Reaction of 5-aminosalicylic acid with peroxyl radicals: protection and recovery by ascorbic acid and amino acids.
OBJECTIVE
The aims of the study are to analyze the interaction between 5-aminosalicylic acid (5-ASA) and peroxyl radicals and to evaluate the effect of some endogenous compounds such as ascorbic acid and amino acids on the oxidation of 5-ASA induced by 2,2'-azo-bis(2-amidinopropane) dihydrochloride.


METHODS
The consumption and/or the recovery of 5-ASA (7.6 microM) exposed to a peroxyl radical source [2,2'-azo-bis(2-amidinopropane)] was followed by techniques such as spectrofluorescence, high-performance liquid chromatography, and differential pulse voltammetry.


RESULTS
5-Aminosalicylic acid was found to readily react with peroxyl radicals at micromolar concentrations and to protect c-Phycocyanin in a very similar fashion to that shown by Trolox. Exposure of 5-ASA to peroxyl radicals led to its oxidation into the corresponding quinone-imine. Disappearance of 5-ASA was prevented by tryptophan, cysteine, glutathione, and ascorbic acid. Furthermore, some of these compounds induced the partial (cysteine and glutathione) or total (ascorbic acid) recovery of 5-ASA when added after its almost total consumption.


CONCLUSIONS
5-Aminosalicylic acid is a very efficient peroxyl radical scavenger. The 5-ASA oxidation by peroxyl radicals was prevented by ascorbic acid, cysteine, and glutathione. In addition, 5-ASA can be regenerated by these endogenous compounds, which would be a valuable mechanism to preserve 5-ASA in tissues undergoing oxidative stress conditions.
López-Alarcón
Camilo
C
Instituto de Nutricíon y Tecnología de los Alimentos (INTA), Universidad de Chile, El Líbano 5524, Macul, Santiago, Chile.
Rocco
Claudia
C
Lissi
Eduardo
E
Carrasco
Catalina
C
Squella
J Arturo
JA
Nuñez-Vergara
Luis
L
Speisky
Hernan
H
D000578:Amidines / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry / Q000494:pharmacology*; D004563:Electrochemistry; D019804:Mesalamine / Q000737:chemistry* / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry* / Q000378:metabolism; D010798:Phycocyanin / Q000737:chemistry; D014364:Tryptophan / Q000737:chemistry / Q000494:pharmacology*
D000578:Amidines; D000894:Anti-Inflammatory Agents, Non-Steroidal; D016877:Oxidants; D010545:Peroxides; D010798:Phycocyanin; C049375:perhydroxyl radical; D019804:Mesalamine; C046728:2,2'-azobis(2-amidinopropane); D014364:Tryptophan; D003545:Cysteine; D001205:Ascorbic Acid