Determination of the Antioxidant Activity of Potential Scavengers of Nitrogen Oxide

Overview

Nitrogen oxide is a relatively stable, highly reactive radical, which develops in the organism byoxidation of the guanidine nitrogen of the amino acid L-arginine by the action of NO-synthase withthe development of L-citrulline. It participates in a number of physiological and pathologicalprocesses. The difference between the physiological and pathological concentration of nitrogen oxideis very small, and for that reason we search for suitable methods of its determination and thesubstances influencing the level of nitrogen and thus decreasing its overproduction. Testing ofscavenger activity against NO was performed by the method following Griess (spectrophotometricdetermination of nitrites as the oxidation products of NO), which was compared with the HPLC(high-performance liquid chromatography) method developed by the present authors. The antiradicaleffect of the compounds being assayed (acetylsalicylic acid, piracetam, paracetamol, serotonin,stobadin dihydrochloride, 5-hydroxy-L-tryptophan, N-acetyl-L-cysteine, L-glutathion, and N-acetyl--DL-penicillamine) against NO was compared with the so-called total antioxidant activity – TRAP(total radical-trapping antioxidant parameter), which corresponds to the capability to trap peroxylradicals. On the basis of the obtained data, piracetam and acetylsalicylic acid show no antioxidantactivity, paracetamol shows probably moderate scavenging action against nitrogen oxide, and othercompounds tested (primarily 5-hydroxy-L-tryptophan, serotonin, stobadin) are strong antioxidantsagainst both NO and peroxyl radical.

Key words:
nitrogen oxide – nitrogen oxide scavengers – Griess reaction – TRAP