Sargassum yezoense Extract Inhibits Carbohydrate Digestive Enzymes In Vitro and Alleviates Postprandial Hyperglycemia in Diabetic Mice

In this study, we investigated whether Sargassum yezoense extract (SYE) could inhibit α-glucosidase and α-amylase activities, and alleviate postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. Freeze-dried S. yezoense was extracted with 80% ethanol and concentrated for use in this study. The hypoglycemic effect was determined by evaluating the inhibitory activities of SYE against α-glucosidase and α-amylase as well as its ability to decrease postprandial blood glucose levels. The half-maximal inhibitory concentrations of SYE against α-glucosidase and α-amylase were 0.078±0.004 and 0.212±0.064 mg/mL, respectively. SYE was a more effective inhibitor of α-glucosidase and α-amylase activities than the positive control, acarbose. The increase in postprandial blood glucose levels was significantly alleviated in the SYE group compared with that in the control group of STZ-induced diabetic mice. Furthermore, the area under the curves significantly decreased with SYE administration in STZ-induced diabetic mice. These results suggest that SYE is a potent inhibitor of α-glucosidase and α-amylase activities and alleviates postprandial hyperglycemia caused by dietary carbohydrates.