Anti-Diabetic Effects of Phenolic Extract from Rambutan Peels (Nephelium lappaceum) in High-Fat Diet and Streptozotocin-Induced Diabetic Mice

Recent studies have shown that rambutan peel phenolic (RPP) extract demonstrate high antioxidant and antiglycation activities in vitro and in vivo. This study further evaluated the anti-diabetic activity of RPP in a mouse model of Type II diabetes induced by streptozotocin combined with high-fat diet. Results showed that RPP increased the body weight and reduced the fasting blood glucose level of the diabetic mice. RPP significantly reduced the serum levels of total cholesterol, triglyceride, creatinine, and glycated serum protein in diabetic mice in a dose-dependent manner. Glycogen content in mice liver was recovered by RPP, which further increased the activity of superoxide dismutase and glutathione peroxidase and reduced lipid peroxidation in diabetic mice. Histological analysis showed that RPP effectively protected the tissue structure of the liver, kidney, and pancreas. In addition, RPP decreased the mesangial index and inhibited the expression of TGF-beta in the kidney of diabetic mice.