Anti-diabetic activities of phenolic compounds in muscadine against alpha-glucosidase and pancreatic lipase

Inhibitory mode and anti-diabetic activities of the Carols muscadine extracts on the α-glucosidase and pancreatic lipase were investigated. The IC50 values of the muscadine and its seed methanolic extracts against the α-glucosidase were 1.92 and 1.53 mg/mL, and those against the lipase were 34.41 and 8.63 mg/mL, respectively, which indicated the muscadine possessed the strong anti-diabetes activity. Particularly, the ethyl acetate (EtOAc) extract fractions exhibited the highest inhibitory activities against both enzymes. Since most of the phenolic compounds existed in the EtOAc fractions, it is suggested that phenolic compounds may be the main source against the α-glucosidase and pancreatic lipase. Twelve individual phenolics were identified by HPLC-MS. Ellagic acid and quercetin exhibited much stronger anti-diabetic activities among the selected phenolic standards. Besides, the extracts and the phenolic standards obeyed the competitive mode in their enzymatic inhibitions.

► The muscadine samples against the α-glucosidase and pancreatic lipase obeyed the competitive inhibition mode. ► The accurate dissociation constant (Ki) and IC50 values of the inhibitors were calculated to estimate the inhibitory efficiency. ► The muscadine extracts possessed the strong anti-diabetes activities might be contributed from the phenolics. ► The phenolic profile of the Muscadine was identified by HPLC-MS.