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

Abstract

This paper focused on untargeted MS^All, also called MS^E, 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 MS^All. SWATH fragmentation was applied as a comparable and complementary method for resolving co-eluting species. A workflow based on MS^All 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.

Keywords: Acanthopanax senticosus; MS(All); SWATH; Saponins; UPLC-QTOF.