Abstract: A comparative kinetic study of ortho-phenylenediamine (PDA) oxidation in the "pseudoperoxidase" system Methemalbumin-H2O2 in the presence of 2-amino-4-tret-butylphenol (ATBP), 2-amino-4,6-di-tret-butylphenol (ADTBP) and its four N-acyl derivates, as well as flavonoids (quercetin, morin, silibin, hesperidin and naringin) has been carried out under standart conditions at 20°C in phosphate buffered saline, pH 7.4, containing 5.25% ethanol and DMFA. ATBP, ADTBP and two its N-acyl-derivatives as well as all five flavonoids inhibited with different efficiency the PDA oxidation characterized in terms of the inhibition constants, Ki, M, or the percent of inhibition degree at the maximal taking concentrations of these inhibitors.Most effective antioxidants were quercetin (Ki = 7.7×10-5 M) and ATBP (Ki = 1.26×10-4 M). Using these characteristics and other necessary criteria, the pairs PDA-quercetin and PDA-ATBP were proposed for a practical application in the test-systems for total antioxidant activity of biological objects.
Reference: Grigorenko Yu.A., Karasyova E.I., Metelitza D.I., Sorokin V.L., Ksendsova G.A., Shadyro O.I., Substituted aminophenols and flavonoids as potential componentsfor test-systems of total antioxidant activity, Biomeditsinskaya khimiya, 2007, vol:
1. Rice-Evans C., Miller N. (1994) Meth. Enzymol., 234, 279-293.