Structure elucidation of a bimetallic -hydroxo-bridged Cu(II)-flufenamate-bpy complex and cytotoxic evaluation against MDA-MB-231 and A549 carcinoma cell lines

In this work, we report the synthesis, spectral characterization, and in vitro biological assessment of a bimetallic copper complex with formulation [Cu-2(fluf)(3)(bpy)(2)(mu-OH)(H2O)] (complex 1) as a potential chemotherapeutic agent. The structural elucidation of synthesized complex was ascertained by various spectroscopic methods, namely, UV-vis, Fourier transform infrared (FTIR), electron paramagnetic resonance (EPR), and single-crystal X-ray diffraction studies. Complex 1 crystalizes in a monoclinic crystal system with space group P21/c, and the lattice parameters were recorded as a = 18.95 angstrom, b = 17.81 angstrom, c = 20.56 angstrom, and alpha = gamma = 90 degrees and beta = 117.12 degrees per unit cell. The density functional theory (DFT) studies were performed to comprehend the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) electron densities over the complex 1 and the energy difference in between them. Hirshfeld surface studies were performed to understand the various non-covalent interactions including O-H center dot center dot center dot O, N-H center dot center dot center dot center dot H, and C-H center dot center dot center dot O, which determined the stability of crystal lattice framework. The preliminary in vitro binding studies of complex 1 with human serum albumin (HSA) and bovine serum albumin (BSA) targets was carried out to determine the binding mode and to evaluate its cytotoxic potential using various biophysical techniques. The antioxidant activity of complex 1 was examined against the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) using ascorbic acid as standard, which demonstrated higher radical scavenging activity (IC50 = 14 mu M). Furthermore, the cytotoxic action of complex 1 was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against MDA-MB-231 (triple-negative breast) and A549 (lung) cancer cell lines, which revealed remarkable cytotoxicity of the complex against the tested cancer cell lines that was reflected in their low IC50 values.