Low-dimensional compounds containing bioactive ligands. Part VIII: DNA interaction, antimicrobial and antitumor activities of ionic 5,7-dihalo-8-quinolinolato palladium(II) complexes with K+ and Cs+ cations

Starting from well-defined NH2(CH3)2[PdCl2(XQ)] complexes, coordination compounds of general formula Cat[PdCl2(XQ)] have been prepared by cationic exchange of NH2(CH3)2+ and Cat cations, where XQ are biologically active halogen derivatives of quinolin-8-ol (5-chloro-7-iodo-quinolin-8-ol (CQ), 5,7-dibromo-quinolin-8-ol (dBrQ) and 5,7-dichloro-quinolin-8-ol (dClQ)) and Cat is K+ or Cs+. The cation exchange of all prepared complexes, K[PdCl2(CQ)] (1), K[PdCl2(dClQ)] (2), K[PdCl2(dBrQ)] (3), Cs[PdCl2(CQ)] (4), Cs[PdCl2(dClQ)] (5) and Cs[PdCl2(dBrQ)] (6) was approved using IR spectroscopy, their structures in DMSO solution were elucidated by one- and two-dimensional NMR experiments, whereas their stability in solution was verified by UV–VIS spectroscopy. Interaction of complexes to ctDNA was investigated using UV–VIS and fluorescence emission spectroscopy. The minimum inhibitory concentration and the minimum microbicidal concentration values were detected against 15 bacterial strains and 4 yeast strains to examine the antimicrobial activity for the complexes. The in vitro antitumor properties of the complexes were studied by testing the complexes on leukemic cell line L1210, ovarian cancer cell line A2780 and non-cancerous cell line HEK293. The majority of the prepared compounds exhibited moderate antimicrobial and very high cytotoxic activity. Six new Cat[PdCl2(XQ)] complexes (Cat=K+ or Cs+, XQ=biologically active halogen derivatives of quinolin-8-ol) were synthesized by cationic exchange between NH2(CH3)2+ and alkali metals cations. All prepared complexes were characterized by IR, UV–VIS, NMR, elemental and thermal analyses, and their interaction to DNA, antimicrobial and antitumor activities were evaluated. [Display omitted] •Six new ionic Pd(II) complexes with halogen derivatives of quinolin-8-ol were prepared.•Complexes interact with DNA by intercalative binding mode.•Antimicrobial activity of complexes was tested against 19 strains of microorganisms.•Antitumor properties were studied on three cancerous and non-cancerous cell lines.•Complexes are selective cytotoxic against leukemic cell line L1210.