Dietary Antioxidants Fail in Protection against Oxidative Genetic Damage in In Vitro Evaluation

概要

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Carcinogenesis is believed to be induced through the oxidative damage of DNA, and antioxidants are expected to suppress it. So, the polyphenolic antioxidants in daily foods were investigated to see whether they protect against genetic damage by active oxygen. In the evaluation, we used a bioassay and a chemical determination, a Salmonella mutagenicity test for mutation by a N-hydroxyl radical from one of the dietary carcinogens 3-amino-1-methyl-5H-pyrido [4,3-b] indole and the formation of 8-hydroxyl (8-OHdG) from 2'-deoxyguanosine (2'-dG) in a Fenton OH-radical generating system. Thirty-one antioxidants including flavonoids were compared in terms of radical-trapping activity with bacterial DNA and 2'-dG. Antioxidants inhibited the mutation but the IC_<50> values were in the mM order. Against 8-OHdG formation, only α-tocopherol had a suppressive effect with an IC_<50> of 1.5 μM. Thus, except α-tocopherol, the dietary antioxidants did not scavenge the biological radicals faster than bacterial DNA and intact 2'-dG, indicating that they failed to prevent oxidative gene damage and probably carcinogenesis.
社団法人日本農芸化学会の論文
2000-11-23