Identification of chemical constituents in Rhizoma Paridis Saponins and their oral administration in rat plasma by UPLC/Q-TOF/MS.

On-line ultra-performance liquid chromatography (UPLC) coupled with diode-array detection (UPLC/DAD) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) were used for separation, identification and structural analyses of saponins in Rhizoma Paridis saponins (RPS) and rat plasma after oral administration of RPS. Thirty steroidal saponins in RPS were identified by comparing their retention time, accurate mass measurement and positive and negative mass spectrometry data with that of reference compounds. The UPLC/Q-TOF-MS method was proved to be rapid and efficient in that 30 steroidal saponins, including three kinds of saponins (prototype, pennogenyl and diosgenyl saponins) were tentatively characterized within 6 min. After oral administration of RPS, 21 original saponins were absorbed in RPS-treated rat plasma. Our results indicated that UPLC/Q-TOF-MS is a rapid and effective tool for identification of a series of saponins at trace level.