Synthesis, characterization and biological activities of two novel orthopalladated complexes: Interactions with DNA and bovine serum albumin, antitumour activity and molecular docking studies

Abstract

[Pd(L1)(C,N)]CF3SO3 and [Pd(L2)(C,N)]CF3SO3 (L1 = 2,2′‐bipyridine, L2 = 1,10‐phenanthroline and C,N = benzylamine) novel orthopalladated complexes have been synthesized and characterized using various techniques. The binding of the complexes with native calf thymus DNA (CT‐DNA) was monitored using UV–visible absorption spectrophotometry, fluorescence spectroscopy and thermal denaturation studies. Our results indicate that these complexes can strongly bind to CT‐DNA via partial intercalative mode. In addition, fluorescence spectrometry of bovine serum albumin (BSA) with the complexes shows that the fluorescence quenching mechanism of BSA is a static process. The results of site‐competitive replacement experiments with specific site markers clearly indicate that the complexes bind to site I of BSA. Notably, the complexes exhibit significant in vitro cytotoxicity against two human cancer cell lines (Jurkat and MCF‐7) with IC50 values varying from 37 to 53 μM. Finally, a molecular docking experiment effectively proves the binding of the Pd(II) complexes to DNA and BSA.