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

Low-dimensional compounds containing bioactive ligands. Part XVII: Synthesis, structural, spectral and biological properties of hybrid organic-inorganic complexes based on [PdCl4]2- with derivatives of 8-hydroxyquinolinium

In this study, four hybrid organic-inorganic compounds (8-H₂Q)₂[PdCl₄] (1), (H₂ClQ)₂[PdCl₄] (2), (H₂NQ)₂[PdCl₄] (3) and (H₂MeQ)₂[PdCl₄]·2H₂O (4) (where 8-H₂Q = 8-hydroxyquinolinium, H₂ClQ = 5-chloro-8-hydroxyquinolinium, H₂NQ = 5-nitro-8-hydroxyquinolinium and H₂MeQ = 2-methyl-8-hydroxyquinolinium) were synthesized through organic cation modulation. Single-crystal X-ray structure analysis of compounds 1 and 3 indicates that their structures are planar and consist of [PdCl₄]^2- anions and 8-H₂Q or H₂NQ cations, respectively. Both ionic components are held together through ionic interactions and hydrogen bonds forming infinite chains linked through π-π interactions to form 2D structures. Furthermore, NMR spectroscopy, UV-Vis spectroscopy, elemental analysis, and FT-IR spectroscopy were used to explore the synthesized compounds. The DNA interaction, antimicrobial activity, antiproliferative activity, and radical scavenging effect of the compounds were evaluated. The hybrid compounds and their free ligands can interact with the calf thymus DNA via an intercalation mode involving the insertion of the aromatic chromophore between the base pairs of DNA; compound 1 has the highest binding affinity. Moreover, they have high antimicrobial efficacy against the tested 14 strains of microorganisms with minimum inhibitory concentration values ranging from <1.95 to 250 μg/mL. The antiproliferative activity of the compounds was investigated against three different cancer cell lines, and their selectivity was verified on mesenchymal stem cells. Compounds 1 and 2 displayed selective and high cytotoxicity against human lung and breast cancer cells and showed moderate cytotoxicity against colon cancer cells. Accordingly, they might be auspicious candidates for future pharmacological investigations in lung and breast cancer research.

Quinolines, a perpetual, multipurpose scaffold in medicinal chemistry

Quinoline is a versatile pharmacophore, a privileged scaffold and an outstanding fused heterocyclic compound with a wide range of pharmacological prospective such as anticancer, anti-inflammatory, antibacterial, antiviral drug and superlative moiety in drug discovery. The quinoline hybrids have already been shown excellent results with new targets with a different mode of actions as an inhibitor of cell proliferation by cell cycle arrest, apoptosis, angiogenesis, disruption of cell migration and modulation. This review emphasized the mode of action, structure activity relationship and molecular docking to reveal the various active pharmacophores of quinoline hybrids accountable for novel anticancer, anti-inflammatory, antibacterial and miscellaneous activities. Therefore, several quinoline candidates are under clinical trials for the treatment of certain diseases, for example ferroquine (antimalarial), dactolisib (antitumor) and pelitinib (EGFR TK inhibitors) etc. Plenty of research has been summarized the recent advances of quinoline derivatives and explore the various therapeutic prospects of this moiety. This review would help the researchers to strategically design diverse novel quinoline derivatives for the development of clinically viable drug candidates for the treatment of incurable diseases.