Characterization of Phase I and Glucuronide Phase II Metabolites of 17 Mycotoxins Using Liquid Chromatography—High-Resolution Mass Spectrometry

Routine mycotoxin biomonitoring methods do not include many mycotoxin phase I and phase II metabolites, which may significantly underestimate mycotoxin exposure especially for heavily metabolized mycotoxins. Additional research efforts are also needed to measure metabolites in vivo after exposure and to establish which mycotoxin metabolites should be prioritized for the inclusion during large-scale biomonitoring efforts. The objective of this study was to perform human in vitro microsomal incubations of 17 mycotoxins and systematically characterize all resulting metabolites using liquid chromatography–high-resolution mass spectrometry (LC-HRMS). The results obtained were then used to build a comprehensive LC-MS library and expand a validated 17-mycotoxin method for exposure monitoring to screening of additional 188 metabolites, including 100 metabolites reported for the first time. The final method represents one of the most comprehensive LC-HRMS methods for mycotoxin biomonitoring or metabolism/fate studies.

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Metabolic Profile of Four Selected Cathinones in Microsome Incubations: Identification of Phase I and II Metabolites by Liquid Chromatography High Resolution Mass Spectrometry

Frontiers in Chemistry ◽

10.3389/fchem.2020.609251 ◽

2021 ◽

Vol 8 ◽

Author(s):

Beatriz T. Lopes ◽

Maria João Caldeira ◽

Helena Gaspar ◽

Alexandra M. M. Antunes

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

High Resolution ◽

Phase I ◽

Metabolic Profile ◽

High Resolution Mass Spectrometry ◽

Synthetic Cathinones ◽

High Resolution Mass ◽

Resolution Mass ◽

Phase I And Ii

Consumption of synthetic cathinones, the second largest class of new psychoactive substances (NPS) reported worldwide, represents a serious public health risk. One of the biggest challenges created by the rapid spread of NPS on the illegal drug market is the discovery of selective biomarkers for their detection in biological matrices, which is only possible through the study of their metabolic profile. The synthetic cathinones 4′-methyl-N,N-dimethylcathinone (4-MDMC), 4′-methyl-N,N-diethylcathinone (4-MDEC), 4′-chloro-α-pyrrolidinovalerophenone (4Cl-PVP), and 4′-chloroethylcathinone (4-CEC) are NPS recently seized in Europe, and, with the exception of 4-CEC, no metabolism study was reported for these cathinones. With the ultimate goal of overcoming this gap, these cathinones were incubated in vitro in human and rat liver microsomes in the presence of Phase I and II (glucuronidation) co-factors, using α-pyrrolidinovalerophenone (α-PVP) as positive control. The metabolite identification was performed by liquid chromatography coupled to tandem high resolution mass spectrometry (LC-HRMS/MS). This allowed the identification of multiple Phase I and glucuronide metabolites of the selected cathinones. Additionally, a new glucuronide conjugate, derived from the recreational drug α-PVP, was herein identified for the first time. Importantly, we have demonstrated that 4-MDMC and 4-MDEC can act as prodrugs of the controlled substances 4-MMC and 4-MEC, respectively. The metabolites herein identified are expected to play an important role not only by acting as potential selective biomarkers of the intake of the synthetic cathinones selected for this study but also to understand their potential adverse effects and link these causative agents to toxicities, thereby helping in the treatment of non-fatal intoxications.

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