5-Hydroxy-6-methyluracil, an Efficient Scavenger of Peroxyl Radical in Water

Abstract

The reactivity of 5-hydroxy-6-methyluracil (HMU) towards peroxyl radicals generated from the aerobic thermal decomposition of 2,2-azo-bis(2-amidinopropane)dihydrochloride (AAPH) has been investigated. The oxidation product of HMU is dihydro-5,5,6-trihydroxy-6-methylpyrimidin-2,4-dion-e (94%). The relative oxidation rate of HMU vs. quercetin by peroxyl radicals generated from AAPH has been measured as 0.20 ± 0.04 at 54.6°C, hence HMU is the effective scavenger of peroxyl radicals. The overall kinetic parameters and the efficiency of radical generation from AAPH in water solution at pH 7.0 (0.1 M phosphate buffer) have been determined using HMU in temperature range 26° - 84°C.