Protein interaction and in vitro cytotoxicity studies of newly designed palladium (II) nitrate complexes: spectrochemical, theoretical and biological assessments

The biological assessments of new synthesized palladium (II) complexes [1, 10-phenanthroline hexyl dithiocarbamato palladium (II) nitrate (complex I), and 1, 10-phenanthroline butyl dithiocarbamato palladium (II) nitrate (complex II)] were investigated using in vitro cytotoxicity and molecular interaction studies. The in vitro cytotoxicity studies were done against human cervical HeLa cancer cell line and human breast MDA-MB-468 cancer cell line. The interaction evaluations were done using human hemoglobin (Hb) as the primary target of novel palladium (II) complexes using spectroscopy methods of fluorescence and circular dichroism at various temperatures of 25, 37, 42, and 47 °C as well as molecular docking. The results have indicated complex I and complex II are quite similar in functionality. They induced apoptotic cell death so that they showed a significant growth inhibitory effect against HeLa and MDA-MB-468 cells. The fluorescence spectroscopy and molecular docking indicated that there is only one binding site for new palladium (II) complexes on Hb. The interaction studies revealed complex I and complex II have the same structural effects and similar binding properties on Hb. Finally, the results showed the newly synthesized palladium (II) complexes have no structural degradation on Hb. Therefore, they can be introduced as promising candidates in cancer treatment.