BMPO-OOH Spin-Adduct as a Model for Study of Decomposition of Organic Hydroperoxides and the Effects of Sulfide/Selenite Derivatives. An EPR Spin-Trapping Approach

Abstract

Lipid hydroperoxides play an important role in various pathophysiological processes. Therefore, a simple model for organic hydroperoxides could be helpful to monitor the biologic effects of endogenous and exogenous compounds. The electron paramagnetic resonance (EPR) spin-trapping technique is a useful method to study superoxide (O2•−) and hydroxyl radicals. The aim of our work was to use EPR with the spin trap 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO), which, by trapping O2•− produces relatively stable•BMPO-OOH spin-adduct, a valuable model for organic hydroperoxides. We used this experimental setup to investigate the effects of selected sulfur/selenium compounds on•BMPO-OOH and to evaluate the antioxidant potential of these compounds. Second, using the simulation of time-dependent individual BMPO adducts in the experimental EPR spectra, the ratio of•BMPO-OH/•BMPO-OOH—which is proportional to the transformation/decomposition of•BMPO-OOH—was evaluated. The order of potency of the studied compounds to alter•BMPO-OOH concentration estimated from the time-dependent•BMPO-OH/•BMPO-OOH ratio was as follows: Na2S4 > Na2S4/SeO32− > H2S/SeO32− > Na2S2 ~Na2S2/SeO32− ~H2S > SeO32− ~SeO42− ~control. In conclusion, the presented approach of the EPR measurement of the time-dependent ratio of•BMPO-OH/•BMPO-OOH could be useful to study the impact of compounds to influence the transformation of•BMPO-OOH.