Effect of anti-inflammatory drugs on xanthine oxidase and xanthine oxidase induced depolymerization of hyaluronic acid

Abstract

The inhibitory effect of various anti-inflammatory drugs on the xanthine oxidase derived depolymerization of hyaluronic acid was studied. The depolymerization was assayed by repeated viscosity measurements. By using a low xanthine oxidase activity, the decrease in viscosity with time followed first order reaction kinetics and was therefore suitable for kinetic analysis. The xanthine oxidase activity was monitored by assay of O₂-consumption with a Clark-electrode and by assay of ureate production. We present evidence that salicylic, acetylsalicylic, gentisic and azodisalicylic acid and sulfasalazine inhibit the production of oxygen-derived free radicals by xanthine oxidase. We found that sulfapyridine, 5-aminosalicylic acid, allopurinol, mannitol, glucuronic acid andN-acetylglucoseamine in addition to the earlier studied drugs, paracetamol, ibuprofen, benoxaprofen and gentisic acid exert their effect via seavenging of free radicals. These drugs had very little effect on the enzyme activity.