Study On α-glucosidase Inhibitory Activities Of Edible Chinese Medicine And Inhibition Mechanism

Diabetes mellitus(DM) has been seriously threatening the health of human being. It’s a effective way to reducing postprandial hyperglycemia(PPHG) by a-glucosidase inhibitors. Therefore,the study on a-glucosidase inhibitory activities of edible traditional Chinese medicine (ETCM) would not only offer appropriate and reasonable dietary guide for diabetic patients,but also screen better drug efficacy, less side effects and more kinds of a-glucosidase inhibitors to search for novel antidiabetic drugs.A high throughput screening method for a-glucosidase inhibitors from ETCM was established by HPLC in vitro.The inhibitory activity of a-glucosidase were determined by monitoring the release of PNP from the substrate PNPG according to the change of concentration. In this paper,72species of ETMC were systematic extracted by petroleum ether, dichloromethane,ethylacetate,methanol and water successively. Then the inhibitory activity against a-glucosidase of these compounds were determined in vitro for high throughput screening from360species of compounds by using the above method. The results showed that the active polar fractions of ETCM were different which could inferred that the structures and functional mechanisms were different. Compared with positive control acarbose, inhibitory rates of150extracts were higher than acarbose, inhibitory rates of52extracts were higher than90%,and inhibitory rates of16extracts mostly in methanol fraction were up to100%,so they were screened for the second time by IC50values,which were much smaller than acarbose.In this paper a bioactivity-guided isolation and purification process was used to identify the a-glucosidase avtivity inhibiting components from Cinnamomi Cortex.3active compounds were isolated and idntified as trans-cinnamaldehyde(1)(IC50=277.89μg·mL-1and cinnamic acid(2)(IC50=286.22μg·mL-1) and tannin(3)(IC50=83.66ug-mL-1.The IC50of all compounds were lower than that of acarbose (IC50=1028.99μg·mL-1),so their a-glucosidase inhibitory activities were much higher than acarbose,in which compound3was the best.All of them showed noncompetitive type manner on a-glucosidase with Ki value of178.07μg·mL-1、229.43μg-mL-1and23.95μg/mL.