Influence of carboxylic acid functionalities in ruthenium (II) polypyridyl complexes on DNA binding, cytotoxicity and antioxidant activity: Synthesis, structure and in vitro anticancer activity

Four new Ru(II) complexes [RuHCl(bpy)(PPh3)(CO)] (1), [RuHCl(bpy)(AsPh3)(CO)] (2) (bpy = 2,2'-bipyridine), [RuCl(HL)(PPh3)(2)(CO)] (3) and [RuCl(HL)(AsPh3)(2)(CO)] (4) (HL = 2,2'-bipyridine-4,4'-dicarboxylic acid) were synthesized and characterized. X-ray diffraction was used to characterize 3 in solid state. The interactions of these complexes with DNA were explored by different techniques which revealed that the complexes could bind to CT-DNA through non-intercalation. The in vitro cytotoxic and antioxidant activities of the complexes validated against a panel of cancer cell lines and free radicals showed that 3 and 4 possess quite high anticancer and antioxidant activities over 1, 2 and standard drugs. An apparent dependence of biological activities on incorporation of COOH in bipyridine moiety was noticed: Inclusion of COOH caused significant differences in DNA binding, cytotoxicity and antioxidant activity. (C) 2012 Elsevier Masson SAS. All rights reserved.