Antioxidant and lipoxygenase inhibition studies of 4-(4-bromophenyl)-2,2'-bipyridine and its metal complexes...

Synthesis of new antioxidants and enzyme inhibitors is an active area of research in pharmaceutical sciences. This can be used for development of new active product ingredients which can prevent body from different diseases. This study comprises of preparation of transition metal complexes using 4-(4-bromophenyl)-2,2'-bipyridine (BPBP) and their screening for antioxidant and lipoxygenase inhibition properties. 4-(4-bromophenyl)-[2,2'-bipyridine]-6-carboxylic acid was used as starting material and its decarboxylation resulted in BPBP. Decarboxylation by conventional heating method was compared with microwave decarboxylation method. Selected metal complexes of the ligand were synthesized with Ruthenium (II), Iron (II) and Cobalt (II) ions. The complexes were characterized using UV, IR, ¹H-NMR, ESI-MS and CHNS techniques. It was observed that BPBP acted as a bidentate ligand. The metal to ligand stoichiometry was 1:3 for all the synthesized complexes. The complexes had octahedral structure with C3 symmetry. The antioxidant activity was evaluated using free radical scavenging assay. BPBP showed insignificant antioxidant and lipoxygenase activities while its transition metal complexes showed promising activities. Antioxidant activity of Fe and Co-complexes was found significantly higher than the reference drug used in this study.