Research on chemical constituent differences in wild and cultivated Arnebia euchroma by combining UPLC-QTOF-MS with chemometrics†

In this study, ultra-high performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS) was used to analyze the wild and cultivated Arnebia euchroma and the chemical constituent differences were determined by chemometric analysis including principal component analysis (PCA), hierarchical cluster analysis (HCA), and orthogonal partial least squares-discrimination analysis (OPLS-DA). The MS data were processed using UNIFI combined with an in-house library to characterize the metabolites automatically. Based on the multiple adduct ions, exact mass, diagnostic fragment ions, peak intensity, retention time of compounds, and the fragmentation mechanism and retention behavior of references, the structures identified by UNIFI were further verified and the unidentified compounds were also tentatively elucidated. 68 compounds were identified, including 26 shikonins, 14 shikonofurans, 7 flavonoids, 7 phenolic acids, 5 esters, 2 phenylpropanoids, 2 saccharides and 5 others. The chemometrics results showed that the compositions of wild and cultivated Arnebia euchroma were significantly different; 8 differential components were obtained through VIP >1 screening. The quality of wild and cultivated products is strongly influenced by altitude, and the higher the altitude, the more favorable the accumulation of chemical constituents, especially shikonofurans. These results provide basic information for revealing the effects of the ecological environment on the metabolite synthesis and accumulation of Arnebia euchroma and provide an important basis for further research and clinical application of wild and cultivated Arnebia euchroma.