Antioxidants; DNA damage; Plasmid; Reactive oxygen species; Strand breaks

The aim of the work was to study interactions of chemical agents with nucleic acids. A wide variety of chemicals can cause damage of macromolecules, particularly oxidative stress leads to DNA damage. In this study, we tested chemicals that can cause oxidative DNA damage at sugar-phosphate backbone level. For the study of the effects of chemical agents on DNA plasmid DNA was used. The method using plasmid DNA was based on the different mobility of various topological forms of plasmid DNA. The changes in conformation were detected by means of agarose gel electrophoresis. Significant increases in formation of DNA strand breaks in plasmid DNA were detected after incubation of plasmid DNA with KMnO4, K2S2O8, peroxiacetic acid and NaClO. The results also show the effect of metal ions on DNA damage. In the present work, the effects of the agents with promising antioxidant activity (N-acetyl-cysteine, mannitol, dimethylsulfoxide, etc.) on plasmid DNA strand breakage has been studied.