Insight into flavonoid structure for mammalian α‐amylase and α‐glucosidase inhibition to control starch digestion rate

In this study we investigated the structural specificity of flavonoids for starch digestive enzyme inhibition to modulate glucose release from glycemic carbohydrate digestion. Using three different flavonoids [eriodictyol, luteolin, and quercetin], chosen based on the degree of hydroxylation and planarity of the C‐ring, structural specificities were found for selectively inhibiting α‐amylase and α‐glucosidases, resulting in different inhibition constants ( K i ) and mechanisms. The double bond between C2 and C3 on the C‐ring of flavonoids was particularly important for α‐amylase inhibition, which leads to a π‐stacking interaction between flavonoids and α‐amylase, while the hydroxyl group at C3 of the C‐ring played a key role in inhibiting α‐glucosidases. These structural specificities of flavonoids toward starch degrading enzymes are likely the result of different protein structures of α‐amylase and α‐glucosidases, as they belong to different families, GH13 and GH31. Our findings provide insights into structure‐function aspects of flavonoids in controlling starch digestion rate. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .