Anti-inflammatory Activities of Taurine Chloramine

Abstract

Neutrophils recruited into the site of inflammation generate a large number of highly reactive oxidants, including hypochlorous acid (HOCl), produced by the myeloperoxidase-catalyzed oxidation of C1 by hydrogen peroxide¹. Hypochlorous acid is the major neutrophil microbicidal agent but its excessive production leads to tissue damage. Oxidative tissue damage is thought to be of pathogenic significance in a large number of diseasese.g.atherosclerosis, malignancy and rheumatoid arthritis. Taurine (Tau), a dominant free amino acid present in most mammalian tissues and in the cytosol of phagocytic cells at high (10–20 mM) concentration², acts as a major trap for HOCl. The reaction of Tau with HOCl forms the long-lived but weaker oxidant taurine chloramine (Tau-Cl) and thus reduces HOCl toxicity. On the other hand, there is growing evidence that Tau-Cl: (i) down-regulates the production of pro-inflammatory mediators by macrophages, neutrophils and other cells engaged in inflammatory response³, (ii) regulates the function of dendritic cells⁴, and (iii) enhances protein immunogenecity by chlorination⁵. This implies Tau-Cl to act as an important physiologic immunoregulatory factor maintaining the delicate balance between mounting an effective immune response, and minimizing the destruction of the tissue by the inflammatory cells.