Structural Elucidation of Metabolites of Synthetic Cannabinoid UR-144 by Cunninghamella elegans Using Nuclear Magnetic Resonance (NMR) Spectroscopy
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The number of new psychoactive substances keeps on rising despite the controlling efforts by law enforcement. Although metabolism of the newly emerging drugs is continuously studied to keep up with the new additions, the exact structures of the metabolites are often not identified due to the insufficient sample quantities for techniques such as nuclear magnetic resonance (NMR) spectroscopy. The aim of the study was to characterise several metabolites of the synthetic cannabinoid (1-pentyl-1H-indol-3-yl) (2,2,3,3-tetramethylcyclopropyl) methanone (UR-144) by NMR spectroscopy after the incubation with the fungus Cunninghamella elegans. UR-144 was incubated with C. elegans for 72 h, and the resulting metabolites were chromatographically separated. Six fractions were collected and analysed by NMR spectroscopy. UR-144 was also incubated with human liver microsomes (HLM), and the liquid chromatography-high resolution mass spectrometry analysis was performed on the HLM metabolites with the characterised fungal metabolites as reference standards. Ten metabolites were characterised by NMR analysis including dihydroxy metabolites, carboxy and hydroxy metabolites, a hydroxy and ketone metabolite, and a carboxy and ketone metabolite. Of these metabolites, dihydroxy metabolite, carboxy and hydroxy metabolites, and a hydroxy and ketone metabolite were identified in HLM incubation. The results indicate that the fungus is capable of producing human-relevant metabolites including the exact isomers. The capacity of the fungus C. elegans to allow for NMR structural characterisation by enabling production of large amounts of metabolites makes it an ideal model to complement metabolism studies.
KEY WORDSSynthetic cannabinoid metabolism Cunninghamella elegans UR-144 NMR
- C. elegans
Electrospray ionisation source
Gradient correlation spectroscopy
Gradient heteronuclear multiple bond correlation
Gradient heteronuclear single quantum correlation
Human liver microsomes
High-performance liquid chromatography
Liquid chromatography-quadrupole time-of-flight mass spectrometry
Nuclear Overhauser effect spectroscopy
Nuclear magnetic resonance
New psychoactive substances
The authors would like to thank Jane Cameron and Zofia Winiarski for the support with fungus culturing and Mahmoud El Safadi for the support with organic synthesis.
Compliance with Ethical Standards
Conflicts of Interest
The authors declare that they have no conflicts of interest.
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