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排序方式: 共有3463条查询结果,搜索用时 15 毫秒
61.
David E. Mery Amanda J. Compadre Paola E. Ordez Edward J. Selvik Vladimir Morocho Jorge Contreras Omar Malagn Darin E. Jones Philip J. Breen Michael J. Balick Flavio G. Gaudio Monica L. Guzman Cesar M. Compadre 《Molecules (Basel, Switzerland)》2022,27(9)
A method to identify anticancer compounds in plants was proposed based on the hypothesis that these compounds are primarily present in plants to provide them with an ecological advantage over neighboring plants and other competitors. According to this view, identifying plants that contain compounds that inhibit or interfere with the development of other plant species may facilitate the discovery of novel anticancer agents. The method was developed and tested using Magnolia grandiflora, Gynoxys verrucosa, Picradeniopsis oppositifolia, and Hedyosmum racemosum, which are plant species known to possess compounds with cytotoxic activities. Plant extracts were screened for growth inhibitory activity, and then a thin-layer chromatography bioautography assay was conducted. This located the major antileukemic compounds 1, 2, 4, and 5 in the extracts. Once the active compounds were located, they were extracted and purified, and their structures were determined. The growth inhibitory activity of the purified compounds showed a significant correlation with their antileukemic activity. The proposed approach is rapid, inexpensive, and can easily be implemented in areas of the world with high biodiversity but with less access to advanced facilities and biological assays. 相似文献
62.
José Maria Esbrí Anna Bernaus Marta ávila David Kocman Eva M. García‐Noguero Beatriz Guerrero Xavier Gaona Rodrigo álvarez Gustavo Perez‐Gonzalez Manuel Valiente Pablo Higueras Milena Horvat Jorge Loredo 《Journal of synchrotron radiation》2010,17(2):179-186
The mobility, bioavailability and toxicity of mercury in the environment strongly depend on the chemical species in which it is present in soil, sediments, water or air. In mining districts, differences in mobility and bioavailability of mercury mainly arise from the different type of mineralization and ore processing. In this work, synchrotron‐based X‐ray absorption near‐edge spectroscopy (XANES) has been taken advantage of to study the speciation of mercury in geological samples from three of the largest European mercury mining districts: Almadén (Spain), Idria (Slovenia) and Asturias (Spain). XANES has been complemented with a single extraction protocol for the determination of Hg mobility. Ore, calcines, dump material, soil, sediment and suspended particles from the three sites have been considered in the study. In the three sites, rather insoluble sulfide compounds (cinnabar and metacinnabar) were found to predominate. Minor amounts of more soluble mercury compounds (chlorides and sulfates) were also identified in some samples. Single extraction procedures have put forward a strong dependence of the mobility with the concentration of chlorides and sulfates. Differences in efficiency of roasting furnaces from the three sites have been found. 相似文献
63.
Antonio Alivert Jorge Bujons Juan-Julio Bonet 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):205-207
Abstract The treatment of 2-acetylthiophene with phosphorus pentachloride led, besides other products reported in previous studies, to 2-(2-thienyl)-2-chloroethenephosphonic acid in 16% yield. This compound was transformed, in the course of purification attempts, into 2-(2-thienyl)-2-oxoethanephosphonic acid. Full spectroscopic data for both compounds are provided. 相似文献
64.
Fernando R. Díaz Jorge L. Torres M. Angélica Del Valle Jorge H. Vélez J. Christian BernÈde Gastón A. East 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1101-1108
Poly(3,5‐dichloroaniline) was prepared by chemical oxidation in the presence of various sulfonic acids as doping agent, using potassium permanganate as oxidant. 1‐Naphtalene sulfonic acid, 2‐naphatalene sulphonic acid, 1,5‐naphtalene disulfonic acid, and p‐toluenesulfonic acid were the acids of choice. Infrared and UV‐Vis spectroscopy, utilized to characterize the polymers, revealed that the compounds exist in the emeraldine (conductive) oxidation state. The level of doping, conductivity, and morphology were determined as well. The presence of a sulfonic acid produces a morphological change, from granular to microtubule structures, which is responsible for the strong increase in the conductivity of the polymer. 相似文献
65.
Núbia Boechat Jorge Carlos Santos da Costa Jorge de Souza Mendonça Karla Ceodaro Paes Elisa Lopes Fernandes Pedro Santos Mello de Oliveira 《合成通讯》2013,43(24):3187-3190
Some heteroaromatic esters were reduced to the corresponding alcohols by using a sodium borohydride–methanol system. The reduction was completed within 0.15–2.0 h in refluxing THF. The alcohol products were isolated after aqueous workup in moderate to excellent yield (48–97%). 相似文献
66.
Easily prepared choline iodide is an active catalyst for the synthesis of cyclic carbonates through the coupling reaction of CO2 and epoxides using low pressure (1 MPa), moderate temperature (85 ºC) and green solvents (ethanol and propan-2-ol). The effects of reaction temperature, pressure, reaction time and amount of catalyst used were also investigated. The results showed moderate to high yields and excellent selectivities of cyclic carbonates with vinyl or acrylate groups under mild reaction conditions. The heterogenization of choline over a Merrifield resin gives access to a supported catalyst with good recyclability and reactivity that can be extended to a variety of terminal epoxide substrates. 相似文献
67.
María C. Araque-Monrós Ana Vidaurre Luis Gil-Santos Sagrario Gironés Bernabé Manuel Monleón-Pradas Jorge Más-Estellés 《Polymer Degradation and Stability》2013
The purpose of this study was to evaluate the effects of hydrolytic degradation on the properties of a PLA hollow braid designed as a new concept of biodegradable prosthesis for the regeneration of tendons and ligaments. The main function of the braided material is to bear mechanical loads while it is being replaced by the newly-generated tissue. The kinetics of braided material degradation is thus an important factor in determining the success of the product. In order to study this mechanism, PLA braid was subjected to a 12-month degradation process at 37 °C in PBS at pH 7.4 (to simulate the human physiological medium) and to accelerated degradation for one month in pH 12 and pH 3 solutions. Degradation of the braid subjected to hydrolysis was evaluated by weight loss, molecular weight distribution, mechanical properties, and calorimetric and morphologic analyses. The weight loss in a basic medium reached 21%, versus no significant change in the other media. Average molecular weight was reduced by approximately 50% in the three media, with loss of mechanical properties in all cases. The morphological changes were more evident in the PLA degraded in the basic medium. The crystallinity of the material increased at the first stages of degradation, regardless of the medium used. 相似文献
68.
Joaquín Barberá Mariel A. Godoy Paulina I. Hidalgo José A. Ulloa Jorge M. Vergara 《Liquid crystals》2013,40(6):679-688
Novel liquid crystal materials based on 1,3,5-benzenetrisamide derivatives with three pendant 2-phenyl-5-(mono-, di-, and/or tri-n-alkoxyphenyl)-1,3,4-oxadiazole arms (Ia–c, IIa–c) were prepared. The mesomorphic properties of these compounds were characterised and studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. The formation of a columnar mesophase was found to be dependent on the number of alkoxy side chains. The compounds Ib and IIb, with a total of six alkoxy chains, and compounds Ic and IIc, with nine alkoxy chains, exhibited an enantiotropic hexagonal columnar (Colh ) phase with high isotropisation temperatures; however, compounds Ia and IIa with a total of three alkoxy chains formed a crystalline phase. Compounds IIb and c were room temperature liquid crystals. 相似文献
69.
Theolyta S. Araújo Claudener S. Teixeira Maria A. P. Falcão Vanir R. Pinto Junior Mayara Quiroz Santiago Raquel G. Benevides Plínio Delatorre Jorge L. Martins Magna S. Alexandre-Moreira Benildo S. Cavada Eliane A. Campesatto Bruno A. M. Rocha 《Applied biochemistry and biotechnology》2013,171(8):1944-1955
Lectins are a structurally heterogeneous group of proteins or glycoproteins with at least one noncatalytic domain binding reversibly to a specific mono- or oligosaccharide. Monocot mannose-binding lectins are an extended superfamily of structurally and evolutionarily related proteins. In this study, we evaluated anti-inflammatory and antinociceptive effects of monocot lectin from the Canna limbata seeds (CLL). To accomplish this, CLL was purified and subjected to pharmacological assays: abdominal writhing induced by acetic acid, formalin, hot plate and Zymosan A-induced peritonitis tests. The CLL was purified by chromatographic chitin column, and the relative mass of 21 kDa observed in electrophoresis was confirmed by electrospray mass spectrometry, which also revealed that purified CLL consists of a dimer having a weight of 49,676 Da. The CLL showed nociceptive activity in the acetic acid test as well as peripheral antinociceptive response. The CLL also showed anti-inflammatory effect with the reduction of inflammation in the formalin test and neutrophil migration into the peritoneal cavity. This is the first report of anti-inflammatory activity for a monocot lectin, and it suggests a new pharmacological tool to understand inflammatory and antinociceptive processes mediated through lectins. 相似文献