Evaluation of the antioxidant, DNA interaction and tumor cell cytotoxicity activities of Copper(II) complexes with Paeonol Schiff-base

Herein, we report for the first time on the preparation of four Paeonol Schiff-base ligands: 1,2-Bis(2-hydroxy-4-methoxy-α-methylbenzylideneimino) ethane (H2L1), 2-hydroxy-4-methoxy-α-methylbenzylidene (benzoyl) hydrazone (HL2), 2-hydroxy-4-methoxyacetophenone-ethanolamine Schiff-base (HL3), and 2-hydroxy-4-methoxyacetophenone(2′-hydroxybenzoyl) hydrazone (H2L4), and their Cu(II) complexes, of which the structure of C11N2O6H14Cu(CuL3.NO3) was confirmed by X-ray diffraction. Antioxidant activities of four Cu(II) complexes were studied by the standard non-enzymatic NBT method and Fenton system, used to produce superoxide anion radicals and hydroxyl radicals, respectively. The results show these Cu(II) complexes have excellent antioxidant activities. DNA-binding and in vitro cytotoxicity experiments were utilized to further investigate the biological activities of C11N2O6H14Cu(CuL3.NO3). These results support C11N2O6H14Cu as a potential candidate for biological use because it shows not only high antioxidant and moderate DNA-binding activities, but also good tumor cell cytotoxicity activities in human cell lines carcinomas Hep-2 (larynx), for the range of concentrations tested.