Metabolomics characterization of different geographical origins of Flos Carthami using UPLC-QTOF/MS and their correlation with climate factors

Flos Carthami, the dried flower of Carthamus tinctorius L. (Compositae), is among the most popular traditional Chinese medicines due to its diverse biological activities such as anticoagulation, vasodilation, antihypertension, antioxidation, neuroprotection, melanin production inhibition, immunosuppression and antitumor activity. At present, Carthamus tinctorius L. is cultivated in various regions under diverse environmental conditions which has led to quality instability of Flos Carthami in the market and may in turn influence its therapeutic efficacy. So it is necessary to characterize the chemical profiles of different geographical origins of Flos Carthami and find differential metabolites contributing to this difference. In this study, a UPLC-QTOF/MS method was developed to characterize chemical differences of Flos Carthami collected in the Xinjiang Uygur Autonomous Region and Henan, Gansu and Yunnan provinces, China. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used to differentiate Flos Carthami samples cultivated in the above-mentioned regions. 32 differential metabolites accountable for such variations were identified through variable importance in the projection (VIP). Grey correlation analysis (GCA) was conducted between 32 differential metabolites and climate factors. Climate factors such as XASD, XRH, XHTJ and XATJ had higher significant correlation with most differential metabolites. Conversely, lower significant correlations were observed between climate factors such as XLTA and XATA and the 32 differential metabolites. So, in order to improve the stability of the chemical quality and guarantee the clinical use of Flos Carthami, its phytogeographical variation cannot be neglected and the differential metabolites could be used to guide the quality control of Flos Carthami.