Decomposition of N-nitrosamines, and concomitant release of nitric oxide by Fenton reagent under physiological conditions.
N-Nitrosodimethylamine (NDMA) in phosphate buffer was rapidly decomposed by Fenton reagent composed of H2O2, and Fe(II) ion. Electron spin resonance (ESR) studies using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) showed that characteristic four line 1:2:2:1 ESR signals due to the DMPO-OH adduct formed on treatment of DMPO with Fenton reagent disappeared in the presence of NDMA, and N-nitrosodiethylamine (NDEA), suggesting the interaction of the N-nitrosamines with Fenton reagent. Treatment of the N-nitrosamines with Fenton reagent generated nitric oxide (NO) as estimated by ESR technique using cysteine-Fe(II), and N-methyl-D-glucaminedithiocarbamate (MGD)-Fe(II) complexes. Characteristic 3, and single line signals due to 2 cysteine-Fe(II)-NO, and 2 cysteine-Fe(II)-2 NO complexes, respectively, and three line signals due to MGD-Fe(II)-NO were observed. Considerable amount of NO were liberated as determined by NO2-, the final oxidation product of NO formed by reaction with dissolved oxygen in the aqueous medium. Spontaneous release of a small amount of NO from the N-nitrosamines was observed only on incubation in neutral buffers. Above results indicate that the N-nitrosamines were decomposed accompanying concomitant release of NO on contact with reactive oxygen species.
Hiramoto
K
K
School of Pharmacy, Tokyo University of Pharmacy, and Life Science, 1432-1 Horinouchi, Hachioji, 192-0392, Tokyo, Japan.
Ryuno
Y
Y
Kikugawa
K
K
D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007501:Iron / Q000378:metabolism / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D009603:Nitroso Compounds / Q000737:chemistry* / Q000378:metabolism*; D010084:Oxidation-Reduction; D026361:Reactive Nitrogen Species / Q000737:chemistry*
C045076:Fenton's reagent; D005609:Free Radicals; D009603:Nitroso Compounds; D026361:Reactive Nitrogen Species; C008651:4-nitrosodimethylaniline; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D007501:Iron