α-Glucosidase inhibiting activity and bioactive compounds of six red wine grape pomace extracts.

•The anti-diabetes potential of 6 red wine grape pomaces was investigated.•Total phenolic content and individual identified phenolic compounds were analysed.•The relationship between rat intestinal α-glucosidase inhibitory activity and phenolic content of grape pomaces was assessed.•Tinta Cão appears to be a promising food-derived α-glucosidase inhibitor for preventing and treating diabetes.