ESI ‐QTof‐MS characterization of hirsutinolide and glaucolide sesquiterpene lactones: fragmentation mechanisms and differentiation based on Na+/H+ adducts interactions in complex mixture

AbstractSesquiterpene lactones (SL) have been reported with various biological effects. Among the described SL skeletons, hirsutinolide and glaucolide have not been extensively studied by mass spectrometry (MS), especially how to distinguish them in organic matrices. Thus, this paper reports i) a strategy of their differentiation based on MS behavior during the ionization and ii) a proposal of the fragmentation pattern for both SL ‐subtypes. ESI(+)‐HRMS data of four isolated SL (hirsutinolides1 and3; glaucolides2 and4) were recorded by direct and UPLC water ‐sample combined injections. These analyses revealed that hirsutinolides and glaucolides formed [M+Na]+ ion during the operation of the direct MS injection, while ([M+Na]+ and [M+H ‐H2O]+) and [M+H]+ ions were respectively observed for hirsutinolides and glaucolides during the operation of combined UPLC water and sample MS injection. Computational simulations showed that the complex hirsutinolide (1) ‐Na+ formed with a lower preparation energy compared to the complex glaucolide (2) ‐Na+. However, despite their different behavior during the ionization process, ESI(+) ‐HRMS/MS analyses of1‐4 gave similar fragmentation patterns atm/z 277, 259, 241, and 231 that can be used as diagnostic ions for both skeletons. Moreover, the differentiation strategy based on the nature of the complex SL ‐adducts and their MS/MS fragmentation pattern were successfully applied for the chemical characterization of the extract f...

Source: Journal of Mass Spectrometry - September 1, 2019 Category: Chemistry Authors: Layzon A.L. Silva, Louis P. Sandjo, Alechania Misturini, Giovanni F. Caramori, Maique W. Biavatti Tags: RESEARCH ARTICLE Source Type: research