Exploration of phenolic profile from mangosteen (Garcinia mangostana L.) pericarp and their contribution to inhibitory effects on α-amylase and α-glucosidase

The aim of this study was to reveal the phenolic profile of mangosteen (Garcinia mangostana L.) pericarp and investigate their inhibitory effects on α-amylase and α-glucosidase. Mangosteen pericarp polyphenols (MPP) obtained by acetone extraction were fractionated with gradient ethanol elution. A total of twenty nine phenolic chemicals were found and quantified by UPLC-Q-TOF-MS/MS. MPP eluted by the 60% ethanol solution (MPP60%) showed the highest total phenolic content. Moreover, MPP60% displayed the greatest inhibition activities on α-amylase and α-glycosidase by competitive and mixed inhibitions. Mechanistically, the inhibitory effects of MPP60% on α-amylase and α-glucosidase involved the changes of the secondary structure as well as the static fluorescence quenching of these enzymes. Pearson correlation coefficients revealed that procyanidin B2, quercetin glucoside, and mangostain contributed most to inhibiting the activities of α-amylase and α-glucosidase. This study indicated that polyphenols from mangosteen pericarps can be developed into potential inhibitors of α-amylase and α-glucosidase, offering a viable strategy for the valorization of mangosteen pericarps. •Phenolic profile was revealed by gradient ethanol elution and UPLC-Q-TOF-MS/MS.•The inhibitory effects of polyphenols on α-amylase and α-glucosidase were detected.•Inhibition kinetic was calculated by Lineweaver-Burk, Dixon and Cornish-Bowden plot.•Inhibition mechanisms were elucidated by CD spectra and fluorescence quenching.•The contribution of phenolic compounds to α-amylase/α-glucosidase was analyzed.