Comparative study of the reduction rates of various types of imidazoline radicals in tissues

Abstract

During recent years aminoxyls have been studied as perspective contrast agents for NMR imaging in biological systems. We report a study of 30 low-molecular-weight imidazoline radicals in which we have compared the initial rates of reduction of these compounds by rat liver microsomes and ascorbate. The nuclear magnetic relaxation rate of water protons in microsomes was determined in the presence of a number of aminoxyls and it was found that the rates depend on the substituents. In microsomes the weakest oxidants among these aminoxyls are imidazolines. This type of radical is also the most resistant reduction by ascorbate.