significant protective effect of TLS on acute and chronic alcohol-induced liver injury. The mechanisms of which may due to:(1) TLS could relieve the lipid peroxidation induced by ethanol metabolism, eliminate oxygen free radicals, protect the function and structure of liver cell and organelle.(2) TLS could control the key enzyme in ethanol metabolism, especially the expression of CYP2E1, and decrease the formation of ROS to ease the oxidative damage on liver. In addition, TLS could induce the expression of HO-1, and activate its antioxidant effect inhibited by ethanol metabolism. HO-1could decrease the activity of CYP2E1through degradating it as a substrate, enhance the antioxidant capacity of body, and then ameliorate the oxidative damage induced by ethanol intake. |
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