| Research Abstract |
1.Determination of marker in the oxidation of antioxidants induced by reactive nitrogen species (RNS)
Antioxidants, α-tocopherol and y-tocopherol, were oxidized by NO2, SIN-1, and peroxynitrite in solution. Quinones and 5-nitro-γ-tocopherol (5NO-γ-T) were yielded as oxidized products. Then, low density lipoprotein and plasma from healthy volunteers were also oxidized by RNS. It was confirmed that quinones and 5NO-γ-T were formed concomitantly with the formation of lipid hydroperoxides.
2.Antioxidants effects as evaluated biomarkers
When mice were fed for 1 month on an E-free diet supplemented with a lipophilic antioxidant (0.04 wt%), namely, αT, α-tocotrienol (aT3), γ-tocopherol (yT), or 2,3-dihydro-5-hydroxy-4,6-di-tert-butyl-2,2-dipentylbenzofuran (BO-653), a potent synthetic antioxidant, theincreases of tHODE and t8-iso-PGF_<2α> in the plasma, erythrocytes, liver, and brain were suppressed to the levels lower than those of mice fed a standard diet. These results show that the tHODE level and the (Z, E/E, E) HODE ratio are useful biomarkers for the assessment of antioxidant capacity in vivo and that the antioxidant capacity decreased in the order : BO-653 > αT3≧αT, γT, as assessed by tHODE levels from blood, liver, and brain.
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