A magnetic beads-based ligand fishing method Coupled with UHPLC-QTOF MS for screening and identification of -glucosidase inhibitors from Houttuynia cordata Thunb

In this study, a method for the screening and identification of alpha-glucosidase inhibitors from natural products was developed. The alpha-glucosidase was immobilized on carboxyl terminated magnetic beads to form a ligand fishing system to screen the potential inhibitors. A total of 9 compounds were fishing out from the crude Houttuynia cordata Thunb. extract. Meanwhile, ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) was used for the identification of the chemical structures, including 3 chlorogenic acid isomers, 2 flavone C-glycosides and 4 flavone O-glycosides. The combination of enzyme immobilization magnetic beads and UHPLC-QTOF MS could be used for the screening of bioactive multi -components from herbs with appropriate targets. Taking the advantage of the specificity of enzyme binding and the convenience of magnetic separation, the method has great potential for rapid screening of alpha-glucosidase inhibitors from complicated natural product extracts.