In vitro evaluation of phenolic-enriched maple syrup extracts for inhibition of carbohydrate hydrolyzing enzymes relevant to type 2 diabetes management

Phenolic-enriched extracts of Canadian maple syrup, namely ethyl acetate (MS-EtOAc) and butanol (MS-BuOH), were evaluated for their ability to inhibit carbohydrate hydrolyzing enzymes relevant to type 2 diabetes management. Extracts were standardized to phenolic contents by the Folin–Ciocalteau method and assayed for yeast α-glucosidase inhibitory activities. On normalization to phenolic content, MS-BuOH exhibited higher inhibitory activity than MS-EtOAc (IC50 = 68.38 and 107.9 μg phenolics, respectively). The extracts were further assayed for inhibition of porcine α-amylase and rat α-glucosidase enzymes. MS-BuOH exhibited higher rat α-glucosidase and porcine α-amylase inhibitory activities (IC50 = 135 and 103 μg phenolics, respectively) than MS-EtOAC extract (IC50 > 187 μg phenolics in both assays). These results suggest that maple syrup extracts may have potential for phenolic-mediated type 2 diabetes management, with the MS-BuOH phenolic-enriched fraction having highest bioactivity.

► Phenolic-enriched extracts, namely ethyl acetate and butanol, were prepared from pure maple syrup.
► Both extracts showed inhibitory effects against carbohydrate hydrolyzing enzymes relevant to type-2 diabetes management.
► Butanol extract was more active than the ethyl acetate extract.