Acta Pharmacol Sin. 2002 Dec; 23(12): 1181-7.

Increase of insulin sensitivity in diabetic rats received die-huang-wan, a herbal mixture used in Chinese traditional medicine.

Wu YC, Hsu JH, Liu IM, Liou SS, Su HC, Cheng JT.

Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung City, Taiwan, China. jtcheng@mail.ncku.edu.tw

AIM: Effects on insulin sensitivity of die-huang-wan, the herbal mixture widely used to treat diabetic disorder in Chinese traditional medicine, were investigated in vivo. METHODS: The obese Zucker rats were employed as insulin-resistant animal model. Also, insulin-resistance was induced by the repeated intraperitoneal injections of long-acting human insulin at 0.5 U/kg three times daily into adult male Wistar rats. Insulin resistance was identified using the loss of tolbutamide (10 mg/kg) or electroacupuncture (EA)-induced plasma glucose lowering action. The plasma glucose concentration was examined by glucose oxidase assay. RESULTS: The plasma glucose-lowering action induced by tolbutamide was significantly enhanced in obese Zucker rats receiving the repeated administration of die-huang-wan at dosage of 26 mg/kg for 3 d. Furthermore, administration of die-huang-wan delayed the formation of insulin resistance in rats that were induced by the daily repeated injection of human long-acting insulin at 0.5 U/kg three times daily and identified by the loss of tolbutamide- or EA-induced hypoglycemia. In streptozotocin-induced diabetic rats, oral administration of metformin at 320 mg/kg once daily made an increase of the response to exogenous short-acting human insulin 15 d later. This is consistent with the view that metformin can increase insulin sensitivity. Similar treatment with die-huang-wan at an effective dose (26.0 mg/kg) also increased the plasma glucose lowering action of exogenous insulin at 10 d later. The effect of die-huang-wan on insulin sensitivity seems to produce more rapidly than that of metformin. CONCLUSION: The present study found that oral administration of die-huang-wan increased insulin sensitivity and delayed the development of insulin resistance in rats.