Protective effect of phytic acid on oxidative DNA damage with reference tocancer chemoprevention

Phytic acid (myo-inositol hexaphosphate) is one of the most promising cance r chemopreventive agents. We investigated the mechanism by which phytic aci d expresses preventive action to cancer. Phytic acid inhibited the formatio n of 8-oxo-7,8-dihydro-2 ' -deoxyguanosine in cultured cells treated with a n H2O2-generating system, although it did not scavenge H2O2. Site-specific DNA damage by H2O2 and Cu(II) at GG and GGG sequences was inhibited by phyt ic acid, but not by myo-inositol. Phytic acid alone did not cause DNA damag e and thus, it should not act as a prooxidant. We conclude that phytic acid acts as an antioxidant to inhibit the generation of reactive oxygen specie s from H2O2 by chelating metals, resulting in chemoprevention of cancer. (C ) 2001 Academic Press.