De-novo design and synthesis of cu(II) complex from Phenylalaninol-based ligand with potent anticancer chemotherapeutics: DNA binding, antioxidant, antimicrobial, molecular docking, and cytotoxic studies against MCF-7 cancer cell lines

Novel Cu(II), Ni(II), and Zn(II) complexes were synthesized using a ligand derived from phenylalaninol and 1,2-dibromoethane with loss of an organic molecule like HBr, through a condensation reaction. The complexes were characterized using FT-IR spectroscopy, 1 HNMR and 13 CNMR spectroscopy, mass spectrometry, elemental analysis, and UV–vis spectroscopy. The DNA-binding affinities of the complexes were quantified using the Scatchard equation, yielding binding constants (K b ) of 4.3 × 10 4 M −1 for Cu(II), 3.7 × 10 4 M −1 for Zn(II), and 2.8 × 10 4 M −1 for Ni(II). These studies were validated by fluorescence quenching experiments, where the Stern-Volmer constants (Ksv) were observed as 4.21 × 10 4 M −1 for Cu(II), 1.3 × 10 4 M −1 for Ni(II), and 2.7 × 10 4 M −1 for Zn(II), further confirming the DNA-binding results. Due to its superior binding properties, the Cu(II) complex was selected for further biological evaluation, demonstrating antibacterial activity, antioxidant potential, and cytotoxicity against E. coli , DPPH assay, and MCF-7 cancer cell lines, respectively. These results reveal that the Cu(II) complex acts as a promising drug candidate for targeted drug delivery. UV–vis titration studies indicated an intercalative binding mode for the Cu(II) complex, evidenced by a hyperchromic effect with a slight bathochromic shift. Molecular docking further confirmed its intercalation into DNA base pairs, with binding energies ranging from −5.0 to −7.0 kcal/mol. In antibacterial testing against E. coli , it showed a 6 mm inhibition zone at 6.25 % per disc in the Kirby-Bauer assay, as compared to the ciprofloxacin (26 mm at 10 μg/disc) as a reference. Antioxidant studies using the DPPH assay highlighted its redox-active nature, likely due to the Cu(II)/Cu(I) redox couple. Additionally, the complex demonstrated significant cytotoxicity against MCF-7 breast cancer cells, inducing apoptosis through ROS generation and mitochondrial dysfunction. The results obtained from DNA binding and other biological studies revealed that the Cu(II) complex can serve as a promising multifunctional agent with strong selective DNA-binding, antimicrobial, and anticancer capabilities. Such findings make it appropriate for targeted drug delivery. The observations facilitate further structural alterations intended to enhance selectivity and diminish off-target activity for clinical application.