Steroidal saponins profiling of Rohdea chinensis (Baker) N.Tanaka by high performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry

The rhizome of Rohdea chinensis (Baker) N.Tanaka (RRc) is a famous folk medicine for the treatment of carbuncles and pharyngitis. Steroidal saponins (SSs) were considered to be the most abundant active constituents in RRc. However, to date, the in-depth study of SSs is still lacking. This study was aimed to investigate the SSs profiles of RRc extract by HPLC-ESI-QTOF-MS/MS. Analysis was performed on an Agilent poroshell 120 EC-C18 column (2.1 mm × 100 mm, i.d., 2.7 μm) with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase under gradient conditions. The results showed that 32 SSs including 20 furospirostanol, 11 spirostanol and 1 pseudo-spirostanol saponins were identified, 5 of which were reported in this plant for the first time. This is the first report on the analysis of SSs in RRc. This novel analysis method may stimulate further research regarding the identification of SSs in other plant species.