Integrated quality evaluation strategy for multi-species resourced herb medicine of Qinjiao by metabolomics analysis and genetic comparation

BACKGROUND: Quality evaluation of multi-species resourced herb medicine (MSRHM) is a main problem for quality control of herb medicine. Current quality evaluation methodology lost consideration of species discrepancy. New quality evaluation strategy for MSRHM is in urgent need. Qinjiao, a representative MSRHM, originated from Gentiana macrophylla Pall., Gentiana straminea Maxim., Gentiana crassicaulis Duthie ex Burk. or Gentiana dahurica Fisch., has been used as an important herb medicine over 2000 years for expelling wind-dampness and relieving impediment pain. However, quality evaluation among species has never been revealed. The current work proposes an integrated quality evaluation strategy for MSRHM of Qinjiao, which may promote innovation of quality control of MSRHM. METHODS: In this work, 58 batches of Qinjiao covering 4 species were collected. Genetic comparative analysis based on ITS2 sequence was conducted. Metabolomics analysis based on TOF–MS and NMR spectrum were carried out. Compounds underlying species differences were identified and their discrepancies among species were investigated by ANOVA analysis and multivariate analysis. RESULTS: Four species of Qinjiao can be authenticated by ITS2 sequence comparation. Metabolomics analysis by TOF/MS and NMR revealed chemical discrepancies among species of Qinjiao. Maximum discrepancy was present between Gentiana crassicaulis Duthie ex Burk. and Gentiana dahurica Fisch. Chemical difference among species were tentative explored. For TOF–MS profiling, 28 constituents were tentative identified, 17 of which were further confirmed by standards. For (1)H-NMR profiling, signals from 5 compounds were assigned. Contents discrepancies were investigated by ANOVA analysis. It seems that (seco)iridoids like loganic acid, gentiopicroside or swertiamarin were richer in specie of Gentiana crassicaulis Duthie ex Burk., while flavonoid (morroniside) and triterpenoids (roburic aicd, ursolic acid, oleanolic acid, β-sitosterone) were richer in specie of Gentiana dahurica Fisch. The current research demonstrates that metabolite profiling based on both UPLC/Q-TOF MS and (1)H-NMR coupled with ITS2 sequence comparation can be a powerful tool for quality investigation of MSRHM of Qinjiao. CONCLUSIONS: A comprehensive quality evaluation strategy for MSRHM was proposed by integrating UPLC-Q-TOF–MS, NMR based metabolic analysis and ITS2 sequence genetic comparation. The proposed quality evaluation strategy shall promote innovation of quality control of traditional Chinese medicine.