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Search Results: 1 - 10 of 20733 matches for " Leoberto Costa;Abdalla "
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Avalia??o das concentra??es plasmática e urinária de isoflavonas purificadas de soja
Pereira, Isabela Rosier Olimpio;Damasceno, Nágila Raquel Teixeira;Pereira, Edimar Cristiano;Tavares, Leoberto Costa;Abdalla, Dulcineia Saes Parra;
Revista Brasileira de Ciências Farmacêuticas , 2002, DOI: 10.1590/S1516-93322002000300005
Abstract: soy isoflavones show antioxidant and estrogenic effects and have been related to decreased risk of cancer and cardiovascular diseases. the goal of the present study was to standardize the extraction of isoflavones from soy molasses and to evaluate the plasmatic and urinary concentrations of isoflavones in rabbits after consumption of extracted isoflavones. isoflavones were extracted with 90% ethanol and purified with a c18 column. the extraction yield was 81%. the purified isoflavone extract was added to the chow (5 mg isoflavone/ kg body weight/ day) used for feeding rabbits during 6 months. the concentration of isoflavones (genistein and daidzein) in the extracts, chow, blood plasma and urine was determined by high performance liquid chromotagraphy. the mean concentration of isoflavones in blood plasma was 4 mm and the urinary excretion was 22 μmol/24 h. the extraction of isoflavones from soy molasses resulted in a suitable preparation for experimental studies.
QSAR: a abordagem de Hansch
Tavares, Leoberto Costa;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000400018
Abstract: the hansch analysis, also known by qsar-2d, is an extremely effective tool in the identification and/or improvement of the pharmacological or toxicological profile of xenobiotics. this article presents the theme didactically and with enough detail to clarify the conceptual basis of hansch analysis. besides, it shows the application of the technique in measuring the influence of physicochemical properties on the biological activity of compounds with pharmacological interest.
QSAR: a abordagem de Hansch
Tavares Leoberto Costa
Química Nova , 2004,
Abstract: The Hansch Analysis, also known by QSAR-2D, is an extremely effective tool in the identification and/or improvement of the pharmacological or toxicological profile of xenobiotics. This article presents the theme didactically and with enough detail to clarify the conceptual basis of Hansch Analysis. Besides, it shows the application of the technique in measuring the influence of physicochemical properties on the biological activity of compounds with pharmacological interest.
Origens e trajetórias da indústria farmacêutica no Brasil
Leoberto Costa Tavares
Revista Brasileira de Ciências Farmacêuticas , 2008, DOI: 10.1590/s1516-93322008000100020
Abstract:
Aplica??o de estudos de QSAR-2D em derivados 5-nitro-2-tiofilidênicos com atividade antimicrobiana frente a Staphylococcus aureus multi-resistente (MRSA)
Masunari, Andrea;Tavares, Leoberto Costa;
Revista Brasileira de Ciências Farmacêuticas , 2006, DOI: 10.1590/S1516-93322006000200005
Abstract: with the constant advance of qsar (quantitative structure-activity relationships) studies as molecular modification methodology, a frequent application of this procedure in many science areas was observed. besides, the rational ligand development for many diseases has been growing in recent years. thus, in order to ally these medicinal chemistry advances with the necessity to combat the high incidence of antibiotic-resistant microorganisms, the purpose of this study was the 2d-qsar study of p-substituted 5-nitro-2-thiophylidene derivatives with antimicrobial activity against staphylococcus aureus, considering hydrophobicity range experimentally determined. the statistical significant correlations obtained by hansch/fujita analysis showed significant influence of hydrophobicity on antimicrobial activity, prove by reasoning the potential of synthesized compounds as a good alternative to the rational development, on molecular level, of selective drugs used to the treatment of infections caused by staphylococcus aureus multidrug-resistant strains.
Valida??o de ?C=O como descritor estrutural de caráter eletr?nico para aplica??o em estudos de QSAR/QSPR
Furlanetto, Marcos;Tavares, Leoberto Costa;
Revista Brasileira de Ciências Farmacêuticas , 2003, DOI: 10.1590/S1516-93322003000400013
Abstract: with the aim of validanting the use of carbonyl group absorption frequency, ?c=o, at the ir as electronic descriptor for application in qsar/qspr studies, this paper correlates quantitatively the chemical structure of the benzhydrazides para-substituted with the electronic effect of its substituents. the validation has been achieved with application of the hammett equation adapted to the ir absorption frequency using the billin program, 98 version. it has been used the hammett substituents constants, ?p, ?i, ?r and the swain and lupton constants, n, o, observing an excellent correlation with ?c=o and ?p, also allowing, on the set of compounds analysed, quantify individually the inductive and resonance effects influence on the polarity of carbonyl group.
Estudos de QSAR-3D em derivados 5-nitro-2-tiofilidênicos com atividade frente a Staphylococcus aureus multi-resistente
Masunari, Andrea;Tavares, Leoberto Costa;
Revista Brasileira de Ciências Farmacêuticas , 2007, DOI: 10.1590/S1516-93322007000200015
Abstract: studies in three-dimensional molecular fields generally contain a large amount of data, some of which are redundant or not relevant. the program volsurf, a quite fast method, is able to compress the relevant information present in 3d molecular structures into a few easy bidimensional descriptors. this study correlates the antimicrobial activity of eighteen 5-nitro-2-thiophylidene derivatives against multidrug-resistant staphylococcus aureus with three-dimensional molecular fields of these ligands. for molecular structures sketching and 3d conversion, sybyl and corina programs were used, respectively. the grid force field was applied to generate the 3d interaction energies. the volsurf characterization results on significant statistic model with 48 descriptors (r2 = 0,93, q2= 0,87), observing a significant influence of hydrophobic properties on antimicrobial activity performance.
Síntese e determina??o da atividade antimicrobiana de derivados 5-nitro-2-tiofilidênicos frente a Staphylococcus aureus multi-resistente
Masunari, Andrea;Tavares, Leoberto Costa;
Revista Brasileira de Ciências Farmacêuticas , 2006, DOI: 10.1590/S1516-93322006000300016
Abstract: infection diseases caused by methicillin-resistant staphylococcus aureus have been an increasing problem worldwide presenting significant morbidity and mortality rates. thus, fourteen benzoic acid [(5-nitro-thiophen-2-yl)-methylene]-hydrazides were designed, synthesized and tested against standard (atcc 25923) and multidrug-resistant strains of staphylococcus aureus. all compounds exhibited significant bacteriostatic activity and, in such cases, also bactericidal activity, especially the p-coch3 derivative with mic = 0.14 mg/ml. the results have demonstrated the potential of synthesized compounds as alternative to the development of selective antimicrobial agents.
Aspectos mecanísticos da bioatividade e toxicidade de nitrocompostos
Paulai, Fávero Reisdorfer;Serrano, Silvia Helena Pires;Tavares, Leoberto Costa;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000400032
Abstract: nitrocompounds are bioactive molecules used as antibacterial, antiparasitic and antitumoral agents. in the past of years, these molecules have been broadly studied in several fields, such as medicinal chemistry, organic chemistry, biochemical, toxicology and electrochemistry. the nitrocompounds mode of action involves the biotransformation of the nitro group, releasing intermediates in the redox process. some of those intermediates attack enzymes, membranes and dna, providing the basis for their biological activity and adverse effects. in this report, some aspects regarding the biological activity, mechanism of action and toxicity of nitrocompounds are explored, purposing the research of new bioactive derivatives having low toxicity.
Micellar solubilization of ibuprofen: influence of surfactant head groups on the extent of solubilization
Rangel-Yagui, Carlota O.;Hsu, Helen Wei Ling;Pessoa-Jr, Adalberto;Tavares, Leoberto Costa;
Revista Brasileira de Ciências Farmacêuticas , 2005, DOI: 10.1590/S1516-93322005000200012
Abstract: an important property of micelles with particular significance in pharmacy is their ability to increase the solubility of poorly soluble drugs in water, thus increasing their bioavailability. in this work, the solubilization of ibuprofen (ibu) was studied in micellar solutions of three surfactants possessing the same hydrocarbon tail but different hydrophilic head groups, namely sodium dodecyl sulphate (sds), dodecyltrimethylammonium bromide (dtab), and n-dodecyl octa(ethylene oxide) (c12eo8). the results showed that, irrespective of the surfactant type, the solubility of ibu increased linearly with increasing surfactant concentration, as a consequence of the association between the drug and the micelles. the 80 mm dtab and the 80 mm c12eo8 micellar solutions resulted in a 16-fold increase in solubility of ibu when compared to the buffer solution, whereas the 80 mm sds micellar solution resulted in a 5.5-fold increase in ibu solubility. the highest value of molar solubilization capacity (c) was obtained with dtab, c = 0.97, followed by c12eo8 ,c = 0.72, and finally sds, c = 0.23. however, due to the stronger tendency of the nonionic surfactant in forming micelles in solution, at the same surfactant concentration, we obtained the same solubility of ibu in both dtab and c12eo8.
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