To investigate the hypoglycemic effects of ethyl acetate extract of Alismatis Rhizoma (AREEA) on type 2 diabetes mellitus,the model of type 2 diabetic rats was induced by high-fat diet feeding for 4 weeks and then intraperitoneal injection of a low dose of streptozotoin (STZ).Rats without the above-mentioned treatment were selected as the normal control group.The diabetic rats were randomly divided into 5 groups:the model control group,low doses (20 mg/kg),medium doses (50 mg/kg),high doses (100 mg/kg) of AREEA groups and positive control-metformin group (100 mg/kg).After four weeks,oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed,respectively.12 hours after the last administration,the levels of serum glucose,glycated hemoglobin(HbA1 c),insulin (Ins),total cholesterol (TC),triglyceride (TG),high density lipoprotein (HDL-C),low density lipoprotein (LDL-C),superoxide dismutase (SOD),malondialdehyde (MDA),glutathione (GSH-Px),tumor necrosis factor-or (TNF-α),interleukin-6 (IL-6),insulin-mediated tyrosine of IRS-1 and Akt phosphorylation in adipose tissue were determined.In addition,the pathological changes of pancreas were examined.After administration for 4 weeks,all doses of AREEA significantly reduced the fasting blood glucose of type 2 diabetic rats (P ＜0.05).In the high doses group of AREEA,the levels of GLU,HbA1c,TC,TG,MDA,TNF-α and IL-6 in serum were decreased significantly,and the levels of SOD and GSH-Px were increased (P ＜ 0.05).These results suggest that AREEA has the therapeutic effect on type 2 diabetes-related symptoms by metabolic regulation of glucose and lipids.

The research of triterpenoids on hypoglycemic and anti-diabetic activities have made great progress. Findings indicated that triterpenoids could reduce blood glucose via different mechanisms, including increasing insulin secretion, enhancing insulin sensitivity, promoting glucose uptake by activation of AMP-activated protein kinase(AMPK), decreasing glycogenolysis and gluconeogenesis, and inhibiting protein tyrosine phosphates 1B(PTP1B), α-glycosidase, aldose reductase(AR)and dipeptidyl peptidase-4(DPP-4). This article reviews the hypoglycemic effects and mechanisms of triterpenoids, providing the reference for further research and development of triterpenoids.