DNA/Protein Binding, Molecular Docking and Cytotoxicity Studies of Piperazinyl-Moiety-Based Copper(II) Complexes

Copper(II) complexes {[Cu(HL)(ClO4)(H2O)](ClO4)⋅3H2O} (1), {[Cu (HL)(m-phth)]⋅5H2O} (2) and {[Cu(HL)(NCS)]2(ClO4)2⋅2H2O} (3) (HL=2-{[2-(1-piperazinyl)ethylimino]methyl}phenol; m-phth= 1,3-benzenedicarboxylate] have been synthesized and characterized by structural determination and spectroscopic studies. The mononuclear square pyramidal complex 1 resulted from the reaction of HL with copper perchlorate hexahydrate. Then mononuclear square planar complex 2 and dinuclear thiocyanato bridged complex 3 were obtained by reacting 1 with disodium 1,3-benzenedicarboxylate (Na2(m-phth)) and potassium thiocyanate, respectively. The interactions of 1–3 with CTDNA / serum albumins were investigated by UV-visible absorption and fluorescence spectroscopy. The intrinsic binding constants of 1, 2 and 3 with CT-DNA were calculated. Study of the interactions of 1–3 with human serum albumin (HSA) / bovine serum albumin (BSA) showed that all the complexes could quench intrinsic fluorescence of HSA and BSA through a static quenching process. Molecular docking technique was utilised to confirm the mode of interaction of complexes with CT-DNA / serum albumin. Anticancer activities of the complexes have been tested using human breast cancer cell lines MCF7 and MBAMB- 231. Among the complexes studied 3 shows the higher cytotoxic activity and growth inhibition of cancer cells via induction of apoptotic cell death.