In situ reduction synthesis of quinoline-based copper(I) complexes: “Self-activating” chemical nuclease, antioxidation and anticancer activity

Abstract

Two new Cu(І) complexes, [Cu2(L1)2(μ-Br)2] (1) and [Cu2(L1)2(μ-Cl)2] (2) were synthesized from Cu(II) halogen salts and the reduced Schiff base ligand. Stable Cu(І) complexes were obtained via in situ reduction of Cu(II) to Cu(I) and the CN was oxidize to C = N in the ligand. The structures of two complexes were characterized by X-ray single crystal diffraction analysis as well as IR and UV–Vis spectra. The two complexes have potential antioxidant capacity and exhibit efficiently self-activated DNA cleavage activity and hydroxyl radical ROS cleavage mechanism. MTT was used to assay cytotoxicity of the complexes toward a series of tumor cell and HUVEC cell lines. Both complexes exhibited higher selective cytotoxicity against tumor cells than normal cells, which is significantly superior to the positive control. The complexes could induce cell apoptosis via mitochondrial pathway by increase of ROS levels and decrease of mitochondrial membrane potential (Δψm). Furthermore, the complexes can obviously inhibit the migration and invasion of the quiz tumor cells, as well as inhibit the angiogenesis of HUVEC cells.