Protection of superoxide dismutase by caffeine in rat liver mitochondria against gamma-irradiation

Radiation is one of the physical agents that induce oxidative stress. Expos ure of rat liver mitochondria to high doses of Co-60 gamma-rays (45-600 Gy) results in the loss of activity of superoxide dismutase (SOD), Presence of caffeine, even in micromolar amounts, during exposure prevents loss of SOD activity. Caffeine, at a concentration of 1 mM also showed protection agai nst radiation-induced inhibition of two other mitochondrial enzymes, namely succinate dehydrogenase and cytochrome c oxidase, The observed radioprotec tive ability of caffeine may be due to its ability to scavenge the reactive oxygen species generated by radiation and to inhibit radiation-induced mem brane damage, as assessed by lipid peroxidation and protein oxidation.