α-Glucosidase immobilization on calcium-sodium alginate-chitosan gel beads for inhibitory activity evaluation from traditional Chinese medicines

Discovering α-glucosidase inhibitors is one of the effective ways to develop new anti-diabetic drugs. In this study yeast α-glucosidase immobilized in calcium alginate-chitosan gel treated with polyethyleneimine and capillary electrophoresis analysis was used to select enzyme inhibitor compounds in 12 traditional Chinese medicine. The immobilized α-glucosidase shows enhanced tolerance to temperature (70°C), excellent repeatability (RSD = 1.9%, n = 5), high stability and good reusability (retained 57.8% and 74% of its initial activity after storing at 4℃ for 30 days and reusing 10 times, respectively). Moreover, the Michaelis constant of immobilized α-glucosidase and half-maximal inhibitory concentration of acarbose were calculated to be 1.79 mM and 0.70 μM, respectively. These results demonstrate that the immobilized α-glucosidase for inhibitory activity evaluation is feasible. The immobilized α-glucosidase was applied to screen inhibitors from 12 traditional Chinese medicines, and Sanguisorbae Radix the root of Sanguisorba officinalis L. exhibited the strongest inhibitory activity on α-glucosidase.