Cheng-Hui Zeng

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 of ruthenium(II) complexes and characterization of their cytotoxicity in vitro, apoptosis, DNA-binding and antioxidant activity

A new ligand DBHIP and its two ruthenium (II) complexes [Ru(bpy)(2)(DBHIP)](ClO(4))(2) (1) and [Ru(phen)(2)(DBHIP)](ClO(4))(2) (2) have been synthesized and characterized. The binding behaviors of the two complexes to calf thymus DNA were investigated by absorption spectra, viscosity measurements, thermal denaturation and photoactivated cleavage. The DNA-binding constants for complexes 1 and 2 have been determined to be 8.87+/-0.27 x 10(4)M(-1) (s=1.83) and 1.32+/-0.31 x 10(5)M(-1) (s=1.84). The results suggest that these complexes interact with DNA through intercalative mode. The cytotoxicity of DBHIP, complexes 1 and 2 has been evaluated by MTT assay. The apoptosis assay was carried out with acridine orange/ethidium bromide (AO/EB) staining methods. The studies on the mechanism of photocleavage demonstrate that superoxide anion radical (O(2)(-)) and singlet oxygen ((1)O(2)) may play an important role.

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

) 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.

Bis(2,9-dimethyl-1,10-phenanthroline-κ2N,N′)(10,11,12,13-tetra­hydro­dipyrido[3,2-a:2′,3′-c]phenazine-κ2N4,N5)ruthenium(II) bis­(perchlorate) dihydrate

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.

Bis[bis-(4,4'-dimethyl-2,2'-bipyridine)(10,11,12,13-tetra-hydro-dipyrido[3,2-a:2',3'-c]phenazine)ruthenium(II)] tetra-kis(perchlorate) acetonitrile disolvate monohydrate.

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.

Synthesis, characterization, photocleavage of DNA and cytotoxicity of ruthenium(II) mixed-ligand complexes

The title compound, [Ru(C14H12N2)2(C18H14N4)](ClO4)2·2H2O, consists of an RuII complex cation, two perchlorate anions and two uncoordinated water molecules. The RuII ion is chelated by a 10,11,12,13-tetrahydrodipyrido[3,2-a:2′,3′-c]phenazine ligand and two 2,9-dimethyl-1,10-phenanthroline ligands in a distorted octahedral geometry. The two uncoordinated water molecules are disordered over five positions, with an occupancy factor of about 0.4 for each site. A supramolecular structure is formed by weak π–π interactions between neighbouring molecules, with centroid–centroid distances of 3.618 (2) and 3.749 (2) Å.

2-(3,5-Dibromo-4-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthrolinoruthenium(II) complexes: synthesis, characterization, cytotoxicity, apoptosis, DNA-binding and antioxidant activity

The asymmetric unit of the title compound, [Ru(C12H12N2)2(C18H14N4)]2(ClO4)4·2CH3CN·H2O, contains two RuII complex cations, four perchlorate counter-anions, two uncoordinated acetonitrile molecules and one water molecule. The RuII ions are chelated by one 10,11,12,13-tetrahydrodipyrido[3,2-a:2′,3′-c]phenazine (dpqc) and two 4,4′-dimethyl-2,2′-bipyridine (dmb) ligands in a distorted octahedral geometry. The uncoordinated water molecule is disordered over three positions, with occupancy factors of 0.398 (9), 0.312 (8) and 0.290 (8). A supramolecular structure is formed by weak π–π interactions between neighbouring molecules, with face-to-face distances of 3.51 (1) Å [centroid–centroid distance 3.81 (1) Å].