Structural characterization and identification of five triterpenoid saponins isolated from Momordica cochinchinensis extracts by liquid chromatography/tandem mass spectrometry

Abstract

In this work, we reported the use of high-performance liquid chromatography (HPLC) with electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn) to study the characterization of five triterpenoid saponins from Momordica cochinchinensis extracts in positive ion mode and negative ion mode, revealed the fragmentation behavior of these five M. cochinchinensis saponins in different ion modes. Results showed that in negative ion mode, fragmentation on the M. cochinchinensis triterpenoid saponins at positions C28 and O bond were the primary pathways. In positive ion mode, the predominant diagnostic ions were a series of ions resulting from the rupture of the saccharic chain on C28. Comparison of different fragmentation patterns showed that the results from positive and negative ion ESI MSn were complementary. Both modes can yield structurally different information for the characterization of triterpenoid saponins. This study provides a powerful method for the online structural identification of five triterpenoid saponins from M. cochinchinensis, and some of which have not been reported.