Old drawback on azlactone formation revealed by a combination of theoretical and experimental studies

New insights into the formation of azlactone heterocycles bearing different substituents are hereby presented. The sum of both kinetic and thermodynamic factors contributes for the formation of 2-alkyl or 2-aryl substituted azlactones, while the cyclization of 2-alcoxy azlactones is less favored. These results are in perfect accordance with experimental observations obtained by infrared (IR) and electrospray ionization mass spectrometry (ESI(+)-MS) of the crude reaction mixture.

Comportamiento de cultivares de arroz en condiciones de bajo nivel tecnológico

Nitrogen is an essential element for rice crop development. Once this cereal is taken as the basefor food security, employment generation and source of income for most countries, we aimed to evaluateupland rice genotypes development submitted to nitrogen stress in southern Cerrado of Tocantins State.Field experiments were carried out at Chaparral Farm and at the Experimental unit of Federal University ofTocantins in the growing seasons of 2008/2009, 2009/2010, 2010/2011, 2011/2012 and 2012/2013. Experimentaldesign consisted of randomized blocks in factorial scheme 3 x 5, consisting of three genotypes in five yearswith four replications. It was concluded that growing season 2012/13 provided the highest grain yield; thehydric stress, as well as nitrogen stress, reduced significantly yield enhancement and; cultivar BRS-Bonançapresented the highest grain yield average.El nitrógeno es considerado un elemento esencial en el desarrollo del cultivo del arroz, y teniendo esecereal como la base para la seguridad alimentaria, generadora de empleos y renta para la mayoría de los países,el objetivo de este trabajo fue evaluar el comportamiento de cultivares de arroz de tierras altas sometidas alestrés del nitrógeno, en el Cerrado del Sur del Estado de Tocantins. Los experimentos fueron realizados encampo en la Fazenda Chaparral y en la Estación Experimental de la Universidad Federal de Tocantins enlos años agrícolas 2008/2009, 2009/2010, 2010/2011, 2011/2012 y 2012/2013. El diseño experimental fue deblocos al azar con cuatro repeticiones, en un esquema factorial 3 x 5, constituido por tres genotipos y cinco años. Se concluye que el periodo 2012/2013 tuvo las mayores medias de producción de granos; el estrés hídrico, así como el estrés de nitrógeno, reducen significativamente las ganancias productivas y; el cultivar BRS-Bonança presento la mayor media de producción de granos. O nitrogênio é considerado elemento essencial no desenvolvimento da cultura do arroz, e tendo esse cereal como a base para a segurança alimentar, geradora de empregos e renda para maioria dos países, objetivou-se com este trabalho avaliar o comportamento de cultivares de arroz de terras altas submetidos ao estresse de nitrogênio, no Cerrado do sul do Estado do Tocantins. Os experimentos foram conduzidos em campo na Fazenda Chaparral e na Estação Experimental da Universidade Federal do Tocantins nos anos agrícolas 2008/2009, 2009/2010, 2010/2011, 2011/2012 e 2012/2013. O delineamento experimental foi de blocos casualisados com quatro repetições, num esquema fatorial 3 x 5, constituído por três genótipos e cinco anos. As características avaliadas foram número de dias para florescimento, altura da planta, massa de cem grãos e produtividade de grãos. Conclui-se que a safra 2012/13 resultou nas maiores médias de produtividade de grãos; o estresse hídrico, assim como o estresse de nitrogênio, reduzem significativamente os ganhos produtivos e; o cultivar BRS-Bonança apresenta a maior média de produtividade de grãos

Molecular modeling study of complexes between ferriprotoporphyrin IX and antimalarial 4-quinolinecarbinolamines: a proposal of pharmacophore

Quinine and quinidine are well-known 4-quinolinecarbinolamines that exhibit antimalarial activity, but, in contrast, their epimers 9-epiquinine and 9-epiquinidine are almost inactive. Literature data are conflicting in describing the 4-quinolinecarbinolamine interaction mode with the molecular target, the ferriprotoporphyrin IX [Fe(III)PPIX]. In the present paper, a pharmacophore is proposed based on the binding of the non-aromatic nitrogen to the iron atom. The 4-quinolinecarbinolamine antimalarials were superimposed on the pharmacophore under consideration and complexes with Fe(III)PPIX were constructed. Conformational analyses of the complexes were performed applying the MM+ molecular mechanics method. The analysis of the complexes showed that the proposed ligand mode is possible although it does not explain the activity differences between epimers. A discussion of the structural aspects is also provided.

Tetraciclinas e glicilciclinas: uma visão geral

Tetracyclines exhibits activity to a broad range of Gram-negative and Gram-positive bacteria and this fact allied to the low toxicity, low cost, and the advantage of administration by oral route led to their indiscriminate use, which caused the appearance of bacterial resistance to these agents, wich has restricted its clinical utility, though new applications have emerged. On the other hand, the glycylcyclines, semi-synthetic products are similar to tetracyclines, which are active against many bacteria resistant to tetracycline and other classes of antibiotics. The purpose of this paper is to give an overview of this important class of antibiotics focusing on its coordination chemistry and possible applications

Using the plants of Brazilian Cerrado for wound healing : from traditional use to scientific approach

Ethnopharmacological relevance The Brazilian Cerrado is a biome with a remarkable diversity of plant species, many of which are used mainly by local communities as a source of treatment to several pathologic processes, especially for the treatment of wounds. However, no systematic review exists focusing on the plants used in this respect and on the appropriate pharmacological investigations that substantiate the actions that are reported. This study revisits the traditional use of medicinal plants from the Brazilian Cerrado in the treatment of wounds and the pharmacological characteristics of the reported plant species. Methodology For the present article, previous studies on plants of the Brazilian Cerrado used for wound healing carried out between 1996 and 2018 were researched on various academic databases (PubMed, Elsevier, Springer, Lilacs, Google Escolar, and Scielo). Results A total of 33 studies were carried out on 29 plant species distributed into 18 families, mainly Fabaceae or Leguminosae (9), Bignoniaceae (2), Asteraceae (2), Euphorbiaceae (2). Considering the great diversity of Cerrado plants, only a small number of wound healing studies were carried out between 1996 and 2018. It was observed that there is a large gap between experimentation assay and traditional use. There are only few connections between the form of use by the population and the experiments conducted in the laboratory. We found that only about 12% of these studies considered to use the methodologies, or at least in parts, to obtain extracts such as those used in folk medicine. Approximately 37% of the experiments were performed using the bark as well as the same ratio for leaves, 6% using the fruits, and 9% using the seeds, roots or flowers. In several studies, there are reports of chemical constituents such as flavonoids and tannins, followed by steroid terpenes, saponins, and fatty acids, and alkaloids. However, approximately 35% of the studies did not supply information about compounds present in the preparation or the effect which could be attributed to these agents in respect to wound healing. Regarding treatment, most of the studies employed a topical treatment, though intraperitoneal and oral treatment were also described using either topical, oil-based formulations, but also gel- or saline-based formulations. Conclusions Although, there has been an increase in knowledge about the biological actions of plants from Cerrado biome, the scientific basis for the traditional use of these local medicinal plants in wound healing does not provide sufficient information on the efficacy of the treatment, the molecular mechanisms, or, in particular, the effective doses used and the drug interactions. Thus, focused research investigating these hypotheses from traditional knowledge is necessary to prove the evidence of the potential pharmacological action

Análise da presença de benzodiazepínicos no ambiente aquático e o possível cenário de impacto ambiental / Analysis of the presence of benzodiazepines in the aquatic environment and the possible environmental impact scenario

Os benzodiazepínicos são fármacos psicotrópicos amplamente utilizados, que podem atingir o meio aquático por diversas vias e persistirem nestes ambientes como micropoluentes, devido aos processos de tratamento de água e esgoto convencionais não removerem os mesmos em sua totalidade. Dessa forma, foi realizada uma revisão narrativa com o objetivo de avaliar estudos que retratem a presença de benzodiazepínicos em ambientes aquáticos e suas respectivas concentrações, além de analisar os possíveis impactos negativos ao meio ambiente. Foram realizadas buscas de artigos, em quatro bases de dados: PubMed, Science Direct, SciELO e Google Acadêmico, utilizando os descritores “Sewage”, “Benzodiazepine”, “Effluents” e “Wastewater”, juntamente com o operador booleano “AND”. 34 artigos foram incluídos nesta revisão, sendo três realizados no Brasil e 31 em outros países. Foi observado que 32/34 artigos relataram a presença de benzodiazepínicos no ambiente aquático, sendo os mais frequentes o diazepam, oxazepam e lorazepam, e os encontrados em maiores concentraçoes o bromazepam, oxazepam e lorazepam. Dois estudos abordaram também alguns efeitos tóxicos decorrentes da presença de benzodiazepínicos no ambiente aquático, tais como citotoxicidade em leveduras e diatomáceas, bioacumulação e alterações comportamentais em peixes. A presença destes fármacos no ambiente aquático é preocupante, uma vez que os benzodiazepínicos podem causar danos não só aos organismos aquáticos, mas também à saúde pública. Portanto, a presente revisão coloca em foco a presença de benzodiazepínicos no ambiente aquático e seus efeitos nocivos, sendo necessários mais estudos de toxicidade e o desenvolvimento de novas tecnologias para resolução desta problemática.

Lectin genes and their mature proteins: Still an exciting matter, as revealed by biochemistry and bioinformatics analyses of newly reported proteins

Two new lectins were purified through affinity chromatography after crude extract preparation under high ionic strength. The hemagglutinating activity of these lectins from the seeds of the legumes Dioclea bicolor (DBL) and Deguelia scandens (DSL) was inhibited by galactose and glucose, respectively, and the molecular masses were estimated at 24 and 22kDa (via SDS-PAGE), respectively. The alignment of internal peptides of DBL (MS/MS) with known protein sequences revealed similarity to other legume lectins. The N-terminal amino acid sequence of DSL also aligned with legume lectins. Cross-similarities among the two studied lectins were observed only after sequence permutation. More than a dozen lectins have been reported for the genus Dioclea but none that recognize galactose. DSL is the first lectin reported for the Deguelia genus in the tribe Millettieae. With the aid of bioinformatics tools and searches for genome/transcriptome information about closely related sequences, new lectin members of Millettieae were also identified. Electrophoresis profiling and amino acid sequence analysis suggested that DBL-Gal and DSL do not undergo post-transcriptional ConA-like circular permutation. Molecular modeling of the deduced amino acid sequences of the Millettieae lectins suggested that the overall folding of the monomeric structures of legume lectins is conserved. This and other recent studies highlight native plants of the Amazon as renewed sources of lectins. © 2015 Elsevier Ltd