Low-dimensional compounds containing bioactive ligands. Part IX: Synthesis, structures, spectra, in vitro antimicrobial and anti-tumor activities and DNA binding of Pd(II) complexes with 7-bromo-quinolin-8-ol

摘要

Graphical abstract [Pd(BrQ)2] (1) and HBrQ[PdCl2(dBrQ)] (2) (BrQ=7-bromo-quinolin-8-ol) have been prepared as potential anticancer agents. Both complex 2 and BrQ ligand showed significantly higher cytotoxicity against human colorectal cancer cells than cisplatin and this effect is particularly pronounced at low concentrations that can be tested in vivo. Display Omitted Abstract New Pd(II) complexes with 7-bromo-quinolin-8-ol (BrQ), [Pd(BrQ)2] (1a) and (1b) and HBrQ[PdCl2(BrQ)] (2) have been synthesized and characterized. X-ray structure analysis of 1a and 1b revealed that the molecular structures of these square-planar polymorphs are very similar, nevertheless in the supramolecular structure the molecules are differently arranged and held by different intermolecular forces. The structure of 2 in DMSO solution was elucidated using one- and two-dimensional NMR experiments which showed that the complex decomposes to BrQ ligand. Antimicrobial activity of soluble complex 2 was tested by determining the minimum inhibitory concentration and minimum microbicidal concentration against 9 strains of bacteria and 5 strains of fungi; its activity on Proteus mirabilis is more than 250 times higher than a positive control. Complex 2 is also significantly more cytotoxic against human colorectal cancer cells HCT116 than cisplatin at all tested concentrations and this effect is particularly pronounced at low concentrations; cytotoxicity of BrQ is four times higher than cytotoxicity of 2 at these concentrations and is selectively cytotoxic. Interaction of 2 with DNA was investigated using UV–VIS spectroscopy and fluorescence spectroscopy; the binding studies indicate that complex 2 can interact with ctDNA through intercalation mechanism. ]]>