In-Depth Excavation and Screening of Triterpene Saponins From the Rhizome of Panax japonicus Using High Performance Liquid Chromatography Coupled to Electrospray Ionization and Quadrupole Time-of-Flight Mass Spectrometry.

The rhizome of Panax japonicus (RPJ) has been used for thousands of years in west China. Triterpene saponins (TSs) were considered to be the main pharmacologically bioactive ingredients in RPJ. However, it is difficult and time-consuming to profile and identify them according to the traditional phytochemical methods. High-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS) was used for chemical identification of TSs from the extract of RPJ in negative ion mode. Their chemical structures were tentatively elucidated based on exact formulas, fragmentation patterns and literature data. In all, 42 TSs were discovered and tentatively characterized in RPJ, of which 12 TSs were identified as potential new compounds according to their molecular mass, fragmentation pattern and chromatographic behavior. The results demonstrated that the developed HPLC-ESI-QTOF-MS/MS method was conducive to the discovery of the active ingredients of RPJ and the establishment of quality standards.