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Abstract: 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. [ABSTRACT FROM AUTHOR]

Abstract: Two novel 2-oxo-quinoline-3-carbaldehyde (4′-hydroxybenzoyl) hydrazone, thiosemicarbazone ligands and its corresponding Cu(2+) complexes were synthesized, and the two complexes’ structures were determined by X-ray single crystal diffraction. The interaction of the two Cu(2+) complexes with calf thymus DNA (CT-DNA) was investigated by electronic absorption spectroscopy, fluorescence spectroscopy and viscosity measurement. The experimental evidences indicated that the two water-soluble Cu(2+) complexes could strongly bind to CT-DNA via an intercalation mechanism. The intrinsic binding constants of complexes 1 and 2 with CT-DNA were 7.31×106 and 2.33×106 M−1, respectively. Furthermore, the antioxidant activities (hydroxyl radical and superoxide) of the two water-soluble metal complexes were determined by hydroxyl radical and superoxide scavenging method in vitro. [Copyright &y& Elsevier]