Studies on DNA binding, cleavage, molecular docking, antimicrobial and anticancer activities of Cr(III), Fe(III), Co(II) and Cu(II) complexes of o-vanillin and fluorobenzamine Schiff base ligand

The ligand [2-((2-fluorophenylimino)methyl)-6-methoxyphenol] and its metal complexes [Cr(HL)(2)] (1), [Fe(HL)(2)] (2), [Co(HL)(2)] (3) and [Cu(HL)(2)] (4) are synthesized. Characterization of the complexes by sophisticated analytical techniques revealed the geometry around central metal ion to be octahedral for 1, 2 and 3 complexes and complex 4 with square planar geometry. Kinetic parameters of the complexes were estimated by the Coats-Redfern method, and the complexes were found to be thermally stable. DNA binding affinity of these metal complexes was explored by means of fluorescence, UV-visible and viscosity studies, and the studies suggested intercalative mode. K-b and K-SV values were determined from the absorption and fluorescence studies for the synthesized complexes. Nuclease studies in the presence of H2O2 were performed using pUC19 supercoiled DNA. Docking studies were done using human DNA topoisomerase-I (DNA topo I) receptor protein. Biological studies revealed higher activity for complexes than the ligand, and in vitro antitumour studies showed that complexes 3 and 4 possess potential inhibitory efficiency with an IC50 of 48.79 +/- 0.7 and 39.74 +/- 1.6 mu g/ml, respectively. Molecular docking studies were carried out using Argus labs, and geometry optimization is performed. Molecular orbital calculations of the ligand and complexes are computed using the reasonably accurate parametric model PM3 method 16-19.