Synthesis, characterization, cytotoxicity, DNA binding and computational studies of an anionic palladium(II) complex derived from 8-hydroxyquinoline and 1,1-cyclobutanedicarboxylate

Abstract

A novel 1,1-cyclobutanedicarboxylato-8-hydroxyquinolinatopalladate(II), Na[Pd(8-QO)(cbdca)] (8-QO = 8-hydroxyquinoline and cbdca = 1,1-cyclobutanedicarboxylate) has been designed and synthesized. The structure of the complex has been characterized by elemental analysis, molar conductance, FT-IR, UV–Vis, 13C NMR, 1H NMR spectroscopy. The cytotoxic activities of the complex have been tested against human foreskin fibroblast normal cell line, HFFF2 and two human breast cancer cell lines, T47D and MCF-7 by MTT assay techniques. The binding properties of the antitumor complex with calf thymus DNA (ctDNA) have been investigated under physiological condition in Tris–HCl buffer solution at pH 7.0 by absorption spectroscopy, fluorescence titration spectra, EB displacement and gel chromatography studies. All these results demonstrate that the water soluble complex can cooperatively bind to ctDNA at low concentrations through a static quenching procedure. Thermodynamic parameters were calculated according to Van’t Hoff equation which indicated that hydrogen bond and van der Waals force play predominant roles in the binding process. Finally, the results of molecular docking calculations clarify the binding mode which is in good accordance with experimental results.