UPLC‐Q‐TOF‐MS/MS‐guided dereplication of Pulsatilla chinensis to identify triterpenoid saponins

Abstract Introduction Triterpenoid saponins are the major bioactive constituents of Pulsatilla chinensis , playing an important role in various biological activities such as anti‐tumour, cognition‐enhancing, anti‐biosis, anti‐inflammatory, hypoglycemic and immunological adjuvant. Objective To establish a systematic strategy based on ultra‐high‐performance liquid chromatography‐quadrupole time‐of‐flight tandem mass spectrometry (UPLC‐Q‐TOF‐MS/MS) for the efficient characterisation and identification of triterpenoid saponins in crude extracts from Pulsatilla chinensis . Methodology In this work, the strategy includes two aspects: (1) positive mode: by target screening, we can deduce the aglycone type and the composition of sugar moiety according to the fragment ions; untargeted screening includes four steps, find unknown, formula finder, ChemSpider search and MS/MS identification; (2) negative mode: according to the MS/MS spectra, the composition of sugar chain bonded to C‐28 is inferred reasonably. The extract of Pulsatilla chinensis was separated within 60 min on a C 18 column and eluted with methanol and water both containing 0.1% formic acid. Results As a result, a total of 22 triterpenoid saponins (11 pairs of isomers) with four aglycone skeletons were tentatively identified or elucidated in crude extracts from Pulsatilla chinensis based on their retention times, the mass spectrometric fragmentation patterns, and MS and MS/MS data. Conclusion This study provides an efficient analysis strategy to rapidly identify the triterpenoid saponins in Pulsatilla species even in traditional Chinese medicines.