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-alpha-methylbenzylideneimino) ethane (H(2)L(1)), 2-hydroxy-4-methoxy-alpha-methylbenzylidene (benzoyl) hydrazone (HL(2)), 2-hydroxy-4-methoxyacetophenone-ethanolamine Schiff-base (HL(3)), and 2-hydroxy-4-methoxyacetophenone(2'-hydroxybenzoyl) hydrazone (H(2)L(4)), and their Cu(II) complexes, of which the structure of C(11)N(2)O(6)H(14)Cu(CuL(3)center dot NO(3)) 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 C(11)N(2)O(6)H(14)Cu(CuL(3)center dot NO(3)). These results support C(11)N(2)O(6)H(14)Cu 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. (C) 2010 Elsevier B.V. All rights reserved.