Li-Xin He

Synthesis, DNA-binding, photocleavage, cytotoxicity and antioxidant activity of ruthenium (II) polypyridyl complexes

Two new ligands maip (1a), paip (1b) with their ruthenium (II) complexes [Ru(bpy)(2)(maip)](ClO(4))(2) (2a) and [Ru(bpy)(2)(paip)](ClO(4))(2) (2b) have been synthesized and characterized. The results show that complexes 2a and 2b interact with DNA through intercalative mode. The cytotoxicity of these compounds has been evaluated by MTT assay. The experiments on antioxidant activity show that these compounds exhibit good antioxidant activity against hydroxyl radical (OH).

Synthesis, structure, DNA-binding properties, and cytotoxicity of ruthenium(II) polypyridyl complexes.

Many ruthenium(II) complexes show high antitumor activities, and the in vitro antitumor activities are usually related to DNA binding. We designed and synthesized two RuII polypyridyl complexes, [Ru(dmp)2(fpp)]2+ (dmp=2,9‐dimethyl‐1,10‐phenanthroline; fpp=2‐[3,4‐(difluoromethylenedioxy)phenyl]imidazo[4,5‐f] [1,10]phenanthroline and [Ru(phen)2(fpp)]2+ (phen=1,10‐phenanthroline). The DNA‐binding properties of these complexes have been investigated by spectroscopic titration, DNA melting experiments, viscosity measurements, and photoactivated cleavage. The mechanism studies of photocleavage revealed that singlet oxygen (1O2) and superoxide anion radical (O

In vitro cytotoxicity, apoptosis, DNA-binding, and antioxidant activity studies of ruthenium (II) complexes.

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Ruthenium(II) complexes of 2-(2′-pyridyl)naphthoimidazole: synthesis, characterization and DNA-binding studies

) may play an important role in the photocleavage. The cytotoxicity of complexes 1 and 2 have been evaluated by MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) method; complex 2 shows slightly higher anticancer potency than 1 does against all the cell lines screened.

Effect of the ancillary ligands on the binding of ruthenium(II) complexes [Ru(dmp)2(MCMIP)]2+ and [Ru(dmb)2(MCMIP)]2+ with DNA

Two new ligands maip (1) (maip = 2-(3-aminophenyl)imizado[4,5-f][1,10]phenanthroline), paip (2) (paip = 2-(4-aminophenyl)imidazo[4,5-f][1,10]phenanthroline), and their ruthenium (II) complexes [Ru(phen)(2)(maip)](ClO(4))(2) (3) and [Ru(phen)(2)(paip)](ClO(4))(2) (4) (phen = 1,10-phenanthroline) have been synthesized and characterized. The cytotoxicity of these compounds was evaluated by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The apoptosis assay was carried out with acridine orange/ethidium bromide staining methods. The DNA-binding behaviors of complexes 3 and 4 were investigated by viscosity measurements, thermal denaturation, photocleavage, and spectroscopic methods. The results show that the two complexes intercalate into the base pairs of DNA. In the presence of a complex, apoptosis of BEL-7402 cells was observed. Experiments show that these compounds exhibit antioxidant activity against hydroxyl radicals.

DNA interaction studies of ruthenium(II) polypyridyl complex : [Ru(dmb)2(ITAP)](ClO4)2 (ITAP = isatino [1,2-b]-1,4,8,9-tetraazatriphenylene)

The perchlorate salts of two new ruthenium(II) complexes incorporating 2-(2′-pyridyl)naphthoimidazole are synthesized in good yield. Complexes [Ru(phen)2(PYNI)]2+ (phen = 1,10-phenanthroline) 1 and [Ru(dmp)2(PYNI)]2+ (dmp = 2,9-dimethyl-1,10-phenanthroline, PYNI = 2-(2′-pyridyl)naphthoimidazole) 2 are fully characterized by elemental analysis, FAB-MS, ES-MS, 1H NMR and cyclic voltammetric methods. The DNA-binding behavior of the complexes have been studied by spectroscopic titration, viscosity measurements and thermal denaturation. Absorption titration and thermal denaturation studies reveal that these complexes are moderately strong binders of calf-thymus DNA (CT-DNA), with their binding constants spanning the range (2.73–5.35) × 104 M−1. The experimental results show that 1 interacts with calf thymus DNA (CT-DNA) by intercalative mode, while 2 binds to CT-DNA by partial intercalation.

Ruthenium(II) complexes containing 2,9-dimethyl-1,10-phenanthroline and 4,4′-dimethyl-2,2′-bipyridine as ancillary ligands: synthesis, characterization and DNA-binding

Two polypyridine ruthenium(II) complexes, [Ru(dmp)2(MCMIP)]2+ (1) (MCMIP = 2-(6-methyl-3-chromonyl)imidazo[4,5-f][1,10]-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline) and [Ru(dmb)2(MCMIP)]2+ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine), have been synthesized and characterized by elemental analysis, ES-MS and 1H NMR. The DNA-binding behaviors of these complexes were investigated by electronic absorption titration, fluorescence spectroscopy, viscosity measurements and thermal denaturation. The results show that 1 and 2 effectively bind to CT-DNA; the DNA-binding affinities are closely related to the ancillary ligand.

Interaction studies of DNA binding of ruthenium(II) mixed-ligand complexes: [Ru(phen)2(dtmi)]2+ and [Ru(phen)2(dtni)]2+.

A new ligand ITAP and its complex [Ru(dmb)2(ITAP)](ClO4)2 (ITAP = isatino [1,2-b]-1,4,8, 9-tetraazatriphenylene, dmb = 4,4′-dimethyl-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, Fast atom bombardment mass spectra, Electrospray mass spectra, and 1H NMR. Thermal denaturation and absorption titration experiments show the complex binds to calf thymus DNA (CT-DNA) with moderate affinities. Viscosity measurements and thermal denaturation indicate that the DNA-binding mode could be intercalative interaction. The Ru(II) complex in the presence of plasmid pBR322 DNA has been found to promote the cleavage of plasmid pBR322 DNA from the supercoiled Form I to the open circular Form II upon irradiation. Mechanisms for DNA cleavage by the complex were also investigated.