Differentiating Between Three Licorice Species Using SFC-TOF/MS Analysis With Principal Component Analysis

Abstract

Objective Although the discrimination of crude drugs by metabolomics analysis using liquid chromatography–mass spectrometry (LC–MS) has been widely reported, there are few reports on natural products analysis using supercritical fluid chromatography (SFC)–MS. This study aimed to compare the results of metabolomic analysis of licorice obtained using SFC–MS and LC–MS. Methods We analyzed 14 CHCl3 extracts of licorice roots ( Glycyrrhiza glabra, G. uralensis, and G. inflata) using SFC-time-of-flight (TOF)/MS and LC-TOF/MS in conjunction with principal component analysis (PCA). The three species were assessed for discrimination based on the PCA results. The characteristic constituents of each variety were purified, and their chemical structures were elucidated using various spectroscopic analyses. Results The PCA score plots of the results of both SFC and LC classified the licorice samples into three groups. Seven compounds (six known compounds and one new phenolic compound, glyglabone) were isolated from G. glabra, five known compounds were isolated from G. uralensis, and four known compounds were isolated from G. inflata. Conclusions The 16 isolated compounds may be characteristic compounds in the three licorice species. The SFC and LC methods showed comparable results in distinguishing the three species. SFC was highly effective for directly analyzing CHCl3 extracts, reducing analysis time and organic solvent consumption by over 50% compared to the LC analysis. Thus, SFC-TOF/MS in combination with PCA can be used to differentiate between G. glabra, G. uralensis, and G. inflata.