COUMARIN SCHIFF BASE-METAL COMPLEXES AS PROMISING ANTIMICROBIAL AND ANTICANCER AGENTS: SYNTHESIS, PHYSICO-CHEMICAL AND BIOLOGICAL EVALUATION

This study reports the synthesis, characterization, and biological evaluation of Schiff base-metal complexes derived from substituted acetyl coumarin Schiff bases as potential antibacterial and anticancer agents. The synthesized compounds were characterized by using various spectroscopic techniques, including elemental analysis (C, HandN), Fourier-transform infrared spectroscopy (FTIR), mass spectrometry (MS), and proton nuclear magnetic resonance ( 1H-NMR). Further, the stability constant and ionisation constant of metal complexes were evaluated by potentiometric studies. The compounds demonstrated varying levels of effectiveness against different bacterial strains, with moderate to good activity. In particular, Bis(2-(((E)-1-(2-oxo-2H-chromen-3- yl)ethylidene)amino)phenoxy)metal(II) complex (Copper, 4b) exhibited increased antibacterial activity when compared to that of its ligand 3. Complex 4b also showed the maximum growth inhibition for S. aureus, E. coli, and S. flexneri with inhibition zones measuring 13, 15, and 14 mm, respectively, when treated with 100 µL. In-vitro cytotoxicity was evaluated using human hepatocellular adenocarcinoma, MCF7 cancer cells, by colorimetric MTT assay at 570 nm. Results showing a dose-dependent reduction in cell viability at various concentrations. From the results, it is manifested that the copper complex 4b showed a remarkable IC50 value of 178.56 µg/mL when compared to that of Ligand 3 with an IC50 value of 229.32 µg/mL. These results highlight the capability of coumarin-based Schiff base-metal complexes as lead compounds for the development of new anticancer and antibacterial agents.