Abstract: α-Glucosidase inhibitors are therapeutic agents for reducing postprandial hyperglycemia,which are widely applied in clinics for prevention and management of type II diabetes mellitus.In this study,two in vitro assay methods were modified to adopt the screening α-glycosidase inhibitors (α-GI) produced in reconstituted skimmed milk by lactic acid bacteria,enrolling acarbose as a positive control.Both of the modified in vitro assay methods were proved to be suitable for screening α-GI produced by lactic acid bacteria,with the half inhibitory concentration (IC₅₀) for acarbose of 0.6056 mg/mL obtained by PNPG method and 0.3843 mg/mL by maltose α-glycosidase method respectively.The inhibitory effects of 12 selected lactic acid bacteria strains were consistent between the PNPG and the maltose α-glycosidase method,although the inhibitory rates measured by the latter method were slightly higher.When in low concentration,the inhibitory rates of acarbose in reconstituted skimmed milk obtained by maltose α-glycosidase (invertase) method were higher than those by PNPG method.

Key words: &alpha, -glucosidase inhibitor, acarbose, p-nitrophenol-&alpha, -glucopyranoside, maltose, lactic acid bacteria