Hits:

Indexed by:期刊论文

Date of Publication:2021-02-25

Journal:JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

Volume:68

Issue:33

Page Number:8774-8787

ISSN No.:0021-8561

Key Words:baicalein; 1-DNJ; positive allosteric inhibitor; mechanism; maltase-glucoamylase

Abstract:1-Deoxynojirimycin (1-DNJ) is the major effective component of mulberry leaves, exhibiting inhibitory activity against alpha-glucosidase. However, due to the low content of 1-DNJ in mulberry products, its level cannot meet the lowest dose to exhibit its activity. In this study, a combination of dietary 5,6,7-trihydroxy-flavonoid aglycones with 1-DNJ showed synergistic inhibitory activity against maltase of mice alpha-glucosidase and recombinant C- and N-termini of maltase-glucoamylase (MGAM) and baicalein with 1-DNJ exhibited the strongest synergistic effect. The synergistic effect of the combination was also confirmed by the maltose tolerance test in vivo. Enzyme kinetics, molecular docking, fluorescence spectrum, and circular dichroism spectrometry studies indicated that the major mechanism of the synergism is that baicalein was a positive allosteric inhibitor and bound to the noncompetitive site of MGAM, causing an increase of the binding affinity of 1-DNJ to MGAM. Our results might provide a theoretical basis for the design of dietary supplements containing mulberry products.