Characterization of steroidal saponins in crude extracts from Dioscorea zingiberensis C. H. Wright by ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry

Steroidal saponins are the major bioactive constituents of Dioscorea zingiberensis C H Wright (D zingiberensis) In this work, ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS/MS) was applied to the separation and characterization of steroidal saponins in crude extracts from D zingiberensis. The results showed that fragment ions from glycosidic and cross-ring cleavages gave a wealth of structural information related to aglycone skeletons, sugar types and the sequence of sugar units. According to the summarized fragmentation patterns, identification of steroidal saponins from D zingiberensis could be fulfilled, even when reference standards were unavailable As a result, a total of thirty-one saponins with five aglycone skeletons, including fourteen new trace saponins, were identified or tentatively elucidated in crude extracts from D zingiberensis based on their retention times, the mass spectrometric fragmentation patterns, and MS and MS/MS data (c) 2010 Elsevier B V All rights reserved