Kinetic measurements of peroxynitrite scavenging properties of hydroxybenzoates

Abstract

Beáta Veliká*, Beáta Hubková*, Juraj Guzy

Objective: Hydroxybenzoic acids and their derivatives belongs to phenols, which are characterized by salubrious properties, leading to a reduction of the incidence of chronic diseases. The most significant health related features of hydroxybenzoic acids and their derivatives are their antioxidant properties. Peroxynitrite is a reactive nitrogen compound which can cause lipid peroxidation with subsequent cellular damage. The aim of the present work was to determine the peroxynitrite scavenging property of different hydroxybenzoates, with regard to their chemical structure. Methods: In our study, we tested 14 hydroxybenzoic acids and a number of their derivatives in the reaction with peroxynitrite. The compounds were selected to have different number and different position of the hydroxyl group(s) attached to the benzene ring. In this way we ensured the study of different suitable model compounds by testing their antioxidant properties. The peroxynitrite scavenging properties of the model compounds were studied using kinetic spectrophotometric measurements. The reaction rate was calculated based on the decrease in peroxynitrite concentration. Results: The most significant peroxynitrite scavenging properties based on the reaction rate were detected in compounds with hydroxyl groups substituted in the positions meta and para: 3,4-dihydroxybenzoic acid, gallic acid and caffeic acid. Also, increased reaction rates were recorded in the reaction of 2,4-dihydroxybenzoic acid, acetylsalicylic acid and 2-hydroxybenzoic acid with peroxynitrite. Conclusion: Our results confirmed the thesis that the free radical scavenging properties are dependent on the position and the number of the hydroxyl group(s) in relation to the carboxylic functional group attached to the benzene ring. Better understanding of the relations between the structure and the action of these antioxidants may be helpful in their proper utilization during prevention and treatment of diseases.