ABSTRACT
The antioxidant effects of the triterpenoid-rich extracts from Euryale ferox shell (ES) have been confirmed in vitro. This study examined whether the triterpenoid-rich extract from ES eases human hyperglycemia and diabetes caused by metabolic disorders. Normal and streptozocin (STZ)-induced diabetic mice were used as controls for the four groups that received the triterpenoid-rich extracts of ES suspended in distilled water orally at doses of 200, 300, 400, 500±2 mg/L. Body weight, blood glucose and pancreatic tissue morphology were observed after 4 weeks. The expression of protein tyrosine phosphatase-1B (PTP1B) and insulin receptor substrate (IRS-1) proteins, which are related to the regulation of glucose metabolism in vivo, were also investigated. Compared with the model group (LD50 900±2 mg/L), it was found that the triterpenoid-rich extracts of ES could regulate glucose metabolism (P<0.01) and cause body weight to return to normal levels (P<0.05). Islet morphology recovered well, the expression of the negative regulation protein PTP1B gene was reduced and insulin receptor IRS-1 protein expression was increased. These data prove that the triterpenoid-rich extracts from ES have a therapeutic effect on diabetes by insulin resistance.
Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Hypoglycemic Agents/pharmacology , Nymphaeaceae , Phytotherapy , Plant Extracts/pharmacology , Triterpenes/pharmacology , Animals , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Insulin Receptor Substrate Proteins/physiology , Male , Mice , Protein Tyrosine Phosphatase, Non-Receptor Type 1/physiology , StreptozocinABSTRACT
The hypoglycemic and hypolipidemic effects of a triterpenoid-rich extract from the Euryale shell (ES) was analyzed in streptozotocin-induced diabetic mice. Normal and diabetic mice treated with glimepiride were used as negative and positive controls, respectively. Body weight, organ weight index and cholesterol-related lipid profile parameters were observed after 4 weeks. The hypoglycemic activity was assessed by fasting blood glucose (FBG) and fasting insulin (FINS) to calculate the insulin sensitivity index (ISI). In addition, the potentially regulative mechanisms on insulin resistance were discussed. The results indicated that a triterpenoid-rich extract of ES could inhibit reduction in the body weight of diabetic mice and regulate glucose metabolism. The hypolipidemic action after this extract supplementation was confirmed by significant (p<0.05) decreases in the levels of cholesterol, LDL and triglycerides and increase in HDL compared with the untreated diabetic mice, especially when using a high dose, which suggested that the ES extract could effectively reverse the abnormal enlargement of the liver and spleen (p<0.01). The present data suggest that the triterpenoid-rich extract from the ES has both hypoglycemic and hypolipidemic effects that can not only help cure and manage diabetes but also improve insulin resistance (IR).
