Abstract: Objective To investigate the effect of Biondia Heriyi (BH) extract on Streptozocin(STZ)-induced diabetic rats. Methods Thirty two male rats were divided randomly into four groups: control group (A) and three groups of diabetic models. The diabetic model was established after three days according to blood glucose level (>16.65mmol•L^-1) measured by blood glucose analyzer. Then the diabetic rats were divided into three group, one was control group of diabetic rats, the other two groups were received BH (465 mg•kg^-1) and XKW (625 mg•kg^-1)into stomach respectively, the glucose concentration in blood was measured once a week. For all the three groups of diabetic rats, at the three days after injection of STZ and the end of the experiment, the insulin concentrations in blood were determined by radioimmunoassay. The morphological structure of the pancreatic island was also observed. Results After administration of BH extract and XKW for five weeks respectively ,the level of blood glucose in diabetic rats of BH-administration group decreased from (18.3±1.8) mmol•L^-1 to (5.3±1.2)mmol• L^-1, the level of blood glucose in diabetic rats of XKW-administration group decreased from (18.4±1.9)mmol•L^-1 to (5.2±0.8)mmol•L^-1,compared with the level in control group of diabetic rats ［(19.9±1.9)mmol•L^-1］,there was significant differente (P<0.001). The blood insulin level in diabetic rats of BH-administered group was increased from (18.8±2.3)mU• L^-1 to（42.2±3.5）mU•L^-1. The blood insulin level in diabetic rats of XKW-administration group increased from (18.1±3.3)mU• L^-1 to（40.9±3.7）mU•L^-1, compared with the level in the control group of diabetic rats［(18.7±3.1)mU •L^-1］, there was significant difference （P<0.01）. To corresponding the changes of the blood glucose and insulin, the morphological changes of the pancreatic island cells in diabetic rats were the changes in the cell atrophy, nucleus pyknosis, secretion particles and so on which were recovered to the normal situation five weeks after BH　extract and XKW were administered. Conclusion BH could effectively decrease the blood glucose and increase the insulin level of STZ-induced diabetic rats, and has effects to protect and recover the pancreatic island cells.

Key words: plant extracts, diabetes mellitus, insulin-dependent, diabetes mellitus, experimental