We evaluated the presence of the
melatonin metabolite N1-acetyl-N2-formyl-5-methoxykynuramine (
AFMK), in cerebrospinal fluid (CSF) of patients with
viral meningitis (n = 20) and control samples (n = 8) and correlate
AFMK levels with inflammatory markers such as cellularity,
protein,
tumor necrosis factor (
TNF)-alpha,
interleukin (IL)-8 and IL-1beta levels. A portion of the CSF was extracted with
dichloromethane (1:5) and analyzed by high-performance liquid chromatography (HPLC) under standardized conditions for
AFMK.
AFMK was detected in 16 of 20 CSF samples of patients with
viral meningitis; the concentration of
AFMK was found to be above the quantification limit (50 nmol/L) in six of these samples.
AFMK was not detected in any of the eight control samples. The samples were classified into groups according to
AFMK levels: undetectable (<10 nmol/L, group I), detectable but below the quantification limit (< 50 nmol/L, group II), and quantified (>50 nmol/L, group III). Group II presented the highest levels of
proteins and
IL-8, whereas group III showed the lowest levels of the inflammatory parameters. This study supports our hypothesis that
inflammation favors the formation of
AFMK and that this compound has immunomodulatory activity in vivo.