Inhibition mechanisms of wounded okra on the α-glucosidase/α-amylase

Abstract

Okra has attracted increasing interests to be used as functional food ingredients due to various human health benefits such as the inhibition of α-glucosidase and α-amylase in this paper. Results showed that the α-glucosidase (and α-amylase) inhibition capacity of polyphenols in wounded okra significantly increased by 31.6% (and 28.6%) when the wounding intensity was 1.87 cm2/g. The UPLC-MS analysis indicated that quercetin and catechin derivatives were the major polyphenols in wounded okra, of which quercetin 3-O-gentiobioside and epigallocatechin dimer were the most abundant compounds. Fluorescence quenching confirmed that wound and healing process promoted the affinity between α-glucosidase (and α-amylase) and polyphenols, which interacted with enzymes in a mixed type manner. Molecular docking suggested that quercetin-3-O-gentiobioside, quercetin-3-O-glucosyl-xyloside, isoquercitrin, querce-tin-3-O-(malonyl)-glucoside, epigallocatechin, and epigallocatechin dimer can interact with the activity cavities of enzymes by amino acids residues (Arg195, Leu162, and His305). The results of this study support the potentials of wounded okra to inhibit α-glucosidase and α-amylase in the food industries, without associated risks to consumers.