Experimental and molecular docking investigation of anticancer activity of new mixed-ligand Schiff base complexes against human colorectal (HCT116), lung (A549) and breast (MCF7) carcinoma cell lines

•Three new mixed-ligand Schiff-base complexes with [Cu(SB)L1–3]ClO4 formulae were synthesized.•Anticancer studies were performed on three human carcinoma cell lines that showed promising results.•The results revealed that the complex with bpy co-ligand was the most effective against all the three cell lines.•Molecular docking was also used that further supported the experimental results. New mixed-ligand Cu(II) complexes, [Cu(SB)L1–3]ClO4, that contain a tridentate NN'O type unsymmetrical Schiff-base main ligand (SB) and a heterocyclic co-ligand (L) (py in (1), bpy in (2) and phen in (3)) were synthesized and characterized. The SB is the product of 1:1 condensation between 1,3-propanediamine with 2‑hydroxy-4-methoxybenzaldehyde, which was formed during the template synthesis of complex (1). Complexes (2) and (3) were obtained by the exchange of monodentate py with bidentate bpy or phen, respectively. The crystal structure of (2) was obtained by single-crystal x-ray crystallography (SCXRC). From the crystal structure, (2) is pentacoordinated with square-based pyramidal geometry around Cu(II). The anticancer activity of the complexes was studied against three human carcinoma cell lines. All the complexes showed a potent cytotoxic effect on the Human colorectal (HCT116), lung (A549) and breast (MCF7) cancerous cells that exert their cytotoxicity in a dose and time dependent manner. Among these complexes, (2) had the highest cytotoxicity that made it a promising candidate for developing new anticancer drugs. The IC50 values for (2) were 4.16, 4.97 and 7.82 μM against A549, MCF7 and HCT116, respectively, after 48 h of incubation. The IC50 values order were (2)