Navegando por Autor "Teixeira, Robson Ricardo"
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Item Chemical variability and biological activities of Eucalyptus spp. essential oils(Molecules, 2016-09-07) Barbosa, Luiz Claudio Almeida; Filomeno, Claudinei Andrade; Teixeira, Robson RicardoMany plant species produce mixtures of odorous and volatile compounds known as essential oils (EOs). These mixtures play important roles in Nature and have been utilized by mankind for different purposes, such as pharmaceuticals, agrochemicals, aromatherapy, and food flavorants. There are more than 3000 EOs reported in the literature, with approximately 300 in commercial use, including the EOs from Eucalyptus species. Most EOs from Eucalyptus species are rich in monoterpenes and many have found applications in pharmaceuticals, agrochemicals, food flavorants, and perfumes. Such applications are related to their diverse biological and organoleptic properties. In this study, we review the latest information concerning the chemical composition and biological activities of EOs from different species of Eucalyptus. Among the 900 species and subspecies of the Eucalyptus genus, we examined 68 species. The studies associated with these species were conducted in 27 countries. We have focused on the antimicrobial, acaricidal, insecticidal and herbicidal activities, hoping that such information will contribute to the development of research in this field. It is also intended that the information described in this study can be useful in the rationalization of the use of Eucalyptus EOs as components for pharmaceutical and agrochemical applications as well as food preservatives and flavorants. View Full-TextItem A comparative study on the crystal structure of bicycle analogues to the natural phytotoxin helminthosporins(Journal of Molecular Structure, 2016-02-05) Barbosa, Luiz Cláudio de Almeida; Teixeira, Robson Ricardo; Nogueira, Leonardo Brandão; Maltha, Celia Regina Alvares; Doriguetto, Antônio Carlos; Martins, Felipe TerraHerein we described structural insights of a series of analogues to helminthosporin phytotoxins. The key reaction used to prepare the compounds corresponded to the [3 + 4] cycloaddition between the oxyallyl cation generated from 2,4-dibromopentan-3-one and different furans. Their structures were confirmed upon IR, NMR and X-ray diffraction analyses. While bicycles 7, 8 and 9 crystallize in the centrosymmetric monoclinic space group P21/c, compound 10 was solved in the noncentrosymmetric orthorhombic space group P212121. The solid materials obtained were shown to be racemic crystals (7, 8, 9) or racemic conglomerate (10). In all compounds, there is formation of a bicycle featured by fused tetrahydropyranone and 2,5-dihydrofuran rings. They adopt chair and envelope conformations, respectively. Crystal packing of all compounds is stabilized through C–H•••O contacts. Conformational aspects as well as similarities and differences among the crystal structures of the synthesized analogues are discussed.Item Corymbia spp. and Eucalyptus spp. essential oils have insecticidal activity against Plutella xylostella(Industrial Crops and Products, 2017-12-15) Filomeno, Claudinei Andrade; Barbosa, Luiz Claudio Almeida; Teixeira, Robson Ricardo; Pinheiro, Antônio Lelis; Farias, Elizeu de Sá; Silva, Eliete Meire de Paula; Picanço, Marcelo CoutinhoPlutella xylostella (L.) is the main brassica pest worldwide and is difficult to control even with commercial insecticides. In this study, assessments were made of the contact toxicity of essential oils (EOs) from ten Myrtaceae species. For this, the leaves of four Corymbia species (C. citriodora, C. intermedia, C. maculata, and C. ptychocarpa) and six Eucalyptus species (E. andrewsii, E. crebra, E. punctata, E. pyrocarpa, E. siderophloia, and E. sphaerocarpa) were collected during the Brazilian dry season and subjected to hydrodistillation for extraction of EOs. For C. citriodora, another sample was also collected during the rainy season. The essential oil (EO) content of all samples ranged from 0.07% w/w to 3.3% w/w and GC–MS analyses allowed the identification of 52 compounds. For E. andrewsii, E. pyrocarpa, and C. ptychocarpa there was no previous report on EO chemical composition. For C. citriodora, a higher EO content for the samples collected during the dry season was found (2.72% versus 1.53% for the rainy season). The insecticidal activity of all eleven EOs was evaluated via topical application on the second-instar larvae of P. xylostella. The most active EOs were produced by C. citriodora collected during the dry season, with citronellal (86.8%) and isopulegol (4.7%) being the main constituents. At 30 μg/mg of insect, these EOs caused 80% P. xylostella mortality, being more active than neem oil used as positive control. These EOs presented low toxicity for Solenopsis saevissima, a natural predator of P. xylostella. Bioassays also demonstrated a synergistic effect between citronellal and (-)-isopulegol at all tested proportions. The results described here suggest that C. citriodora EOs can be an environmentally friendly alternative method to control P. xylostella.Item Estudo da atividade inseticida e dos constituintes voláteis das partes aéreas (folhas e cascas) de Gallesia gorazema Moq. por cromatografia em fase gasosa e espectrometria de massas(Universidade Federal de Viçosa, 1995-08-24) Teixeira, Robson Ricardo; Barbosa, Luiz Claúdio de Almeida; http://lattes.cnpq.br/6104660258664620Gallesia gorazema, da família das fitolacáceas, é uma espécie vegetal que faz parte da imensa flora medicinal brasileira. De grande valor terapêutico, é utilizada, popularmente, para combater os mais diferentes tipos de enfermidades. Além disso, no meio rural acredita-se que suas cascas possuam atividade inseticida contra baratas e repelente contra vários insetos. O presente trabalho teve por meta realizar testes biológicos para averiguar se as cascas apresentavam ou não atividade inseticida e, ou, repelente, bem como analisar a composição química das cascas, objetivando identificar os compostos responsáveis por tais atividades. Os testes biológicos conduzidos em laboratório, com baratas e cascas de Gallesia gorazema, evidenciaram que as mesmas são altamente repelentes para tais insetos e não mostraram possuir nenhuma atividade inseticida. Para o propósito de se estudar a composição química das cascas da espécie vegetal, foram preparados extratos etéreo e por arraste a vapor das cascas. Estes extratos foram, então, analisados por cromatografia em fase gasosa e espectrometria de massas (CG/EM). O cromatograma do extrato etéreo das cascas mostrou a presença de um grande número de compostos, sendo possível a identificação dos organossulfurados 2,3,4-tritiapentano (trissulfeto de metila), metilmetanotiossulfinato, metilmetanotiossulfonato, 1,2,4-tritiolano, metiotiometildissulfeto, metiltiometildimetilsulfona, 2,3,4,6-te-tratiaeptano, 1-metilsulfonil-2,3-ditiabutano, 2,3,5,7-tetratiaoctano, 2,4,5,7-te-tratiaoctano (bis (metiltiometil)dissulfeto), 2,3,5,6- tetratiaoctano, 2,3,4,6,8-pentatianonano, 2,3,5,6,8-pentatianonano, 1,4- dimetilsulfinil-2,3-ditiabutano e 2,4,5,6,8-pentatianonano, além dos compostos não-sulfurados hidroquinona, 4-hidroxi-3-metilacetofenona e 2,3-diidro-3,5-diidroxi-6-metil-4H-piran-4-ona. A análise do óleo essencial das cascas revelou a presença dos organossulfurados 2,3,4- tritiapentano (trissulfeto de metila), metilmetanotiossulfinato, metilmetanotiossulfonato, 1,2,4-tritiolano, metiotiometildissulfeto, 2,3,4,5-tetratiaexano (tetrassulfeto de metila), 2,3,5,6-tetratioeptano, 2,3,4,6-tetratiaeptano, 1,2,4,5-tetratiano, 2,3,4,6-tetratiaeptano, 1- metilsulfonil-2,3-ditiabutano, 2,3,5,7-tetratiaoc-tano, 2,4,5,7-tetratiaoctano (bis (metiltiometil)dissulfeto), 2,3,4,6,8-penta-tianonano, 2,3,5,6,8- pentatianonano, 1-metilsulfinil-2,3,4-tritiaexano, 1,4-dimetilsulfinil-2,3- ditiabutano e 2,4,5,6,8-pentatianonano. Ainda foi analisado por CG/EM o extrato etéreo das folhas, no qual foi possível identificar os compostos organossulfurados dimetilsulfona, metilmetanotios-sulfonato, benzotiazol, 1-metilsulfonil-2,3,-ditiabutano e, ainda, os com-postos não-sulfurados hidroquinona, 4-hidroxi-3-metilacetofenona, 3-oxo-α-ionol e vitamina E na forma de α-tocoferol. Tendo-se em vista a possibilidade de utilização de Gallesia gorazema como uma fonte alternativa de vitamina E, subseqüentemente procedeu-se à quantificação do teor desta vitamina, em diferentes tipos de amostras de folhas, por cromatografia em fase gasosa.Item Potential antileukemia effect and structural analyses of SRPK inhibition by N-(2- (Piperidin-1-yl)-5-(Trifluoromethyl)Phenyl) isonicotinamide (SRPIN340)(Plos One, 2014-04-08) Siqueira, Raoni Pais; Barbosa, Éverton de Almeida Alves; Polêto, Marcelo Depólo; Righetto, Germanna Lima; Seraphim, Thiago Vargas; Salgado, Rafael Locatelli; Ferreira, Joana Gasperazzo; Oliveira, Leandro Licursi de; Laranjeira, Angelo Brunelli Albertoni; Almeida, Márcia Rogéria; Fietto, Juliana Lopes Rangel; Kobarg, Jörg; Oliveira, Eduardo Basílio de; Teixeira, Robson Ricardo; Borges, Júlio César; Silva Júnior, Abelardo; Bressan, Gustavo Costa; et al.Dysregulation of pre-mRNA splicing machinery activity has been related to the biogenesis of several diseases. The serine/arginine-rich protein kinase family (SRPKs) plays a critical role in regulating pre-mRNA splicing events through the extensive phosphorylation of splicing factors from the family of serine/arginine-rich proteins (SR proteins). Previous investigations have described the overexpression of SRPK1 and SRPK2 in leukemia and other cancer types, suggesting that they would be useful targets for developing novel antitumor strategies. Herein, we evaluated the effect of selective pharmacological SRPK inhibition by N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340) on the viability of lymphoid and myeloid leukemia cell lines. Along with significant cytotoxic activity, the effect of treatments in regulating the phosphorylation of the SR protein family and in altering the expression of MAP2K1, MAP2K2, VEGF and FAS genes were also assessed. Furthermore, we found that pharmacological inhibition of SRPKs can trigger early and late events of apoptosis. Finally, intrinsic tryptophan fluorescence emission, molecular docking and molecular dynamics were analyzed to gain structural information on the SRPK/SRPIN340 complex. These data suggest that SRPK pharmacological inhibition should be considered as an alternative therapeutic strategy for fighting leukemias. Moreover, the obtained SRPK-ligand interaction data provide useful structural information to guide further medicinal chemistry efforts towards the development of novel drug candidates.Item Synthesis of novel glycerol-derived 1,2,3-triazoles and evaluation of their fungicide, phytotoxic and cytotoxic activities(Molecules, 2017-10-07) Costa, Adilson Vidal; Oliveira, Marcos Vinicius Lacerda de; Pinto, Roberta Tristão; Moreira, Luiza Carvalheira; Gomes, Ediellen Mayara Corrêa; Alves, Thammyres de Assis; Pinheiro, Patrícia Fontes; Queiroz, Vagner Tebaldi de; Vieira, Larissa Fonseca Andrade; Teixeira, Robson Ricardo; Jesus Júnior, Waldir Cintra deThe synthesis of a series of 1,2,3-triazoles using glycerol as starting material is described. The key step in the preparation of these triazolic derivatives is the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), also known as click reaction, between 4-(azidomethyl)-2,2-dimethyl-1,3-dioxolane (3) and different terminal alkynes. The eight prepared derivatives were evaluated with regard to their fungicide, phytotoxic and cytotoxic activities. The fungicidal activity was assessed in vitro against Colletotrichum gloeosporioides, the causative agent of papaya anthracnose. It was found that the compounds 1-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)-cyclo-hexanol (4g) and 2-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)propan-2-ol (4h) demonstrated high efficiency in controlling C. gloeosporioides when compared to the commercial fungicide tebuconazole. The triazoles did not present any phytotoxic effect when evaluated against Lactuca sativa. However, five derivatives were mitodepressive, inducing cell death detected by the presence of condensed nuclei and acted as aneugenic agents in the cell cycle of L. sativa. It is believed that glycerol derivatives bearing 1,2,3-triazole functionalities may represent a promising scaffold to be explored for the development of new agents to control C. gloeosporioides.