The strategy for establishment of the multiple reaction monitoring based characteristic chemical profile of triterpenes in Alismatis rhizoma using two combined tandem mass spectrometers

It was reported that triterpenes compounds in Alismatis rhizoma (AR) contributed to the lipid lowering effect on high fat diet (HFD)-induced hyperlipidemia. To date only 24 triterpenes (including the isomers) were characterized by LC-QTOF-MS/MS due to the lack of strategies for systematic discovery, classification and identification of triterpenes in AR. In this study, an integrated strategy combining various QTOF-MS/MS and QTRAP-MS/MS scan functions was developed for systematic identification and specific characterization of triterpenes in AR and processed AR. First, MS/MS fragmentation behaviors of different types of triterpenes were investigated and their diagnostic product ions were systematically summarized for discovery and classification of triterpenes. Second, diagnostic product ions were used to filter the data acquired by UHPLC-QTOF MS/MS for efficient identification of targeted triterpenes. Third, MRM-based characteristic chemical profile (CCP) of triterpenes was established using 30 MRM transitions by UHPLC-QTRAP-MS/MS. Fourth, MRM-based CCP was applied for comparative analyses of triterpenes in AR from different regions and from two other processed AR (salt processed AR and bran processed AR). Consequently, a total of 80 triterpenes including 14 novel compounds were identified in the AR, and 7 more triterpenes compounds were discovered using MRM-based CCP in the processed AR. This work is the most comprehensive characterization of triterpenes compounds in AR to date. The established MRM-based CCP of triterpenes compounds can be instructive for qualitative analyses and relative quantitative analyses of triterpenes in AR and its related medicinal products for potential applications including quality control and classification of different AR materials.