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Query: UNIPROT:O14944 (EPR)
 13,097 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nicotinamido-4-bis(2-chloroethyl)aminobenzaldimine (NBAB) was synthesized and characterized by elemental analysis, IR and 1H NMR spectra. The complex of Cu(NBAB)2(NO3)2 was prepared in ethanol and characterized by elemental analysis, conductivity, cyclic voltammetry, IR, UV-Vis, fluorescence, CD and EPR spectra. The characteristic data suggest that the complex has an elongated octahedral structure, and NBAB behaves as bidentate in the keto form. The antitumor activities of NBAB and the complex against L1210 murine leukemia and K562 were investigated with both the MTT method and the colony formation test. The results in vitro indicate that antitumor activities of NBAB are superior to 2,2'-chlorodiethylamine hydrochloride (nitrogen mustard) for L1210, and inferior to nitrogen mustard for K562, but the antitumor activities of the complex for both cell lines are superior to nitrogen mustard.
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PMID:Synthesis, characterization and antitumor activity of copper(II) complex with nicotinamido-4-bis(2-chloroethyl)aminobenzaldimine. 1037 43

We have previously demonstrated that tetrahedral bis(cyclopentadienyl)vanadium(IV) complexes and square pyramidal oxovanadium(IV) complexes of vanadium are rapid and selective spermicidal agents at low micromolar concentrations. This study investigated the potential utility of oxovanadium in combination with thiourea non-nucleoside inhibitors (NNIs) of HIV-1 reverse transcriptase (RT) for the development of an effective dual-function anti-HIV spermicide. Two rationally designed substituted phenyl-ring containing pyridyl thiourea NNIs, N-[2-(2-chlorophenethyl)]-N(')-[2-(5-bromopyridyl)-thiourea) [1] and N-[2-(2-methoxyphenethyl)]-N(')-[2-(pyridyl)-thiourea [2] that exhibited subnanomolar IC(50) values against the drug-sensitive, drug-resistant, and multidrug-resistant strains of HIV-1, were complexed with oxovanadium. The oxovanadium-thiourea [OVT] NNIs, C(29)H(27)Br(2)Cl(2)N(6)O(2)S(2)V [3], and C(31)H(35)N(6)O(4)S(2)V [4], were synthesized by reacting VOSO(4), a V(IV) compound, with the corresponding deprotonated thiourea NNI compounds as ligands. Elemental analysis showed that each OVT-NNI used two thiourea molecules as ligands. The existence of the Vz.dbnd6;O bond (968cm(-1)) was confirmed by IR spectroscopy. No d-d bands were observed in the visible spectra of OVT-NNIs and their EPR spectra were featureless, indicating that the vanadium centers were oxidized to V(V). The new OVT-NNIs as well as their thiourea NNI ligands were evaluated for (i) anti-HIV activity using the cell-free recombinant RT inhibition assays, (ii) cellular HIV replication assays, (iii) spermicidal activity against human sperm by computer-assisted sperm analysis (CASA), and (iv) cytotoxicity against normal human female genital tract epithelial cell using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) dye-reduction assays. Similar to thiourea NNIs 1 and 2, the OVT-NNIs 3 and 4, exhibited potent anti-HIV activity with submicromolar IC(50[p24]) values (0.08 and 0.128 microM, respectively) and submicromolar IC(50[RT]) values (2.1 and 0.87 microM, respectively). Notably, OVT-NNIs were spermicidal against human sperm at low micromolar concentrations (IC(50)=34 and 55 microM, respectively) and induced rapid sperm immobilization (T(1/2)=12 and 240s) when compared with their respective thiourea NNI ligands (EC(50)=>400 microM and T(1/2)=>180min). Moreover, OVT-NNIs displayed high selectivity indices against normal female genital tract epithelial cells (IC(50) values >250 microM) when compared to the detergent-type spermicide, nonoxynol-9, which was cytotoxic at spermicidal concentrations (IC(50) values 32-64 microM). This is the first report on the dual anti-HIV and spermicidal activities of a vanadium/oxovanadium complex. Our discovery of potent anti-HIV and rapid spermicidal activities of OVT-NNIs may be useful for the development of an effective and safe vaginal anti-HIV spermicide for women who are at high risk for acquiring HIV/AIDS by heterosexual transmission.
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PMID:Potent dual anti-HIV and spermicidal activities of novel oxovanadium(V) complexes with thiourea non-nucleoside inhibitors of HIV-1 reverse transcriptase. 1260 39

The complexation of VO(2+) ion by ten acetamidrazone and 2-phenylacetamidrazone derivatives (L) was studied. Sixteen novel VO(2+) complexes were synthesised and characterised through the combined application of analytical and spectroscopic (EPR (electron paramagnetic resonance), FT-IR and diffuse reflectance electronic absorption) techniques. Eight are 1:2 species of composition [VOL(2)]SO(4) x xH(2)O and eight are 1:1 species with formula [VOL(SO(4))](n) x xH(2)O. The experimental data suggest a bidentate coordination mode for L with the donor set formed by the imine nitrogen and the carbonyl oxygen. EPR spectra indicate a square-pyramidal geometry for the 1:1 complexes and a penta-coordinated geometry intermediate between the square-pyramid and the trigonal-bipyramid for the 1:2 species. The hyperfine coupling constant along z axis, A(z), of the 1:2 complexes exhibits a marked reduction with respect to the predicted value (approximately 148x10(-4)cm(-1) vs. approximately 170x10(-4)cm(-1)). IR spectroscopic evidence supports the presence of sulphate as a counter-ion in the 1:2, and as a bridging bidentate ligand in the 1:1 complexes. Insulin-mimetic tests on modified fibroblasts, based on a modified MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide) assay, performed on three of the bis-chelated and eight of the mono-chelated derivatives, indicate that they are biologically active. The similar hydro/lipophilicity and the lack of ligand substituents recognizable by cell membrane receptors prevent substantial differentiation in the insulin-mimetic action.
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PMID:Synthesis, characterisation and insulin-mimetic activity of oxovanadium(IV) complexes with amidrazone derivatives. 1699 35

Biological effects of photoexcited in UV/VIS region water-soluble fullerenes C60 and synthesized C60-containing composites after its addition to cell incubation medium are studied. It is shown by EPR method, that in the presence of photoexcited C60 (10(-5) M) reactive oxygen species (ROS) are generated both in water solution and cell suspensions. ROS generation is accelerated if C60 is included into aminopropylaerosyl or antracenaliminopropylaerosyl. Photodynamic damage of Erlich ascites carcinoma cells by photoexcited C60-composites is confirmed by a decrease of cell viability, enhanced content of Schiff base fluorescent products of malonaldehyde as indicator of lipid peroxidation and the decrease in respiratory activity, estimated by MTT-test. No effects of photoexcited C60-composites were detected in thymocytes suspension. The data obtained testity to perspective utility of C60-composites for optimization of photodynamic therapy methods.
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PMID:[Oxidative properties of photoexcited fullerenes C60 and C60-containing composites in suspension of thymocytes and Ehrlich ascites carcinoma cells]. 1723 31

Novel trinuclear complexes C23H31N6O6CuSn2Cl5 [1], C23H31N6O6CuZr2Cl5 [2], C23H31N6O6ZnSn2Cl5 [3], and C23H31N6O6ZnZr2Cl5 [4] were synthesized and characterized by spectroscopic (IR, 1H, 13C, 2D COSY, and 119Sn NMR, EPR, UV-vis, ESI-MS) and analytical methods. In complexes 1-4, the geometry of copper and zinc metal ions were described as square-based pyramidal with l-tryptophan coordinated to copper/zinc via carboxylate group while Sn/Zr was present in the hexacoordinate environment. The interaction of 1 and 2 with calf thymus DNA in Tris buffer was studied by electronic absorption titration, luminescence titration, cyclic voltammetry, circular dichroism, and viscometric measurements. The emission quenching of these complexes by [Fe(CN)6]4- depressed greatly when bound to DNA. Observed changes in the circular dichoric spectra of DNA in presence of 1 and 2 support the strong binding of complexes with DNA. The relative specific viscosity of DNA bound to 1 and 2 decreased, indicating that the complexes bind to DNA via covalent binding. The results reveal that the extent of DNA binding of 1 was greater than that of 2. To evaluate the mechanistic pathway of DNA inhibition, counting experiments and MTT assay were employed to assess the induction of apoptosis by 1. Western blot analysis of whole cell lysates and mitochondrial fractions with Bcl-2 and p-53 family proteins and caspase-3 colorimetry assay were also carried out on a human neuroblastoma cell line SY5Y.
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PMID:DNA binding studies of novel Copper(II) complexes containing L-tryptophan as chiral auxiliary: in vitro antitumor activity of Cu-Sn2 complex in human neuroblastoma cells. 1737 49

A series of ternary metal(ii) complexes {M(phen)(edda); 1a (Cu), 1b (Co), 1c (Zn), 1d (Ni); H(2)edda = N,N(')-ethylenediaminediacetic acid} of N,N'-ethylene-bridged diglycine and 1,10-phenanthroline were synthesized and characterized by elemental analysis, FTIR, UV-visible spectroscopy and magnetic susceptibility measurement. The interaction of these complexes with DNA was investigated using CD and EPR spectroscopy. MTT assay results of 1a-1c , screened on MCF-7 cancer cell lines, show that synergy between the metal and ligands results in significant enhancement of their antiproliferative properties. Preliminary results from apoptosis and cell cycle analyses with flow cytometry are reported. seems to be able to induce cell cycle arrest at G(0)/G(1). The crystal structure of 1a is also included.
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PMID:Synthesis, characterization, DNA-binding study and anticancer properties of ternary metal(II) complexes of edda and an intercalating ligand. 1818 60

An efficient synthesis of a family of heteroaromatic triazinium compounds, [2a]X-[2g]X (X = Cl, ClO4, NO3, and HSO4), from 2-(arylazo)pyridines via proton-catalyzed heterocyclization is described. Characterization of the compounds is made by different spectroscopic, electrochemical techniques, as well as single-crystal structure determination of the triflate salt of a representative compound, [2a]CF3SO3. The bond parameters indicate that the tricyclo compound, 2a(+), is planar and aromatic with a N-N bond length of 1.275(6) A. These exhibited fluorescence with an emission maximum in the range of 540-535 nm with moderate quantum yields. The triazinium salts can be reduced in two successive one-electron steps as probed by cyclic voltammetry and coulometry. The paramagnetic radical intermediate 2a(*) is distinguished by a sharp and intense EPR spectrum. Fluorescence spectroscopy, circular dichroism, cyclic voltammetry, viscosity measurements, together with DNA melting studies have been used to characterize the binding of 2a(+) with calf thymus DNA. The emission quenching of the compound by [Fe(CN)6](4-) decreased when bound to DNA. As determined by a MTT assay, 2a(+) exhibited significant cytotoxicity at a higher concentration range of 1 mg/mL to 1 microg/mL; however, the % survival ratio increased with dilution. Cellular uptake studies of the referenced compound were followed by FACS analysis.
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PMID:Mild synthesis of a family of planar triazinium cations via proton-assisted cyclization of pyridyl containing azo compounds and studies on DNA intercalation. 1833 91

This paper reports on the synthesis and properties of a new UV-absorber (OC-NO) based on the most popular UV filter worldwide, ethylhexyl methoxycinnamate (OMC) in which the methoxy group has been replaced with a pyrrolidine nitroxide bearing antioxidant activity. This sunscreen active has therefore both UV-absorbing and antioxidant properties which could ideally address both the UV-B and UV-A skin photo-damage. For broad-spectrum coverage, the combinations of OC-NO with two commonly used UV-A absorbers (BMDBM and DHHB) were also studied. The results obtained reveal that OC-NO: (a) is as photostable as OMC after UV-A exposure; (b) acts as free radical scavenger as demonstrated by EPR and chemical studies; (c) reduces UV-A and UV-A+BMDBM induced lipid peroxidation in liposomes and cells, measured as reduced TBARS levels and increased C11-BODIPY red fluorescence, respectively; (d) has comparable antioxidant activity to that of vitamin E and BHT commonly used in skin care formulations; (e) is non-cytotoxic to human skin fibroblasts as assessed with the MTT assay when exposed to increasing doses of UV-A; and (f) OC-NO+DHHB is a promising, photostable broad spectrum UV-filter combination that concomitantly reduces UV-induced free radical damage. These results suggest that nitroxide/antioxidant-based UV-absorbers may pave the way for the utilization of 'multi-active' ingredients in sunscreens thereby reducing the number of ingredients in these formulations.
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PMID:In vitro photostability and photoprotection studies of a novel 'multi-active' UV-absorber. 1848 19

We studied the antitumor properties of the dinuclear copper(II) complex of l-carnitine [Cu 2( l-carnitine) 2Cl 2(H 2O) 2]Cl 2, as well as those of l-carnitine and copper chloride dihydrate, in human leukemic cells. The complex was synthesized and characterized using EPR, (1)H NMR, (13)C NMR, IR, and UV-vis analyses. Its cytotoxic effect on the human leukemia cell lines HL-60 and K562 was studied by assessing the metabolic activity of cells (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT method), the structural integrity of cell membrane using Trypan blue assay, and the proliferation capacity of cells studying growth curves. Both leukemia cell lines showed a concentration-specific increased cytotoxicity of the complex, compared to l-carnitine or copper chloride dihydrate, with distinct underlying mechanisms, which were decreased proliferation efficiency for HL-60 cells and increased necrotic phenomena for K562 cells. Our results are indicative of a concentration-specific enhanced antileukemic effect of the complex, implying its value as a tool in the implementation of leukemia.
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PMID:Enhanced concentration-dependent cytotoxic effect of the dinuclear copper(II) complex of L-carnitine [Cu2(L-carnitine)2Cl2(H2O)2]Cl2, compared to L-carnitine or copper chloride dihydrate, in human leukemic cell lines. 1852 42

Interactions of multivalent anionic porphyrins and their iron(III) complexes with cationic peptides, V3(Ba-L) and V3(IIIB), which correspond to those of the V3 loop regions of the gp120 envelope proteins of the HIV-1(Ba-L) and HIV-1(IIIB) strains, respectively, are studied by UV/Vis, circular dichroism, (1)H NMR, and EPR spectroscopy, a microcalorimetric titration method, and anti-HIV assays. Tetrakis(3,5-dicarboxylatophenyl)porphyrin (P1), tetrakis[4-(3,5-dicarboxylatophenylmethoxy)phenyl]porphyrin (P2), and their ferric complexes (Fe(III)P1 and Fe(III)P2) were used as the multivalent anionic porphyrins. P1 and Fe(III)P1 formed stable complexes with both V3 peptides (binding constant K>10(6) M(-1)) through combined electrostatic and van der Waals interactions. Coordination of the His residues in V3(Ba-L) to the iron center of Fe(III)P1 also played an important role in the complex stabilization. As P2 and Fe(III)P2 form self-aggregates in aqueous solution even at low concentrations, detailed analysis of their interactions with the V3 peptides could not be performed. To ascertain whether the results obtained in the model system are applicable to a real biological system, anti-HIV-1(BA-L) and HIV-1(IIIB) activity of the porphyrins is examined by multiple nuclear activation of a galactosidase indicator (MAGI) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. There is little correlation between chemical analysis and actual anti-HIV activity, and the size rather than the number of the anionic groups of the porphyrin is important for anti-HIV activity. All the porphyrins show high selectivity, low cytotoxicity, and high viral activity. Fe(III)P1 and Fe(III)P2 are used for the pharmacokinetic study. Half-lives of these iron porphyrins in serum of male Wistar rats are around 4 to 6 h owing to strong interaction of these porphyrins with serum albumin.
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PMID:Binding of multivalent anionic porphyrins to V3 loop fragments of an HIV-1 envelope and their antiviral activity. 2011 33


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