Related Experiment Video
Updated: Aug 30, 2026

A High-performance Liquid Chromatography Measurement of Kynurenine and Kynurenic Acid: Relating Biochemistry to Cognition and Sleep in Rats
Published on: August 19, 2018
N1-acetyl-N2-formyl-5-methoxykynuramine is a product of melatonin oxidation in rats
Stanislav V Rozov1, Elena V Filatova, Alexandr A Orlov
1Sechenov Institute of Evolutionary Physiology and Biochemistry of Russian Academy of Sciences, Saint-Petersburg, Russia.
Abstract:
The product of melatonin oxidation, N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), was synthesized and a method for its determination in biological samples was developed. High performance liquid chromatography (HPLC) with fluorescence detection provided good sensitivity and selectivity. Wavelengths of 350 and 480 nm were used for excitation and emission, respectively. Serum and retinal homogenates were extracted with chloroform prior to analysis by HPLC. Endogenous AFMK was detected in the retina of rats but the serum concentration of this melatonin metabolite was below the detection limit of the method for measurement. Retinal AFMK concentration was higher during the dark phase of the light/dark cycle, when the retinal melatonin content is maximal. Intraperitoneal administration of melatonin significantly increased serum and retinal AFMK levels. Formation of AFMK from melatonin was also confirmed by in vivo microdialysis with the probe implanted into the brain lateral ventricle. The study shows that AFMK is indeed a product of melatonin oxidation in vivo. The possible physiological significance of melatonin oxidation metabolic pathway is discussed.
Related Concept Videos
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
Phase II Reactions: Acetylation Reactions
The substrates for acetylation are typically drugs or their metabolites with an amino, sulfonamide, or hydrazine functional group. Acetylation can occur at several points in the drug molecule, including primary, secondary, and...
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
2° Amines to N-Nitrosamines: Reaction with NaNO2
Aldehydes and Ketones with Amines: Imine and Enamine Formation Overview
Phase I Reactions: Oxidation of Carbon-Heteroatom and Miscellaneous Systems
In carbon-nitrogen systems, aliphatic and aromatic amines can undergo oxidative reactions. Secondary and tertiary amines, like those found in tricyclic antidepressants, can undergo N-dealkylation, a process that involves the oxidation of the alkyl group. In addition, oxidative...

