DEFAR - Artigos publicados em periódicos

URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531

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Agora exibindo 1 - 10 de 139
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    Synthesis of 4-octyl-2H-1,4-benzo-thiazin-3-ones.
    (2003) Guarda, Vera Lúcia de Miranda; Perrissin, Monique; Thomasson, François; Ximenes, Eulália Camelo Pessoa de Azevedo; Galdino, Suely Lins; Pitta, Ivan da Rocha; Luu-Duc, Cuong; Barbe, Jacques
    Synthesis, physical and analytical properties of 6-alkylacylamino-4-octyl-2H-1,4-benzo-thiazin-3-ones derivatives are described. These new compounds were prepared by acylation and/or alkylation of the amino group under phase transfer catalysis conditions. Acid hydrolysis of the alkylacylamino-2H-1,4-benzo-thiazin-3-ones afforded N-alkylamino-benzothiazin-3-ones. Some of these compounds were evaluated in vitro for possible bacteriostatic activity.
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    Interactions between a macrophage cell line (J774A1) and surface-modified poly(D, L-lactide) nanocapsules bearing poly(ethylene glycol).
    (1999) Mosqueira, Vanessa Carla Furtado; Legrand, Philippe; Gref, Ruxandra; Heurtault, Béatrice; Appel, M.; Barratt, Gillian
    The interactions of naked and surface-modified poly(D,L-lactic acid) (PLA) nanocapsules (NC), where polyethyleneglycol (PEG) was adsorbed or covalently attached, have been studied with a macrophage-like cell line. The fluorescent oil marker, DiD, was successfully encapsulated in NCs in order to follow their interactions with cells. The cell-associated fluorescence obtained with PEG-PLA NC was about 3- to 13-fold lower than that obtained with naked-PLA NC. The effects of PEG chain length, its content as a percentage of total polymer and NC concentration in the culture medium were evaluated. PEG-PLA NC showed dramatically reduced fluorescence association with cells during an 18 h incubation compared with naked-PLA NC, showing that covalent attachment of PEG is important for the persistence of low uptake. The best results in reducing cell-associated fluorescence were obtained with a surface-modified PEG-PLA NC bearing a chain with 20000 MW. Increasing the percentage of PEG produced a reduction in marker association for a given PEG chain length. Moreover, when the PEG-containing poloxamer was simply adsorbed, marker association was dependent on the extent of dilution and the type of serum in the culture medium. Serum proteins, especially immunoglobulins, increased cell-associated fluorescence for PEG-adsorbed NC, but had very little effect on PEG-PLA NC. Marker association was only partially inhibited in the presence of cytochalasin B. The mechanisms of cell-NC interaction depended on the characteristics of the NC surface in each formulation. When the NC was physically separated from cells no diffusion of fluorescent marker in aqueous medium occurred. Nevertheless, collision-mediated transfer of DiD from NC to J774 cells was a non-negligible route of marker transfer, mainly for naked NC. However, this collision-mediated transfer was reduced for the PEG-PLA NC probably due to the restricted contact between NC and cells afforded by PEG steric hindrance at the surface.
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    Poly (D,L-lactide) nanocapsules prepared by solvent displacement process : influence of composition on physico-chemical and structural properties.
    (2000) Mosqueira, Vanessa Carla Furtado; Legrand, Philippe; Alphandary, Huguette Pinto; Puisieux, Francis; Barratt, Gillian
    Nanocapsules (NC) were prepared by interfacial deposition of preformed biodegradable polymer (PLA50) after a solvent displacement process. The influence of the composition used for the preparation of NC was evaluated in terms of particle size, polydispersity, zeta potential, homogeneity, and structural characteristics of the systems. The nature of the oil phase, polymer molecular weight, type and concentration of different surfactants were investigated to optimize the formulation to obtain NC suitable for intravenous administration. The influence of the physicochemical properties of the different oils used in NC preparation on the NC size was evaluated. The interfacial tension between the oil and water phases seems to have a greater effect on NC size than the oil viscosity. Miglyol 810 and ethyl oleate lead to the formation of smaller NC, probably because of the reduced interfacial tension. The polymer molecular weight plays only a small role in NC surface charge in the presence of lecithin, whereas NC surface charge, size, polydispersity, and short-term stability were highly influenced by lecithin purity. It appears that the absence of poloxamer 188 leads to smaller polydispersity, less contamination with nanospheres, and reduced formation of structures other than NC. Furthermore, electron microscopy and density gradient density techniques were used to examine the structure of the particles formed and their homogeneity. NC formation was evidenced by the bands with intermediate density between nanoemulsion and nanospheres; however, other bands of low intensity were observed. The presence of liposomes and multilayers in NC preparation was confirmed by electron microscopy. The percentage of carboxyfluorescein entrapped in different NC formulations allowed us to estimate the contamination by liposomes. It has been show that, under our experimental conditions, an excess of lecithin is an essential prerequisite for a stable preparation of PLA NC.
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    Potencial fitotóxico de Pterodon polygalaeflorus Benth (Leguminosae) sobre Acanthospermum australe (Loefl.) O. Kuntze e Senna occidentalis (L.).
    (2009) Belinelo, Valdenir José; Vieira Filho, Sidney Augusto; Almeida, Marcelo Suzart de; Alves, Dalton Luiz Ferreira
    O objetivo dessa pesquisa foi sintetizar e caracterizar a atividade alelopática de derivados do ácido 6α,7β–di-hidroxivouacapan-17β–óico, isolado de sementes de Pterodon polygalaeflorus Benth (Leguminosae). A caracterização dos compostos envolveu espectrometria no infravermelho (IV) e ressonância magnética nuclear de hidrogênio e de carbono (RMN de 1H e de 13C) incluindo experimentos em duas dimensões (COSY 1H 1H, HMQC e HMBC). Os efeitos alelopáticos foram avaliados através de bioensaios de germinação de sementes e crescimento radicular, em condições controladas de temperatura (25 °C) e fotoperíodo (12 h claro/12h escuro), durante 72 horas. Concentrações de 1,0, 100,0 e 1000,0 mg.L-1 foram testadas. Senna occidentalis (fedegoso) e Acanthospermum australe (carrapichinho) foram utilizadas como espécies daninhas alvo. Foi observado que o efeito alelopático dos compostos aumentou em função do aumento da concentração, mostrando assim uma relação dose dependente. A tendência geral observada nos resultados foi de aumento da intensidade dos efeitos alelopáticos inibitórios em função do aumento da concentração. A N-Etil-6α-acetoxi-7β- hidroxivouacapan-17β–amida e N,N-Dietil-6α-acetoxi-7β-hidroxivouacapan-17β–amida foram os derivados que apresentaram maior efeito inibidor da germinação e do crescimento radicular do fedegoso e do carrapichinho. Portanto, esses compostos representam grande potencial aleloquimico contra essas ervas daninha.
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    Attainment of O/W emulsions containing liquid crystal from annatto oil (Bixa orellana), coffee oil, and tea tree oil (Melaleuca alternifolia) as oily phase using HLB system and ternary phase diagram.
    (2008) Morais, Gilsane Garcia; Santos, Orlando David Henrique dos; Oliveira, Wanderley Pereira; Rocha Filho, Pedro Alves da
    Emulsions containing liquid crystals present interesting properties and advantages such as the skin moisturize increase, active release modulation, and emulsion stabilization. In this work, emulsions containing annatto, coffee and tea tree oils, and nonionic surfactants were developed. The HLB method was used for selection of surfactants. The required HLB value was established (9.0). Liquid crystals were attained when used the surfactant mixture Ceteareth-5 and Steareth-2 and identified as lamellar. The emulsions showed pseudoplastic behavior and tixotropy. The ternary diagram was useful in the selection of the proportion of surfactant and oily phase considering skin compatibility and liquid crystal presence.
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    Comparison of bidirectional lamivudine and zidovudine transport using MDCK, MDCK-MDR1, and Caco-2 cell monolayers.
    (2009) Souza, Jacqueline de; Benet, Leslie Z.; Huang, Yong; Storpirtis, Sílvia
    Bidirectional transport studies were conducted using Caco-2, MDCK, and MDCK–MDR1 to determine P-gp influences in lamivudine and zidovudine permeability and evaluate if zidovudine permeability changes with the increase of zidovudine concentration and/or by association of lamivudine. Transport of lamivudine and zidovudine separated and coadministrated across monolayers based on these cells were quantified using LC–MS–MS. Drug efflux by P-gp was inhibited using GG918. Bidirectional transport of lamivudine and zidovudine was performed across MDCK–MDR1 and Caco-2 cells. Statistically significant transport decrease in B!A direction was observed using MDCK–MDR1 for zidovudine and MDCK–MDR1 and Caco-2 for lamivudine. Results show increased transport in B!A and A!B directions as concentration increases but data from Papp increase in both directions for both drugs in Caco-2, decrease in MDCK, and does not change significantly in MDCK–MDR1. Zidovudine transport in A!B direction increases when coadministrated with increasing lamivudine concentration but does not change significantly in B!A direction. Zidovudine and lamivudine are P-gp substrates, but results assume that P-gp does not affect significantly lamivudine and zidovudine. Their transport in monolayers based on Caco-2 cells increase proportionally to concentration (in both directions) and zidovudine transport in Caco-2 cell monolayer does not show significant changes with lamivudine increasing concentrations.
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    Purification and characterization of an extracellular trypsin-like protease of Fusarium oxysporum var. lin.
    (2002) Barata, Ricardo Andrade; Andrade, Milton Hércules Guerra de; Rodrigues, Roberta Dias; Castro, Ieso de Miranda
    An alkaline serineprotease, capable of hydrolyzing Nu-benzoyl-DL arginine p-nitroanilide, was secreted by Fusurium oxysporum var. hi grown in the presence of gelatin as the sole nitrogen and carbon source. The protease was purified 65-fold to electrophoretic homogenity from the culture supernatant in a three-step procedure comprising QSepharose chromatography, aMnity chromatography, and FPLC on a MonoQ column. SDS-PAGE analysis of the purified protein indicated an estimated molecular mass of 41 kDa. The protease had optimum activity at a reaction temperature of 45OC and showed a rapid decrease of activity at 48OC. The optimum pH was around 8.0. Characterization of the protease showed that Ca*+ and MgZ+ cations increased the activity, which was not inhibited by EDTA or l,lO-phenanthroline. The enzyme activity on Nubenzoyl-DL arginine p-nitroanilide was inhibited by 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride,p-aminobenzamidine dihydrochloride, aprotinin, 3-4 dichloroisocoumarin, and IVtosyl-L-lysine chloromethyl ketone. The enzyme is also inhibited by substrate concentrations higher than 2.5x lo-4 M. The protease had a Michaelis-Menten constant of 0.16 mM and a V,, of 0.60 pm01 released product .min-‘.mg’ enzyme when assayed in a non-inhibiting substrate concentration. The activity on Nu-benzoyl-DL arginine p-nitroanilide was competitively inhibited by p-aminobenzamidine dihydrochoride. A Ki value of 0.04 mM was obtained.
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    Complete assignment of the 1H and 13C NMR spectra of a new polyester sesquiterpene from Austroplenckia populnea.
    (2000) Vieira Filho, Sidney Augusto; Duarte, Lucienir Pains; Santos, Marcelo Henrique dos; Silva, Grácia Divina de Fátima; Lula, Ivana Silva; Afonso, Robson José de Cássia Franco
    new polyester sesquiterpene (4-hydroxy-1,2,6,15-tetraacetyl-9-benzoylagarofuran), together with known friedelane triterpenes (friedelin, -friedelinol and 28-hydroxyfriedelin), was isolated from the leaves of Austroplenckia populnea. The structure and relative stereochemistry of the new ester were based on 2D NMR spectroscopic techniques including HMBC, HMQC and NOESY.
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    Uptake and metabolism of the Cyanobacterial Hepatotoxin Microcystin-RR by Spirodela intermedia from Brazil.
    (2009) Ferreira, Tanare Cambraia Ribeiro; Freitas, Tália Carvalho de; Paula, Ana Cláudia Chagas de; Jardim, Fernando Antônio; Guarda, Vera Lúcia de Miranda
    Spirodela intermedia was exposed to low (10 µg L-1) and high concentration (100 µg L-1) of microcystin-RR (Arginin-Arginin) over aperiod of two weeks. Depuration in the water phase, as weIl as uptake in the plant was determined using HPLC with photodiode array (PDA) detection. After the toxin uptake, metabolism of microcystin-RR occuored resulting in the formation of a glutathione conjugate. This conjugate was further processed yielding in a cysteine conjugate, a weIl known breakdown product in the biotransformation pathway of microcystins. The results indicate the uptake, accumulation and metabolism of microcystin-RR in a surface floating aquatic plant and raise the possibilities, to use these plants within water purification or toxin removal. Further implication on aquatic ecosystem and the transfer of toxin in the food web might occur and needs more investigation.
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    Two epimeric friedelane triterpenes isolated from Maytenus truncata Reiss : 1H and 13C chemical shift assignments.
    (2000) Meléndez Salazar, Gloria Del Carmen; Silva, Grácia Divina de Fátima; Duarte, Lucienir Pains; Lula, Ivana Silva
    An NMR study of 3˛- and 3ˇ-friedelinol is described. In addition to conventional 1D NMR methods, 2D shift-correlated NMR experiments HMQC [(1J(C,H)], HMBC [nJ(C,H); n D 2 and 3] and 2D 1H,1H-NOESY were used for 1H and 13C chemical shift assignments of these triterpenes.