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

Abstract

Fenton-reaction initiated in vitro oxidation and in vivo oxidative biotransformation of salicylic acid was investigated by HPLC-UV-Vis method. By means of the developed high performance liquid chromatography (HPLC) method salicylic acid, catechol, and all the possible monohydroxylated derivatives of salicylic acid can be separated. Fenton oxidations were performed in acidic medium (pH 3.0) with two reagent molar ratios: (1) salicylic acid: iron: hydrogen peroxide 1:3:1 and (2) 1:0.3:1. The incubation samples were analysed at different time points of the reactions. The biological effect of elevated reactive oxygen species concentration on the intestinal metabolism of salicylic acid was investigated by an experimental diabetic rat model. HPLC-MS analysis of the in vitro samples revealed presence of 2,3- and 2,5-dihydroxybenzoic acids. The results give evidence for nonenzyme catalysed intestinal hydroxylation of xenobiotics.

Keywords:

• Diabetes
• Fenton reaction
• nonsteroidal anti-inflammatory agents (NSAIDs)
• reactive oxygen species (ROS)
• salicylic acid

Acknowledgements

The present scientific contribution is dedicated to the 650th anniversary of the foundation of the University of Pécs, Hungary.

Disclosure statement

The authors confirm that this article content has no conflict of interest.

Additional information

Funding

This study was supported by the European Union, cofinanced by the European Social Fund (EFOP-3.6.1.-16-2016-00004).