Ascorbic Acid as a Radiation-Protective Agent Against Ionizing Radiation

Ascorbic acid (AA) is well known as a good radical scavenger and antioxidant. Here, the protection effects of AA against free radicals (mainly hydroxyl radicals) caused by low and high linear energy transfer radiation were examined. In this study, cobalt-60 gamma rays and helium ion beams were used as the sources of ionizing radiation. DNA strand breaks of PUC118 plasmid in the presence and absence of AA were monitored using agarose gel electrophoresis. Moreover, the survival rates of Saccharomyces cerevisiae yeast cells irradiated with different AA concentrations in growing medium were analysed using the linear quadratic survival model. Based on the results of DNA strand break experiments, the yield of strand breaks increased with an increase in absorbed dose. In the presence of AA, the yield of strand breaks decreased with an increase in AA concentration. In other words, the greater the additive concentration, the more effective the radiation-protective agent. On the other hand, in the survival rate experiments, the dependence on additive concentration was not similar to that of the DNA experiments. We consider that the main reason for our observations is the difference in additive concentration between the outside and inside of the cell membrane of yeast cells. These results suggest that AA plays an effective role as a radiation-protective agent for DNA and living cells against free radicals formed by radiation.