Synthesis, spectral, structural characterization and biological activity of new palladium(II) complexes containing 3-acetyl-8-methoxy-2H-chromen-2-one derived Schiff bases

Four different mononuclear palladium(II) complexes of 3-acetyl-8-methoxycoumarin Schiff bases were synthesized and characterized by spectrochemical techniques. Further analysis through X-ray crystallography confirmed the structures of the complexes. Their interactive ability with Calf Thymus DNA and protein (Bovine Serum Albumin and Human Serum Albumin) were investigated by means of absorption and emission methods. The intercalative mode of binding with DNA was supported by EB displacement studies and viscosity measurements. Configurational changes that occurred in the proteins have been analysed with the help of 3D fluorescence studies. The complexes were shown to have good antimicrobial activity against the tested bacterial and fungal pathogens. In addition, antiproliferative activity of the complexes was evaluated on A549 and MCF-7 cell lines and the complexes were comparatively more active than the standard drug cisplatin. Among the compounds, complex 3 was the most effective against MCF-7 (IC50 value of 5.20 +/- 0.15 mu M) and A549 (5.09 +/- 0.13 mu M) compared with the other complexes 1 (6.48 +/- 0.17 mu M; 5.98 +/- 0.09 mu M), 2 (5.53 +/- 0.12 mu M; 5.85 +/- 0.11 mu M), 4 (6.73 +/- 0.19 mu M; 6.63 +/- 0.16 mu M) and cisplatin (16.79 +/- 0.08 mu M; 15.10 +/- 0.05 mu M) respectively. LDH and NO release assays confirmed the cytotoxic potential of the synthesized complexes.