Fast repair of the radical cations of dCMP and poly C by quercetin and rutin

The effects of quercetin and rutin on the repair of the radical cations of dCMP and poly C were studied using the technique of pulse radiolysis, The r adical cations of dCMP and poly C were formed by the reaction of dCMP and p oly C with SO4-. After pulse irradiation of nitrogen-saturated aqueous solu tions containing dCMP, 20 mM K2S2O8, 200 mM t-BuOH and either rutin or quer cetin, the initially formed radical cation of dCMP, detected spectrophotome trically, rapidly decayed with the concurrent formation of the phenoxyl rad ical of rutin or quercetin within 8-40 mus. The repair efficiencies of the tested compounds towards the poly C radical cation were also determined usi ng the same procedure. The results indicate that dCMP and poly C radical ca tions can be rapidly repaired by quercetin and rutin. The rate constants of the repair reactions were determined to be 4.3-8.8 x 10(8) Mis and 1.5-3.6 x 10(8) M/s for dCMP and poly C radical cations, respectively. Together wi th findings from our previous studies, the present results demonstrate that non-enzymatic fast repair may be a universal form of repair involving phen olic antioxidants.