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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.
21

Estudos químico e biológico de taninos e antraquinonas que atuam no sistema gastrointestinal / Chemical and biological studies of tannins and anthraquinones acting on the gastrointestinal tract

Demarque, Daniel Pecoraro 27 November 2017 (has links)
Diversas plantas com atuação no trato gastrointestinal - ricas em taninos e antraquinonas - ainda deixam muitas dúvidas quanto a sua caracterização estrutural, o seu mecanismo de ação e toxicidade. O presente trabalho objetivou o estudo químico e biológico de duas plantas utilizadas para doenças relacionadas ao sistema gastrointestinal: barbatimão (Stryphnodendron rotundifolium), rico em procianidinas e taninos (utilizada para combater gastrite); e cáscara sagrada (Rhamnus purshiana), rica em antraquinonas (utilizada para constipação). Inicialmente foi realizado um estudo químico com as plantas envolvendo isolamento e caracterização de componentes do extrato por RMN (1H, 13C, DEPT e NOESY), espectrometria de massas (MS), infravermelho e dicroísmo circular vibracional (VCD). Essas substâncias foram utilizadas para a padronização dos extratos utilizados em estudo biológico. O estudo biológico envolveu testes in vitro para avaliar a toxicidade de diferentes componentes do extrato de cáscara sagrada e teste in vivo com barbatimão, visando, através do tratamento de animais e remoção do estômago para estudo em microscopia confocal, entender o mecanismo de proteção gástrica. Com o desenvolvimento do trabalho foi possível desenvolver novas metodologias para a identificação de antraquinonas utilizando espectrometria de massas e provar a veracidade de regras empíricas utilizadas para a determinação da configuração absoluta de moléculas dessa classe. Os testes in vitro com antraquinonas isoladas e padrões comerciais indicam a possibilidade de aprimoramento dos perfis químicos utilizados para a produção de medicamentos a base de extratos de cáscara sagrada, visando à redução de toxicidade. Quanto ao barbatimão, o estudo químico possibilitou a aplicação da técnica de VCD para a diferenciação de procianidinas diasteroisomericas. Os estudos in vivo confirmaram a eficácia do uso de taninos para combater gastrite através da formação de um revestimento protetor. / Several plants with action in the gastrointestinal tract - rich in tannins and anthraquinones - cause many doubts concerning their chemical characterization, mechanism of action and toxicity. The present work aimed to develop a chemical and biological study of two plants used for gastrointestinal system related diseases: barbatimão (Stryphnodendron rotundifolium), rich in procyanidins and tannins (used to treat gastritis); and cascara sagrada (Rhamnus purshiana), rich in anthraquinones (used for constipation). Initially, a chemical study with plants was performed comprising isolation and characterization of components of the extract through NMR (1H, 13C, DEPT and NOESY), mass spectrometry (MS), and infrared and vibrational circular dichroism (VCD). These substances were used for extract standardization used in biological studies. The in vitro tests were performed in order to evaluate the toxicity of different components of the cascara extract. The in vivo tests with barbatimão aimed to better understand the mechanism of gastric protection, by treating animals with the extract, removing their stomachs, and analyzing them with fluorescence microscopy. Through this work we were able to develop new methods for identifying anthraquinones by mass spectrometry and to prove empirical NMR rules used to determine the absolute configuration of molecules of this class. The tests with isolated anthraquinones indicated the possibility of improving chemical profile to further reduce cascara sagrada toxicity. The barbatimão chemical study allowed the application of VCD technique for the differentiation of diasteroisomeric procyanidins, and confirmed the effectiveness of using tannins for gastritis treatment through the formation of a protective coating.
22

Estudos comportamentais da exposição à Senna occidentalis durante o período perinatal em ratos / Behavioral studies of Senna occidentalis exposure during the perinatal period in rats

Carvalho, Vanessa Anastacio da Costa 20 August 2013 (has links)
A Senna occidentalis (sinônimo Cassia occidentalis) é uma planta amplamente utilizada pela população para fins medicinais, embora esteja associada a casos de intoxicação humana e animal. Por isso, além de ser considerada um problema de saúde pública, é tida também como uma planta tóxica de interesse pecuário. Sua toxicidade é atribuída à diantrona, uma quinolona, cujo mecanismo de ação tóxico se deve ao desacoplamento da fosforilação oxidativa mitocondrial, promovendo dano mitocondrial especialmente nos órgãos com maior demanda de oxigênio. O objetivo deste trabalho foi estudar, em ratos, os possíveis efeitos tóxicos causados pela exposição à Senna occidentalis durante o período de gestação. Para tanto, 36 fêmeas prenhes foram divididas em 5 grupos, que foram tratados do 6º ao 20º dia de gestação (período de organogênese e de desenvolvimento fetal) com 1%, 2%, 3% e 4% de sementes da planta na ração; o grupo controle recebeu a ração normal do laboratório. A escolha dessas concentrações foi embasada em estudos prévios de toxicidade subaguda em ratos, que mostraram efeito dose-dependente. Durante o período de gestação foram avaliados o peso corpóreo e o consumo de ração e água das fêmeas. Após o nascimento, os filhotes foram analisados quanto ao número de vivos e mortos e para a detecção de possíveis malformações externas. Foi avaliado também o desempenho reprodutivo e o comportamento materno das fêmeas. Com relação à prole, observou-se o seu desenvolvimento físico e de reflexos, bem como atividade geral no campo aberto, comportamento de brincar, labirinto em cruz elevado e labirinto em T. Os resultados do presente estudo mostraram diminuição no ganho de peso das ratas tratadas com 2%, 3% e 4% da planta na ração, além de diminuição no consumo de ração, prejuízo no desempenho reprodutivo e sinais de intoxicação em ratas do grupo de 4%. Ratas tratadas com 2% de S. occidentalis na ração apresentaram prejuízo no comportamento materno. Ainda, houve adiantamento para o aparecimento de pelos e erupção dos dentes incisivos em filhotes do grupo de 1%, bem como adiantamento para o desenvolvimento do reflexo de geotaxia negativa e para a perda do reflexo de preensão palmar em filhotes dos grupos de 3% e 1% respectivamente. Estes resultados indicam que a exposição à S. occidentalis durante a gestação causou toxicidade materna acompanhada de prejuízo no comportamento materno e alteração no desenvolvimento físico e reflexológico da prole destas ratas. / The Senna occidentalis (synonym Cassia occidentalis) is a plant widely used by people for medicinal purposes, although it is associated with cases of human and animal poisoning. So, besides being considered a public health problem, it is also regarded as a toxic plant of livestock interest. Its toxicity is attributed to diantrone, a quinolone, whose mechanism of action is due to the toxic uncoupling of mitochondrial oxidative phosphorylation, promoting mitochondrial damage especially in organs with higher oxygen demand. The objective of this work was to study, in rats, the possible toxic effects caused by exposure to Senna occidentalis during the gestation period. For this purpose, 36 female rats were divided into 5 groups, which were treated from the 6th to the 20th day of gestation (period of organogenesis and fetal development) with 1%, 2%, 3% and 4% of plant seeds in the diet; the control group received normal chow lab. The choice of these concentrations was based on previous studies of subacute toxicity in rats, which showed dose-dependent effect. During the period of gestation were evaluated: body weight, feed intake and water consumption of females. After birth, pups were analyzed for the number of living and dead, and for the detection of possible external malformations. We also evaluated the reproductive performance and maternal behavior of females. With regard to offspring, it was observed their physical and reflexes development, their general activity in the open field, their play behavior and their behavior in elevated plus maze and T maze. The results of this study showed a decrease in body weight of dams treated with 2%, 3% and 4% of the plant in the diet, in addition to reduced feed intake, impaired reproductive performance and signs of poisoning in dams of group 4%. Dams treated with 2% of S. occidentalis in diet showed impaired maternal behavior. Still, there was an advance for the appearance of hair and for the eruption of incisors in pups from 1%, as well as an advance to the development of negative geotaxis reflex and to the loss of palmar grasp reflex in puppies of 3% and 1% groups respectively. These results indicate that exposure to S. occidentalis during pregnancy caused maternal toxicity accompanied by impairment in maternal behavior and change in reflexology and physical development of the offspring of these rats.
23

Estudo quÃmico e farmacolÃgico de Senna reticulata / Chemical and pharmacological study of Senna reticulata

RogÃrio Nunes dos Santos 30 March 2007 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Este trabalho descreve a investigaÃÃo fitoquÃmica de Senna reticulata Willd., (Leguminoseae), popularmente conhecida no Cearà como mangerioba grande, que tem uso na medicina popular no tratamento de doenÃas do fÃgado, reumatismo e cÃlicas menstruais. Os gÃneros Senna, Chamaecrista e Cassia foram investigados a partir de seus compostos antraquinÃnicos relatados na literatura atà os dias atuais, no interesse de se traÃar um perfil, que contribuÃsse com distinÃÃo quÃmica dos mesmos que atà alguns anos eram confundidos devido as suas grandes semelhanÃas botÃnicas. O tratamento cromatogrÃfico dos extratos etanÃlicos das folhas, caule e cascas de Senna reticulata possibilitou o isolamento e identificaÃÃo de seis antraquinonas, um flavonÃide e uma biantrona, a identificaÃÃo da mistura de dois triterpenos e dois fitoesterÃis glicosilados e em forma livre. Outra etapa do trabalho foi dedicada ao estudo farmacolÃgico de S. reticulata, que atravÃs de ensaios analisou o potencial antioxidante, a atividade antiparasitÃria, antibacteriana e anticonvulsivante dos extratos etanÃlicos das cascas, folhas, caule e substÃncias isoladas da referida espÃcie. As determinaÃÃes estruturais foram realizadas atravÃs de anÃlises espectroscÃpicas tais como: espectroscopia na regiÃo do infravermelho, de ressonÃncia magnÃtica nuclear de hidrogÃnio-1 e carbono-13, incluindo tÃcnicas bidimensionais do tipo 1H, 13C-COSY (nJCH, n = 1, 2 e 3) com detecÃÃo inversa, espectrometria de massas e comparaÃÃo com dados da literatura. / This work decrib the phytochemical investigations of Senna reticulata Willd., (Leguminoseae), popularly known as âmangerioba grandeâ in the Brazilian Northeastern. Medicinal plant used for of liver illnesses, for rheumatism and menstrual pains. The genera Senna, Chamaecrista and Cassia were investigated from to from your compounds anthraquinones told in the literature until the current days, in the interest of tracing a profile, that contributed with chemical distinction of the same ones that to some years they were confused due your great botanical similarities. The chemical studies of ethanol extract of leaves, trunk and trunk bark of S. reticulata, making possible the isolation and identification of six anthraquinones, one flavone and one bianthrone, a mixture of two triterpenes and two a mixture of glucosilated and free β-sitosterol and stigmasterol. Another stage of the work was dedicated to the study pharmacologic of S. reticulata, that through rehearsals analyzed the antioxidant potential, the activity antiparasite, antibacterials and anticonvulsant of the extracts ethanol the leaves, trunk and trunk bark and isolated substances of the referred species. The molecular structures of compounds were elucidated by spectroscopic methods such as infrared, mass epectrometry, and nuclear magnetic resonance including special pulse sequences such as 1H, 13C-COSY (nJCH, n = 1, 2 e 3) with inverse detection and comparison with literature data.
24

Estudos comportamentais da exposição à Senna occidentalis durante o período perinatal em ratos / Behavioral studies of Senna occidentalis exposure during the perinatal period in rats

Vanessa Anastacio da Costa Carvalho 20 August 2013 (has links)
A Senna occidentalis (sinônimo Cassia occidentalis) é uma planta amplamente utilizada pela população para fins medicinais, embora esteja associada a casos de intoxicação humana e animal. Por isso, além de ser considerada um problema de saúde pública, é tida também como uma planta tóxica de interesse pecuário. Sua toxicidade é atribuída à diantrona, uma quinolona, cujo mecanismo de ação tóxico se deve ao desacoplamento da fosforilação oxidativa mitocondrial, promovendo dano mitocondrial especialmente nos órgãos com maior demanda de oxigênio. O objetivo deste trabalho foi estudar, em ratos, os possíveis efeitos tóxicos causados pela exposição à Senna occidentalis durante o período de gestação. Para tanto, 36 fêmeas prenhes foram divididas em 5 grupos, que foram tratados do 6º ao 20º dia de gestação (período de organogênese e de desenvolvimento fetal) com 1%, 2%, 3% e 4% de sementes da planta na ração; o grupo controle recebeu a ração normal do laboratório. A escolha dessas concentrações foi embasada em estudos prévios de toxicidade subaguda em ratos, que mostraram efeito dose-dependente. Durante o período de gestação foram avaliados o peso corpóreo e o consumo de ração e água das fêmeas. Após o nascimento, os filhotes foram analisados quanto ao número de vivos e mortos e para a detecção de possíveis malformações externas. Foi avaliado também o desempenho reprodutivo e o comportamento materno das fêmeas. Com relação à prole, observou-se o seu desenvolvimento físico e de reflexos, bem como atividade geral no campo aberto, comportamento de brincar, labirinto em cruz elevado e labirinto em T. Os resultados do presente estudo mostraram diminuição no ganho de peso das ratas tratadas com 2%, 3% e 4% da planta na ração, além de diminuição no consumo de ração, prejuízo no desempenho reprodutivo e sinais de intoxicação em ratas do grupo de 4%. Ratas tratadas com 2% de S. occidentalis na ração apresentaram prejuízo no comportamento materno. Ainda, houve adiantamento para o aparecimento de pelos e erupção dos dentes incisivos em filhotes do grupo de 1%, bem como adiantamento para o desenvolvimento do reflexo de geotaxia negativa e para a perda do reflexo de preensão palmar em filhotes dos grupos de 3% e 1% respectivamente. Estes resultados indicam que a exposição à S. occidentalis durante a gestação causou toxicidade materna acompanhada de prejuízo no comportamento materno e alteração no desenvolvimento físico e reflexológico da prole destas ratas. / The Senna occidentalis (synonym Cassia occidentalis) is a plant widely used by people for medicinal purposes, although it is associated with cases of human and animal poisoning. So, besides being considered a public health problem, it is also regarded as a toxic plant of livestock interest. Its toxicity is attributed to diantrone, a quinolone, whose mechanism of action is due to the toxic uncoupling of mitochondrial oxidative phosphorylation, promoting mitochondrial damage especially in organs with higher oxygen demand. The objective of this work was to study, in rats, the possible toxic effects caused by exposure to Senna occidentalis during the gestation period. For this purpose, 36 female rats were divided into 5 groups, which were treated from the 6th to the 20th day of gestation (period of organogenesis and fetal development) with 1%, 2%, 3% and 4% of plant seeds in the diet; the control group received normal chow lab. The choice of these concentrations was based on previous studies of subacute toxicity in rats, which showed dose-dependent effect. During the period of gestation were evaluated: body weight, feed intake and water consumption of females. After birth, pups were analyzed for the number of living and dead, and for the detection of possible external malformations. We also evaluated the reproductive performance and maternal behavior of females. With regard to offspring, it was observed their physical and reflexes development, their general activity in the open field, their play behavior and their behavior in elevated plus maze and T maze. The results of this study showed a decrease in body weight of dams treated with 2%, 3% and 4% of the plant in the diet, in addition to reduced feed intake, impaired reproductive performance and signs of poisoning in dams of group 4%. Dams treated with 2% of S. occidentalis in diet showed impaired maternal behavior. Still, there was an advance for the appearance of hair and for the eruption of incisors in pups from 1%, as well as an advance to the development of negative geotaxis reflex and to the loss of palmar grasp reflex in puppies of 3% and 1% groups respectively. These results indicate that exposure to S. occidentalis during pregnancy caused maternal toxicity accompanied by impairment in maternal behavior and change in reflexology and physical development of the offspring of these rats.
25

Reductive biotransformation and decolorization of reactive anthraquinone dyes

Lee, Young H. 01 December 2003 (has links)
No description available.
26

The effect of oxygen and anthraquinone on the alkaline depolymerization of amylose

Arbin, Folke Lennart Anders. January 1980 (has links) (PDF)
Thesis (Ph. D.)--Institute of Paper Chemistry, 1980. / Includes bibliographical references (p. 54-57).
27

A study of the kinetics of delignification during the early stage of alkaline sulfite anthraquinone pulping

Biasca, Karyn L. January 1989 (has links) (PDF)
Thesis (Ph. D.)--Institute of Paper Chemistry, 1989. / Bibliography: leaves 87-89.
28

Time-resolved spectroscopic studies of meta methyl activation reaction of selected benzophenone and anthraquinone derivatives

Ma, Jiani, 马佳妮 January 2013 (has links)
Femtosecond time-resolved transient absorption (fs-TA), nanosecond time-resolved transient absorption (ns-TA), and nanosecond time-resolved resonance Raman spectroscopy (ns-TR3) methods were used to study the behaviors of the transient intermediates involved in the photophysical and photochemical processes of 3-methylbenzophenone (3-MeBP), 3-(hydroxymethyl)benzophenone (m-BPOH), and 2-(1-hydroxyethyl) 9,10-anthraquinone (2-HEAQ). A particular focus of this work was to study the unusual meta methyl activation reactions of these compounds in water-containing solutions. Density functional theory (DFT) calculations were conducted to help make assignments of the observed experimental transient species and to better understand the reaction mechanisms. First, the photophysical and photochemical reactions of m-BPOH were investigated in selected solvents. In acetonitrile (MeCN) the formation of the triplet state of m-BPOH, (denoted as (m-BPOH)3 ), was detected via an intersystem crossing (ISC). In 2-propanol (IPA), (m-BPOH)3 abstracted a hydrogen atom from the solvent molecule to form an aryl ketyl radical. In an acidic mixed aqueous solution at pH 2, the photoredox reaction appeared to be the predominant reaction. In a more acidic aqueous solution with [H+] =1.0 M, the photoredox reaction faced some competition from the overall photohydration reaction. Second, the photophysical and photochemical reactions of 2-HEAQ in MeCN, IPA, and neutral, acid and basic aqueous solutions were studied. The ISC process of 2-HEAQ took place in MeCN with generation of the triplet excited state species of 2-HEAQ, (2-HEAQ)3. In IPA solvent, (2-HEAQ)3 underwent a hydrogen abstraction with the solvent. A photoredox reaction takes place via an initial protonation process of the AQ group that is followed by deprotonation of the methylene C-H bond in aqueous solutions within a pH range from 2 to 10. Under a stronger acidic aqueous condition with [H+] =1.0 M, the photohydration reaction becomes the major reaction. In strong basic solutions (pH=12) only ISC was observed to take place. The unusual photoredox reaction takes place via protonation of the carbonyl oxygen first followed by deprotonation of the C-H bond in the side chain for both m-BPOH and 2-HEAQ. The protonation of the excited carbonyl oxygen group has been widely studied. On the other hand, the deprotonation of methylene C-H bond is unusual. Therefore, this photoredox reaction for m-BPOH and 2-HEAQ is termed as a meta methyl activation reaction. Third, the photophysical and photochemical reactions of 3-MeBP were explored and compared to those of 4-methylbenzophenone (4-MeBP). This work found that 3-MeBP and 4-MeBP exhibit similar behaviors with m-BPOH and 2-HEAQ in MeCN and IPA. In MeCN, both 3-MeBP and 4-MeBP undergo an efficient ISC process producing triplet excited state species, (3-MeBP)3 and (4-MeBP)3, respectively. In IPA, the (3-MeBP)3 and (4-MeBP)3 intermediates were quenched by the hydrogen abstraction reaction with the solvent. In acidic aqueous solutions (pH  2), the protonated carbonyl oxygen species (3-MeBPH+)3 and (4-(MeBPH+)3 are directly observed by fs-TA spectra. In the case of 4-MeBP, a photohydration is detected and the m-(4-MeBPH2O)3 and o-(4-MeBPH2O)1 species are observed. In contrast, an unusual meta methyl activation reaction is observed for 3-MeBP. In a stronger acid aqueous solution ([H+] =1.0 M) the meta methyl activation reaction becomes the predominant reaction. / published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
29

A comprehensive mechanism for anthraquinone mass transfer in alkaline pulping

Samp, James Christian 05 May 2008 (has links)
A mechanism for the mass transfer of anthraquinone (AQ) into wood during alkaline pulping has been developed. Although the chemistry of action of AQ is well-developed, there has not been much work conducted on its diffusion properties. The discrepancies between different experiments with AQ indicate that something other than the chemistry is at work. Because most of the differences arise from differences in pulping conditions, it is likely that mass transfer is the source of these discrepancies. A model system was therefore developed to explore the mass transfer properties of AQ. It was shown that AQ must be reduced to anthrahydroquinone (AHQ) at the membrane surface before any permeation of a membrane can occur. It was also shown that increasing surface coverage of the membrane through AQ particle size reduction could improve the rate of membrane permeation. The mechanism described by the model system was then tested against pulping data. It was shown that the addition of surfactants increases the pulping efficiency of AQ. This is probably through better dispersion of AQ particles to cover more chip surface area. Bulk reduction effects were also tested, and it was shown that bulk phase reducing agents decrease the efficacy of AQ in pulping. This led to the development of the mechanism for AQ diffusion in alkaline pulping.
30

Part 1 controlling barriers to charge transfer in DNA : Part 2 : DNA-directed assembly of conducting oligomers /

Güler, Gözde. January 2008 (has links)
Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2009. / Committee Chair: Schuster, Gary; Committee Member: Barry, Bridgette; Committee Member: Collard, David; Committee Member: Tolbert, Laren; Committee Member: Wartell, Roger. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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