Presidencia Roque Sáenz Peña, Argentina
Presidencia Roque Sáenz Peña, Argentina
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Islas M.S.,National University of La Plata | Martinez Medina J.J.,UNCAUS | Lopez Tevez L.L.,UNCAUS | Rojo T.,University of the Basque Country | And 9 more authors.
Inorganic Chemistry | Year: 2014

A new Cu(II) complex with the antihypertensive drug telmisartan, [Cu 8Tlm16]·24H2O (CuTlm), was synthesized and characterized by elemental analysis and electronic, FTIR, Raman and electron paramagnetic resonance spectroscopy. The crystal structure (at 120 K) was solved by X-ray diffraction methods. The octanuclear complex is a hydrate of but otherwise isostructural to the previously reported [Cu8Tlm 16] complex. [Cu8Tlm16]·24H2O crystallizes in the tetragonal P4/ncc space group with a = b = 47.335(1), c = 30.894(3) Å, Z = 4 molecules per unit cell giving a macrocyclic ring with a double helical structure. The Cu(II) ions are in a distorted bipyramidal environment with a somewhat twisted square basis, cis-coordinated at their core N2O2 basis to two carboxylate oxygen and two terminal benzimidazole nitrogen atoms. Cu8Tlm16 has a toroidal-like shape with a hydrophobic nanometer hole, and their crystal packing defines nanochannels that extend along the crystal c-axis. Several biological activities of the complex and the parent ligand were examined in vitro. The antioxidant measurements indicate that the complex behaves as a superoxide dismutase mimic with improved superoxide scavenger power as compared with native sartan. The capacity of telmisartan and its copper complex to expand human mesangial cells (previously contracted by angiotensin II treatment) is similar to each other. The antihypertensive effect of the compounds is attributed to the strongest binding affinity to angiotensin II type 1 receptor and not to the antioxidant effects. The cytotoxic activity of the complex and that of its components was determined against lung cancer cell line A549 and three prostate cancer cell lines (LNCaP, PC-3, and DU 145). The complex displays some inhibitory effect on the A549 line and a high viability decrease on the LNCaP (androgen-sensitive) line. From flow cytometric analysis, an apoptotic mechanism was established for the latter cell line. Telmisartan and CuTlm show antibacterial and antifungal activities in various strains, and CuTlm displays improved activity against the Staphylococcus aureus strain as compared with unbounded copper(II). © 2014 American Chemical Society.

Urquiza N.M.,Institute Quimica Analitica | Islas M.S.,CONICET | Dittler M.L.,CONICET | Moyano M.A.,Institute Quimica Analitica | And 8 more authors.
Inorganica Chimica Acta | Year: 2013

Methimazole (MeimzH), a sulfur containing compound, is an antithyroid drug commonly used to treat Graves' disease acting as an inhibitor of the enzyme thyroid peroxidase. A new ternary [Cu(MeimzH)2 (phen)(H 2O)2]Cl2 (Cu-Met-phen) complex of this drug containing also phenanthroline as a second ligand (phen) was synthesized and characterized by elemental analysis, dissolution behavior, thermogravimetric analysis, UV-Vis, diffuse reflectance, FTIR and EPR spectroscopies. As it is previously reported, the binary [Cu(MeimzH)2(H2O) 2](NO3)2·H2O (Cu-Met) complex can act as an inhibitor of alkaline phosphatase (ALP). In this work, the inhibitory effect of methimazole, phenanthroline, [Cu(phen)2Cl]Cl (Cu-phen) and the new ternary complex has also been investigated and compared with Cu-Met together with in vitro tests of susceptibility against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis bacteria. To our knowledge, the antibacterial activity of methimazole is determined for the first time. For the ternary complex, the results show that the coordination of the drug increased its antibacterial effect especially against E. faecalis demonstrating a strong effect against S. aureus and S. epidermidis. The assays also indicate that in same strains the new complex show better activity than their ligands. The ability for the inhibition of alkaline phosphatase (ALP) was lower than that of the binary complex (Cu-Met) probably due to the absence of labile ligands around the metal center. Moreover, the antioxidant activity of the complexes decreases as follows: Cu-Met > Cu-Phen > Cu-Met-Phen. © 2013 Elsevier B.V. All rights reserved.

Tevez L.L.L.,UNCAUS | Islas M.S.,National University of La Plata | Medina J.J.M.,UNCAUS | Diez M.,UNCAUS | And 4 more authors.
Journal of Coordination Chemistry | Year: 2012

An octahedral Zn complex with o-phenanthroline (o-phen) and cyanoguanidine (cnge) has been synthesized and characterized. The crystal structural data show the formation of a ZnN 5O core where the metal coordinates to two mutually perpendicular o-phenanthrolines as bidentate ligands [Zn-N bond lengths in the 2.124(2)-2.193(2) Å range], the cyanide nitrogen of a cnge [d(Zn-N) = 2.092(2)A, ∠(Zn-N-C) = 161.1(2)°], and a water molecule [d(Zn-Ow) = 2.112(2) Å]. Spectral data (FT-IR, Raman, and fluorescence) and speciation studies are in agreement with the structure found in the solid state and the one proposed to exist in the solution. To evaluate the changes in the microbiological activity of Zn, antibacterial studies were carried out by observing the changes in minimum inhibitory concentration of the complex, the ligands, and the metal against five different bacterial strains. The antibacterial activity of Zn improved upon complexation in three of the tested strains. © 2012 Taylor & Francis.

Lopez Tevez L.L.,UNCAUS | Martinez Medina J.J.,UNCAUS | Islas M.S.,National University of La Plata | Piro O.E.,CONICET | And 4 more authors.
Journal of Coordination Chemistry | Year: 2011

A new coordination complex, aqua bis(o-phenanthroline) cadmium(II) sulfate cyanoguanidine pentahydrate, [Cd(o-phen)2(SO4)(H 2O)](cnge) 5H2O, was synthesized and characterized. The crystal structure was solved by X-ray diffraction methods. It crystallizes in the monoclinic space group P2x/n with a= 13.7650(2) Å, b = 10.2796(2) Å, c = 21.4418(3) Å, (β = 90.106(2)°, and Z = 4 molecules per cell unit. The cadmium(II) is in a distorted octahedral environment coordinated to two nearly planar and mutually perpendicular o-phenanthrolines, one oxygen atom of sulfate, and a water molecule. Non-bonded and planar cyanoguanidine and five crystallization water molecules complete the asymmetric unit. Vibrational (FT-IR and FTRaman) spectroscopies and thermogravimetric determinations support this structure. Intensity enhancement of the fluorescence spectrum may be a demonstration of the interaction of the metal with phenanthroline. In solution the coordination behavior is rather different, and the speciation studies point to coordination of both enge and phenanthroline to cadmium. The improvement of the antibacterial activity of cadmium upon complexation has been determined. © 2011 Taylor and Francis.

Buchhamer E.E.,UNCAus | Gimenez M.C.,UNCAus | Navoni J.A.,Catedra de Toxicologia Y Quimica Legal | Villaamil Lepori E.C.,Catedra de Toxicologia Y Quimica Legal
One Century of the Discovery of Arsenicosis in Latin America (1914-2014): As 2014 - Proceedings of the 5th International Congress on Arsenic in the Environment | Year: 2014

The aim of this study was to compare different enzymatic hydrolysis procedures for the extraction and determination of total arsenic in cooked foods by FI-HG-AAS. According to the characteristics of the studied food (rice stew, vegetables and meat cooked with water with arsenic concentration of 220 mg/L), two enzymes (cellulase and pancreatin) were selected and combined with two processes of agitation (thermostatic bath/ultrasound). The reliability of the procedures was tested with certified reference material (Brown rice SYTED105PI0272) and the results were compared with the conventional method for extracting total arsenic Dry Ashing. The recoveries obtained were as follows: 101% for the circulator-pancreatin, 104% for thermostatic bath-cellulase, 99% for ultrasound-cellulase and 85% for ultrasound-pancreatin. The mean comparison test T (p < 0.05) showed that the values of total arsenic extracted in the first three procedures were similar, with very good yields, being different and less ultra-sound-pancreatin combination. © 2014 Taylor & Francis Group.

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