Superoxide dismutase activity studies of Mn(III)/Co(III)/Fe(III) complexes with Schiff base ligands

Mimetics of superoxide dismutases (SOD), with certain ability to eliminate superoxide radicals under aerobic conditions, would be promising as drug candidates for antioxidant therapy. Many efforts have been devoted to synthesize small molecular compounds to mimic the functionality of natural SOD. In this paper, the Mn(III)/Co(III)/Fe(III) complexes have been synthesized with the Schiff base ligand (NaH 2 L), which was condensed from 2-hydroxynaphthalen-1-naphthaldehyde and 3,4-diaminobenzenesulfonic acid. The structures of complexes 1 and 3 have been determined by X-ray crystallographic method, and all the complexes have been investigated using FT-IR, MS. The binding constants between metal complexes and bovine serum albumin (BSA) have been determined by fluorescence spectroscopy. Meanwhile, we have synthesized 3 hybrid proteins through the interaction of the complexes and BSA. The SOD-like activity was tested by xanthine/xanthine oxidase method. The result shows that BSA molecule can increase the SOD activity of the transition metal complexes.