Purification, characterization and anti-diabetic activity of a polysaccharide from mulberry leaf

In the present study, a high-purity polysaccharide from mulberry leaf (MLP) was purified and characterized, and its anti-diabetic effects were investigated in streptozotocin (STZ)-induced diabetic rats. Our results showed that the obtained MLP (purity 99.8%) was determined to be composed of D-arabinose, D-xylose, D-glucose, D-rhamnose and D-mannose with molar ratio of 1:2.13:6.53:1.04:8.73. Oral administration of MLP at 50-200 mg/kg body weight daily for 5 weeks significantly reduced the levels of fasting blood glucose (FBG), glycosylated serum protein (GSP), serum total cholesterol (TC), and serum triglyceride (TG), and increased the body weight, fasting insulin (FINS), C-peptide (C-P), liver glycogen, liver glucokinase, and serum high-density lipoprotein cholesterol (HDL-C). Moreover, MLP promoted marked pancreatic beta-cell regeneration and insulin secretion, and reduced liver fat accumulation in diabetic rats. The treatment effect of MLP on diabetes was similar to the effect of antidiabetic drug glibenclamide. These results clearly indicated that MLP may have a potential for the treatment of hyperglycemia and hyperlipidemia in diabetes. (C) 2014 Elsevier Inc. All rights reserved.