In vitro anti-proliferative and in silico docking studies of heteroleptic copper(II) complexes of pyridazine-based ligands and ciprofloxacin

Three heteroleptic copper(II) complexes of the type [Cu(L1-3)(cf)(ClO4)] (1-3), where cf = ciprofloxacin, have been synthesized using pyridazine-based ligands 3-chloro-6-(salicylidenehydrazinyl)pyridazine (HL1), 3-chloro-6-(4-diethylaminosalicylidenehydrazinyl)pyridazine (HL2) and 3-chloro-6-(5-bromosalicylidenehydrazinyl)pyridazine (HL3). Electronic spectral data and magnetic moment values suggest octahedral geometry for the synthesized copper(II) complexes. Electrochemical data of the copper(II) complexes present an irreversible one-electron reduction wave in the cathodic potential region (E-pc) between -0.631 and -0.670 V. Frontier molecular orbital calculations were carried out, and the obtained low-energy gap supports the bio-efficacy of the complexes. All the complexes were screened for their in vitro cytotoxicity activity against three human cancerous (breast adenocarcinoma (MCF-7), hepatoma (HepG-2) and cervical (HeLa)) and one non-cancerous (non-tumorigenic human dermal fibroblast (NHDF)) cell lines using MTT assay, in which complex 2 exhibited higher activity. The apoptosis induction by the complexes was analysed using the Hoechst dye staining method with MCF-7 cell line, which indicates higher apoptotic activity of complex 2. A molecular docking study was carried out to ascertain the binding affinity of the synthesized heteroleptic copper(II) complexes with phosphoinositide 3-kinase gamma (PI3K gamma) receptor.