Effect of Flavonoids in Morus indica on Blood Lipids and Glucose in Hyperlipidemia-diabetic Rats

Objective To investigate the effect and possible mechanism of flavonoids extracted from Morus indica (FMI) on blood lipids and glucose. Methods The experimental hyperlipidemia-diabetic rats were induced by high-fat diet (HFD) and low dose of Streptozotocin (STZ). Flavonoids-treated rats were pretreated with FMI (50, 100, and 200 mg/kg). The plasma, skeletal muscle, and livers were isolated for biochemical assays, HE staining, immuno- histochemistry, and Western blotting analysis. Results The results showed that the body weight in flavonoids- treated (100 and 200 mg/kg) rats was reduced (P < 0.05, 0.01) compared to HFD-fed rats. FMI obviously reduced total cholesterol (P < 0.01), triglycerides (P < 0.05), and low-density lipoprotein cholesterol (P < 0.05), increased high-density lipoprotein (P < 0.05), and significantly decreased the atherosclerosis index (P < 0.01); FMI (100 and 200 mg/kg) also down-regulated the elevation of blood glucose induced by STZ (P < 0.05, 0.01); At the meantime, FMI increased hepatic superoxide dismutase (SOD) activity and reduced hepatic malondialdehyde (MDA) content obviously. In addition, the results showed that the expression of hepatic CYP2E1 was markedly decreased while the expression of GLUT-4 in skeletal muscles was increased by FMI. Conclusion The above results demonstrate that the effect of FMI is related to its up-regulation of hepatic SOD activity, reduction of hepatic MDA content, down-regulation of hepatic CYP2E1 expression, and increase of GLUT-4 expression in skeletal muscle, which suggests that FMI may prevent or improve hyperlipidemia and hyperglycemia caused by an excessive HFD.