Identification of novel α-glucosidase inhibitory peptides in rice wine and their antioxidant activities using in silico and in vitro analyses

Many peptides are contained in rice wine, which may have various bioactivities, and need to be investigated. The aim of this study was to identify novel peptides with high α-glucosidase inhibition and antioxidant activities in rice wine and to illustrate their underlying mechanisms. Peptide composition, α-glucosidase inhibition and antioxidant activities of the different elution fractions from macroporous resin adsorption chromatography were investigated. Potentially bioactive peptides were screened via in silico analyses and validated by in vitro experiments, and then, their mechanisms were further investigated by molecular docking and molecular dynamics simulations. Results showed that the peptides from 50% ethanol-eluted rice wine (50%-RP) exhibited strong α-glucosidase inhibition and antioxidant activities. Three novel peptides, SSLFR, QFTPR and FTYPR screened out by in silico analyses, were confirmed to have good α-glucosidase inhibition and antioxidant activities, and FTYPR exhibited the best bioactivities. These peptides could bind to ABTS and DPPH radicals and the active site of α-glucosidase through hydrogen bonding, Pi bonding and van der Waals forces. This study may not only provide new knowledge for the health effects of rice wine, but also supply theoretical bases for the development of health products of rice wine to improve its economic value.