Characterization of phenolics and discovery of α-glucosidase inhibitors in Artemisia argyi leaves based on ultra-performance liquid chromatography-tandem mass spectrometry and relevance analysis

Artemisia argyi leaves (AAL) has been widely used as herbal medicine and food supplement and in China and other Asian countries. The aim of this work is to qualitative and quantitative characterization of phenolic compounds in AAL and screening of natural product inhibitors of α-glucosidase from AAL. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) was employed to rapid and comprehensive identification of phenolic compounds in AAL, and a total of thirty-three phenolic compounds were identified. High performance liquid chromatography with diode array detection (HPLC-DAD) was established and validated to simultaneously determinate ten main bioactive phenolics compounds in different batches of AAL samples. Meanwhile, the inhibitory capacities of different batches of AAL samples on α-glucosidase were evaluated. Then, relevance analysis, including grey relational analysis and Pearson correlation analysis were employed to investigate the correlations between the contents of phenolic compounds and α-glucosidase inhibitory activities, and discover the α-glucosidase inhibitors in AAL. The relevance analysis results indicated that three phenolic compounds, 3-caffeoylquinic acid, 3,4-dicaffeoylquinic acid and 3,5-dicaffeoylquinic acid could be potential α-glucosidase inhibitors in AAL. Moreover, the α-glucosidase inhibitory activities of the three phenolic compounds were validated by in vitro and in vivo experiments. The possible inhibiting effect of the three phenolic compounds on α-glucosidase was also explored by molecular docking analysis, and the results indicated that the binding of the three α-glucosidase inhibitors to α-glucosidase mainly by hydrogen bonds, hydrophobic forces and ionic bonds. The present research provided a deep insight into phenolic compounds and α-glucosidase inhibitory activities of AAL, and discovered the α-glucosidase inhibitors in AAL.