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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Efeito do processamento sobre a composiÃÃo de compostos fenÃlicos presentes no suco de cajà / Effect of processing on the composition of phenolic compounds present in the juice of cashew

NÃdia Maria dos Santos Matos SÃ 21 June 2012 (has links)
Empresa Brasileira de Pesquisa AgropecuÃria / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Na indÃstria de processamento de frutas, a polpa de caju à utilizada durante a entressafra do caju para a obtenÃÃo de diversos produtos, tais como o suco de caju. O consumo cada vez mais frequente de alimentos industrializados desperta o interesse na qualidade desses produtos que estÃo sendo consumidos e a influÃncia do processamento ainda à pouco estudada. Por isso a importÃncia em verificar a influÃncia desse processamento nos compostos benÃficos que estÃo presentes no suco de caju. Este trabalho visou quantificar o teor de fenÃlicos e avaliar a atividade antioxidante in vitro pelo mÃtodo ABTS no suco de caju processado. O suco foi obtido a partir dos pedÃnculos do clone de cajueiro CCP 76 em prensa tipo expeller. O tratamento tÃrmico foi realizado em escala de bancada com cinco faixas de temperaturas (55, 65, 75, 85 e 95ÂC) e quatro tempos (5, 15, 30 e 60 minutos). Imediatamente apÃs o tratamento tÃrmico, as amostras foram resfriadas em banho de gelo, e armazenadas em frascos plÃsticos para posterior anÃlise. Os Ãcidos fenÃlicos identificados foram 1-O-trans-cinamoil--D-glucopiranose, Ãcido cinÃmico e seus isÃmeros. Com relaÃÃo à atividade antioxidante, os resultados encontrados utilizando o radical ABTS, apresentaram valores TEAC de 7,11  0,08 para o extrato aquoso e 6,59  0,02 para o extrato metÃnÃlico (ÂM TROLOX/mL de suco). A partir desses resultados pode-se concluir que apesar da mudanÃa na concentraÃÃo dos compostos fenÃlicos durante o processamento, nÃo houve alteraÃÃo na atividade antioxidante do suco de caju em funÃÃo do tratamento tÃrmico. / In the fruit processing industry, the cashew pulp is used during the offseason to obtain various products such as cashew juice. The increasingly frequent consumption of processed foods arouses interest in the products that are being consumed and the influence of processing is still poorly studied. Hence the importance of verifying the influence of processing on the beneficial compounds present in cashew apple juice. This study aimed to quantify the amount of phenolics and evaluate the in vitro antioxidant activity by ABTS method in processed cashew juice. The juice was obtained from the peduncle of the cashew clone CCP 76 in an expeller type press. The thermal treatment was carried out in a bench scale at five temperature (55, 65, 75, 85 and 95  C) and four times (5, 15, 30 and 60 minutes). Immediately after the heat treatment, the samples were cooled in an ice bath and stored in plastic bottles for further analysis. The phenolics were identified as 1-O-trans-cinnamoyl--D-glucopyranose, cinnamic acid and isomers. With regard to antioxidant activity, the results using the ABTS radical, had TEAC values of 7.11  0.08 for the aqueous extract and 6.59  0.02 for the methanol extract (mM Trolox / mL of juice). From these results we can conclude that still of phenolic concentration changes during processing, there was no change on cashew juice antioxidant activity related to thermal treatment.
12

Development of flow methodologies for the [2+2] photocycloaddition of cinnamic acid derivatives and biological exploration of truxinic acid derived scaffolds

Telmesani, Reem 16 February 2019 (has links)
Cinnamic acids and their derivatives are building blocks for cyclobutanes in many natural products. In nature, dimerization of these derivatives is thought to occur through a [2+2] photocycloaddition. Experimentally, efficient dimerization of these substrates using UV irradiation has predominantly been achieved in the solid state and is thought to be a result of stringent requirements for distance and orientation of the participating olefins. In the following pages a new strategy is presented which achieves [2+2] dimerization of these substrates in solution through the use of a bis-thiourea catalyst that induces proximity via hydrogen bonding while exploiting novel flow technology. Using these platforms, we demonstrate the ability to perform the [2+2] photocycloaddition on a variety of electron rich and poor cinnamates to yield two major truxinic ester products in good yields and regioselectivity. The methodology is also readily scalable to a decagram scale and has enabled access to large quantities of a variety of truxinic ester products. Using a liquid-liquid slug flow strategy greatly accelerated reactivity by nearly four-fold in most cases and has allowed for an expansion of the substrate scope to include historically unreactive substrates such as cinnamamide dimers. This rate increase is attributed to improved mixing and an organic thin film known to occur within these systems. More recently, this flow methodology has been further developed to enable access to various heterodimers similar to those found in various bioactive natural products in a simple and efficient manner by using a cinnamic acid monomer in combination with an excess of cinnamic ester or amide monomer. The heterodimer can be easily separated from the homodimers and unreacted ester or amide monomers through an acid-base workup. Finally, to demonstrate the utility of these methodologies for biological exploration, a small library of truxinic amides was synthesized and underwent biological testing in breast cancer cell lines. Single dose inhibition data showed promising anti-cancer activity. Lastly, this methodology has also been applied to the synthesis of two interesting bioactive natural products, eucommicin A and piperarborenine D in an efficient modular fashion in both cases. These syntheses open the doors to future SAR studies which have yet to be performed on these and most truxinic and truxillic acid derived natural products. / 2020-02-15T00:00:00Z
13

Effect of cinnamic acid-cyclodextrin inclusion complexes on populations of Escherichia coli O157:H7 and Salmonella enterica in fruit juices

Truong, Vy Thuy 14 November 2007 (has links)
Cinnamic acid (CA) is a naturally occurring organic acid that is found in some fruits and a number of spices. CA has antimicrobial activity against certain spoilage microorganisms and pathogenic bacteria. However, the acid is poorly soluble in water. Cyclodextrin molecules have a hydrophobic cavity that allows them to serve as a host for insoluble molecules in aqueous matrices. This study was conducted to determine if the aqueous solubility of cinnamic acid could be improved via complexation with α- or β-cyclodextrins, and if these complexes could be used to control bacterial pathogens in juices. Based upon phase solubility analysis, α-cyclodextrin was chosen as the host molecule for the remainder of this study. In complex with α-cyclodextrin, the solubility of cinnamic acid increased from approximately 400 mg/L to 3800 mg/L. Prepared cinnamic acid complexed with α-cyclodextrin was aseptically added (400 mg/L and 1000 mg/L) to orange juice inoculated with a Salmonella enterica (7 log CFU/mL) and apple cider inoculated with Escherichia coli O157:H7 (7 log CFU/mL). Cider and orange juice samples were extracted on day 0 and at 24 h intervals for seven days and spread plated onto Tryptic Soy Agar. Cinnamic acid was effective for reducing populations of both bacterial pathogens in juice. Populations of E. coli O157:H7 in the apple cider were significantly reduced after 7 days at 25.6 ± 0.42°C at concentrations of 400 mg/L (5-log CFU/mL reduction) and 1000 mg/L (6-log CFU/mL reduction) cyclodextrin-cinnamic acid. S. enterica counts were also reduced in orange juice at 4° C treated with 400 mg/L (2.7-log CFU/mL reduction) and 1000 mg/L (3.2-log CFU/mL reduction) complexed cinnamic acid. The much improved solubility of this compound provides food processors with greater flexibility in using cinnamic acid in their product formulations. / Master of Science
14

Radiação gama ou antimicrobianos naturais na conservação de melão minimamente processado /

Moreira, Gláucia Cristina, 1981- January 2009 (has links)
Orientador: Rogério Lopes Vieites / Banca: Giuseppina Pace Pereira Lima / Banca: Vera Lúcia Mores Rall / Banca: Maria Monteiro Sigrist / Banca: Nelida Lúcia Del Mastro / Resumo: O presente trabalho teve por objetivo verificar os efeitos da radiação gama e de antimicrobianos naturais na conservação de melão minimamente processado, armazenado sob refrigeração. Foram realizados 4 experimentos: 1 e 2 - frutos de melão Cantaloupe e Pele de Sapo provenientes de Baraúna/RN e Juazeiro/BA, respectivamente; 3 e 4 - frutos de melão Cantaloupe e Gália provenientes da região de Cartagena (Espanha). Após a colheita, os frutos dos experimentos 1 e 2 foram transportados ao Laboratório de Frutas e Hortaliças da Faculdade de Ciências Agronômicas - UNESP - Botucatu/SP, e os dos experimentos 3 e 4 transportados para o Laboratório de Postrecolección e Refrigeración da Universidad Politécnica de Cartagena/Espanha. Após o processamento manual (corte em seções trapezoidais) os melões MP (minimamente processados) dos experimentos 1 e 2 foram acondicionados em embalagens de poliestireno expandido recobertas com filme de polietileno e irradiados nas doses: 0,0kGy; 0,1kGy; 0,2kGy; 0,3kGy; 0,4kGy e 0,5kGy. Os melões MP dos experimentos 3 e 4, após o processamento, foram imersos durante 1 minuto a 5ºC em: água (testemunha); vanilina (1000 mg L-1 e 2000 mg L-1); ácido cinâmico (148,16 mg L-1 e 296,32 mg L-1) e outros dois tratamentos consistiram em aplicação de vapor de ácido cinâmico (148,16 mg L-1 e 296,32 mg L-1) nos melões MP dentro da embalagem (bandejas de polipropileno termo seladas com filme de polipropileno). O armazenamento refrigerado foi realizado durante 10 dias 5±1ºC e 85-90% UR (experimentos 1 e 2) e à 5±1ºC e 85-95% UR (experimentos 3 e 4). As alterações na qualidade foram detectadas por meio das análises: perda de massa fresca, conservação pós-colheita, firmeza, pH, acidez titulável, sólidos solúveis, teores de açúcares redutores e redutores totais, ácido ascórbico, vitamina C, taxa respiratória, produção de etileno... (Resumo completo, clicar acesso electrônico abaixo) / Abstract: The aim of this research was to evaluated the effects of the gamma radiation and the natural antimicrobials in the conservation of fresh-cut melon storaged under refrigeration. Four experiments were accomplished: 1 and 2 - the varieties used were 'Cantaloupe' and 'Pele de Sapo' from Baraúna/RN and Juazeiro/BA, respectively; 3 and 4 - the varieties used were 'Cantaloupe' and 'Gália' from Cartagena (Spain). After harvesting, fruits from experiment 1 and 2 were sent to the Laboratory of Fruits and Vegetables at the University of Sao Paulo State (UNESP - Botucatu/SP). Fruits from experiment 3 and 4 were sent to the Postharvest and Refrigeration Group at the Technical University of Cartagena/Spain. After the manual processing (cut in trapezoidal sections) the fresh-cut melons of the experiment 1 and 2 were conditioned in polystyrene trays involved by polyethylene film and irradiated with doses: 0,0kGy; 0,1kGy; 0,2kGy; 0,3kGy; 0,4kGy and 0,5kGy. After processing, fresh-cut melons from experiment 3 and 4 were immersed for 1 min at 5ºC in water (control); vanillin (1000 mg L-1 and 2000 mg L-1); cinnamic acid (148,16 mg L- 1 and 296,32 mg L-1). Two additional treatments consisted on the application of cinnamic acid vapor (148,16 mg L-1 e 296,32 mg L-1) on fresh-cut melons within the packages (polypropylene trays heat-sealed with polypropylene). The storage was realized during 10 days in a cold camera to 5±1ºC and 85-90% HR (experiment 1 and 2) and to 5±1ºC and 85- 95% HR (experiment 3 and 4). The quality alterations were detected through the analyses: loss of fresh mass, postharvest conservation, firmness, pH, acidity titratable, soluble solids, reducing and total reducing sugar content, ascorbic acid, vitamin C, respiration rate, ethylene production, gas composition (CO2 and O2), enzymes activity (peroxidase, polygalacturonase and pectinmethylesterase), antioxidant... (Complete abstract click electronic access below) / Doutor
15

Radiação gama ou antimicrobianos naturais na conservação de melão minimamente processado

Moreira, Gláucia Cristina [UNESP] 01 June 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-01Bitstream added on 2014-06-13T18:43:52Z : No. of bitstreams: 1 moreira_gc_dr_botfca.pdf: 1778915 bytes, checksum: c6b29f50c1945159f217677f6de1a95a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho teve por objetivo verificar os efeitos da radiação gama e de antimicrobianos naturais na conservação de melão minimamente processado, armazenado sob refrigeração. Foram realizados 4 experimentos: 1 e 2 - frutos de melão Cantaloupe e Pele de Sapo provenientes de Baraúna/RN e Juazeiro/BA, respectivamente; 3 e 4 - frutos de melão Cantaloupe e Gália provenientes da região de Cartagena (Espanha). Após a colheita, os frutos dos experimentos 1 e 2 foram transportados ao Laboratório de Frutas e Hortaliças da Faculdade de Ciências Agronômicas – UNESP – Botucatu/SP, e os dos experimentos 3 e 4 transportados para o Laboratório de Postrecolección e Refrigeración da Universidad Politécnica de Cartagena/Espanha. Após o processamento manual (corte em seções trapezoidais) os melões MP (minimamente processados) dos experimentos 1 e 2 foram acondicionados em embalagens de poliestireno expandido recobertas com filme de polietileno e irradiados nas doses: 0,0kGy; 0,1kGy; 0,2kGy; 0,3kGy; 0,4kGy e 0,5kGy. Os melões MP dos experimentos 3 e 4, após o processamento, foram imersos durante 1 minuto a 5ºC em: água (testemunha); vanilina (1000 mg L-1 e 2000 mg L-1); ácido cinâmico (148,16 mg L-1 e 296,32 mg L-1) e outros dois tratamentos consistiram em aplicação de vapor de ácido cinâmico (148,16 mg L-1 e 296,32 mg L-1) nos melões MP dentro da embalagem (bandejas de polipropileno termo seladas com filme de polipropileno). O armazenamento refrigerado foi realizado durante 10 dias 5±1ºC e 85-90% UR (experimentos 1 e 2) e à 5±1ºC e 85-95% UR (experimentos 3 e 4). As alterações na qualidade foram detectadas por meio das análises: perda de massa fresca, conservação pós-colheita, firmeza, pH, acidez titulável, sólidos solúveis, teores de açúcares redutores e redutores totais, ácido ascórbico, vitamina C, taxa respiratória, produção de etileno... / The aim of this research was to evaluated the effects of the gamma radiation and the natural antimicrobials in the conservation of fresh-cut melon storaged under refrigeration. Four experiments were accomplished: 1 and 2 – the varieties used were ‘Cantaloupe’ and ‘Pele de Sapo’ from Baraúna/RN and Juazeiro/BA, respectively; 3 and 4 - the varieties used were ‘Cantaloupe’ and ‘Gália’ from Cartagena (Spain). After harvesting, fruits from experiment 1 and 2 were sent to the Laboratory of Fruits and Vegetables at the University of Sao Paulo State (UNESP – Botucatu/SP). Fruits from experiment 3 and 4 were sent to the Postharvest and Refrigeration Group at the Technical University of Cartagena/Spain. After the manual processing (cut in trapezoidal sections) the fresh-cut melons of the experiment 1 and 2 were conditioned in polystyrene trays involved by polyethylene film and irradiated with doses: 0,0kGy; 0,1kGy; 0,2kGy; 0,3kGy; 0,4kGy and 0,5kGy. After processing, fresh-cut melons from experiment 3 and 4 were immersed for 1 min at 5ºC in water (control); vanillin (1000 mg L-1 and 2000 mg L-1); cinnamic acid (148,16 mg L- 1 and 296,32 mg L-1). Two additional treatments consisted on the application of cinnamic acid vapor (148,16 mg L-1 e 296,32 mg L-1) on fresh-cut melons within the packages (polypropylene trays heat-sealed with polypropylene). The storage was realized during 10 days in a cold camera to 5±1ºC and 85-90% HR (experiment 1 and 2) and to 5±1ºC and 85- 95% HR (experiment 3 and 4). The quality alterations were detected through the analyses: loss of fresh mass, postharvest conservation, firmness, pH, acidity titratable, soluble solids, reducing and total reducing sugar content, ascorbic acid, vitamin C, respiration rate, ethylene production, gas composition (CO2 and O2), enzymes activity (peroxidase, polygalacturonase and pectinmethylesterase), antioxidant... (Complete abstract click electronic access below)
16

Vibrational spectroscopy in crystals of trans-cinnamic acid complexed with Europium under extreme conditions / Espectroscopia vibracional em cristais do Ãcido trans-cinÃmico complexado com eurÃpio sob condiÃÃes extremas

Josà Enedilton Medeiros Pereira 16 July 2014 (has links)
This work is focused on characterization of a polycrystalline sample of the coordination compound with ions Eu3+ using as a binder the trans-cinnamic acid , [Eu(cin)3]. The interest in coordination with lanthanide compounds is due to their large technological applications. The process of luminescence of coordination compounds containing lanthanide, also called antenna effect, has a main objective the use of new ligands with various applications, both in increasing the efficiency of energy receptors in the ultraviolet region and the development of biomarkers. In this work, to characterize the polycrystalline material, Raman spectroscopy was used to determine the vibrational behavior of the material at ambient temperature and pressure. It was also shown the behavior of the compound at low temperatures, in which variations in various vibrational modes were observed, indicating thus the occurrence of phase transition. Using a diamond anvil cell the material was studied by high hydrostatic pressure Raman spectroscopy. The purpose of this methodology was to map possible phase transitions and discover the occurrence of possible polymorphism. However, until the pressure reached in the experiments - about 5.2 GPa - it was found that the original phase remained stable. A discussion of the luminescence of the sample is also provided in this work. / O presente trabalho està focado na caracterizaÃÃo de uma amostra policristalina do composto de coordenaÃÃo com Ãons Eu3+ utilizando como ligante o Ãcido trans-cinÃmico, [Eu(cin)3]. O interesse em compostos de coordenaÃÃo com lantanÃdeos deve-se Ãs suas amplas aplicaÃÃes tecnolÃgicas. O processo de luminescÃncia dos compostos de coordena- ÃÃo contendo lantanÃdeo, tambÃm chamado de efeito antena, tem como principal objetivo o uso de novos ligantes com aplicaÃÃes diversas, tanto no aumento da eficiÃncia de re- ceptores de energia na regiÃo do ultravioleta quanto no desenvolvimento de marcadores biolÃgicos. Neste trabalho, para realizar a caracterizaÃÃo do material policristalino, foi utilizada a espectroscopia Raman, a fim de determinar o comportamento vibracional do material à temperatura e pressÃo ambiente. TambÃm foi verificado o comportamento do composto sob baixas temperaturas, no qual foram observadas variaÃÃes em vÃrios modos vibracionais, indicando, por conseguinte, a ocorrÃncia de transiÃÃo de fase. Utilizando uma cÃlula de pressÃo a extremos de diamante o material foi estudado a altas pressÃes hidrostÃticas atravÃs de espectroscopia Raman. O intuito desta metodologia era mapear possÃveis transiÃÃes de fase e descobrir a ocorrÃncia de eventual polimorfismo. Entretanto, atà a pressÃo atingida nos experimentos â cerca de 5,2 GPa â verificou-se que a fase ori- ginal permaneceu estÃvel. Uma discussÃo sobre a luminescÃncia da amostra tambÃm à fornecida neste trabalho.
17

Etude de couplages croisés directs catalytiques décarboxylants d'acides picoliniques et cinnamiques / Study of direct catalytic decarboxylative cross croupling reaction of carboxyazine N-oxide and cinnamaic acid

Rouchet, Jean-Baptiste 29 September 2015 (has links)
La fonctionnalisation des hétéroaromatiques suscite grand intérêt tant en chimie supramoléculaire qu’en chimie pharmaceutique. Parmi les techniques les plus employées, la chimie organométallique catalysée par les métaux de transition est une méthode de choix et apporte depuis plus d’un siècle une contribution majeure notamment depuis l’avènement des couplages croisés. Les défis méthodologiques contemporains reposent en grande partie sur le concept du ‘mieux avec moins’ et visent notamment au développement de couplages croisés directs catalytiques impliquant des liaisons C-CO₂H et C−H avec le souci (i) d’éviter la préparation et/ou l’isolement d’intermédiaires organométalliques hautement réactifs souvent préparés dans des conditions drastiques et/ou sensibles à l’humidité et parfois instables, (ii) de réduire la production massive de sels; (iii) d’éviter les étapes de protection/déprotection des fonctions sensibles aux attaques nucléophiles. Ce travail de thèse s’inscrit dans ce contexte et a pour objectif le développement de nouveaux couplages croisés directs décarboxylants de type CCO₂H/C-X et C-CO₂H/C-H impliquant deux partenaires de couplages inédits, les acides carboxyaziniques N-oxydés et les acides cinnamiques α-méthoxylés, traités dans deux parties distinctes. Un premier travail a conduit au développement d’une méthodologie générale de couplage décarboxylant,catalysée au palladium (0) et assistée par l’argent (I), d’acides quinaldiques et picoliniques N-oxydés ainsi que de l’acide isoquinoline 3-carboxylique avec des halogéno(hétéro)arènes. En effet, bien que le cuivre (I) se soit révélé plus performant par calculs DFT pour conduire l’ipso-décarboxylation-métallation, seul l’argent favorise la catalyse conventionnelle coopérative Pd(0)/Ag(I) assurant la sélectivité en lieu et place de la fonction acide carboxylique. Ayant montré un large spectre de réactivité, la méthodologie tolère en particulier la présence de substituants sur le noyau azinique. Elle représente également une alternative synthétique à l’arylation directe de la liaison C−H des azines N-oxydées pour accéder aux azines 2-hétéroarylées ainsi qu’aux pyridines 2,5-disubstituées et aux isoquinoléïnes 3-arylées. Comme application, une approche modulable et flexible a été développée pour la synthèse d’une isoquinoline fonctionnalisée en position 1 et 3 connue comme agent antitumoral. Le second travail a porté sur la mise au point des premiers couplages croisés décarboxylants oxydants de type CCO₂H/C−H pallado-catalysés et assistés par le cuivre (II) d’acides cinnamiques α-méthoxylés sur une large gamme d’hétérocycles pour conduire à la formation stérécontrollée d’éthers d’enol héteroarylés en position géminale. L’introduction directe et inédite de la fonction éther vient enrichir le panel des méthodologies de fonctionnalisation des liaisons C−H des hétérocycles. Leur haut potentiel d’aménagement fonctionnel permet de diversifier consécutivement et très largement la nature de la fonctionnalisation pour accéder en particulier aux hétéroarylalkyl cétones et aux alcènes poly-fonctionnalisés. / The functionalization of heterocycles arouse an interest both in supramolecular chemistry and in pharmaceuticals. Based on the so-called concept better with less, the development of direct functionalization methodologies of heterocycles involving C–H and C–CO₂H bonds has emerged as an efficient, modern alternative and complementary process to traditional cross coupling methods, avoiding thus the use of stoichiometric organometallic reagents that are often air and moisture sensitive. In this context, the aim of this PhD work was to develop new decarboxylative cross couplings, CO₂H / C-X and CO₂H / C−H, using substituted 2-carboxyazine N-oxides and α-methoxyacrylic acids as new coupling partners.The first part of this work has been focused on the development of the versatile Pd-catalyzed and Ag-assisted decarboxylative coupling of quinaldic and picolonic acids N-oxides as well as 3-carboxyisoquinoline acids with (hetero)aryl halides. Although copper (I) appeared to be more efficient by DFT calculations to perform ipsodecarboxylation-metallation step, only silver catalysis revealed to be much more adequate to achieve the conventional decarboxylative coupling and this was then pointed out with the high regioselectivity observed at the carboxy function site. This reaction showed a large reactivity spectrum and tolerated for the first time substituents on azinic core. It is also a synthetic alternative to the direct C−H arylation on azine N-oxides for the regioselective synthesis of 2-arylated substituted pyridines and 3-arylated isoquinolines. As application, a modular and flexible approach has been developed for the synthesis of the highly functionalized 1,3-substitute disoquinoline 5, shown as an antitumor agent.In the second part, the first Pd-catalyzed and Cu-assisted decarboxylative / C-H alkenylation of heterocycleswith various α−methoxyacrylic acids was reported offering general stereocontrolled access to heteroarylated enol ethers in geminal position. The direct introduction of vinyl ether allows to expand the panel of C-H bond functionalizations methodologies of heterocycles. The high potential for subsequent post-functional adjustment of the vinyl ether moiety enable thus the synthesis of heteroarylated α,β-enolizable ketones and polysusbituted alkenes.
18

L'acide cinnamique régule l'expression post-transcriptionnellede la cyclooxygénase-2 / Cinnamic acid prevents 12-phorbol myristate 13-acetate-induced post-transcriptional regulation of cyclooxygenase-2-expression

Legrand, Noémie 29 November 2012 (has links)
L'inflammation est considérée comme un promoteur de la cancérogenèse. La cyclooxygénase-2 (COX-2), la forme inductible de la famille des cyclooxygénases est un médiateur important de l'inflammation. Cette enzyme est constitutivement exprimée dans un grand nombre de cancers tels que les cancers du sein, du colon ou de la prostate. De nombreuses études mettent en évidence que COX-2 est surexprimée lors des étapes pré-néoplasiques. La COX-2 représente de ce fait une cible thérapeutique potentielle en chimioprévention et également pour le traitement des cancers. L'utilisation d'inhibiteurs synthétiques de COX-2 qui ciblent l'activité enzymatique est le seul traitement clinique actuellement disponible pour réduire l'activité de COX-2. Cependant, ces agents présentent des effets secondaires sévères, ce qui limite leur prise chronique chimiopréventives ou au cours des traitements anti-cancéreux. Une stratégie alternative pour cibler la fonction de COX-2 est d'inhiber son expression. Un grand nombre d'études montrent que certains produits naturels (la curcumine, le resveratrol ou l'apigénine par exemple) inhibent, préférentiellement l'expression de COX-2, sans être toxique. Notre projet analyse l'effet de l'acide cinnamique, un produit naturel extrait de la plante Cinnamonium cassia, sur l'expression de COX-2 au cours de la cancérogenèse dans le but d'évaluer son intérêt en chimioprévention. Nous avons utilisé comme modèle les cellules mammaires non carcinogènes, MCF10A stimulées avec un ester de phorbol, le 12-phorbol myristate 13-acetate (PMA), qui induit l'expression de COX-2. Nous avons observé une diminution de l'expression de COX-2 au niveau de l'ARNm et de la protéine après le traitement avec différentes concentrations d'acide cinnamique (1 et 10μM). L'analyse des mécanismes impliqués dans la diminution de l'expression de COX-2 a mis en évidence que l'acide cinnamique régule l'expression de COX-2 de façon post-transcriptionnelle en réduisant la stabilité de son ARNm. Cet effet est associé à une prévention de la diminution de l'expression de microARN (miR)-16 et une inhibition de l'expression de p38 induite par l'acide cinnamique en réponse au traitement avec le PMA. / Inflammation is considered a cancer-promoting factor. Cyclooxygenase-2 (COX-2), the inducible form of the family of cyclooxygenases is an important mediator of inflammation, which has been found constitutively expressed in many forms of cancer including breast, colon or prostate. A number of studies show that COX-2 is stably expressed since the early pre-neoplastic stages. This encourages us to consider COX-2 as a potential target in chemoprevention as well as in the treatment of cancer. Synthetic inhibitors of COX-2, which target enzymatic activity, are the only clinical strategy to counteract COX-2. However, these compounds present severe side effects, a fact that limits their prolonged intake, like requested in chemoprevention or during anti-cancer treatment.An alternative strategy to target COX-2 is at the level of its expression. A number of studies show that several natural compounds including curcumin, resveratrol or apigenin preferentially target COX-2 expression without showing toxicity.Our study analyses the effect of cinnamic acid, a natural compound derived from Cinnamonium cassia on COX-2 expression during carcinogenesis, with the final aim to evaluate its potential in chemoprevention/therapy.For our chemopreventive purposes, we used the non-carcinogenic breast cell line MCF10A, stimulated by the phorbol ester 12-phorbol myristate 13-acetate (PMA), which typically induces COX-2. We show a reduction of induced COX-2 expression after treatment with different concentrations of cinnamic acid (1 and 10μM). The analysis of the mechanisms involved in COX-2 protein expression decrease shows that cinnamic acid regulated COX-2 expression at the post-transcriptional level by reducing COX-2 mRNA stability. This effect is associated with the ability of cinnamic acid to prevent downregulation of miR-16 expression and p38 activation in response to PMA treatment.
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Efeitos de ácido cinâmico sobre melanócitos e células derivadas de melanomas humanos: avaliação do seu potencial antitumoral e de proteção contra danos celulares causados por radiação ultravioleta. / Cinnamic acid effects on cultured human melanocytes and melanoma derived cells: evaluation of its antitumor potential and protection against cell damage caused by ultraviolet radiation.

Niero, Evandro Luís de Oliveira 14 July 2010 (has links)
Poucos tratamentos têm efeito sobre melanomas metastáticos, mas novas drogas vêm sendo estudadas para combater esta doença. Este trabalho avaliou efeito de ácido cinâmico (AC) em melanócitos (NGM) e células de melanoma (HT144) sobre alterações no ciclo, morte, comunicação e mobilidade celular e morfologia nuclear e investigou efeito de proteção à radiação ultravioleta (UV). AC inibiu crescimento de HT144 em relação a NGM. Essa inibição deve ocorrer devido a dano no DNA que levou à inibição da fase S, formação de aberrações nucleares e indução de morte. AC induziu formação de micronúcleos nas células NGM. O citoesqueleto foi reorganizado após AC o que diminuiu a mobilidade celular. Apesar de não induzir comunicação entre as células HT144 o AC aumentou níveis citoplasmáticos de cx43 em células de hepatocarcinoma, o que contribui para a morte celular. Isto sugere maior citotoxicidade de AC em células HT144 em comparação com NGM. Porém, AC não protegeu as células dos efeitos de UV e sua genotoxicidade em células NGM indica que sua atividade depende de mais estudos. / Consumption of vegetables could decrease the risk of malignancies. Cinnamic acid (CA), commonly found in plants have been studied because their antitumor activitie. The present work aimed to evaluate effect of CA in melanocytes (NGM) and melanoma cells (HT-144) by focusing the cell cycle, death, mobility and communication and formation of nuclear aberration and to investigate potential of protection against UV radiation. CA inhibited cell growth of melanoma cells compared to melanocytes, probably due to DNA damage leading to DNA synthesis inhibition, induction of nuclear aberrations and apoptosis. High concentration of CA induced micronuclei in NGM cells. We observed cytoskeleton reorganization that decreased cell mobility in both cells. We have not observed communication in HT144 after treatment, but CA increased expression of cx43 in hepatocarcinoma cells, probably leading to apoptosis. CA did not showed protection effects against ultraviolet radiation and its genotoxic effects in NGM cells indicates that its mechanism of action must be further investigated.
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Efeito de tratamentos químicos, revestimentos comestíveis e irradiação na conservação de mamões minimamente processados / Effect of chemical treatments, edible coatings, and irradiation on fresh-cut papaya conservation

Albertini, Silvana 25 November 2011 (has links)
Avaliou-se o efeito de tratamentos químicos, revestimentos comestíveis e irradiação na conservação de mamões processados minimamente. Após seleção, lavagem e sanitização, os mamões foram descascados e cortados em meias rodelas, as quais foram submetidas a diferentes tratamentos, embaladas e armazenadas a 5±1°C e 90±2%UR. Os mamões PM foram avaliados após 1, 3, 6, 9, 12 e 15 dias. As análises microbiológicas foram fundamentadas na quantificação de coliformes totais e termotolerantes, bactérias psicrotróficas, bolores e leveduras, assim como na verificação da presença de Salmonella. As avaliações físico-químicas basearam-se na determinação da concentração de CO2 no interior das embalagens, perda de massa, cor, firmeza, sólidos solúv eis, acidez titulável, ratio e pH. As características sensoriais aparência, aroma, sabor e textura foram avaliad as por meio de testes com escala hedônica. No primeiro experimento os tratamentos foram: controle, aldeído cinâmico a 0,1%, cloreto de cálcio a 0,75% e combinação de aldeído cinâmico a 0,1% com cloreto de cálcio a 0,75%. O uso de tratamentos químicos em mamões PM resultou em: maior controle de coliformes totais para os mamões PM tratados com aldeído cinâmico e com a combinação de aldeído cinâmico e cloreto de cálcio; menor concentração de CO2 e maior manutenção da firmeza para mamões PM tratados com a combinação de aldeído cinâmico e cloreto de cálcio; e maior concentração de CO2 para os mamões PM tratados apenas com aldeído cinâmico. A imersão nos tratamentos químicos resultou em maior descoloração da polpa dos mamões PM e redução do teor de sólidos solúveis ao longo do armazenamento. No segundo experimento foram utilizados os tr atamentos: controle, amido de arroz a 3%, alginato de sódio a 0,5% e carboximetilcelulose a 0,25%. O uso desses três tipos de revestimento resultou em maior controle de coliformes totais do que o observado no controle. Mamões PM revestidos com amido de arroz e carboximetilcelulose apresentaram redução e aumento da concentração de CO2, respectivamente. Os mamões PM revestidos apresentaram menores teores de sólidos solúveis e seus valores de pH se tornaram menores após 9 dias de armazenamento refrigerado. O r evestimento com carboximetilcelulose proporcionou maior firmeza da polpa no 15° dia. No terceiro experimento foram utilizados os tratamentos: controle, radiação nas doses de 2kGy e 4kGy. O uso de radiação gama em mamões PM resultou em: maior controle de coliformes totais; menor concentração de CO2 nos mamões PM tratados com 2kGy; maior concentração de CO2 e maior descoloração da polpa nos mamões PM tratados com 4kGy; redução da firmeza nos mamões PM tratados com 2kGy e 4kGy; ligeira redução do teor de sólidos solúveis e pequenas variações da acidez titulável em todos os tratamentos. As características sensoriais dos mamões PM tratados com radiação gama não diferiram significativamente do controle durante os 15 dias de armazenamento / The effect of chemical treatments, edible coatings , and irradiation on fresh-cut papaya conservation was evaluated. After selection, washing, and sanitation the papayas were peeled and cut into half slices, which were submitted to different treatments, packed, and stored at 5±1°C and 90±2%RU. The fresh-cut papayas were evaluated after 1, 3, 6, 9, 12, and 15 days. The microbiological analyses were based on the count of total coliform, thermotolerant and psychrotrophic bacteria, molds and yeasts, as well as on the presence of Salmonella. The physicochemical evaluations were based on the determination of CO2 concentration inside the package, weight loss, color, firmness, soluble solids, titratable acidity, ratio, and pH. The sensory characteristics appearance, aroma, flavor, and texture were evaluated using a hedonic scale. In the first experiment, the treatments tested we re: control, cinnamic aldehyde 0.1%, calcium chloride 0.75%, and the combination of cinnamic aldehyde 0.1% and calcium chloride 0.75%. Using chemical treatments to preserve fresh cut papaya resulted in: higher control of total coliforms in fresh-cut papayas treated with cinnamic aldehyde and with the combination of cinnamic aldehyde and calcium chloride; lower CO2 concentration and increased maintenance of firmness in freshcut papayas treated with the combination of cinnamic aldehyde and calcium chloride; and increased in the CO2 concentration in fresh-cut papayas treated only with cinnamic aldehyde. Immersion in chemical treatments caused higher pulp discoloration and reduction in solu ble solids during storage. In the second experiment, the treatments tested were: control, rice starch 3%, sodium alginate 0.5%, and carboxymethylcellulose 0.25%. The use of these three coatings resulted in higher control of total coliforms compared to the control treatment. The fresh-cut papayas coated with rice starch and carboxymethylcellulose presented reduction and increase in the CO2 concentration, respectively. Coated fresh-cut papayas presented lower soluble solids and pH values were lower after 9 days of cold storage. Carboxymethylcellulose coating increased firmness maintenance at day 15. In the third experiment, the following treatments were used: control, radiation at the doses of 2kGy and 4kGy. The use of Gamma radiation in fresh-cut papaya resulted in: higher control of total coliforms; lower CO2 concentration in fresh-cut treated with 2kGy; increased CO2 concentration and increased pulp discoloration in fresh-cut papayas treated with 4kGy; reduction in firmness in fresh-cut papayas treated with 2kGy and 4kGy; slight reduction in soluble solids and small changes in titratable acidity in all treatments. The sensory characteristics of fresh-cut papayas treated with gamma radiation did not significantly differ from the control during the 15 days of storage

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