DNA fastening and scission actions of Cu(II), Co(II), Ni(II) and Zn(II) complexes: synthesis, spectral characterization and cytotoxic study

Abstract

A heterocyclic compound, 2‐(aminomethyl)benzimidazole dihydrohydrochloride, was treated with nitrobenzaldehyde to form a Schiff base that was made to react with divalent metals. A co‐ligand, either 1,10‐phenanthroline or 2,2′‐bipyridine, was added to this mixture to obtain metal chelators of type [ML(co‐L)2]Cl2. They were in 1:1:2 stoichiometry ratio, which was characterized by various spectroscopic techniques that suggested an octahedral geometry around the central metal ions. These complexes were investigated for their binding affinities with calf thymus (CT) DNA, using various techniques, such as UV–Vis, viscosity, cyclic voltammetry (CV), etc. The binding interaction studies revealed intercalation as the possible binding mode of the complexes with the CT DNA. In addition, these complexes were screened for their antimicrobial potential and DNA denaturing tendencies using gel electrophoretic assay. The antimicrobial screening investigation showed that the complexes behaved as better antimicrobial agents than the ligand, especially, complex 5 shows exceptional activity even in the electrophoretic assay along with the antimicrobial efficacy. Moreover, complex 5 was able to denature the plasmid DNA better than the other compounds. All the compounds were screened for cytotoxic efficacy, and the IC50 values suggest that the compounds possess cytotoxic activity to some extent that is almost the same as the activity of cisplatin.

Structure and cytotoxicity of zinc (II) and cobalt (II) complexes based on 1,3,5‐tris(1‐imidazolyl) benzene

“…Cobalt is a biologically relevant element and many enzymes that depend on cobalt for their activity have been identified, while zinc is an essential trace element in the human body and is also an important component of many enzymes in the human body, such as carbonic anhydrase, DNA polymerase and alkaline phosphatase. Zn (II) and Co (II) drug complexes have been receiving much attention due to excellent biological applicability, such as anti‐epileptic, anti‐convulsant, anti‐bacterial, anti‐fungal, anti‐microbial, anti‐cancer/anti‐proliferative activities, interesting DNA‐binding properties and efficient photonucleases . In addition, 1,3,5‐tris(1‐imidazolyl) benzene as an N‐donor ligand has attracted extensive attention due to its excellent coordination ability and diverse structure.…”