Gas-Phase Fragmentation Reactions of Protonated Pumiliotoxin (+)-251D and Allopumiliotoxin (+)-267A in ESI-MS/MS

In recent years, there has been great interest in understanding the chemistry of natural products from different organisms and their role in ecological processes. Some species of frogs sequester and metabolize dietary alkaloids obtained primarily from mites and ants as chemical defense. Most of these studies have employed gas chromatography techniques coupled with mass spectrometry, which restricts the possibility of observing more polar metabolites. In the case of pumiliotoxin (+)-251D and allopumiliotoxin (+)-267A, the fragmentation mechanisms in electrospray ionization systems with collision-induced fragmentation are undescribed. The present study aims to elucidate the fragmentation pathways of these two toxins. For this purpose, we used direct infusion of toxins in a time-of-flight hyphenated quadrupole electrospray ionization tandem mass spectrometry (ESI-MS/ MS) system. Different collision energies were applied, and the data rationalized from the concepts of reaction mechanisms. The joint analysis allowed to present a robust map of fragmentation opening perspectives for their application in studies of the occurrence of new polar analogues.