DNA Binding, Cleavage Activity, Molecular Docking, Cytotoxicity and Genotoxicity Studies of Newly Synthesized Copper Based Metal Complexes

Abstract

The design and synthesis of medicinal chemotherapeutic agents of copper with 2-(benzothiazol-2-yl iminomethyl)-phenol, 2-(benzothiazol-2-yliminomethyl)-valine, cyanoaceto (2-mer- captobenzylidene)-hydrazide, 2-(phenacyl bromide)-aminothiophenol, (2-mercaptobenzaldehyde) thio- semicarbazone, N-(phenacyl bromide)-2- yliminobenzothiazole, 2-aminobenzothiazole, benzothiazol-2-yliminomethyl)-phenol and 2-[(2E¹-aminobenzylidene)- amino]-benzenethiol were synthesized. The characterization was done by FTIR, 1H and 13C NMR, MS, TGA and elemental analysis. Interaction of complexes 8 and 9 with CT DNA was done by using UV-vis and fluorescence spectroscopy depicting the hyperchromic behaviour of complexes. The intrinsic binding constants (Kb) for complex 8 and 9 were 2.35 × 103 M-1 and 2.12 × 103 M-1. The cleavage studies of complex 8 and 9 were done with pBR322 plasmid showing the potential cleaving ability of the complexes at very low concentration. The gel electrophoresis pattern also demonstrated that the complex 8 alone or in presence of Cu (II) causes the nicking of supercoiled pBR322 and it seems to follow the mechanistic pathway involving generation of hydroxyl radicals that are responsible for initiating DNA strand scission. The molecular docking studies showed the minor groove binding behaviour of the complexes 8 and 9 with DNA. During the MTT assay against different cancer cell lines like SW480, HepG2, HT29 and HL60, all the complexes showed potential cytotoxic behaviour by giving effective IC50 close to Cisplatin. The bioactivity score and PASS analysis also depicted the drug like nature of the complexes. During the comet assay, apoptotic degradation of DNA in the presence of complex 8 and 9 was analysed by agarose gel electrophoresis and visualized by ethidium bromide staining.