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.

The Intestinal and Biliary Metabolites of Ibuprofen in the Rat with Experimental Hyperglycemia

“…The key features of the reaction are believed to be the reaction conditions, such as reagent concentrations, pH, and temperature [37]. Earlier, we applied the reactions to study the oxidative transformation of salicylates [20,38].…”

“…Earlier, we investigated how the ratio of the molar concentration of the substrate (salicylic acid) to the iron(II) ion in the Fenton test affects the effectiveness of the hydroxylation reaction. The present investigations were performed using the more effective conditions, using the substrate: iron(II): hydrogen peroxide molar ratio as 1:3:1 [20].…”

“…The experiments were performed as described before [20]. Iron(II) sulfate (100 µL of 30 mM) solution (in pH 3.0 sulfuric acid) was mixed with 700 µL of sulfuric acid (pH 3.0) and the mixture was vortexed for 30 s. Then, 100 µL of 10 mM IBP in phosphate buffer pH 7.2 was added and vortexed.…”

Biochemical and physiological responses induced in Mytilus galloprovincialis after a chronic exposure to salicylic acid

“…Salicylic acid (SA) is the main primary metabolite of acetylsalicylic acid (ASA) (Nyúl et al, 2018) that represents the most widely consumed anti-inflammatory agent in the world, and belongs to the class of non-steroidal anti-inflammatory drugs as a result of its antipyretic, analgesic and anti-rheumatic properties (Buntenkötter et al, 2016;Maclagan, 1876). In dermatology, it is used as a keratolytic agent, possessing also bacteriostatic and fungicidal properties.…”