Discovery of α-Glucosidase/Acetylcholinesterase Inhibitors from a Traditional Herbal Prescription of Qi-Li-Qiang-Xin Capsule by Time-Based Fractionation and Enzymatic Activity Assay

Abstract

Objectives The aim is to discover α-glucosidase/acetylcholinesterase inhibitors as lead compounds from a traditional herbal prescription of Qi-Li-Qiang-Xin capsule (QLQX). Methods A novel strategy combining time-based fractionation, LC-QTOF-MS, enzymatic activity assay, molecular docking and component-target association analysis was performed to discover α-glucosidase/acetylcholinesterase inhibitors from QLQX. Time-based fractionation combined with enzymatic activity assay was used to find the distribution period of active compounds in the herbal prescription. LC-QTOF-MS was used to analyze the structure of active compounds. Molecular docking was applied to explore the interaction between active compounds and targets. Results According to time-based fractionation, the active components of QLQX for acetylcholinesterase were primarily concentrated in the highly polar region, whereas the active components for α-glucosidase were predominantly found in the moderately polar area. A total of 33 compounds were identified by comparing with chemical reference substances. Dihydrotanshinone Ⅰ (16.98 µM), hydroxysafflor yellow A (84.57 µM), salvianolic acid A (76.62 µM) and cryptotanshinone (112.68 µM) were identified as acetylcholinesterase inhibitors from QLQX. Similarly, rosmarinic acid (62.29 µM), isochlorogenic acid A (17.95 µM), 4,5-dicaffeoylquinic acid (117.93 µM), danshensu (207.88 µM), salvianolic acid A (1.31 µM), 3,4-dicaffeoylquinic acid (91.71 µM), formononetin (67.26 µM), ginsenoside Rd (3.43 µM), ginsenoside Rb1 (26.37 µM) and ginsenoside F1 (18.79 µM) were discovered as α-glucosidase inhibitors. Notably, salvianolic acid A inhibited both acetylcholinesterase and α-glucosidase. The results of molecular docking indicated that hydrogen bonds, hydrophobic interactions and Pi-Pi T-shaped interactions were crucial for inhibiting acetylcholinesterase. Meanwhile, hydrogen bonds, hydrophobic interactions and Pi-Pi stacked interactions were significant in suppressing α-glucosidase. Conclusion QLQX contains numerous acetylcholinesterase and α-glucosidase inhibitors, demonstrating its potential therapeutic benefits for Alzheimer's disease and diabetes.