HPLC study on Fenton-reaction initiated oxidation of salicylic acid. Biological relevance of the reaction in intestinal biotransformation of salicylic acid

The photochemically initiated oxidation of salicylic acid by molecular oxygen in the presence of [Fe(C2O4)3]3- leads to a mixture of 2,3- and 2,5-dihydroxybenzoic acids. Iron(II) generated by the photoreduction is reoxidized by dioxygen. Hydrogen peroxide formed in this reaction takes part in the Fenton reaction in the presence of Fe(II). Experiments with OH. radical scavengers document the role of the radicals in the photochemical and thermal hydroxylation of salicylic acid.

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Degradation of salicylic acid by photo-assisted Fenton reaction using Fe ions on strongly acidic ion exchange resin as catalyst

Chemical Engineering Journal ◽

10.1016/j.cej.2004.01.031 ◽

2004 ◽

Vol 100 (1-3) ◽

pp. 159-165 ◽

Cited By ~ 42

Author(s):

J FENG ◽

X HU ◽

P YUE

Keyword(s):

Salicylic Acid ◽

Ion Exchange ◽

Fenton Reaction ◽

Exchange Resin ◽

Ion Exchange Resin ◽

Fe Ions

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Chemical, Biological and Medical Controversies Surrounding the Fenton Reaction

Progress in Reaction Kinetics and Mechanism ◽

10.3184/007967403103165468 ◽

2003 ◽

Vol 28 (1) ◽

pp. 75-104 ◽

Cited By ~ 32

Author(s):

Mark J. Burkitt

Keyword(s):

Ascorbic Acid ◽

Hydroxyl Radical ◽

Fenton Reaction ◽

Nitrosative Stress ◽

Iron Status ◽

Critical Evaluation ◽

Oxidative And Nitrosative Stress ◽

Iron Regulatory Proteins ◽

Biological Relevance

A critical evaluation is made of the role of the Fenton reaction (Fe2+ + H2O2 → Fe3+ + •OH + OH-) in the promotion of oxidative damage in mammalian systems. Following a brief, historical overview of the Fenton reaction, including the formulation of the Haber–Weiss cycle as a mechanism for the catalysis of hydroxyl radical production, an appraisal is made of the biological relevance of the reaction today, following recognition of the important role played by nitric oxide and its congers in the promotion of biomolecular damage. In depth coverage is then given of the evidence (largely from EPR studies) for and against the hydroxyl radical as the active oxidant produced in the Fenton reaction and the role of metal chelating agents (including those of biological importance) and ascorbic acid in the modulation of its generation. This is followed by a description of the important developments that have occurred recently in the molecular and cellular biology of iron, including evidence for the presence of ‘free’ iron that is available in vivo for the Fenton reaction. Particular attention here is given to the role of the iron-regulatory proteins in the modulation of cellular iron status and how their functioning may become dysregulated during oxidative and nitrosative stress, as well as in hereditary haemochromatosis, a common disorder of iron metabolism. Finally, an assessment is made of the biological relevance of ascorbic acid in the promotion of hydroxyl radical generation by the Fenton reaction in health and disease.

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Oxidation of Hydroxy- and Dihydroxybenzoic Acids Under the Udenfriend's Conditions. An HPLC Study

The Open Medicinal Chemistry Journal ◽

10.2174/1874104501812010013 ◽

2018 ◽

Vol 12 (1) ◽

pp. 13-22 ◽

Cited By ~ 1

Author(s):

Mónika Kuzma ◽

Nikoletta Kovács ◽

Lilla Sziva ◽

Gábor Maász ◽

Péter Avar ◽

...

Keyword(s):

Salicylic Acid ◽

Biological Action ◽

Dihydroxybenzoic Acid ◽

Intermediate Precision ◽

Hydroxylated Metabolites ◽

Oxidative Reactions ◽

Rp Hplc ◽

Oxidized Products ◽

Hplc Study

Background:Non-enzymatic hydroxylation of aromatic compounds to the respective phenolic derivatives is a possible metabolic pathway of xenobiotics. The formed metabolites can undergo consecutive oxidative reactions with free radicals to form potential toxic molecules.Objective:Development of HPLC methods to separate, identify and quantitate the main products formed from salicylic acid, 2,3-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid underin vitrohydroxylation conditions (Udenfriend's system).Method:An RP-HPLC-UV-Vis method was developed to separate salicylic acid and isomeric dihydroxybenzoic acids formed in the Udenfriend's system. Confirmation of structures of the oxidized products of salicylic acid, 2,3-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid was performed by HPLC-ESI-MS/MS method.Results:The HPLC-UV-Vis method was evaluated for a number of validation characteristics (selectivity, repeatability and intermediate precision, LOD, LOQ and calibration range). It was found that oxidation of salicylic acid resulted in the formation of 2,3- and 2,5-dihydroxybenzoic acids. Furthermore, the hydroxylated metabolites can be further metabolized under the Udenfriend’s conditions.Conclusion:The results give evidence for possible involvement of the oxidized metabolites of salicylic acid in the development of biological action of salicylates at the site of inflammation, where high hydroxyl radical level can be detected.

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