Epr Study Of Ko2 As A Source Of Superoxide And (Bmpo)-B-Center Dot-Oh/Ooh Radical That Cleaves Plasmid Dna And Detects Radical Interaction With H2s And Se-Derivatives

Superoxide radical anion (O-2(center dot-)) and its derivatives regulate numerous physiological and pathological processes, which are extensively studied. The aim of our work was to utilize KO2 as a source of O-2(center dot-) and the electron paramagnetic resonance (EPR) spin trapping 5-tert-butoxycarbonyl-5-methyl-1-pyrroline N-oxide (BMPO) technique for the preparation of (BMPO)-B-center dot-OOH and/or (BMPO)-B-center dot-OH radicals in water solution without DMSO. The method distinguishes the interactions of various compounds with (BMPO)-B-center dot-OOH and/or (BMPO)-B-center dot-OH radicals over time. Here, we show that the addition of a buffered BMPO-HCl mixture to powdered KO2 formed relatively stable (BMPO)-B-center dot-OOH and (BMPO)-B-center dot-OH radicals and H2O2, where the (BMPO)-B-center dot-OOH/OH ratio depended on the pH. At a final pH of similar to 6.5-8.0, the concentration of (BMPO)-B-center dot-OOH radicals was >= 20 times higher than that of (BMPO)-B-center dot-OH, whereas at pH 9.0-10.0, the (BMPO)-B-center dot-OH radicals prevailed. The (BMPO)-B-center dot-OOH/OH radicals effectively cleaved the plasmid DNA. H2S decreased the concentration of (BMPO)-B-center dot-OOH/OH radicals, whereas the selenium derivatives 1-methyl-4-(3-(phenylselanyl) propyl) piperazine and 1-methyl-4-(4-(phenylselanyl) butyl) piperazine increased the proportion of (BMPO)-B-center dot-OH over the (BMPO)-B-center dot-OOH radicals. In conclusion, the presented approach of using KO2 as a source of O-2(center dot-)/H2O2 and EPR spin trap BMPO for the preparation of (BMPO)-B-center dot-OOH/OH radicals in a physiological solution could be useful to study the biological effects of radicals and their interactions with compounds.