Laboratorio Of Quimica Organica

Montevideo, Uruguay

Laboratorio Of Quimica Organica

Montevideo, Uruguay

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Giglio J.,Catedra de Radioquimica | Fernandez S.,Catedra de Radioquimica | Pietzsch H.-J.,Helmholtz Center Dresden | Dematteis S.,Catedra de Inmunologia | And 3 more authors.
Nuclear Medicine and Biology | Year: 2012

The evaluation of oxygenation status of solid tumors is an important field of radiopharmaceutical research. With the aim to develop new potential 99mTc-radiopharmaceuticals for imaging hypoxia, we have synthesized two novel isocyanide derivatives of metronidazole, which has demonstrated high affinity for hypoxic tumors in vitro and in vivo. Methods: Metronidazole derivatives 4-isocyano-N-[2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl]butanamide (M1) and 1-(4-isocyanobutanoyl)-4-[2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl]piperazine (M2) were synthesized, and labeling was performed through preparation of their corresponding 99mTc-(4+1) complexes, 99mTc-NS3M1 and 99mTc-NS3M2. The structure of the technetium complexes was corroborated by preparation and characterization of the corresponding rhenium complexes. We have studied the main physicochemical properties (stability, lipophilicity and plasma protein binding). Biological behavior in HCT-15 cells both in oxia and in hypoxia was assessed. Biodistribution in normal mice and in animals bearing induced 3LL Lewis murine lung carcinoma was also studied. Results: Metronidazole derivatives were successfully synthesized. Labeling with high radiochemical purity was achieved for both ligands. 99mTc complexes were stable in labeling milieu and human plasma. However, presence of the piperazine linker in M2 resulted in higher lipophilicity and protein binding. Although cell uptake in hypoxic conditions was observed for both radiotracers, 99mTc-NS3M2 biodistribution was considered unsuitable for a potential radiopharmaceutical due to high liver uptake and poor blood clearance. However, 99mTc-NS3M1 demonstrated a very favorable in vivo profile both in normal mice and in mice bearing induced tumors. Conclusion: Selective uptake and retention in tumor together with favorable tumor/muscle ratio make 99mTc-NS3M1 a promising candidate for further evaluation as potential hypoxia imaging agent in tumors. © 2012 Elsevier Inc..


Alvarez G.,Laboratorio Of Quimica Organica | Varela J.,Laboratorio Of Quimica Organica | Cruces E.,Laboratorio Of Quimica Organica | Fernandez M.,University of the Republic of Uruguay | And 6 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2015

Although the parasitic infection Chagas' disease was described over 100 years ago, even now there are not suitable drugs. The available drugs nifurtimox and benznidazole have limited efficacies and tolerances, with proven mutagenic effects. Attempting to find appropriate drugs to deal with this problem, here we report on the development and pharmacological characterization of new amide-containing thiazoles. In the present study, we evaluated the in vitro and in vivo effects of new candidates against Trypanosoma cruzi, the etiological agent of Chagas' disease. The lead amide-containing thiazole derivative had potent in vitro activity, an absence of both in vitro mutagenic and in vivo clastogenic effects, and excellent in vitro selectivity and in vivo tolerance. The compound suppressed parasitemia in mice, modifying the anti-T. cruzi antibodies like the reference drug, benznidazole, and displayed the lowest mortality among the tested drugs. The present evidence suggests that this compound is a promising anti-T. cruzi agent surpassing the lead optimization stage in drug development and leading to a candidate for preclinical study. © 2015, American Society for Microbiology.


Cabrera M.,Laboratorio Of Quimica Organica | Lavaggi M.L.,Laboratorio Of Quimica Organica | Croce F.,Laboratorio Of Quimica Organica | Celano L.,Laboratorio Of Enzimologia | And 9 more authors.
Bioorganic and Medicinal Chemistry | Year: 2010

Cancer preventive agents (CPA) are drugs able to suppress the carcinogen metabolic activation or block the formation of ultimate carcinogens. CPA could act through various molecular mechanisms, for example by interfering with the action of procarcinogen. This could be attained by increasing the phase II enzymes levels of quinone reductase (QR) and glutathione S-transferase (GST). New flavonoids, especially chalcones, have been identified as in vivo monofunctional phase II enzymes inducers. Oral administration of chalcone, 4, and both p-methoxy-substituted chalcones, 6 and 14, increased hepatic QR activity with concomitant decrease in CYP1A1 activity, a member of the most important group of phase I enzymes cytochrome P450. Among them, 4 also increased GST activity. While p-bromo-substituted chalcone 8 was the best inducer of QR it decreased hepatic GST expression and cytochrome P450, being the most effective decreasing cytochrome P450-expression. Thienyl-chalcone 20 being the bioisostere of chalcone 4 did not display the same in vivo profile in the phase I level modification. As chalcone 4 its bioisostere, chalcone 20, displayed low DNA strand breakage and absence of mutagenicity. Also, in our preliminary in vivo tumourigenesis/chemopreventive and acute-toxicity studies, chalcones 4, 6 and 8 showed the best behaviours as CPA justifying additional studies that are ongoing. © 2010 Elsevier Ltd. All rights reserved.


Neto B.A.D.,University of Brasilia | Carvalho P.H.P.R.,University of Brasilia | Santos D.C.B.D.,University of Brasilia | Gatto C.C.,University of Brasilia | And 7 more authors.
RSC Advances | Year: 2012

The present manuscript describes the synthesis of two novel 2,1,3-benzothiadiazole (BTD) derivatives containing an excited state intramolecular proton transfer (ESIPT) site. Photophysical properties, X-ray analysis, ESIPT and intramolecular charge-transfer (ICT) of these novel fluorescent monosubstituted BTD derivatives were investigated. It is also shown that ESIPT and ICT can take place concomitantly. Theoretical calculations (ab initio and DFT) corroborate the high stability of these derivatives in the excited state due to efficient ESIPT and ICT processes. Also, the optimized calculated geometries of these new structures allowed a better understanding of the different behaviour of the dyes in a wide pH range (1-13). Finally, the new compounds exhibit impressive cellular selectivity and stain only mitochondria in different cell lines and are far better than the commercially available MitoTracker-red. © 2012 The Royal Society of Chemistry.


Hernandez P.,Laboratorio Of Quimica Organica | Rojas R.,Cayetano Heredia Peruvian University | Gilman R.H.,Cayetano Heredia Peruvian University | Sauvain M.,Toulouse 1 University Capitole | And 4 more authors.
European Journal of Medicinal Chemistry | Year: 2013

Neglected diseases represent a major health problem. It is estimated that one third of the world population is infected with tuberculosis and additionally Leishmaniosis and Chagas disease affect approximately 30 million people. N-Acylhydrazone moiety is a repeated functional group present in several prototypes and drug candidates for these neglected diseases. On the other hand, furoxan system has been studied as pharmacophore for Leishmaniosis and Chagas diseases. Here we report on the design and preparation of forty hybrid furoxanyl N-acylhydrazones and on their activity on Mycobacterium tuberculosis, H37Rv and MDR strains, Trypanosoma cruzi, and Leishmania amazonensis. Among them, four derivatives displayed excellent to good selectivity indexes against the three different microorganisms. Hybrid compound N′-(4-phenyl-3- furoxanylmethylidene)isoniazide 9 showed the best antibacterial profile with MIC value 4.5 lesser than the value for the reference isoniazid against MDR strain. Furoxanyl N-acylhydrazone (E)-2-methyl-N′-(4-phenyl-3- furoxanylmethylidene)-4H-imidazo[1,2-a]pyridine-3-carbohydrazide 15 was ten-fold more potent against T. cruzi Amastigotes than the standard drug nifurtimox. On the other hand, derivatives (E)-N′-(5-benzofuroxanylmethylidene)benzo[d] [1,3]dioxole-5-carbohydrazide 25 and (E)-N′-(4-hydroxy-3- methoxyphenylmethylidene)-3-methylfuroxan-4-carbohydrazide 37 emerged as leads for the development of new leishmanicidal agents. The adequate stability, in simulated biological system and plasma, and the lack of mutagenicity of these derivatives allow us to propose them as candidates for further pre-clinical studies.© 2012 Elsevier Masson SAS. All rights reserved.


Hernandez P.,Laboratorio Of Quimica Organica | Cabrera M.,Laboratorio Of Quimica Organica | Lavaggi M.L.,Laboratorio Of Quimica Organica | Celano L.,University of the Republic of Uruguay | And 9 more authors.
Bioorganic and Medicinal Chemistry | Year: 2012

We report the design, the synthesis and the biological evaluation of the analgesic and anti-inflammatory activities of furoxanyl N-acylhydrazones (furoxanyl-NAH) by applying molecular hybridization approach. Hybrid compounds with IL-8-release inhibition capabilities were identified. Among them, furoxanyl-NAH, 17, and benzofuroxanyl-derivative, 24, together with furoxanyl-NAH derivative, 31, without IL-8 inhibition displayed both orally analgesic and anti-inflammatory activities. These hybrid derivatives do not have additional LOX- or COX-inhibition activities. For instance, LOX-inhibition by furoxanyl-NAH derivative, 42, emerged as a structural lead to develop new inhibitors. The lack of mutagenicity of the active derivatives 17, 31, and 42, allow us to propose them as candidates for further clinical studies. These results confirmed the success in the exploitation of hybridization strategy for identification of novel N-acylhydrazones (NAH) with optimized activities. © 2011 Elsevier Ltd. All rights reserved.


Barriga G.,University of Chile | Olea-Azar C.,University of Chile | Norambuena E.,Metropolitan University of Educational Sciences | Castro A.,Institute Quimica Medica | And 4 more authors.
Bioorganic and Medicinal Chemistry | Year: 2010

A new series of heteroaryl nitrones, 1-7, bearing furoxanyl and thiadiazolyl moieties, were evaluated for their free radical-trapping properties. The physicochemical characterization by electron paramagnetic resonance (EPR) demonstrated its capability to trap and stabilize oxygen-, carbon-, sulfur-, and nitrogen-centered free radicals. The 4-furoxanyl nitrone 3 (FxBN), α(Z)-(3-methylfuroxan-4-yl)-N-tert-butylnitrone, showed appropriate solubility in aqueous solution and taking into account that this physicochemical property is very important for biological applications, we studied it deeply in terms of its trapping and kinetic behaviors. For this, kinetic studies of the hydroxyl adduct decay gave rate constants kST of 1.22 × 1010 dm3 mol-1 s-1 and half-live up to 7200 s at physiological pH, without any artifactual signals. The ability of FxBN to directly traps and stabilizes superoxide free radical, with a half-life of 1620 s at physiological pH, was also demonstrated. Besides, FxBN-hydroxyl and -superoxide adducts exhibited distinct and characteristic EPR spectral patterns. Finally, we confirmed the ability of FxBN to act as spin trap in a specific biological system, that is, in the free radical production of experimental anti-trypanosomatid drugs using Trypanosoma cruzi microsomes as biological system. Moreover, previous observations of low FxBN toxicity transform it in a good candidate for in vivo spin trapping. Crown Copyright © 2009.


Pizzo C.,University of the Republic of Uruguay | Saiz C.,University of the Republic of Uruguay | Talevi A.,National University of La Plata | Gavernet L.,National University of La Plata | And 8 more authors.
Chemical Biology and Drug Design | Year: 2011

A series of 18 novel 2-hydrazolyl-4-thiazolidinones-5-carboxylic acids, amides and 5,6-α,β-unsaturated esters were synthesized, and their in vitro activity on cruzipain and T. cruzi epimastigotes was determined. Some agents show activity at 37μm concentration in the enzyme assay. Computational tools and docking were used to correlate the biological response with the physicochemical parameters of the compounds and their cruzipain inhibitory effects. © 2011 John Wiley & Sons A/S.


PubMed | Laboratorio Of Quimica Organica
Type: Journal Article | Journal: Bioorganic & medicinal chemistry | Year: 2012

We report the design, the synthesis and the biological evaluation of the analgesic and anti-inflammatory activities of furoxanyl N-acylhydrazones (furoxanyl-NAH) by applying molecular hybridization approach. Hybrid compounds with IL-8-release inhibition capabilities were identified. Among them, furoxanyl-NAH, 17, and benzofuroxanyl-derivative, 24, together with furoxanyl-NAH derivative, 31, without IL-8 inhibition displayed both orally analgesic and anti-inflammatory activities. These hybrid derivatives do not have additional LOX- or COX-inhibition activities. For instance, LOX-inhibition by furoxanyl-NAH derivative, 42, emerged as a structural lead to develop new inhibitors. The lack of mutagenicity of the active derivatives 17, 31, and 42, allow us to propose them as candidates for further clinical studies. These results confirmed the success in the exploitation of hybridization strategy for identification of novel N-acylhydrazones (NAH) with optimized activities.


PubMed | Laboratorio Of Quimica Organica
Type: Journal Article | Journal: Bioorganic & medicinal chemistry | Year: 2010

Cancer preventive agents (CPA) are drugs able to suppress the carcinogen metabolic activation or block the formation of ultimate carcinogens. CPA could act through various molecular mechanisms, for example by interfering with the action of procarcinogen. This could be attained by increasing the phase II enzymes levels of quinone reductase (QR) and glutathione S-transferase (GST). New flavonoids, especially chalcones, have been identified as in vivo monofunctional phase II enzymes inducers. Oral administration of chalcone, 4, and both p-methoxy-substituted chalcones, 6 and 14, increased hepatic QR activity with concomitant decrease in CYP1A1 activity, a member of the most important group of phase I enzymes cytochrome P450. Among them, 4 also increased GST activity. While p-bromo-substituted chalcone 8 was the best inducer of QR it decreased hepatic GST expression and cytochrome P450, being the most effective decreasing cytochrome P450-expression. Thienyl-chalcone 20 being the bioisostere of chalcone 4 did not display the same in vivo profile in the phase I level modification. As chalcone 4 its bioisostere, chalcone 20, displayed low DNA strand breakage and absence of mutagenicity. Also, in our preliminary in vivo tumourigenesis/chemopreventive and acute-toxicity studies, chalcones 4, 6 and 8 showed the best behaviours as CPA justifying additional studies that are ongoing.

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