Resumen de Novel Insights into the Inhibitory Effect and Mechanism of Proanthocyanidins from Pyracantha fortuneanaFruit on α‐Glucosidase
Mankun Wei, Wei‐Ming Chai, Qin Yang, Rui Wang, Yiyuan Peng
Proanthocyanidins were extracted from Pyracantha fortuneanafruit (PFF), and their structures were investigated through 13C nuclear magnetic resonance (13C NMR), high performance liquid chromatography (HPLC) and high resolution mass spectrometry (HRMS). The results showed that these compounds were predominantly constituted of procyanidin with A‐type and B‐type linkage and coexistence of procyanidins glucoside. Spectroscopy methods were used to analyze the inhibitory activity of proanthocyanidins on α‐glucosidase. The results demonstrated that these compounds exhibited excellent inhibitory effect on α‐glucosidase with the IC50value of 0.15 ± 0.01 μg/mL, and they reversibly inhibited α‐glucosidase in a non‐competitive type. The fluorescence quenching analysis revealed that proanthocyanidins statically quenched the fluorescence spectra by forming an inhibitor‐α‐glucosidase complex. Molecular docking results further indicated that the driving powers of the interaction between proanthocyanidins and α‐glucosidase were hydrogen bonds and hydrophobic force. The main inhibitory mechanism of proanthocyanidins on α‐glucosidase may be due to the insertion of proanthocyanidins into the pocket of the enzyme altering the catalytic configuration of the active site in a manner, thus reducing substrate binding affinity. The findings of this work provided a new perspective that proanthocyanidins from PFF with a possibility to be used as novel natural anti‐diabetic agents in functional food industries. In this study, Pyracantha fortuneanafruit proanthocyanidins with a yield of 3.05% were identified for the first time as predominantly constituted of procyanidin with A‐type and B‐type linkage and coexistence of procyanidins glucoside. Proanthocyanidins from P. fortuneanafruit had higher anti‐α‐glucosidase activity value compared with positive control acarbose, which indicated that P. fortuneanafruit proanthocyanidins with a possibility to be used as novel natural antidiabetic agents in functional food industries.
