Abstract: tFree radical plays a key role in the biological science. Under the normal situation, the equilibrium state of generation and elimination of the free radicals is assured to the health of the body. When the generation of free radicals increases and tissues fail to remove it, bio-molecules will be damaged. Many lesions are produced by the highly reactive hydroxyl radical and the DNA bases or the sugar moiety in the body. DNA can be permanently damaged by free radicals, manifested as decomposition of pentose and oxidation of bases. There is an obvious evidence for an important role of free radical-induced DNA damage in the etiology of numerous diseases. This paper provides an overview of the mechanisms of DNA damage, such as oxidation of bases, breakup of sugar moiety which induced by hydroxyl radicals. A deep understanding to the mechanisms of DNA damages induced by free radical would be of outmost importance for disease prevention and treatment, and the prospect of research in DNA damage by free radicals was also presented in this paper.

Key words: free radical, sports, DNA, damage