DNA interaction, antioxidant activity, and bioactivity studies of two ruthenium(II) complexes.

Two new ruthenium(II) polypyridyl complexes [Ru(dmb)(2)(dcdppz)](ClO4)(2) (I) and [Ru(bpy)(2) (dcdppz)](ClO4)(2) (2) were prepared and characterized. The crystal structure of the complex 2 was solved by single crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group P2(1)/n with a = 12.9622(14) angstrom, b = 17.1619(19) angstrom, c = 22.7210(3) angstrom, beta = 100.930(2)degrees R = 0.0536, R-omega = 0.1111. The DNA-binding constants for complexes 1 and 2 were determined to be 1.92 x 10(5) (s = 1.72) and 2.24 x 10(5) (s = 1.86) M-1, respectively. The DNA-binding behaviors showed that complexes 1 and 2 interact with DNA by intercalative mode. The antioxidant activities of the ligand and the complexes were performed. Ligand, dcdppz, has no cytotoxicity against the selected cell lines. Complex 1 shows higher cytotoxicity than complex 2, but lower than cisplatin toward selected cell lines. The apoptosis and cell cycle arrest were investigated, and the apoptotic mechanism of BEL-7402 cells was studied by reactive oxygen species (ROS), mitochondrial membrane potential and western blot analysis. Complex 1 induces apoptosis in BEL-7402 cells through ROS-mediated mitochondrial dysfunction pathway and by regulating the expression of Bcl-2 family proteins. (C) 2014 Elsevier B.V. All rights reserved.