Mechanisms of free radical-induced damage to DNA

Free Radic Res. 2012 Apr;46(4):382-419. doi: 10.3109/10715762.2011.653969.


Endogenous and exogenous sources cause free radical-induced DNA damage in living organisms by a variety of mechanisms. The highly reactive hydroxyl radical reacts with the heterocyclic DNA bases and the sugar moiety near or at diffusion-controlled rates. Hydrated electron and H atom also add to the heterocyclic bases. These reactions lead to adduct radicals, further reactions of which yield numerous products. These include DNA base and sugar products, single- and double-strand breaks, 8,5'-cyclopurine-2'-deoxynucleosides, tandem lesions, clustered sites and DNA-protein cross-links. Reaction conditions and the presence or absence of oxygen profoundly affect the types and yields of the products. There is mounting evidence for an important role of free radical-induced DNA damage in the etiology of numerous diseases including cancer. Further understanding of mechanisms of free radical-induced DNA damage, and cellular repair and biological consequences of DNA damage products will be of outmost importance for disease prevention and treatment.

Publication types

  • Review

MeSH terms

  • Animals
  • DNA / metabolism*
  • DNA Damage / drug effects*
  • Free Radicals / pharmacology*
  • Humans
  • Oxidative Stress


  • Free Radicals
  • DNA