Screening and Determination for Potential a-Glucosidase Inhibitors from Leaves of Acanthopanax senticosus Harms by Using UF-LC/MS and ESI-MSn

Introduction Acanthopanax senticosus Harms is a typical Chinese herb with flavonoids existing in all parts of the plant but with the largest content in leaves. However, leaves have been neglected in past research. To investigate the potential use of leaves of A. senticosus Harms for discovering lead compounds to treat type 2 diabetes, the herb leaves were selected for screening the potential of a-glucosidase inhibitors. Objective To screen for candidates of a-glucosidase inhibitors from leaves of A. senticosus Harms and evaluate the structureactivity relationship of the a-glucosidase inhibitors. Methodology Ultrafiltration liquid chromatography/mass spectrometry (UF-LC/MS) assay was developed for screening candidates of a-glucosidase inhibitors from leaves of A. senticosus Harms. The interesting compounds were identified by using reversed-phase high performance liquid chromatography with diode array detector and electrospray ionisation multiple-stage tandem mass spectrometry (RP-HPLC-DAD-ESI-MSn), and confirmed by using electrospray ionisation Fourier transform ion cyclotron resonance multiple-stage tandem mass spectrometry (ESI-FT-ICR-MSn). Furthermore, the a-glucosidase inhibitory activity of the compounds detected was estimated using in vitro assays. Results Eight compounds that might bind to a-glucosidase were screened and seven of them were identified successfully. The a-glucosidase inhibitory activity of the related compounds in leaves of A. senticosus Harms was determined. Conclusion The results obtained provided new information for the discovery of potential a-glucosidase inhibitors and the potential anti-diabetic application of the leaves of A. senticosus Harms. Copyright (C) 2011 John Wiley & Sons, Ltd.