Huijuan Zhang, Jing Wang, Yingli Liu, Baoguo Sun
Background: Oat, as a “third staple food” following rice and wheat in China, has been widely utilized due to the hypoglycemic activities of oat β-glucan. Oat also contains 15-20% protein, which consists of balanced amino acid profile devoid of anti-nutritional factors. Peptides from albumin, whey protein and other foods have been proposed to have hypoglycemic activities while the hypoglycemic activities of oat peptides have not been reported to our knowledge. Results: The hypoglycemic activities and underlying mechanisms of alcalase2.4 L oat hydrolysates purified by ultrafiltration were investigated in streptozotocininduced diabetic mice using metformin as the positive control. The hypoglycemic activities of oral administration of oat peptides (0.25, 0.5 and 1.0 g kg bw-1) were in a dose-depended manner. In the highest does treatment group, mice had the significantly (P < 0.05) lower total food intake and fasting blood glucose (FBG) and the higher food efficiency, serum fasting insulin (Fins), insulin activity index (IAI), and hepatic glycogen content compared with the 0.25 and 0.5 g kg bw-1 treatment groups. Moreover, the FBG concentrations positively correlated with total food intake (r =0.994, p < 0.01) and negatively correlated with Fins concentrations (r =- 0.979, P < 0.01), IAI (r = -0.942, P < 0.01), and hepatic glycogen contents (r = -0.952, P < 0.01). Conclusion: The results indicated that the underlying mechanisms of the oat peptides’ antidiabetic action could be linked to more than one mechanism, such as controlling the food intake, stimulating the insulin secretion and insulin sensitizing, and elevating the glycogenesis.