Cytotoxicity, apoptosis, cellular uptake, cell cycle arrest, photocleavage, and antioxidant activity of 1, 10-phenanthroline ruthenium(II) complexes.

Two new ruthenium(II) complexes, [Ru(phen)2(DNPIP)](ClO4)2 (1) and [Ru(phen)2(DAPIP)](ClO4)2 (2), were synthesized and characterized. The DNA-binding properties of these complexes were investigated using UV/vis absorption titration, viscosity measurements, thermal denaturation, and photoactivated cleavage. The DNA binding constants for complexes 1 and 2 are 2.63 ± 0.25×10(5) M(-1) (s=2.45) and 1.51±0.18×10(5) M(-1) (s=1.34). The results indicated that these complexes interacted with DNA through the intercalative mode. The cytotoxicity in vitro of complexes 1 and 2 were assessed against BEL-7402, HepG-2, and MCF-7 cell lines by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was studied with the acridine orange/ethidium bromide staining method. The antiproliferative mechanism was explored with flow cytometry. Cellular uptake studies showed that complexes 1 and 2 can enter into the cytoplasm and accumulate in the nuclei. Cell cycle arrest and antioxidant activity were also investigated.