Hypolipidemic effects of Myrica rubra extracts and main compounds in C57BL/6j mice.

The present study evaluated the antihyperlipidemic activity of myricetin, myricetrin, the alcohol fraction (AF) and the ethyl acetate fraction (EF) obtained from the bark of Myrica rubra (MR) in high-fat and high-cholesterol (HFHC) induced hyperlipidemic C57BL/6j mice. Mice were treated with myricetin, myricetrin, AF and EF with a dose of 130 mg per kg per day for 35 days. After treatment, serum parameters including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), total bile acids (TBA), etc., were examined. The results revealed that EF showed the highest weight lowering activity (P < 0.01). All tested samples decreased the levels of the TC, TG, LDL-C, TBA and LPS (lipopolysaccharide) content in the serum of mice to different extents. Liver fat deposition was significantly reduced after myricetin, myricetrin, AF and EF therapy (P < 0.01). Additionally, the cell size of epididymal adipose tissue was also decreased in myricetin, AF and EF groups (P < 0.05). The antihyperlipidemic activity of these samples may be attributed to the inhibition of lipid synthesis via suppressing the expression of HMGCR (3-hydroxy-3-methylglutaryl coenzyme A reductase) and ACC1 (acetyl-CoA carboxylase), promoting the metabolism and excretion of lipids via up-regulating the expression of SREBP2 (sterol regulatory element binding proteins), LDLR (low density lipoprotein receptor), UCP2 (uncoupling protein 2) and CYP7A1 (cholesterol 7α-hydroxylase). These results may provide a powerful foundation for seeking and utilizing Myrica rubra bio-active compounds for the treatment of hyperlipidemia and cardiovascular diseases.