Luminescence binding of biomolecules and biological activities of Co(II), Ni (II), Cu(II) and Zn(II) complexes with diiodosalicylimine Schiff base ligand

Four Schiff base metal complexes (ISNPCo, ISNPNi, ISNPCu and ISNPZn) such as Co(II), Ni(II), Cu(II) and Zn(II) were synthesised by the reaction of respective metal salts with ISNP Schiff base ligand (3, 5-diiodosalicylaldehyde + N-phenyl-o-phenylenediamine) and characterized by various spectral, spectrometric and thermal techniques. Mueller-Hinton Agar method was used to determine the antibacterial activity of these compounds against five bacterial strains: S. aureus, S. epidermidis, B. cereus, B. amyloliquefaciens and B. subtilis. From these results, the ISNPCu metal complex showed more active than that of the free ligand and other metal complexes. In order to find out the antioxidant activity of these metal complexes, DPPH free radical scavenging method was utlized, which revealed the strong antioxidant action of metal complexes against the DPPH radical. UV-vis, Fluorescence and docking studies were used to investigate the binding behaviour of biomolecules (CT-DNA, BSA, and HSA) with metal complexes.These results highlighted that ISNPCu and ISNPNi complexes had strong binding affinity towards biomolecules. Furthermore, Agarose Gel Electrophores is method (DNA cleavage studies) was performed to investigate the interaction between ligand and metal complexes with CT-DNA. Based on these investigations, we understood that both ISNPCu and ISNPNi complexes had more biological activity than that of free ligand and other metal complexes.These metal complexes have potential uses in biochemistry and medicine due to their increased biological activity is depending upon the structure and flexibility of the complexes and reactivity of the metal ions.