Identification and quantification of C21 steroidal saponins from Radix Cynanchi Atrati by high-performance liquid chromatography with evaporative light scattering detection and electrospray mass spectrometric detection

Abstract

High-performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-ESI/MS) and evaporative fight scattering detection (HPLC-ELSD), respectively, has been performed for the simultaneous identification and quantification of six C21 steroid saponins, including cynanversicoside A, B, D, G, glaucoside C and glaucogenin C-3-O-β-D-thevetopyranoside in Radix Cynanchi Atrati. The extraction of the C21 steroidal saponins was performed using a B-811 Buchi Universal Extraction System in Warm Solvent Mode, and the analyte was concentrated by column chromatography before HPLC analysis. The chromatographic separation was performed on an Agilent Zorbax Extend C18 analytical column efficiently using gradient elution with acetonitrile and water. The method was validated with acceptable linearities (r > 0.9991) and recoveries (98.2-101.3%). The limits of detection of the C21 steroid saponins were from 0.2 μg for glaucogenin C-3-O-β-D-thevetopyranoside to 0.5 μg for cynanversicoside B. The intra- and inter-day precisions of the method were evaluated and were less than 5.0%. The method was successfully used to analyse 20 batches of Radix Cynanchi Atrati. The content of C21 steroid saponins in the plant material varied significantly from habitat to habitat, confirming the necessity to control the quality of Radix Cynanchi Atrati during its preparation and application in the clinic. Copyright © 2007 John Wiley & Sons, Ltd.