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1
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Chelating ability of proctolin tetrazole analogue

100%
Łodyga-Chruścińska E., Sanna D., Micera G., Chruściński L., Olejnik J., Nachman R. J., Zabrocki J.
Acta Biochimica Polonica
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2006
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vol. 53
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issue 1
65-72
EN
The aim of the investigation was to establish the chelating ability of a new proctolin analogue of the sequence Arg-Tyr-LeuΨ[CN4]Ala-Thr towards copper(II) ions. The insertion of the tetrazole moiety into the peptide sequence has considerably changed the coordination ability of the ligand. Potentiometric and spectroscopic (UV-Vis, CD, EPR) results indicate that the incorporation of 1,5-disubstituted tetrazole ring favours the formation of a stable complex form of CuH-1L. This 4N coordination type complex is the dominant species in the physiological pH range. The tetrazole moiety provides one of these nitrogens. The data indicate that Cu(II) ions are strongly trapped inside the peptide backbone. These findings suggest that Cu(II) can hold peptide chains in a bent conformation. This bent conformation may be essential for bioactivity of the tetrazole peptides.
2
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Synthesis, spectral characterization, redox and antimicrobial activity of Schiff base transition metal(II) complexes derived from 4-aminoantipyrine and 3-salicylideneacetylacetone

88%
Raman N., Thangaraja C., Johnsonraja S.
Open Chemistry
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2005
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vol. 3
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issue 3
537-555
EN
A novel tetradentate N2O2 type Schiff base, synthesized from 1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one(4-aminoantipyrine) and 3-salicylidene-acetylacetone, forms stable complexes with transition metal ions such as CuII, NiII, CoII and ZnII in ethanol. Microanalytical data, magnetic susceptibility, IR, UV-Vis.,1H-NMR, ESR and Mass spectral techniques were used to confirm the structures. Electronic absorption spectra of the complexes suggest a square-planar geometry around the central metal ion. These complexes show higher conductance values, supporting their electrolytic nature. The monomeric nature of the complexes was confirmed from their magnetic susceptibility values. Cyclic voltammogram of the copper(II) and nickel(II) complexes in DMSO solution at 300 K were recorded and the results are discussed. The X-band ESR spectra of the copper complex were recorded and the molecular orbital coefficient values were calculated from the spectra. The in vitro antimicrobial activities of the investigated compounds were tested against bacteria such as Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis and Escherichia coli and fungi like Aspergillus niger and Rhizoctonia bataicola. Most of the metal chelates show higher antimicrobial activity for the above microorganisms than that of the free ligand.
3
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SELENO-L-METHIONINE MODULATE THE TOXIC EFFECT OF NEW DOXORUBICIN METAL COMPLEXES IN PROKARYOTIC MODEL –ESCHERICHIA COLI RFM443 RECA::LUX

88%
Matejczyk M., Świderski G., Lewandowski W.
Acta Poloniae Pharmaceutica - Drug Research
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2019
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vol. 76
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issue 1
115-125
EN
Abstract: The main problem of modern cancer therapy is their resistance to the drugs used and the toxicity of drugs to healthy cells of the human body. Hope is natural substances that are protective of cells and often support the action of standard anticancer chemotherapy. Among them are selenium compounds. In the present study, we examined the cytotoxic and genotoxic potency of doxorubicin (DOX) metal complexes as new anticancer drug candidates. We also measured the effect of simultaneous administration of seleno –L-methionine as biologically active agent with DOX and its complexes with Mn, Mg, Fe, Co and Ni in prokaryotic model - Escherichia coli RFM443 with plasmid transcriptional fusion of recA promoter and luxCDABE as a reporter gene. The results obtained by us, indicate high biological activity of metal complexes with doxorubicin. The strongest modulatory effect was observed using the DOX complexes with Co and Ni compared to the DOX. The DOX complexes with Mg, Mn and Fe also showed relatively high biological activity. Simultaneous bacteria culture treatment with SeMet decreased the values of the DOX and its metal complexes cyto- and genotoxic parameters. These results encourage further research to assess the value of the doxorubicin metal complexes as new cytostatic drug candidates. While SeMet may be considered as therapeutic option in cancer treatment as modulation agent in anti-cancer therapy.
4
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Voltammetric and potentiometric studies of some sulpha drug-Schiff base compounds and their metal complexes

75%
Ghoneim M., Mabrouk E., Hassanein A., El-Attar M., Hesham E.
Open Chemistry
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2007
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vol. 5
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issue 3
898-911
EN
The electrochemical behavior of some sulpha drug-Schiff bases at a mercury electrode was examined in the Britton-Robinson universal buffer of various pH values (2.5–11.7) containing 20% v/v) of ethanol using DC-polarography, cyclic voltammetry and controlled-potential electrolysis. The DC-polarograms and cyclic voltammograms of the examined compounds exhibited a single, 2-electron, irreversible, diffusion-controlled cathodic step within the entire pH range which is attributed to the reduction of the azomethine group-CH=N- to -CH2-NH-. The symmetry transfer coefficient (α) of the electrode reaction and the diffusion coefficient (D 0) of the reactant species were determined. The electrode reaction pathway of the compounds at the mercury electrode was suggested to follow the sequence: H+, e−, e−, H+. The dissociation constant of the sulpha drug-Schiff bases, the stability constant and stoichiometry of their complexes with various divalent transition metal ions (Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) were determined potentiometrically at room temperature. [...]
5
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The Formation of Polycomplexes of Poly(Methyl Vinyl Ether-Co-Maleic Anhydride) and Bovine Serum Albumin in the Presence of Copper Ions

75%
Karahan M., Mustafaeva Z., Özeroğlu C.
Polish Journal of Chemical Technology
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2014
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vol. 16
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issue 3
97-105
EN
The binary and ternary complex formations of poly(methyl vinyl ether-co-maleic anhydride) (PMVEMA) with copper ions and with bovine serum albumin (BSA) in the presence of copper ions in phosphate buffer solution at pH = 7 were examined by the techniques of UV-visible, fluorescence, dynamic light scattering, atomic force microscopy measurements. In the formation of binary complexes of PMVEMA-Cu(II), the addition of copper ions to the solution of PMVEMA in phosphate buffer solution at pH = 7 forms homogeneous solutions when the molar ratio of Cu(II)/MVEMA is 0.5. Then the formations of ternary complexes of PMVEMA-Cu(II)-BSA were examined. Study analysis revealed that the toxicities of polymer-metal and polymer-metal-protein mixture solutions depend on the nature and ratio of components in mixtures.
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