Further Investigation Into an Environmental Source for Aminorex

Area of Science:

• Equine analytical chemistry
• Pharmacology
• Plant metabolomics

Background:

• Aminorex detections in equine samples lack clear administration links.
• Levamisole was an initial source, but unexplained cases persist.
• Barbarin from Brassicaceae plants is a suspected aminorex precursor.

Purpose of the Study:

• Investigate the link between barbarin and aminorex in horses.
• Identify biomarkers for plant-origin aminorex.
• Develop methods to distinguish plant-based aminorex from administration.

Main Methods:

• Validated analytical methods for aminorex, barbarin, glucobarbarin, and associated compounds.
• Administered aminorex, barbarin, and resedine to horses.
• Analyzed plasma and urine samples post-administration.
• Examined plant material chromatograms.

Main Results:

• Aminorex administration did not yield detectable barbarin.
• Horses ingesting Barbarea plants showed aminorex and some barbarin in plasma.
• Resedine was detected in plasma and urine post-plant ingestion and after direct administration.
• Aminorex was detected in urine after resedine administration.

Conclusions:

• Resedine is an intermediary between barbarin and aminorex in horses.
• Resedine serves as a biomarker to identify plant-origin aminorex.
• This finding helps eliminate false positives in equine drug testing.