Crystal structures, DNA-binding and cytotoxic activities studies of Cu(II) complexes with 2-oxo-quinoline-3-carbaldehyde Schiff-bases

Three novel 2-oxo-quinoline-3-carbaldehyde Schiff-bases and their Cu(II) complexes were synthesized. The molecular structures of Cu(II) complexes were determined by X-ray crystal diffraction. The DNA-binding modes of the complexes were also investigated by UV–vis absorption spectrum, fluorescence spectrum, viscosity measurement and EB–DNA displacement experiment. The experimental evidences indicated that the ligands and Cu(II) complexes could interact with CT-DNA (calf-thymus DNA) through intercalation, respectively. Comparative cytotoxic activities of ligands and Cu(II) complexes were also determined by MTT [3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide] and SRB (sulforhodamine B) methods. The results showed that the three Cu(II) complexes exhibited more effective cytotoxic activity against HL60 cells and HeLa cells than corresponding ligands. Also, CuL3 showed higher cytotoxic activity than CuL1 and CuL2.

Graphical abstractThree new Cu(II) Schiff-bases complexes were synthesized and characterized. The study revealed that the Cu(II) complexes could bind to CT-DNA through intercalation and showed higher cytotoxicity than corresponding ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide