Cellular uptake, cytotoxicity, apoptosis, antioxidant activity and DNA binding of polypyridyl ruthenium(II) complexes

Ruthenium(II) polypyridyl complexes [Ru(phen)(2)(APIP)](ClO4)(2) 1 and [Ru(phen)(2)(HAPIP)](ClO4)(2) 2 have been synthesized and characterized. The DNA-binding behaviors were investigated by electronic absorption titration, luminescence spectra, viscosity measurements, thermal denaturation and photo-activated cleavage. The DNA-binding constants K-b for complexes 1 and 2 were determined to be 3.38 (+/-0.42) x 10(5) M-1 (s = 1.48) and 3.93 (+/-0.60) x 10(5) M-1 (s = 3.14), respectively. The studies on the photocleavage demonstrated that the effects of cleavage are concentration-dependent. The results showed that complexes 1 and 2 interact with CT-DNA by intercalative mode. The cytotoxicity of complexes 1 and 2 has been evaluated by MTT method. The apoptosis assay was carried out with acridine orange/ethidium bromide (AO/EB) staining methods. The cellular uptake showed that complexes can enter into the cytoplasm and accumulate in the nuclei. The antioxidant activity studies suggested that the ligands and complexes may be potential drugs to eliminate the radical. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.