Phenolic Acids from Lycium barbarum Leaves: In Vitro and In Silico Studies of the Inhibitory Activity against Porcine Pancreatic α-Amylase

Nowadays, bioactive compounds from vegetable food and waste are of great interest for their inhibitory potential against digestive enzymes. In the present study, the inhibitory activity of methanolic extract from Lycium barbarum leaves on porcine pancreas alpha-amylase has been studied. The alpha-amylase inhibitory activity of the constituent phenolic acids was also investigated. The leaves were extracted by ultrasound-assisted method, one of the most efficient techniques for bioactive extraction from plant materials, and then the phenolic acids were identified by Accurate-Mass Quadrupole Time-of-Flight (Q-TOF) Liquid Chromatography/Mass Spectrometry (LC/MS). Chlorogenic and salicylic acids were the most abundant phenolic acids in L. barbarum leaf extract. The inhibitory effect against alpha-amylase, determined for individual compounds by in vitro assay, was higher for chlorogenic, salicylic, and caffeic acids. L. barbarum leaf extract showed an appreciable alpha-amylase inhibitory effect in a concentration-dependent manner. Docking studies of the considered phenolic acids into the active site of alpha-amylase suggested a conserved binding mode that is mainly stabilized through H-bonds and pi-pi stacking interactions.