Chapter 14. Biological Applications of Nitroxide Stable Free Radicals

Nitroxide stable free radicals when introduced to biological systems exhibit a broad range of effects centering on their antioxidant properties. These chemicals can mimic superoxide dismutase activity, prevent reduction of hydrogen peroxide to hydroxyl radical, confer catalase/peroxidase activity in heme moieties, and scavenge high energy secondary radicals generated by radiation exposure enabling them to provide protection against oxidative stress. This chapter will outline the chemistry underlying nitroxide antioxidant activity and summarize a variety of conditions where they protect against oxidative damage, including radiation treatment, inflammatory illness, carcinogenesis and obesity. The use of nitroxides to noninvasively image tissue to determine its redox capacity will also be reviewed.