Interactions between Phenols and Alkylamides of Sichuan Pepper (<i>Zanthoxylum</i> Genus) in α-Glucosidase Inhibition: A Structural Mechanism Analysis
Di Zhang, Xuhao Liu, Zhikun Yang, Jiyong Shi, Lei Zhao, Maurizio Battino, Jianbo Xiao, Xinyue Deng, Yan‐Ling Wu, Chengtao Wang, Bolin Shi, Xiaobo Zou
Abstract
The phenols and alkylamides in 26 varieties of Zanthoxylum pericarps (ZP) were comparatively identified, and the contribution of these key components to the inhibition of in vitro α-glucosidase (α-Glu) was confirmed using principal component analysis (PCA) and ingredient recombination models. Additionally, spectrophotometric assays, nuclear magnetic resonance (NMR), and molecular docking (MD) were employed to characterize the interactions among key components in ZP when exposed to α-Glu. Four phenols and hydroxy-α-sanshool (α-SOH), which were recognized as main ingredients, presented an antagonistic effect in the inhibition of α-Glu. 1H NMR demonstrated chemical shifts of certain hydrogens in the B phenolic ring and tetraenyl group, indicating a possible p−π conjugation between phenols and α-SOH. In addition, using MD analysis, the phenol-binding sites were observed to be negatively affected when α-SOH initially interacted with α-Glu. The combined results of the NMR and MD clarified the structural mechanism behind phenol/α-SOH antagonistic behavior in α-Glu inhibition.