Detection of Saponins in Extracts from the Rhizomes of Paris Species and Prepared Chinese Medicines by High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry

Abstract

A highly sensitive and specific method, based on high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS), was developed for simultaneous detection of eleven steroidal saponins and one phytoecdysone in extracts from the rhizomes of thirteen PARIS species and four prepared Chinese medicines (PCMs). The HPLC experiments were performed by means of a reversed-phase C18 column (4.6 mm x 150 mm, 5 microm) and mobile phase system consisting of 0.1 % aqueous formic acid and acetonitrile under gradient elution conditions. The most intensive electrospray ionization signals were found in the negative ion spectra due to HCOO- adducts. The limits of detection (LODs) for the saponins were lower than 40 ng/mL in selected ion monitoring (SIM) mode. The identification of the saponins in the extracts of PARIS species and PCMs was confirmed using their retention times and mass spectral comparisons to standard compounds. The validated method was successfully applied for simultaneous detection of twelve standard compounds in the analytes so that it provided a new means for quality evaluation of Rhizoma Paridis and Chinese multiherb remedies that contain Rhizoma Paridis. The results showed that most species of PARIS contain steroidal saponins, which provided evidence for expanding the botanical origin of Rhizoma Paridis.