Electronic spin resonance quantitative analysis of MN(II) complexes antioxidative activity using phosphate or organic buffer

Superoxide anion is implicated in the pathogenesis of several human diseases including ischaemia, atheroscelerosis and inflammation when molecular or enzymatic antioxidant systems cannot regulate its formation. In order to investigate superoxide dismutase (SOD) mimics, a method using Electron Spin Resonance (ESR) has been developed to quantify antioxidative activities of Mn(II) compounds. The acetaldehyde / xanthine oxidase system produced superoxide anion and the 5,5-dimethy-1-pyroline-N-oxide (DMPO) was used as spin trap. The complexing properties of the usual phosphate buffer towards Mn2+ being not negligible comparatively to those of the studied ligands, activities of Free ligands and Mn(II) complexes have been compared according to the buffer, phosphate or organic.