Comparisons of phenolic compounds and antioxidant activities during different growth stages in Artemisia gmelinii Weber ex Stechm with UPLC-QTOF/MS based on a metabolomics approach

Metabolomics approaches are becoming popular for a rational and efficient approach to standardize research including optimal harvest time determination to improve the values of plant raw materials. In this study, multivariate statistical analysis of metabolites from Artemisia gmelinii Weber ex Stechm (AG) by growth stage according to harvest time (from June to October) was performed by ultra-performance liquid chromatography (UPLC) coupled with quadrupole time of flight mass spectrometry (Q-TOF/MS). Secondary metabolite analysis through PCA provided clearly distinguishable patterns and qualitative R2X values (93.7%) for the corresponding markers. From the OPLS-DA, ten phenolic compounds were found as biomarkers exhibiting distinct patterns according to the harvesting periods (June-Aug: five phenolic acids, Aug-Oct: five flavonoids), and the contents of these phenolic compounds, well-known antioxidants, were increased according to the growth period (Oct > Aug > June). In conclusion, the harvesting time of plant raw materials could be sufficiently determined through the metabolomics study of secondary metabolites.