α-Glucosidase and non-enzymatic glycation inhibitory potential of Eugenia dysenterica fruit pulp extracts

Abstract

Considering the nutritional benefits of fruits on human health, this study aimed to screen 11 fruits found in the Brazilian Savanna for glycoside hydrolases inhibitors with antioxidant and anti-glycation properties. Aqueous and ethanol extracts of pulps were used in enzymatic assays to evaluate the inhibitory potential against α-amylase and α-glucosidase, as well as antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays) and anti-glycation (BSA-fructose model) capacities. Ethanol extracts of Campomanesia xanthocarpa, Byrsonima verbascifolia and Eugenia dysenterica had the lowest DPPH IC50 values (<0.25 mg/ml), while ethanol extracts of Genipa americana and B. verbascifolia had the highest ORAC values (>0.60 mmol trolox equivalents/g). The extracts of E. dysenterica showed potential to inhibit glycation (IC50 < 0.40 mg/ml) and α-glucosidase (IC50 < 20 μg/ml). Liquid-liquid fractionation of the extracts of E. dysenterica fruit pulp resulted in the ethyl acetate fraction showing higher antioxidant (DPPH IC50 10 μg/ml and ORAC 1.3 mmol trolox equivalents/g) and anti-glycation (IC50 0.10 mg/ml) capacities, and α-glucosidase inhibition activity (IC50 11 μg/ml). HPLC-ESI-MS/MS analysis suggested the presence of antioxidant molecules in E. dysenterica fruit pulp, such as ferulic and gallic acids, myricetin, quercetin and kaempferol-pentosides. Non-conventional fruits found in the Brazilian Savanna, a global biodiversity hotspot, with antioxidant and anti-glycation properties, could be potential sources of nutraceuticals to combat oxidative stress, which is present in many pathologies. In addition, the capacity of E. dysenterica to inhibit α-glucosidase and non-enzymatic glycation makes it especially useful for in vivo studies related to diabetes mellitus.