Antioxidant and lipoxygenase inhibition studies of 4-(3-bromophenyl)-[2,2'-bipyridine]-6-carboxylic acid and its metal complexes

Background: Synthesis of novel enzyme inhibitors and antioxidants is active research in pharmaceuticals sciences. Novel compounds with potential therapeutic value can be synthesized to help the body combat oxidative-stress related diseases. Objectives: This study comprised synthesis of 4-(3-bromophenyl)-[2,2'-bipyridine]-6-carboxylic acid, its complexation with Fe(II), Cu(II) and Ni(II), and the evaluation of these compounds as lipoxygenase inhibitors and antioxidant agents. Methods: The ligand and its complexes were characterized using NMR, IR, UV–Vis and mass spectroscopies. The synthesized compounds were also screened to evaluate their antioxidant and lipoxygenase properties. Two sample t-test and ANOVA were used to evaluate the significance of biological activity of the complexes. Results: The ligand acted as a tridentate donor forming ML? complexes. Cu(II) and Ni(II) complexes showed significant lipoxygenase inhibition with the respective IC50 values of 50.6 and 59.8 µM, while antioxidant activity was largely attributed to the ligand itself with IC50 value of 56.4 µM. Conclusion: The study demonstrated that Cu(II) and Ni(II) complexes of the synthesized ligand were promising candidates for lipoxygenase inhibition, while the free ligand exhibited significant antioxidant activity.