Rapid screening and characterization of triterpene saponins in Acanthopanax senticosus leaves via untargeted MSAll and SWATH techniques on a quadrupole time of flight mass spectrometry

This paper focused on untargeted MSAll, also called MSE, and sequential window acquisition of all theoretical fragment-ion spectra (SWATH) fragmentations for comprehensive structural characterization of triterpene saponins (TSs) in leaves of Acanthopanax senticosus through ultra-high performance liquid chromatography electrospray quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF). [M+H]+, [M + NH4]+ and [M + Na]+ precursor ions and the corresponding fragment ions were collected simultaneously in energy-resolved MSAll. SWATH fragmentation was applied as a comparable and complementary method for resolving co-eluting species. A workflow based on MSAll and SWATH fragmentations was constructed for comprehensive structural characterization and rapid discovery of TSs in leaves of A. senticosus. As a result, 89 TSs, along with 14 sapogenins, were unambiguously characterized or tentatively identified. Of these, 33 compounds were characterized as potentially new compounds, including the first report of malonyl-saponin in genus Acanthopanax. This study aimed to systematically analyze TSs in leaves of A. senticosus, and the results are significant for the utilization of A. senticosus leaves.