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

Abstract Two new ruthenium(II) polypyridyl complexes [Ru(dmb) 2 (dcdppz)](ClO 4 ) 2 ( 1 ) and [Ru(bpy) 2 (dcdppz)](ClO 4 ) 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) A, b  = 17.1619(19) A, c  = 22.7210(3) A, β  = 100.930(2) ° , R  = 0.0536, R ω = 0.1111. The DNA-binding constants for complexes 1 and 2 were determined to be 1.92 × 10 5 ( s  = 1.72) and 2.24 × 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.