Yuzo Nishida

Oxygen Activation, Oxidative Stress and Human Health Yuzo Nishida

I have investigated the oxygen activation mechanism in biological oxygenases on the basis of the ligand field theory, and have established new concept on the oxygen activation by metal ions, which is quite different from those reported in many papers published hitherto. According to my new concept, it is quite clear that the responsibility of the hydroxyl radical or free singlet oxygen is negligible as a ?reactive oxygen species? in the biological systems, and that oxidative stress due to the iron ions is induced by the unique properties of the iron ions, i.e., some of the water-soluble non-transferrin-bound iron (NTBI) react with oxygen or hydrogen peroxide, changing these molecules to those exhibiting electrophilicity, similar to singlet oxygen. Based on these results, I have synthesized new super-polyphenols, and found that some of these compounds can eliminate NTBI effectively from the plasma. In addition to this, we have observed that some derivatives of our super-polyphenols exhibits high ability for the removal of H2O2 and phosphoric acid from the solution.