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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.
381

Estudo fitoquímico da raiz de Dictyoloma vandellianum A. Juss

Alves, Iura Muniz January 2008 (has links)
Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2016-08-31T15:49:34Z No. of bitstreams: 1 Estudo fitoquímico da raiz de Dictyoloma vandellianum A. Jus.pdf: 13732713 bytes, checksum: 433553ed8ebe16e3ce80d35862057ca6 (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2016-09-02T16:23:25Z (GMT) No. of bitstreams: 1 Estudo fitoquímico da raiz de Dictyoloma vandellianum A. Jus.pdf: 13732713 bytes, checksum: 433553ed8ebe16e3ce80d35862057ca6 (MD5) / Made available in DSpace on 2016-09-02T16:23:26Z (GMT). No. of bitstreams: 1 Estudo fitoquímico da raiz de Dictyoloma vandellianum A. Jus.pdf: 13732713 bytes, checksum: 433553ed8ebe16e3ce80d35862057ca6 (MD5) / Nesta dissertação são descritos o isolamento e determinação estrutural de alguns produtos naturais, presentes nos extratos orgânicos da raiz de um espécime de Dictyoloma vandellianum A. Juss, coletado na Chapada Diamantina, Bahia. Do extrato diclorometânico da casca da raiz foram isoladas cinco cromonas. Do extrato hexânico do cerne da raiz foi isolado um esteróide. Dois alcalóides foram isolados do extrato metanólico do cerne da raiz. As substâncias isoladas e caracterizadas foram: 6-(3-metil-2-butenil) allopteroxilina éter metílico; 8-(3-metil-2-butenil) spatheliacromeno éter metílico; 6-(3-metil-2-butenil) allopteroxilina; 8-(3-metil-2-butenil) spatheliacromeno; spatheliabiscromeno; β-sitosterol; N-metil-8-metoxiflindersina e 8- metoxiflindersina. Elas foram determinadas por espectroscopia de infravermelho, técnicas de RMN, associações com propostas de biossíntese e comparação com dados da literatura. A localização do gênero Dictyoloma tem sido duvidosa desde a primeira vez em que foi descrito como integrante da família Rutaceae. O isolamento de cromonas preniladas na espécie D. vandellianum A. Juss, metabólitos que não são encontrados em outros gêneros da família Rutaceae, demonstra a singularidade do gênero dentro desta família. Deste modo, o isolamento de metabólitos característicos de Rutaceae e das cromonas preniladas contribui com a quimiotaxonomia do gênero. / This work presents isolation and structural determination of some natural products in organic root extract of Dictyoloma vandellianum A. Juss found in the Chapada Diamantina, Bahia. Five chromones were isolated from root rind dichloromethane extract and a steroid from root core hexane extract. Two alkaloids also isolated from root core methanolic extract. The following compounds were isolated and characterized: 6-(3-methyl-2-butenyl) allopteroxylin methyl ether; 8-(3-methyl-2-butenyl) spatheliachromen methyl ether; 6-(3-methyl-2-butenyl) allopteroxylin; 8-(3-methyl-2-butenyl) spatheliachromen; spatheliabischromen; β-sitosterol; N- methyl-8-methoxyflindersine and 8-methoxyflindersine. That compounds were determined by Infrared Spectroscopy and Nuclear Magnetic Resonance technique. Associations with biosynthesis approach and comparison with literature data were also done in this thesis. The exact localization of the genus Dictyoloma has been doubtful since its first description as member of Rutaceae family. Prenyl-chromones type isolation from D. vandellianum A. Juss demonstrates the importance of the plant study. The prenyl-chromones type has not been found in other genus of Rutaceae family. So, isolation of Rutaceae typical metabolites and prenyl-chromones contributes with the chemotaxonomy of the genus
382

Progress towards the synthesis of perophoramidine : formation of the contiguous quaternary centres

Johnston, Craig A. January 2013 (has links)
Perophoramidine 1 is a halogenated natural product which contains two contiguous quaternary centres within its structure. In this thesis, approaches towards the synthesis of perophoramidine are described. In particular, the synthesis of the tetracyclic core structure and the formation of the quaternary centres have been examined. In Chapter 1, the natural product perophoramidine 1 is introduced and its isolation, structure and biological activity is discussed. The structurally related communesin family of natural products are also introduced before the literature published on both the biosynthesis and laboratory synthesis of perophoramidine 1, is reviewed. Finally the Westwood group's approach towards the synthesis of perophoramidine 1 is introduced with a summary of non-halogenated model system investigations previously carried out within the group being provided. Chapter 2 describes studies towards the synthesis of an appropriately halogenated indolo[2,3-b]quinoline core structure of perophoramidine 1. This then allowed methodology previously developed within the group on model system substrates to be applied to the formation of the first of the two quaternary centres required for the synthesis of perophoramidine 1. Chapter 3 describes the attempted formation of the second quaternary centre using an ester alkylation approach. After initial studies failed to generate the desired quaternary centre, non-halogenated model system studies were carried out in an attempt to develop an alternative approach. In Chapter 4, model system studies were continued with cyclic ether compounds investigated as potential intermediates towards the synthesis of perophoramidine 1. The results obtained in this chapter provided a novel route to the formation of the second quaternary centre and led to a redesigned approach towards perophoramidine 1 being developed. In Chapter 5, this redesigned approach was applied to the halogenated intermediates synthesised in Chapter 1. This led to the formation of the first halogenated intermediate synthesised within the group which contained the two contiguous quaternary centres required for the synthesis of perophoramidine 1.
383

Análise química e biológica em alcalóides do gênero hippeastrum (amarylidaceae) / Chemical and biological analysis of alkaloids from the genus Hippeastrum (AMARYLLIDACEAE)

Andrade, Jean Paulo de January 2007 (has links)
A pesquisa de substâncias biologicamente ativas, advinda principalmente de plantas, tem levado a descoberta de moléculas clinicamente benéficas. A família Amaryllidaceae é conhecida por sintetizar alcalóides biologicamente ativos, principalmente do grupo tetraisoquinolínico. Estudos têm demonstrado que a atividade biológica destes vegetais está relacionada com a presença deste grupo de metabólitos secundários. No Rio Grande do Sul, é encontrado o gênero Hippeastrum, pertencente a família Amaryllidaceae. Neste trabalho, realizou-se a investigação preliminar de alcalóides dos extratos de Hippeastrum papilio, coletada na região serrana do estado. Foram isoladas 12 substâncias, nas quais 9 apresentam carcaterísticas químicas de alcalóides de Amaryllidaceae. Estudos preliminares de CLAE-EM e CG-EM apontam para a existência de alcalóides de núcleos licorina e haemantamina, além de núcleo galantamina, em menor quantidade. Estas análises também mostram a possibilidade de estruturas inéditas. Os extratos enriquecidos em alcalóides de Hippeastrum papilio demonstraram uma grande capacidade de inibição da enzima acetilcolinesterase, pelo método da bioutografia em cromatoplaca. Além disso, foi realizada a análise comportamental do alcalóide montanina, previamente isolada de Hippeastrum vittatum Este alcalóide foi avaliado na tarefa de reconhecimento de objeto, com administração intrahipocampal, testado 24 horas pós-treino (memória de longa duração). Obteve-se curva dose-resposta para o alcalóide, com dose pró-cognitiva estatisticamente significante de 1μg/μl. Esta mesma dose foi avaliada na mesma tarefa para obtenção de curva temporal. Montanina demonstrou atividade pró-cognitiva na mesma tarefa e testada 24 horas pós-treino, em administração imediatamente pós-treino, 180 minutos pós-treino, mas não em 360 min pós-treino. O alcalóide montanina também foi avaliado quanto ao perfil de inibição da enzima acetilcolinesterase, utilizando método de ultravioleta. Obteve-se inibição da enzima em concentrações de 10 μM, 100 μM e 1 mM. Os resultados obtidos neste trabalho apontam para a necessidade de continuação da investigação química de Hippeastrum papilio, motivada pelo grande potencial de inibição da enzima acetilcolinesterase e por possibilidade de isolamento de estruturas inéditas. Além disso, foi confirmado um grande potencial pró-cognitivo do alcalóide montanina, demonstrado comportamentalmente, além de inibir a enzima acetilcolinesterase, atividade esta necessária e importante para que uma substância seja candidata à terapia da Doença de Alzheimer. / A search for biologically active substances in plants has led to the discovery of clinically beneficial molecules. The family Amaryllidaceae is known to synthesize biologically active alkaloids, principally of the tetraisoquinolinic group. Studies have shown that the biological activity of these plants is due to the presence of these secondary metabolites. The Hippeastrum genus, belonging to the Amaryllidaceae family, is found in Rio Grande do Sul. A preliminary investigation of alkaloids from extracts of Hippeastrum papilio, collected in the mountain region of the Rio Grande do Sul was done in this work. Twelve substances were isolated, in which nine have chemical profile of Amaryllidaceae alkaloids. Preliminary studies with HPLC-MS and GC-MS showed the existence of lycorine and haemantamine type alkaloids, as well as galantamine type alkaloids in a lower quantity. These analysis also showed a possibile presence of unknown structures. The extracts, enriched in alkaloids of Hippeastrum papilio, demonstrated a great ability to inhibit the acetylcholinesterase enzyme by a rapid thin layer chromatography bioautographic method. Furthermore, it was done a behavior analysis of montanine, previously isolated from Hippeastrum vittatum This alkaloid was evaluated in recognition object task with intrahippocampal administration and tested for 24 hours postrainig (long term memory). There was found a doseeffect curve of montanine with cognitive-enhanced dose at 1μg/μl. This dose was evaluated in the same task for temporal-curve. Montanine showed procognitive activity in immediately postraining administration and 180 minutes postraining but not with 360 min postraining in the same task. The acetylcholinesterase inhibition profile of montanine alkaloid was also evaluated by a ultraviolet method. The enzyme was inhibited in concentrations of 10 μM, 100 μM and 1 mM of montanine. The results obtained in the present study show a need for further chemical investigation on Hippeastrum papilio due to its large potential for inhibition of the acetylcholinesterase and isolation of potentially new structures. Moreover, these results confirm the great pro-cognitive potential of montanine, behaviorally demonstrated, as well as its ability to inhibit the acetylcholinesterase enzime, which makes the alkaloid a candidate substance for the treatment of Alzheimer's Disease.
384

Alkaloidy čeledi Amaryllidaceae: rod Zephyranthes / Alkaloids of family Amaryllidaceae: genus Zephyranthes

Jánská, Lucie January 2018 (has links)
Author: Lucie Jánská Název: Alkaloids of family Amaryllidaceae: genus Zephyranthes Diploma thesis Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Pharmacognosy 2018, 75 p. The aim of this diploma thesis was to summarize all knowledge about alkaloids izolated from Zephyranthes plants of Amaryllidaceae family. It contains a detail overview of botanical charactericts of phytochemically studied plants of the genus Zephyranthes. Also the overview of alkaloids with bilogical activity was described. Within the genus Zephyranthes 10 species were studied phytochemically and 89 alkaloids were isolated from this plants. This alkaloids are divided in several structural groups. The lycorine-, haemanthamine-, galanthamine- and pancratistatine-type alkaloids occure the most frequently. Acetylcholinesterase-inhibitory, anticancer and antimalarial activity of the alkaloids was described like the most important. The most significant acetylcholinesterase- inhibitory activity was observed in alkaloids from galanthamine sctructural type. Anticancer activity was found the most in lycorine-, pancratistatine- and haemanthamine- type alkaloids. The most notable antimalarial activity was observed in lycorine- and heamanthamine- type alkaloids. Keywords Zephyranthes, Amaryllidaceae,...
385

Vliv biologické ochrany rostlin na produkci sekundárních metabolitů Papaver somniferum IV. / Influence of plant biological protection on production of secondary metabolites of Papaver somniferum IV.

Veselá, Tereza January 2018 (has links)
Vesela T.: Influence of plant biological control on production of secondary metabolites of Papaver somniferum IV. Diploma thesis, Charles University, Faculty of Pharmacy in Hradec Kralove, Department of pharmaceutical botany, Hradec Kralove 2018. In the experimental part of the thesis was studied the influence of plant biological control on the production of the main pharmaceutically usable secondary metabolites of opium poppy (Papaver somniferum L.). The contents of alkaloids morphine, codeine, thebain, papaverine and narcotine were monitored in the capsules and stems. Two poppy varieties, Orbis and Lazur, were selected for the experiment. Half of the plots were treated with the fungicidal biopreparate Polyversum, containing the germinable spores of oomycete Pythium oligandrum. Pythium oligandrum directly attacks the fungal pathogens. It also uses indirect control mechanisms, induces resistance in plants and promotes their growth. The remaining untreated plots served as a reference check. The extract was prepared from the individual samples. Subsequent analysis was performed using high performance liquid chromatography. The results show no positive effect of treatment on the content of all quantified alkaloids in poppy straw. Biosynthesis of alkaloids and Pythium oligandrum activity can be...
386

Alkaloidy Vinca minor (Apocynaceae) a jejich biologická aktivita / Alkaloids of Vinca minor (Apocynaceae) and their biological activities

Klátilová, Anežka January 2018 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical botany Candidate: Anežka Klátilová Supervisor: doc. Ing. Lucie Cahlíková Ph. D. Title of diploma thesis: Alcaloids of Vinca minor (Apocynaceae) and their biological activities The aim of this diploma thesis was to process the assigned fraction isolated from the Vinca minor L. plant and to isolate at least one alkaloid to test its biological activity. Using preparative TLC, the alkaloid was sequentially isolated from the fraction, which was then subjected to a structural analysis. NMR and EI-MS methods were used herein. Thanks to these analyzes, the alkaloid was identified as venoterpine. Furthermore, the alkaloid was prepared to test for biological activity. Thus, the isolated alkaloid was identified as venoterpine and tested for biological activity. The observed inhibitory concentration (IC50) to HuAChE and HuBuChe was more than 500 μM, indicating that venoterpine does not rank as a significant inhibitor of cholinesterase. Likewise, the value of cytotoxic activity, when this activity was found to be greater than 10 μM to colorectal cancer cells as well as to healthy cells, is not significant. Key words: Vinca minor, Apocynaceae, alkaloids, biological activities
387

Alkaloidy čeledi Amaryllidacee: rod Nerine. / Alkaloids of family Amaryllidaceae: genus Nerine.

Hodulová, Adéla January 2018 (has links)
Author: Adéla Hodulová Title: Alkaloids of Amaryllidaceae family, genus Nerine Diploma thesis Charles University, Faculty of pharmacy in Hradec Králové, Department of Pharmaceutical botany 2018, 51 p. The aim of this diploma thesis was to summarize up the findings about alkaloids which where isolated from genus Nerine plants of Amaryllidaceae family. There was introduced a botanical characteristic of the phytochemical studied species of the genus Nerine. The most studied species was Nerine bowdenii. All the knowledges about mentioned alkaloids were sum up. Ten species have been phytochemical studied out of the genus Nerine until now. In total, 40 alkaloids were isolated from these plants. Alkaloids which where isolated from the Nerine are divided into several structural types. Anticancer, acetylcholinesterase-inhibitory of the alkaloids were described. The biological activity is connected with their stucture. The most significant anticancer activity was observed in alkaloids from crinine- and lycorine type . Acetylcholinesterase-inhibitory activity was pronounced the most in crinine-type alkaloids. Keywords: Nerine, Nerine bowdenii, Amaryllidaceae, alkaloids
388

INVESTIGATING THE USE OF BLESSED THISTLE FOR AMELIORATION OF SYMPTOMS OF FESCUE TOXICITY IN BEEF COWS CONSUMING ENDOPHYTE-INFECTED TALL FESCUE SEED

Douglas, Jamie Marguerite 01 December 2015 (has links)
The present investigation was designed to investigate the use of blessed thistle (Cnicus benedictus) in amelioration of fescue toxicosis in beef cattle. Twenty-seven crossbred Angus cows were blocked by age and weight into groups of three. Each group (n=9) was then randomly assigned to one of three dietary treatments: endophyte-free (EF), endophyte-infected (EI), or endophyte-infected with addition of cut and stemmed blessed thistle (EIBT). Each group was also randomly assigned to one of three 29-day replicates. Parameters measured during this trial included: urinary ergot alkaloid concentration (ng ergot alkaloids/mg creatinine), body weight (kg), rectal temperature (°C), serum progesterone (ng/ml), and serum prolactin (ng/ml). No effect of treatment (P>0.05) was detected in any of these parameters. A treatment x time interaction (P<0.0001) was observed for progesterone concentrations, likely a result of estrous cyclicity of cows. Results of this study suggest that we were unsuccessful in inducing fescue toxicity in test subjects assigned to EI and EIBT treatments. Minimal dietary ergovaline (1.72 μg kg-1) and cool ambient temperatures (-6.7°C to 23.3°C) likely contributed to this inability. Data from this research do suggest, however, that C. benedictus can be successfully incorporated into cattle diets. Further research will need to be performed to fully elucidate what, if any, benefits blessed thistle can have in the treatment of fescue toxicity.
389

Análise química e biológica em alcalóides do gênero hippeastrum (amarylidaceae) / Chemical and biological analysis of alkaloids from the genus Hippeastrum (AMARYLLIDACEAE)

Andrade, Jean Paulo de January 2007 (has links)
A pesquisa de substâncias biologicamente ativas, advinda principalmente de plantas, tem levado a descoberta de moléculas clinicamente benéficas. A família Amaryllidaceae é conhecida por sintetizar alcalóides biologicamente ativos, principalmente do grupo tetraisoquinolínico. Estudos têm demonstrado que a atividade biológica destes vegetais está relacionada com a presença deste grupo de metabólitos secundários. No Rio Grande do Sul, é encontrado o gênero Hippeastrum, pertencente a família Amaryllidaceae. Neste trabalho, realizou-se a investigação preliminar de alcalóides dos extratos de Hippeastrum papilio, coletada na região serrana do estado. Foram isoladas 12 substâncias, nas quais 9 apresentam carcaterísticas químicas de alcalóides de Amaryllidaceae. Estudos preliminares de CLAE-EM e CG-EM apontam para a existência de alcalóides de núcleos licorina e haemantamina, além de núcleo galantamina, em menor quantidade. Estas análises também mostram a possibilidade de estruturas inéditas. Os extratos enriquecidos em alcalóides de Hippeastrum papilio demonstraram uma grande capacidade de inibição da enzima acetilcolinesterase, pelo método da bioutografia em cromatoplaca. Além disso, foi realizada a análise comportamental do alcalóide montanina, previamente isolada de Hippeastrum vittatum Este alcalóide foi avaliado na tarefa de reconhecimento de objeto, com administração intrahipocampal, testado 24 horas pós-treino (memória de longa duração). Obteve-se curva dose-resposta para o alcalóide, com dose pró-cognitiva estatisticamente significante de 1μg/μl. Esta mesma dose foi avaliada na mesma tarefa para obtenção de curva temporal. Montanina demonstrou atividade pró-cognitiva na mesma tarefa e testada 24 horas pós-treino, em administração imediatamente pós-treino, 180 minutos pós-treino, mas não em 360 min pós-treino. O alcalóide montanina também foi avaliado quanto ao perfil de inibição da enzima acetilcolinesterase, utilizando método de ultravioleta. Obteve-se inibição da enzima em concentrações de 10 μM, 100 μM e 1 mM. Os resultados obtidos neste trabalho apontam para a necessidade de continuação da investigação química de Hippeastrum papilio, motivada pelo grande potencial de inibição da enzima acetilcolinesterase e por possibilidade de isolamento de estruturas inéditas. Além disso, foi confirmado um grande potencial pró-cognitivo do alcalóide montanina, demonstrado comportamentalmente, além de inibir a enzima acetilcolinesterase, atividade esta necessária e importante para que uma substância seja candidata à terapia da Doença de Alzheimer. / A search for biologically active substances in plants has led to the discovery of clinically beneficial molecules. The family Amaryllidaceae is known to synthesize biologically active alkaloids, principally of the tetraisoquinolinic group. Studies have shown that the biological activity of these plants is due to the presence of these secondary metabolites. The Hippeastrum genus, belonging to the Amaryllidaceae family, is found in Rio Grande do Sul. A preliminary investigation of alkaloids from extracts of Hippeastrum papilio, collected in the mountain region of the Rio Grande do Sul was done in this work. Twelve substances were isolated, in which nine have chemical profile of Amaryllidaceae alkaloids. Preliminary studies with HPLC-MS and GC-MS showed the existence of lycorine and haemantamine type alkaloids, as well as galantamine type alkaloids in a lower quantity. These analysis also showed a possibile presence of unknown structures. The extracts, enriched in alkaloids of Hippeastrum papilio, demonstrated a great ability to inhibit the acetylcholinesterase enzyme by a rapid thin layer chromatography bioautographic method. Furthermore, it was done a behavior analysis of montanine, previously isolated from Hippeastrum vittatum This alkaloid was evaluated in recognition object task with intrahippocampal administration and tested for 24 hours postrainig (long term memory). There was found a doseeffect curve of montanine with cognitive-enhanced dose at 1μg/μl. This dose was evaluated in the same task for temporal-curve. Montanine showed procognitive activity in immediately postraining administration and 180 minutes postraining but not with 360 min postraining in the same task. The acetylcholinesterase inhibition profile of montanine alkaloid was also evaluated by a ultraviolet method. The enzyme was inhibited in concentrations of 10 μM, 100 μM and 1 mM of montanine. The results obtained in the present study show a need for further chemical investigation on Hippeastrum papilio due to its large potential for inhibition of the acetylcholinesterase and isolation of potentially new structures. Moreover, these results confirm the great pro-cognitive potential of montanine, behaviorally demonstrated, as well as its ability to inhibit the acetylcholinesterase enzime, which makes the alkaloid a candidate substance for the treatment of Alzheimer's Disease.
390

Estudo fitoquímico dos frutos de Senna spectabilis e análise comparativa do perfil alcaloídico de S. spectabilis e Cassia leptophylla

Pivatto, Marcos [UNESP] 01 December 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-01Bitstream added on 2014-06-13T19:58:51Z : No. of bitstreams: 1 pivatto_m_me_araiq.pdf: 4500291 bytes, checksum: 41c36cab9b65c53f1fe92528b346a70e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho objetivou o estudo fitoquímico dos frutos de Senna spectabilis e o estudo comparativo do perfil alcaloídico entre S. spectabilis e Cassia leptophylla, outra espécie vegetal relatada como fonte de alcalóides piperidínicos. O estudo fitoquímico dos frutos de S. spectabilis forneceu 4 alcalóides piperidínicos: cassina (1), 3-O-acetil-cassina (20), 3-O-feruloil-cassina (18) e um estereoisômero da cassina (19), cujas configurações, ralativa e absoluta, ainda não foram determinadas. Dentre estes, somente a cassina (1) já era conhecida e foi isolada, em nosso grupo de pesquisa, como o alcalóide majoritário das flores da mesma espécie. Estes alcalóides foram avaliados quanto às atividades seqüestradora de radicais livres (DPPH) e inibidora da enzima acetilcolinesterase. As substâncias 1, 2 e 4 apresentaram forte atividade anticolinesterásica, com concentração inibitória mínima semelhante à galantamina, utilizada como padrão positivo. Quanto à atividade seqüestradora de radicais livres, o único que apresentou leve estabilização do radical foi o derivado feruloil piperidínico (18), quando comparado com a rutina, utilizada como padrão positivo. Entretanto, a maior concentração do alcalóide não atingiu a concentração inibitória de 50% (IC50), observada para a rutina. O estudo do perfil químico entre as espécies S. spectabilis e C. leptophylla foi inicialmente baseado em experimentos comparativos de cromatografia em camada delgada e ressonância magnética nuclear de hidrogênio. Os resultados obtidos demonstraram que somente os extratos das flores e frutos de S. spectabilis apresentavam substâncias alcaloídicas como metabólitos detectáveis. Por outro lado, a análise por espectrometria de massas permitiu evidenciar metabólitos alcaloídicos piperidínicos em ambas as espécies estudadas, levando-nos a concluir sobre a importância desta técnica na bioprospecção de metabólitos minoritários. / The present work aimed the phytochemical study of the fruits of Senna spectabilis and a comparative analysis of the alkaloid profile between S. spectabilis and Cassia leptophylla, another species reported as a source of piperidine alkaloids. The phytochemical study of the fruits of S. spectabilis furnished 4 piperidine alkaloids: cassine (1), 3-O-acetyl-cassine (20), 3-O-feruloyl-cassine (18) and a stereoisomer of cassine (19), whose absolute and relative configurations were not stablished yet. Among these, only cassine (1) was already known and it had been previously isolated as the major alkaloid of the flowers in the same species. These alkaloids were evaluated for their potential as free radical scavengers towards DPPH and acetylcholinesterase inhibitors. Substances 1, 2 and 4 showed strong activity in inhibition of acetylcholinesterase, with a minimum inhibitory concentration similar to galantamina, used as a reference compound. In the free radical scavenger assay, compound 18 was the only active, showing a slightly radical stabilization, when compared with the rutina, used as a reference compound. However, the largest concentration of the alkaloid didn't reach the inhibitory concentration for 50% (IC50), obtained by rutina. The chemical profile study between S. spectabilis and C. leptophylla species was initially based on comparative experiments using thin layer chromatography, and proton nuclear magnetic resonance. The results indicated that alkaloidal metabolites were present only in the S.spectabilis extracts. On the other hand, analysis by tandem mass spectrometry revealed the presence of piperidine alkaloids in both species, leading us to conclude the relevance of this technique in bioprospecting of minority metabolites.

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