Radioprotective action of caffeine: use of Saccharomyces cerevisiae as a test system.

Mechanism of radioprotective action of caffeine by studying the gamma radiation -induced killing of yeast, S. cerevisae is reported. The results reveal that caffeine specifically protects aerobically (oxic) grown cells from gamma - radiation and sensitizes anaerobically (hypoxic) grown cells to some extent. Using radiation sensitive strains which lack recombinational pathway, it was found that protection by caffeine was solely brought about by reducing DNA damage, rather than by interfering with DNA repair process.