ABSTRACT
This chapter discusses a dual role of the food antioxidants in mutagenesis and carcinogenesis, and the possible involvement of oxygen free radicals in producing the effects. The data available in the literature at the present time do not permit definite conclusions about the human risk due to dietary flavonoid intake. However, over production of reactive oxygen species by dietary and environmental factors can overwhelm the antioxidant defenses and induce oxidative stress, which can cause oxidative damage to cellular macromolecules and lead possibly to cancer. The proximity of nuclear DNA to the nuclear membrane may facilitate the interaction of DNA with the peroxyl radicals and other reactive intermediates formed during membrane lipid peroxidation. Certain natural antioxidants in human food are rich sources of oxygen free radicals. They can produce reactive oxygen species by their autoxidation and subsequent redox cycling, and thus can act as pro-oxidants.
