Estrutura, reatividade e propriedades biológicas de hidantoínas

Hydantoin (imidazolidine-2,4-dione) is a 2,4-diketotetrahydroimidazole discovered by Baeyer in 1861. Thiohydantoins and derivatives were prepared, having chemical properties similar to the corresponding carbonyl compounds. Some biological activities (antimicrobial, anticonvulsant, schistosomicidal) are attributed to the chemical reactivity and consequent affinity of hydantoinic rings towards biomacromolecules. Therefore, knowledge about the chemistry of hydantoins has increased enormously. In this review, we present important aspects such as reactivity of hydantoins, acidity of hydantoins, spectroscopy and cristallographic properties, and biological activities of hydantoin and its derivatives

2-Pyridyl thiazoles as novel anti-Trypanosoma cruzi agents: structural design, synthesis and pharmacological evaluation

The present work reports on the synthesis, anti-Trypanosoma cruzi activities and docking studies of a novel series of 2-(pyridin-2-yl)-1,3- thiazoles derived from 2-pyridine thiosemicarbazone. The majority of these compounds are potent cruzain inhibitors and showed excellent inhibition on the trypomastigote form of the parasite, and the resulting structure-activity relationships are discussed. Together, these data present a novel series of thiazolyl hydrazones with potential effects against Chagas disease and they could be important leads in continuing development against Chagas disease

Structural Insights Into Bioactive Thiazolidin-4-one: Experimental and Theoretical Data

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2016-04-14T17:53:03Z No. of bitstreams: 1 Cardoso MVO Structural insights....pdf: 373887 bytes, checksum: 3cbea7d50108fd1d0362e6ddbb01c83e (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2016-04-14T18:02:35Z (GMT) No. of bitstreams: 1 Cardoso MVO Structural insights....pdf: 373887 bytes, checksum: 3cbea7d50108fd1d0362e6ddbb01c83e (MD5)Made available in DSpace on 2016-04-14T18:02:35Z (GMT). No. of bitstreams: 1 Cardoso MVO Structural insights....pdf: 373887 bytes, checksum: 3cbea7d50108fd1d0362e6ddbb01c83e (MD5) Previous issue date: 2015Universidade Federal de Pernambuco. Centro de Ciências da Saúde. Departamento de Ciências Farmacêuticas. Recife, PE, BrasilUniversidade Federal de Pernambuco. Centro de Ciências da Saúde. Departamento de Ciências Farmacêuticas. Recife, PE, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilUniversidade Federal de Pernambuco. Centro de Ciências Exatas e da Natureza. Departamento de Química Fundamental. Recife, PE, BrasilUniversidade de São Paulo. Instituto de Física. Departamento de Física e Informática. São Carlos, SP, BrasilUniversidade Federal de Pernambuco. Centro de Ciências da Saúde. Departamento de Ciências Farmacêuticas. Recife, PE, BrasilAlthough viewed as promising drug candidates, few efforts have been addressed towards the structural chemistry of 2-hydrazonothiazolidin-4-ones. Therefore, 2-[(3-phenylsulfanylpropylidene)- hydrazono]thiazolidin-4-one (ATZ3) was synthesized and its crystal and molecular structure was studied by NMR and X-ray single crystal diffraction. The 1H NMR spectral data indicated that the hydrazone group assumes the Econfiguration, which was further confirmed by bi-dimensional NMR and crystallographic data. Despite agreement between most bond lengths and angleswith their expected values, the crystalline packing provided important information with regard to the double bond position involving the C-4 carbon. Quantum chemical calculations at Semiempirical, Density Functional Theory (DFT) and Ab Initio levels provided a good agreement between calculated and structural results provided by X-ray analysis. The system’s dimerization energies were also estimated. Statistical and Hierarchic Cluster Analysis (HCA) revealed interesting aspects of the calculations and pointed to the B3LYP as the most accurate in the determination of structure among the methods considered, in spite of some good results achieved by semiempirical schemes

Quercetin As An Inhibitor Of Snake Venom Secretory Phospholipase A2.

As polyphenolic compounds isolated from plants extracts, flavonoids have been applied to various pharmaceutical uses in recent decades due to their anti-inflammatory, cancer preventive, and cardiovascular protective activities. In this study, we evaluated the effects of the flavonoid quercetin on Crotalus durissus terrificus secretory phospholipase A2 (sPLA2), an important protein involved in the release of arachidonic acid from phospholipid membranes. The protein was chemically modified by treatment with quercetin, which resulted in modifications in the secondary structure as evidenced through circular dichroism. In addition, quercetin was able to inhibit the enzymatic activity and some pharmacological activities of sPLA2, including its antibacterial activity, its ability to induce platelet aggregation, and its myotoxicity by approximately 40%, but was not able to reduce the inflammatory and neurotoxic activities of sPLA2. These results suggest the existence of two pharmacological sites in the protein, one that is correlated with the enzymatic site and another that is distinct from it. We also performed molecular docking to better understand the possible interactions between quercetin and sPLA2. Our docking data showed the existence of hydrogen-bonded, polar interactions and hydrophobic interactions, suggesting that other flavonoids with similar structures could bind to sPLA2. Further research is warranted to investigate the potential use of flavonoids as sPLA2 inhibitors.1899-1

Development of a validated stability-indicating HPLC- DAD method for dasabuvir and the characterization of its degradation products using LC-QToF-MS/MS

A stability-indicating HPLC-DAD method was developed and validated for the simultaneous determination of dasabuvir and its degradation products in the pharmaceutical formulation. The proposed method utilized a Symmetry® C18 (4.6 x 75 mm, 3.5 µm) column, and the mobile phase consisted of an isocratic elution of formic acid (0.1%) and acetonitrile (55:45, v/v), at a flow of 1 mL min-1; analytes were detected at 244 nm. Dasabuvir was submitted to different stress degradation conditions, such as acidic, alkaline, neutral, thermal, oxidative and photolytic, and the structural elucidation of degradation products was performed using LC-QToF-MS/MS. The HPLC-DAD stability-indicating method was validated for selectivity, linearity, limit of detection and quantification, accuracy, precision and robustness, according to ICH guidelines. Dasabuvir produced two degradation products (DP1 and DP2) from the alkaline stress conditions, which were characterized in negative ion mode. Dasabuvir was linear in the range 9.78 to 136.92 µg mL-1, and DP and DP were linear in the range 2.9 to 20.2 µg mL-1 and 1.3 to 14.9 µg mL-1, respectively. The 1 2 recovery ranged between 99.16 and 100.86%, while precision ranged from 1.02 to 2.89%. As the method can effectively separate the dasabuvir from its degradation products and quantitate them, it may be employed as a stability-indicating method for the pharmaceutical formulation

A docking-based structural analysis of geldanamycin-derived inhibitor binding to human or Leishmania Hsp90

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2019-11-14T13:03:57Z No. of bitstreams: 1 Palma, L. C. A docking....pdf: 2316481 bytes, checksum: 4b22ab5fe091a63eb03467552d28b571 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-11-14T13:31:09Z (GMT) No. of bitstreams: 1 Palma, L. C. A docking....pdf: 2316481 bytes, checksum: 4b22ab5fe091a63eb03467552d28b571 (MD5)Made available in DSpace on 2019-11-14T13:31:09Z (GMT). No. of bitstreams: 1 Palma, L. C. A docking....pdf: 2316481 bytes, checksum: 4b22ab5fe091a63eb03467552d28b571 (MD5) Previous issue date: 2019-01-14Conselho Nacional de Pesquisa e Desenvolvimento Científico (P.S.T.V. – Universal 422867/2016-0 http://www.cnpq.br) and Fundação de Amparo a Ciência e Tecnologia do Estado de Pernambuco (LFGRF – BFP-0063-4.03/17). P.S.T.V. holds a grant from CNPq for productivity in research (307832/2015-5).Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório de Parasita Interação e Epidemiologia do Hospedeiro. Salvador, BA, Brasil.Federal University of Pernambuco. Department of Pharmaceutical Sciences. Recife, PE, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório de Parasita Interação e Epidemiologia do Hospedeiro. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório de Parasita Interação e Epidemiologia do Hospedeiro. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório de Parasita Interação e Epidemiologia do Hospedeiro. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório de Engenharia de Tecidos e Imunofarmacologia. Salvador, BA, Brasil.Federal University of Pernambuco. Department of Pharmaceutical Sciences. Recife, PE, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório de Parasita Interação e Epidemiologia do Hospedeiro. Salvador, BA, Brasil.Leishmaniasis is a neglected disease that affects millions of individuals around the world. Regardless of clinical form, treatment is based primarily on the use of pentavalent antimonials. However, such treatments are prolonged and present intense side effects, which lead to patient abandonment in many cases. The search for chemotherapeutic alternatives has become a priority. Heat Shock Protein 90 (Hsp90) inhibitors have recently come under investigation due to antiparasitic activity in Plasmodium sp., Trypanosoma sp. and Leishmania sp. Some of these inhibitors, such as geldanamycin and its analogs, 17-AAG and 17-DMAG, bind directly to Hsp90, thereby inhibiting its activity. Previous studies have demonstrated that different parasite species are more susceptible to some of these inhibitors than host cells. We hypothesized that this increased susceptibility may be due to differences in binding of Hsp90 inhibitors to Leishmania protein compared to host protein. Based on the results of the in silico approach used in the present study, we propose that geldanamycin, 17-AAG and 17-DMAG present an increased tendency to bind to the N-terminal domain of Leishmania amazonensis Hsp83 in comparison to human Hsp90. This could be partially explained by differences in intermolecular interactions between each of these inhibitors and Hsp83 or Hsp90. The present findings demonstrate potential for the use of these inhibitors in the context of anti-Leishmania therapy

Studies toward the structural optimization of novel thiazolylhydrazone-based potent antitrypanosomal agents

In previous studies, we identified promising anti-Trypanosoma cruzi cruzain inhibitors based on thiazolylhydrazones. To optimize this series, a number of medicinal chemistry directions were explored and new thiazolylhydrazones and thiosemicarbazones were thus synthesized. Potent cruzain inhibitors were identified, such as thiazolylhydrazones 3b and 3j, which exhibited IC(50) of 200-400 nM. Furthermore, molecular docking studies showed concordance with experimentally derived structure-activity relationships (SAR) data. In the course of this work, lead compounds exhibiting in vitro activity against both the epimastigote and trypomastigote forms of T. cruzi were identified and in vivo general toxicity analysis was subsequently performed. Novel SAR were documented, including the importance of the thiocarbonyl carbon attached to the thiazolyl ring and the direct comparison between thiosemicarbazones and thiazolylhydrazones. (C) 2010 Elsevier Ltd. All rights reserved.Pernambuco State Foundation for Science and Technology (FACEPE)[APQ-0123-4.03/08]Pernambuco State Foundation for Science and Technology (FACEPE)Brazilian National Council of Research (CNPq)[472880/2009-8]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPE

Synthesis, Cruzain docking, and in vitro studies of aryl-4-oxothiazolylhydrazones against Trypanosoma cruzi.

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2015-04-16T17:31:27Z No. of bitstreams: 1 Leite A C L Synthesis, docking....pdf: 610757 bytes, checksum: 9534d4781408434b33184616f3a5f517 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2015-04-16T18:10:59Z (GMT) No. of bitstreams: 1 Leite A C L Synthesis, docking....pdf: 610757 bytes, checksum: 9534d4781408434b33184616f3a5f517 (MD5)Made available in DSpace on 2015-04-16T18:10:59Z (GMT). No. of bitstreams: 1 Leite A C L Synthesis, docking....pdf: 610757 bytes, checksum: 9534d4781408434b33184616f3a5f517 (MD5) Previous issue date: 2007Universidade Federal de Pernambuco. Departamento de Ciências Farmacêuticas. Laboratório de Planejamento. Avaliação e Síntese de Fármacos. Recife, PE, BrasilUniversidade Federal de Pernambuco. Departamento de Ciências Farmacêuticas. Laboratório de Planejamento. Avaliação e Síntese de Fármacos. Recife, PE, BrasilUniversidade Federal de Pernambuco. Departamento de Ciências Farmacêuticas. Laboratório de Planejamento. Avaliação e Síntese de Fármacos. Recife, PE, BrasilUniversidade Federal de Pernambuco. Departamento de Ciências Farmacêuticas. Laboratório de Planejamento. Avaliação e Síntese de Fármacos. Recife, PE, BrasilUniversidade Federal de Pernambuco. Departamento de Ciências Farmacêuticas. Laboratório de Planejamento. Avaliação e Síntese de Fármacos. Recife, PE, BrasilUniversidade Federal de Pernambuco. Departamento de Ciências Farmacêuticas. Laboratório de Planejamento. Avaliação e Síntese de Fármacos. Recife, PE, BrasilUniversidade Federal de Pernambuco. Departamento de Ciências Farmacêuticas. Laboratório de Química Teórica Medicinal. Recife, PE, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilResearch in recent years has demonstrated that the Trypanosoma cruzi cysteine protease cruzain (TCC) is a valid chemotherapeutic target. Herein we describe a small library of aryl-4-oxothiazolylhydrazones that have been tested in assays against T. cruzi cell cultures. The docking studies carried out suggest that these compounds are potential ligands for the TCC enzyme. The most promising compound of this series, N-(4-oxo-5-ethyl-2'-thiazolin-2-yl)-N'-phenylthio-(Z)-ethylidenehydrazone (6 f), was shown to be very active at non-cytotoxic concentrations in in vitro assays with mammalian cells and has a potency comparable with reference drugs such as nifurtimox (Nfx) and benznidazole (Bdz)