METAL-BASED BIOLOGICALLY ACTIVE AGENTS: SYNTHESIS, CHARACTERIZATION, ANTIMICROBIAL AND BIOCHEMICAL STUDIES OF MIXED LIGAND COMPLEXES

Mixed ligand complexes of metals (Fe(III), Co(II), Cu(II), Ni(II) and Zn(II)) with the Schiff bases of L1 and HL2 (L1 - obtained through the condensation of 4-aminoantipyrine with furfuraldehyde and HL2 – derived from 2-aminophenol and vanillin) were synthesized. They were characterized using analytical and spectral techniques. Cyclic voltammogram of complexes in DMSO solution at 300 K was recorded and their salient features were summarized. The X-band ESR spectrum of the copper complex in DMSO solution at 300 and 77 K was recorded. All the synthesized metal complexes were screened for their in vitro antimicrobial activity against of bacteria and fungi by disc diffusion method. Comparative study of inhibition values of the Schiff bases and their complexes indicate that the complexes exhibit higher antimicrobial activity than the free ligands. The interaction of metal complexes with CT-DNA was investigated by UV-Vis., cyclic voltammetry, viscosity and thermal denaturation studies. The nuclease activities of the complexes were assayed on pUC19 DNA using gel electrophoreses in the presence of H2O2. All the metal complexes cleave the pUC19 DNA in presence of H2O2. The solvatochromic behaviour of complexes was discussed using UV-Vis., spectrophotometry in various solvents. Superoxide dismutase activity of these complexes has also been studied.