Structure characterization and identification of steroidal saponins from the rhizomes of Anemarrhena asphodeloides by ultra performance liquid chromatography and hybrid quadrupole time-of-flight mass spectrometry

In this work, ultra performance liquid chromatography (UPLC) coupled with a hybrid quadrupole time-of-flight mass spectrometry (Q-TOF MSE) was used to separate and identify steroidal saponins from the crude extracts of Anemarrhena asphodeloides. The fragmentation patterns of seven known steroidal saponins, which could be classified into six types, were investigated by UPLC/Qtof MSE technique in both negative and positive ion modes. By using this strategy, both intact precursor and fragment ion information were obtained from a single injection. Based on the exact mass, fragment ions, and retention times of peaks, and comparison with reference standards and known compounds in the literature, sixty-seven steroidal saponins were identified or tentatively identified from A. asphodeloides. This included sixteen groups of isomers. Fourteen of these saponins were identified as new compounds. This study provides a good example for the rapid identification of chemical constituents in complex samples such as TCM by UPLC/Qtof MSE, in the mean time, avoiding the time-consuming and tedious purification of compounds from the crude extracts. (C) 2013 Elsevier B.V. All rights reserved.