Hydroxybenzoic acids and their derivatives as peroxynitrite scavengers.

A social challenge of the 21(st) century is to reduce the incidence of chronic diseases. A balanced diet rich in polyphenols could contribute to reduce the risk and to the prevention of diabetes, coronary heart disease, cancer, Alzheimer's diseases and cataract(1). Hydroxybenzoic acids (HBA) and their derivatives, which are one of the substances responsible for these beneficial properties, are known mainly due to their antioxidant properties(2). They are effective scavengers of free radicals and reactive nitrogen species, such as peroxynitrite. Peroxynitrite is resulting from the reaction of nitric oxide with superoxide, causes lipid peroxidation and subsequent cellular damage and is responsible for the inactivation of many enzymes, activation of stress signalling pathways, release of proapoptotic factors, as well as cardiovascular dysfunction in septic schock(3). In this study we have tested 2-HBA, 3-HBA, 4-HBA, acetylsalicylic acid, 4-HBA methyl and propyl esters, 2,3-dihydroxybenzoic acid (DHBA), 2,5-DHBA, 2,4-DHBA, 2,6-DHBA, 3,5-DHBA, 3,4-DHBA, gallic acid and caffeic acid, by UV/VIS spectroscopy. The best ability to scavenge peroxynitrite was observed for gallic acid, 2,4-DHBA, 3,5-DHBA and caffeic acid. Improved comprehension of the complex relationship between the antioxidant properties of substances and their structure is important to understand their proper use in the prevention and treatment of diseases and for the detection of pathological processes. Monitoring and improved understanding of the antioxidant properties of hydroxybenzoic acid derivatives are important due to their frequent use in modern medical nutrition therapies.