Synthesis, DNA-binding and spectral properties of novel complexes [RuL2(idpq)]2+ (L=bpy, phen) with embedded CO

Synthesis, characterization, DNA binding, topoisomerase inhibition, and apoptosis induction studies of a novel cobalt(III) complex with a thiosemicarbazone ligand

In this study, 9-anthraldehyde-N(4)-methylthiosemicarbazone (MeATSC) 1 and [Co(phen)2(O2CO)]Cl·6H2O 2 (where phen = 1,10-phenanthroline) were synthesized. [Co(phen)2(O2CO)]Cl·6H2O 2 was used to produce anhydrous [Co(phen)2(H2O)2](NO3)33. Subsequently, anhydrous [Co(phen)2(H2O)2](NO3)33 was reacted with MeATSC 1 to produce [Co(phen)2(MeATSC)](NO3)3·1.5H2O·C2H5OH 4. The ligand, MeATSC 1 and all complexes were characterized by elemental analysis, FT IR, UV-visible, and multinuclear NMR (1H, 13C, and 59Co) spectroscopy, along with HRMS, and conductivity measurements, where appropriate. Interactions of MeATSC 1 and complex 4 with calf thymus DNA (ctDNA) were investigated by carrying out UV-visible spectrophotometric studies. UV-visible spectrophotometric studies revealed weak interactions between ctDNA and the analytes, MeATSC 1 and complex 4 (Kb = 8.1 × 105 and 1.6 × 104 M-1, respectively). Topoisomerase inhibition assays and cleavage studies proved that complex 4 was an efficient catalytic inhibitor of human topoisomerases I and IIα. Based upon the results obtained from the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay on 4T1-luc metastatic mammary breast cancer cells (IC50 = 34.4 ± 5.2 μM when compared to IC50 = 13.75 ± 1.08 μM for the control, cisplatin), further investigations into the molecular events initiated by exposure to complex 4 were investigated. Studies have shown that complex 4 activated both the apoptotic and autophagic signaling pathways in addition to causing dissipation of the mitochondrial membrane potential (ΔΨm). Furthermore, activation of cysteine-aspartic proteases3 (caspase 3) in a time- and concentration-dependent manner coupled with the ΔΨm, studies implicated the intrinsic apoptotic pathway as the major regulator of cell death mechanism.

Microwave-Assisted Synthesis, Characterisation, and DNA-Binding Properties of RuII Complexes Coordinated by Norfloxacin as Potential Tumour Inhibitors

Three novel norfloxacin-based ruthenium(ii) complexes, [Ru(bpy)2(NFLX)]Cl·2H2O (1), [Ru(phen)2(NFLX)]Cl·2H2O (2), and [Ru(dmbpy)2(NFLX)]Cl·2H2O (3) (bpy=2,2′-bipyridine, phen=1,10-phenanthroline, dmbpy=4,4′-dimethyl-2,2′-bipyridine, and NFLX=norfloxacin), were synthesised and characterised with electrospray ionisation mass spectrometry and 1H and 13C NMR spectroscopy. The antitumour properties were evaluated by MTT assay, and the data revealed that 2 can inhibit the growth of human lung adenocarcinoma A549 efficiently. Furthermore, the DNA-binding behaviours of these complexes were investigated by a multiple spectroscopy assay and viscosity study. The results indicated that these complexes interact with calf thymus DNA through electrostatic interactions with a strong binding affinity in the order 2>3>1. Therefore, these results suggested that 2 might be a suitable anticancer agent due to its excellent DNA-binding abilities.

DNA interaction and photocleavage properties of Ru (II) complexes [Ru(bpy)₂(pibi)]²⁺ and [Ru(phen)₂(pibi)]²⁺

A new asymmetry ligand pibi (pibi = 2-(pyridine-2-yl)-1-H-imidazo[4,5-f]benzo[d]imidazolone) and its ruthenium complexes with [Ru(L)2(pibi)](2+) (L = bpy (2, 2'-bipyridine), phen (1, 10-phenanthroline)), have been synthesized and characterized. The binding of two complexes with calf thymus DNA has been investigated by spectroscopic and viscosity measurement. The results indicate that both complexes can bind to CT-DNA through intercalative mode. Under irradiation at 365 nm, both complexes can partly promote the photocleavage of plasmid pBR322DNA. The low singlet oxygen generation abilities of the two complexes may be the factor for the low DNA photocleavage abilities.

Synthesis, spectroscopic characterization, antimicrobial, DNA binding and oxidative-induced DNA cleavage activities: new oxovanadium(IV) complexes of 2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione

A mononuclear complex [(phen)VO(bid)]SO(4)·3H(2)O (1), (phen=1,10-phenanthroline) and a binuclear [(VObid)(2)]·H(2)O (2), with Hbid [(E)-2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione] were prepared and characterized by elemental analysis, IR, mass, UV-Vis spectral studies, ESR, molar conductance and thermogravimetric analysis. The DNA-binding properties of the complexes 1 and 2 were investigated by UV-spectroscopy, fluorescence spectroscopy and viscosity measurements. The superoxide dismutase-like activity of the complexes has been determined. The spectral results suggest that the complexes 1 and 2 can bind to DNA by intercalation. The cleavage properties of these complexes with super coiled pUC19 have been studied using the gel electrophoresis method, where both complexes 1 and 2 displayed chemical nuclease activity in the absence and presence of H(2)O(2)via an oxidative mechanism. All the complexes inhibit the growth of both Gram positive and Gram negative bacteria to competent level. Minimum inhibitory concentration (MIC) was determined by microtiter method.

Synthesis, characterization, DNA binding and cleavage studies of chiral Ru(II) salen complexes

Interaction of chiral Ru(II) salen complexes (S)-1 and (R)-1 with Calf Thymus DNA (CT-DNA) was studied by absorption spectroscopy, competitive binding study, viscosity measurements, CD measurements, thermal denaturation study and cleavage studies by agarose gel electrophoresis. The DNA binding affinity of (S)-1 (6.25 x 10(3)M(-1)) was found to be greater than (R)-1 (3.0 x 10(3)M(-1)). The antimicrobial studies of these complexes on five different gram (+)/(-) bacteria and three different fungal organisms showed selective inhibition of the growth of gram (+) bacteria and were not affective against gram (-) and fungal organisms. Further, the (S)-1 enantiomer inhibited the growth of organisms to a greater extent as compared to (R)-1 enantiomer.