Abstract: Purpose: To investigate the hypoglycemic effect of different doses of dietary fiber from a 1:1:1 mixture of common beans (Phaseolus vulgaris), black soybeans [Glycine max (L.) merr)] and mungbeans (Vigna radiata L. Wilczek) on diabetic rats. Methods: A diabetic rat model was constructed by intraperitoneal injection of strepozotocin solution (150 mg/kg). After successful model establishment, the animals were administered by gavage with the dietary fiber for 42 successive days. Body mass, pancreas to body mass ratio, fasting blood glucose (FBG), and the levels of serum hepatic glycogen, insulin (INS) and glycosylated serum protein (GSP) were measured, and pathological observation of pancreatic tissue sections was carried out by hematoxylin-eosin staining. Results: Compared with the model group, body mass was highly significantly higher in all treatment groups except for the low-dose dietary fiber group (P < 0.01); FBG level was significantly lower in the low-dose dietary fiber group (P < 0.05) and highly significantly lower in the intermediate- and high-dose dietary fiber and glibenclamide groups (P < 0.01). Pancreas to body mass ratio was higher in rats in the treatment groups than that of rats in the model group; the intermediate- and high-dose dietary fiber and glibenclamide groups showed a significant increase in pancreas to body mass ratio (P < 0.05). All dose groups presented an increase in hepatic glycogen and serum INS levels and a decrease in GSP level compared with the model group. Histopathological examination showed that pancreatic injury was significantly alleviated in all dose groups, with increased number of islet cells and decreased degree of edema. Conclusion: Dietary fiber from the bean mixture can reduce blood glucose level and alleviate pancreatic injury in diabetic rats.

Key words: dietary fiber from bean mixture, diabetes, hypoglycemic effect, repairing, rats