Interaction of Galvinoxyl Radical with Ascorbic Acid, Cysteine, and Glutathione in Homogeneous Solution and in Aqueous Dispersions

Abstract

The rates of interaction of galvinoxyl radical with ascorbic acid, cysteine, and glutathione have been studied in homogeneous solution and in water dispersions as a model reaction of vitamin E radical with these reducing agents in biological systems. The rate was measured by following the disappearance of galvinoxyl radical with absorption spectroscopy and electron spin resonance. In every system, galvinoxyl reacted with these reducing substrates and their relative reactivities decreased in the order of ascorbic acid>cysteine>glutathione. For any reducing substrate, the rate was fastest in homogeneous solution and slowest in micelle in Triton X-100 aqueous solution, and the rate in liposome system was in between.