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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.
1

Oleanic acid: its isolation and derivatisation to potential antimicrobial compounds

Wicht, Merril Margaret January 2007 (has links)
A thesis submitted to the Cape Peninsula University of Technology in fulfilment of the requirements for the MASTERS DEGREE IN TECHNOLOGY (CHEMISTRY) Department of Chemistry January 2007 / An increasing number of natural products possessing the oleanolic acid moiety have been shown to demonstrate a wide spectrum of biological activity. This thesis deals with the extraction and isolation of oleanolic acid from Syzigium aromaticum and the examination of its stereochemistry and crystal structure by X-ray diffraction. The synthetic routes used for converting functional groups on the oleanolic acid molecule to afford derivatives are described in Chapter 5. Oleanolic acid and its derivatives were evaluated for antimicrobial activity. Three different procedures viz. Kirby-Bauer, Broth dilution and Tetrazolium salt chemosensitivity were used. Acceptable results were obtained from the last method and these were used to arrive at conclusions regarding this study.
2

Oleanolic acid: its isolation and derivatisation to potential antimicrobial compounds

Wicht, Merrill Margaret January 2007 (has links)
Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2007 / An increasing number of natural products possessing the oleanolic acid moiety have been shown to demonstrate a wide spectrum of biological activity. This thesis deals with the extraction and isolation of oleanolic acid from Syzigium aromaticum and the examination of its stereochemistry and crystal structure by X-ray diffraction. The synthetic routes used for converting functional groups on the oleanolic acid molecule to afford derivatives are described in Chapter 5. Oleanolic acid and its derivatives were evaluated for antimicrobial activity. Three different procedures viz. Kirby-Bauer, Broth dilution and Tetrazolium salt chemosensitivity were used. Acceptable results were obtained from the last method and these were used to arrive at conclusions regarding this study.
3

Ursolic acid and oleanolic acid as novel therapeutic agents in breast cancer

Abukhattala, Emhemed Mohamed January 2015 (has links)
Philosophiae Doctor - PhD / Breast cancer is one of the most common cancers among women in South Africa and the second leading cause of cancer death after lung cancer. According to the American Cancer Society 2015, women have a 12% chance of developing invasive breast cancer and a 3% chance of dying from it. Despite the wide variety of breast cancers e.g. lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS), many share the same etiology and target tissue. Estrogen related carcinogenesis with regard to breast cancer typically results from the activation of distinct signalling pathways. These pathways are not mutually exclusive and are often constituted by receptor mediated stimulation of cell proliferation caused by specific transcriptional gene activation, reactive oxygen species (ROS) formation causing DNA damage and consequently mutations. The molecular pathways that cause drug resistance are not fully understood and the search continues to find novel targets for treatment. The effects of non-toxic triterpenes, oleanolic acid and ursolic acid and the role of autophagy and apoptosis as mechanisms to overcome drug resistance in breast cancer were studied in vitro in MCF-7 breast cancer cells and MCF10A breast cells. In this study the first aim was to establish the influence of OA and UA on cell growth and to see if opposing proliferation patterns could observed between the presumably ERɑ negative (ERɑ/ß -/+) MCF-10A and ERɑ positive (ERɑ/ß +/+) MCF-7 cells. This was followed by morphology studies to establish the possible presence of cytotoxicity and examination of molecular pathways contributing to the anti-cancerous properties of UA and OA and their validity as therapeutic agents. The MCF-7 breast cancer cell line and the immortalized normal mammary cell line, MCF-10A were treated with different concentrations of UA and OA for 6hrs, 12hrs, 24hrs, 48hrs, and 72hrs respectively. Cell morphology was studied in hematoxylin and eosin as well as Hoechst and acridine orange stained cells and viability was measured using crystal violet staining. Molecular techniques employed included the Tali® Apoptosis - and the cellROX assays, flow cytometry and western blotting. Morphological, viability and apoptotic studies have shown that at their lowest concentration, both UA and OA have anti-proliferative and apoptotic effects on MCF-7 and to a lesser extent on MCF-10A. Flow cytometric analysis of treated cells has demonstrated cell arrest in the S- and G2/M phase. The MCF-7 and MCF-10A cells growth inhibition effect may be due to increased autophagy and apoptosis as an alternative to decreased proliferation in MCF-7 cells. This possibility should be evaluated in further studies. The results showed that UA was more effective OA in decreasing cell numbers and it may be applied as treatment for breast cancer. Our observation has shown the treatment with OA and UA increased cell death in MCF-7 cells.The opposing proliferation patterns observed between the presumably ERɑ negative (ERɑ/ß -/+) MCF-10A and ERɑ positive (ERɑ/ß +/+) MCF-7 cells could possibly be ascribed to ERß forming homodimers that may facilitate proliferation, whereas ERɑ/ß heterodimers (expressed in 59% of breast cancers) are frequently associated with the ERɑ antagonising actions of ERß. The results indicate a trend towards biphasic and anti- proliferative effects of the reactants in breast cancer cells which may contribute towards the development of anti- cancer therapies. However, further work is must be done to identify the OA and UA mechanism(s) responsible for anticancer activity. / Libyan Embassy
4

Propriedades terapêuticas de triterpenos ácidos na doença de Chagas experimental - avaliação em fase aguda da infecção / Therapeutic properties of triterpene acids in experimental Chagas\' disease - evaluation in the acute phase of infection.

Ferreira, Daniele da Silva 17 June 2010 (has links)
A doença de Chagas é um problema de saúde pública, com dados preocupantes referentes ao número de pessoas contaminadas e daquelas que ainda permanecem expostas ao risco de infecção. As doenças tropicais desafiam as pesquisas científicas, pois os medicamentos existentes apresentam sérios efeitos colaterais. As tripanossomíases são doenças de grande importância no Brasil, como é o caso da doença de Chagas. Estudos realizados em diversos países têm relatado que muitas espécies vegetais possuem atividade contra o agente etiológico da doença de Chagas, Trypanosoma cruzi. Ácido ursólico e seu isômero, ácido oleanólico, pertencem à classe de compostos triterpenóides e são amplamente distribuídos no reino vegetal e têm sido frequentemente isolados como mistura isomérica. Nesse sentido, a proposta para o presente estudo foi avaliar a atividade tripanocida, sobre a cepa Y e Bolívia de T. cruzi, dos triterpenos ácido ursólico e ácido oleanólico, sintetizar e avaliar a atividade tripanocida do sal derivado de ácido ursólico. As substâncias foram administradas nas concentrações de 20 e 50 mg/kg por via intraperitoneal e oral, após a avaliação da dose letal média (DL50). As três substâncias empregadas nas concentrações de 20 e 50 mg/kg, administradas por via intraperitoneal não foram capazes de reduzir a parasitemia dos animais experimentalmente infectados com as cepas Y e Bolívia de T. cruzi. Entretanto, as três substâncias exibiram atividade tripanocida significativa, na concentração de 50 mg/kg, administradas por via oral, em animais infectados com a cepa Y de T. cruzi. Para a cepa Bolívia de T. cruzi, as substâncias administradas por via oral exibiram atividade biológica na concentração de 20 mg/kg, sendo significativa apenas para o triterpeno ácido ursólico. A análise histológica realizada não demonstrou uma correlação significativa entre os níveis parasitêmicos e o parasitismo tecidual, para todos os grupos avaliados. A avaliação do perfil hepatobiliar e renal das substâncias foi realizada a fim de se verificar possíveis efeitos tóxicos das mesmas. Entretanto, não foi observada nenhuma diferença estatisticamente significativa entre os grupos tratados e o grupo controle, indicando que o aumento dos níveis parasitêmicos não está associado ao efeito das substâncias no tecido. Através da avaliação do efeito dos triterpenos sobre a resposta imune, verificamos uma diminuição dos níveis plasmáticos de IFN- e um aumento das concentrações de IL-10. Dessa maneira, nós sugerimos que o tratamento com essas substâncias pode direcionar a resposta imune para o padrão Th2 e, em conseqüência desse efeito imunossupressor, uma maior quantidade de formas tripomastigotas poderia ser observada na circulação do hospedeiro. / Chagas disease is a public health problem with worrisome data on the number of infected people, not to mention the population that still remains at risk of infection. Tropical diseases defy scientific research since the existing drugs have serious side effects. Trypanosomiases, such as Chagas disease, are of great importance in Brazil. Studies in several countries have reported that many plant species display activity against Trypanosoma cruzi, the causative agent of Chagas disease. Ursolic acid and its isomer, oleanolic acid, belong to a class of triterpenoid compounds that is widely distributed in the plant kingdom and has frequently been isolated as an isomeric mixture. In the present study, the trypanocidal activity of the triterpenoids ursolic acid and oleanolic acid was evaluated against the Y and Bolivia strains of T. cruzi. In addition, the potassium salt derivative of ursolic acid was synthesized and also tested. The triterpenoids were administered intraperitoneally and orally at concentrations of 20 and 50 mg / kg, after evaluation of the median lethal dose (LD50). At the concentrations of 20 and 50 mg / kg, the intraperitoneal administration of each of the substances was not able to reduce parasitemia of the animals infected with the Y and Bolivia strains of T. cruzi. However, ursolic and oleanolic acid, as well as the potassium salt derivative of ursolic acid exhibited significant trypanocidal activity at a concentration of 50 mg / kg when they were orally administered to animals infected with the Y strain of T. cruzi. On the other hand, oral administration of the tested compounds at a concentration of 20 mg / kg evidenced biological activity, which was significant for ursolic acid only. For the most of studied groups, histological analysis did not demonstrate a significant correlation between the levels of parasitemia and tissue parasitism. Determination and evaluation of biochemical parameters in the serum of experimental animals was performed, to assess the hepatic, biliary, and renal toxic effects of the substances. There were no statistically significant differences between the treated groups and the control group, indicating that the increase in parasitemia is not associated with the effects of the substances in the tissue. We suggest the hypothesis of an immunosuppressive effect, since there was a decreased plasma levels of IFN- after treatment with the triterpenes. Moreover, the treated groups also exhibited increased levels of IL-10. Therefore, we suggest that treatment with the substances could be directing the immune response toward the Th2 type and, as a consequence of this immunosuppressive effect, a greater amount of trypomastigotes could be observed in the circulation of the host.
5

Propriedades terapêuticas de triterpenos ácidos na doença de Chagas experimental - avaliação em fase aguda da infecção / Therapeutic properties of triterpene acids in experimental Chagas\' disease - evaluation in the acute phase of infection.

Daniele da Silva Ferreira 17 June 2010 (has links)
A doença de Chagas é um problema de saúde pública, com dados preocupantes referentes ao número de pessoas contaminadas e daquelas que ainda permanecem expostas ao risco de infecção. As doenças tropicais desafiam as pesquisas científicas, pois os medicamentos existentes apresentam sérios efeitos colaterais. As tripanossomíases são doenças de grande importância no Brasil, como é o caso da doença de Chagas. Estudos realizados em diversos países têm relatado que muitas espécies vegetais possuem atividade contra o agente etiológico da doença de Chagas, Trypanosoma cruzi. Ácido ursólico e seu isômero, ácido oleanólico, pertencem à classe de compostos triterpenóides e são amplamente distribuídos no reino vegetal e têm sido frequentemente isolados como mistura isomérica. Nesse sentido, a proposta para o presente estudo foi avaliar a atividade tripanocida, sobre a cepa Y e Bolívia de T. cruzi, dos triterpenos ácido ursólico e ácido oleanólico, sintetizar e avaliar a atividade tripanocida do sal derivado de ácido ursólico. As substâncias foram administradas nas concentrações de 20 e 50 mg/kg por via intraperitoneal e oral, após a avaliação da dose letal média (DL50). As três substâncias empregadas nas concentrações de 20 e 50 mg/kg, administradas por via intraperitoneal não foram capazes de reduzir a parasitemia dos animais experimentalmente infectados com as cepas Y e Bolívia de T. cruzi. Entretanto, as três substâncias exibiram atividade tripanocida significativa, na concentração de 50 mg/kg, administradas por via oral, em animais infectados com a cepa Y de T. cruzi. Para a cepa Bolívia de T. cruzi, as substâncias administradas por via oral exibiram atividade biológica na concentração de 20 mg/kg, sendo significativa apenas para o triterpeno ácido ursólico. A análise histológica realizada não demonstrou uma correlação significativa entre os níveis parasitêmicos e o parasitismo tecidual, para todos os grupos avaliados. A avaliação do perfil hepatobiliar e renal das substâncias foi realizada a fim de se verificar possíveis efeitos tóxicos das mesmas. Entretanto, não foi observada nenhuma diferença estatisticamente significativa entre os grupos tratados e o grupo controle, indicando que o aumento dos níveis parasitêmicos não está associado ao efeito das substâncias no tecido. Através da avaliação do efeito dos triterpenos sobre a resposta imune, verificamos uma diminuição dos níveis plasmáticos de IFN- e um aumento das concentrações de IL-10. Dessa maneira, nós sugerimos que o tratamento com essas substâncias pode direcionar a resposta imune para o padrão Th2 e, em conseqüência desse efeito imunossupressor, uma maior quantidade de formas tripomastigotas poderia ser observada na circulação do hospedeiro. / Chagas disease is a public health problem with worrisome data on the number of infected people, not to mention the population that still remains at risk of infection. Tropical diseases defy scientific research since the existing drugs have serious side effects. Trypanosomiases, such as Chagas disease, are of great importance in Brazil. Studies in several countries have reported that many plant species display activity against Trypanosoma cruzi, the causative agent of Chagas disease. Ursolic acid and its isomer, oleanolic acid, belong to a class of triterpenoid compounds that is widely distributed in the plant kingdom and has frequently been isolated as an isomeric mixture. In the present study, the trypanocidal activity of the triterpenoids ursolic acid and oleanolic acid was evaluated against the Y and Bolivia strains of T. cruzi. In addition, the potassium salt derivative of ursolic acid was synthesized and also tested. The triterpenoids were administered intraperitoneally and orally at concentrations of 20 and 50 mg / kg, after evaluation of the median lethal dose (LD50). At the concentrations of 20 and 50 mg / kg, the intraperitoneal administration of each of the substances was not able to reduce parasitemia of the animals infected with the Y and Bolivia strains of T. cruzi. However, ursolic and oleanolic acid, as well as the potassium salt derivative of ursolic acid exhibited significant trypanocidal activity at a concentration of 50 mg / kg when they were orally administered to animals infected with the Y strain of T. cruzi. On the other hand, oral administration of the tested compounds at a concentration of 20 mg / kg evidenced biological activity, which was significant for ursolic acid only. For the most of studied groups, histological analysis did not demonstrate a significant correlation between the levels of parasitemia and tissue parasitism. Determination and evaluation of biochemical parameters in the serum of experimental animals was performed, to assess the hepatic, biliary, and renal toxic effects of the substances. There were no statistically significant differences between the treated groups and the control group, indicating that the increase in parasitemia is not associated with the effects of the substances in the tissue. We suggest the hypothesis of an immunosuppressive effect, since there was a decreased plasma levels of IFN- after treatment with the triterpenes. Moreover, the treated groups also exhibited increased levels of IL-10. Therefore, we suggest that treatment with the substances could be directing the immune response toward the Th2 type and, as a consequence of this immunosuppressive effect, a greater amount of trypomastigotes could be observed in the circulation of the host.
6

Regulation of Pancreatic α and β Cell Function by the Bile Acid Receptor TGR5

Prasanna Kumar, Divya 01 January 2014 (has links)
The discovery that bile acids act as endogenous ligands of the membrane receptor TGR5 and the nuclear receptor FXR increased their significance as regulators of cholesterol, glucose and energy metabolism. Activation of TGR5, expressed on enteroendocrine L cells, by bile acids caused secretion of GLP-1, which stimulates insulin secretion from pancreatic β cells. Expression of TGR5 on pancreatic islet cells and the direct effect of bile acids on the endocrine functions of pancreas, however, are not fully understood. The aim of this study was to identify expression of TGR5 in pancreatic islet cells and determine the effect of bile acids on insulin secretion. Expression of TGR5 was identified by quantitative PCR and western blot in islets from human and mouse, and in α (αTC1-6) and β (MIN6) cells. Release of insulin, glucagon and GLP-1 were measured by ELISA. The signaling pathways coupled to TGR5 activation were identified by direct measurements such as stimulation of G proteins, adenylyl cyclase activity, PI hydrolysis and intracellular Ca2+ in response to bile acids; and confirmed by the use of selective inhibitors that block specific steps in the signaling pathway. Our studies identified expression of TGR5 receptors in β cells and demonstrated that activation of these receptors by both pharmacological ligands (oleanolic acid (OA) and INT-777) and physiological ligand (lithocholic acid, LCA) induced insulin secretion. TGR5 receptors are also expressed in α cells and, activation of TGR5 by OA, INT-777 and LCA at 5 mM glucose induced release of glucagon, which is processed from proglucagon by the selective expression of prohormone convertase 2 (PC2). However, under hyperglycemia, activation of TGR5 in α cells augmented the glucose-induced increase in GLP-1 secretion, which in turn, stimulated insulin secretion. Secretion of GLP-1 from α cells reflected TGR5-mediated increase in PC1 promoter activity and PC1 expression, which selectively converts proglucagon to GLP-1. The signaling pathway activated by TGR5 to mediate insulin and GLP-1 secretion involved Gs/cAMP/Epac/PLC-ε/Ca2+. These results provide insights into the mechanisms involved in the regulation of pancreatic α and β cell function by bile acids and may lead to new therapeutic avenues for the treatment of diabetes.
7

Estudo da atividade antinociceptiva e possÃveis mecanismos de aÃÃo do Ãcido oleanÃlico em modelos de nocicepÃÃo induzida por capsaicina e Ãleo de mostarda em camundongos. / Antinociceptive study and possible mechanisms of action of oleanolic acid in models of nociception induced by capsaicin and mustard oil in mice.

Juliana Lemos Maia 22 December 2006 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O Ãcido oleanÃlico à um triterpeno pentacÃclico largamente encontrado em vÃrias plantas medicinais. Essa substÃncia demonstrou ter uma variedade de atividades farmacolÃgicas, dentre as quais se destacam: antiinflamatÃria, hepatoprotetora, gastroprotetora e antinociceptiva. Este trabalho objetivou investigar a atividade antinociceptiva do Ãcido oleanÃlico em modelos de nocicepÃÃo aguda induzida por capsaicina (20Âl/ 1,6 &#956;g) e Ãleo de mostarda (0,75%, 50 ÂL/animal) em camundongos, alÃm dos possÃveis mecanismos de aÃÃo envolvidos. Camundongos foram prÃ-tratados com Ãcido oleanÃlico (3, 10, 30, 100 mg/kg, v.o.) ou veÃculo, e os comportamentos de dor foram analisados. As doses de 10, 30 e 100 mg/kg, v.o., foram capazes de reduzir os comportamentos dolorosos expressos pelos animais nos modelos de nocicepÃÃo induzida por capsaicina e Ãleo de mostarda, sendo o maior nÃvel de inibiÃÃo (p<0,001) encontrado na dose de 30 mg/kg. Na tentativa de desvendar os possÃveis mecanismos de aÃÃo do Ãcido oleanÃlico no modelo de nocicepÃÃo induzido por capsaicina, avaliamos a participaÃÃo dos receptores opiÃides, &#945;2, Ãxido nÃtrico e canais de potÃssio. O efeito antinociceptivo do Ãcido oleanÃlico (30 mg/kg, v.o.) foi significantemente revertido pelo prÃ-tratamento com antagonista opiÃide, naloxona (2 mg/kg, i.p.); pelo doador de Ãxido nÃtrico, L-arginina (600 mg/kg, i.p.) e pela glibenclamida (2 mg/kg, i.p.), um antagonista dos canais de potÃssio. Por outro lado, o prÃ-tratamento com um antagonista &#945;2, ioimbina (2 mg/kg, i.p.), nÃo ocasionou a reversÃo da antinocicepÃÃo. Na tentativa de desvendar os possÃveis mecanismos de aÃÃo do Ãcido oleanÃlico no modelo de nocicepÃÃo visceral induzida por Ãleo de mostarda, avaliamos a participaÃÃo dos receptores opiÃides, &#945;2 e TRPV1. O efeito antinociceptivo do Ãcido oleanÃlico (30 mg/kg, v.o.) foi significantemente revertido (p<0,05) pelo prÃ-tratamento com antagonista opiÃide, naloxona (2 mg/kg, i.p.), enquanto que o antagonista &#945;2 , ioimbina (2 mg/kg, i.p.), nÃo teve o mesmo efeito. O prÃ-tratamento com vermelho de rutÃnio (3 mg/kg, s.c.), um antagonista nÃo competitivo do receptor TRPV1 causou inibiÃÃo significativa da nocicepÃÃo (p<0,01) induzida pelo Ãleo de mostarda, entretanto a administraÃÃo conjunta com o Ãcido oleanÃlico nÃo produziu antagonismo nem potenciaÃÃo da antinocicepÃÃo causada pelo Ãcido oleanÃlico. Para avaliar a existÃncia de um impedimento locomotor ou de uma incoordenaÃÃo motora, foram utilizados os testes do campo aberto e o teste do rota rod, respectivamente. Os dados indicaram que o tratamento com o Ãcido oleanÃlico (30 mg/kg, v.o.) nÃo induziu (p>0,05) impedimento locomotor ou incoordenaÃÃo motora nos animais, sendo ainda capaz de reverter (p<0,05) o impedimento locomotor induzido pelo Ãleo de mostarda no teste do campo aberto. Em conjunto os dados revelaram a efetividade do Ãcido oleanÃlico em modelos de nocicepÃÃo possivelmente envolvendo receptores opiÃides, TRPV1, Ãxido nÃtrico e canais de potÃssio. / Oleanolic acid is a triterpene pentacyclic widely distributed in the plant kingdom. Different biologic activities have been reported including: antiinflammatory, hepatoprotective, gastroprotective and antinociceptive. This work was aimed to evaluate the antinociceptive &#61472;effect of oleanolic acid in acute nociception models induced by capsaicin (20Âl/ 1.6 &#956;g) and mustard oil (0.75%, 50 ÂL/animal) in mice and to establish the likely mechanism(s) of action. Mice were pretreated orally with oleonolic acid (3, 10, 30 and 100 mg/kg) or vehicle, and the pain-related behavioral responses were analysed. The pain behavioral responses were significantly suppressed at doses 10, 30 and 100 mg/kg in acute nociception models induced by capsaicin and mustard oil. The maximal suppression (p<0.001) was observed at the dose of 30 mg/kg. In order to verify the possible mechanisms involved in the antinociceptive action of oleanolic acid in the capsaicin-induced nociception, the involvement of endogenous opioids, &#945;2, nitric oxide and KATP channels were analyzed. The antinociception produced by OA (30 mg/kg, v.o.) was found to be significantly blocked in animals pre-treated with the opioid antagonist, naloxone (2 mg/kg, i.p.); the substrate for oxide nitric synthase, L-arginine (600 mg/kg, i.p.); or a KATP-channel blocker, glibenclamide (2 mg/kg, i.p.) but was unaffected by yohimbine (2 mg/kg, i.p.), an &#945;2 -adrenoceptor antagonist. In order to verify the possible mechanisms involved in the antinociceptive action of oleanolic acid in the mustard oil-induced visceral pain model, opioid, &#945;2 adreno and TRPV1 receptors were analyzed. The antinociceptive effect of oleanolic acid (30 mg/kg, v.o.) was significantly blocked (p<0.05) by pretreatment with the opioid antagonist, naloxone (2 mg/kg, i.p.), but the &#945;2-adrenoceptor antagonist, yohimbine (2 mg/kg, s.c.), had no effect. Pretreatment with ruthenium red (3 mg/kg, s.c.), a non-competitive TRPV1 antagonist alone caused significant inhibition (p<0.01) of mustard oil-induced nociception but its co-administration with oleanolic acid produced neither antagonism nor potentiation of oleonolic acid antinociception. Further, to evaluate a possible motor impairment and motor incoordination effects related to oleanolic acid, open-field and rota-rod tests were performed. The data indicated that the treatment of animals with the oleanolic acid (30 mg/kg, v.o.) was unable to cause motor impairment or motor incoordination effects (p>0.05), being even able to reverse (p<0.05) a mustard oil-induced motor impairment in the open field test. The results taken together strongly suggest the therapeutic potential of oleanolic acid in oblitering nociception through the mechanisms that possibly involve the opioids, TRPV1 receptors, nitric oxide and KATP channels.
8

Avaliação do potencial terapêutico e perfil imunológico de triterpenos ácidos na fase crônica da infecção experimental por Trypanosoma cruzi / Evaluation of therapeutic and immunological potential of acid triterpenes in the chronic phase of experimental infection by Trypanosoma cruzi

Silva, Mariana Rosa da 23 August 2013 (has links)
A doença de Chagas é um problema de saúde pública, com dados preocupantes referentes ao número de pessoas contaminadas e daquelas que ainda permanecem expostas ao risco de infecção. A dificuldade do combate a Trypanosoma cruzi, agente etiológico da doença, está intimamente relacionada às interações existentes entre o parasito e o hospedeiro, sendo que até o momento, nenhum medicamento ou substância tem demonstrado real eficácia ao combate ao parasito. Em estudos recentes realizados por nosso grupo de pesquisa, os ácidos ursólico e oleanólico demonstraram um bom potencial tripanocida, além de um efeito imunomodulatório, promovendo a inibição da produção de IFN-? quando de suas utilizações por via intraperitoneal em elevadas concentrações. Considerando essas evidências encontradas em relação a essas substâncias e os efeitos promovidos no processo de avaliação biológica, propusemos como objetivo avaliar o potencial terapêutico dos triterpenos ácido ursólico e ácido oleanólico na fase crônica da infecção chagásica e suas associações ao benzonidazol, fármaco referência indicado ao tratamento da parasitose, verificando a possibilidade de geração de benefícios sobre a patogênese da infecção crônica experimental. A quantificação de linfócitos T CD4+ e T CD8+, e das citocinas IL-2, IL-10, IL-12, IFN-? e TNF-??pela técnica de citometria de fluxo, utilizando o kit BD Cytometric Bead Array®, indicaram que essas substâncias não apresentam efeitos imunomodulatórios significativos sobre a resposta Th1 e Th2 nessa fase da doença, na comparação entre grupos infectados e tratados e aquele que recebeu apenas solvente. O parasitismo tecidual determinado por Real Time PCR e as observações realizadas em cortes histológicos, mostraram, respectivamente, baixo número de cópias de DNA de T. cruzi, e ausência de ninhos amastigotas, porém, com marcante presença de infiltrado inflamatório em todos os grupos. Assim, os dados obtidos levam à conclusão de que apesar da atividade apresentada pelos triterpenos ácidos em estudo na fase aguda da doença de Chagas, o mesmo não ocorre na fase crônica, como seria desejável para favorecer uma melhora do quadro patológico, mesmo não havendo a cura da doença, considerando as conseqüências da infecção de longo prazo. / Chagas disease is a public health problem, with disturbing data about the number of infected people and those who remain at risk of infection. The difficulty of eliminating Trypanosoma cruzi, etiologic agent of the disease is closely related to the interactions between the parasite and the host, and until now, no medicine or substance has demonstrated real effectiveness against the parasite. In recent studies by our research group, the ursolic and oleanolic acids revealed considerable trypanocidal activity, and an immunomodulatory effect, promoting the inhibition of IFN-? with intraperitoneal administration in high concentrations. Considering these evidences and the effects observed during the biological evaluation, our objective was to evaluate the biological potential of the triterpenoids ursolic acid and oleanolic acid in the chronic phase of chagasic infection and their associations to benznidazole, the reference drug indicated for the treatment of this disease, verifying the possibility of benefits on the pathogenesis of experimental chronic infection. Quantification of T CD4+ and T CD8+ cells and of the cytokines IL-2, IL-10, IL-12, IFN-? and TNF-? by flow cytometry using the kit BD cytometric Bead Array®, indicated that these substances do not exhibit significant immunomodulatory effects on Th1 and Th2 responses in this stage of the disease, comparing infected and treated groups and that who received only solvent. The tissue parasitism determined by Real Time PCR and in histological observations showed, respectively, low copy number of T. cruzi DNA, and absence of amastigote nests, however, with marked inflammatory infiltration in all groups. Thus, our data lead to the conclusion that despite the activity presented by the triterpene acids studied in the acute phase of Chagas disease, the same does not occur in the chronic phase, as would be desirable to the reduction of the pathological conditions, even if there is no cure of the disease, considering the consequences of long term infection.
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Triterpene Carboxylic Acids as Cortisol Lowering Agents and Synthesis of Hexadeuterated Beta-Ionone

Mogg, Trevor 13 September 2012 (has links)
In part one, betulinic acid (1) was isolated from the American Sycamore (Platanus occidentalis) in 1.6% yield, while ursolic acid (3) was isolated from Fuji and McIntosh apple peels in 1.0% and 0.8% crude yields, respectively. Oleanolic (4) and dehydrocanophyllic (6) acids were previously available, along with several analogs. Additional analogs of 1, 3 and 4 were prepared, including 9 new compounds, for a total of 51 compounds. Compounds were initially screened for cortisol lowering properties in vitro using a fish head kidney cell assay. Platanic acid (43) was selected for in vivo study in rats, along with 1 and a blend of Platanus occidentalis and Souroubea sympetela. No significant cortisol lowering was observed in vivo. In part two, β-ionone-d6 (75) was synthesized in 6.5% yield from ethyl 2-oxo-cyclohexane carboxylate (77). Total deuterium incorporation was 99.85%, with 0.03% d0 analog. 75 was converted to retinoic acid-d6 (93) in 2.2% yield.
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Análise quimiométrica do extrato das folhas de Zeyheria tuberculosa (Vell) Bureau (Bignoniaceae), com atividade inibidora da linfoproliferação, por ressonância magnética nuclear / Chemometric analysis of the extract of the leaves of Zeyheria tuberculosa (Vell) Bureau (Bignoniaceae), with inhibitory activity of lymphocyte proliferation, for nuclear magnetic resonance

Tenório, Maria Amélia Lima dos Santos 19 February 2015 (has links)
Since ancient times, natural products are used as source of medicines to prevent and treat disease. Currently, high cost and time taken for analysis of natural products have been significantly reduced by the use of modern approaches such as chemometric analysis, which gives flexibility to the process of development of new products. This study aimed to chemometric analysis of the ethanol extract, fraction in chloroform and subfractions of the crude extract of leaves Zeyheria tuberculosa (Veil) Bureau (Bignoniaceae), for Nuclear Magnetic Resonance, with the characterization and quantification of the major compounds present in these, as well as construction of a model to select potentially promising extracts, serving as a guide for further isolation of the substances of interest, enabling the discovery of bioactive compounds. The fraction in chloroform which concentrated almost all the ethanol extract metabolites, showed 100% inhibitory activity lymphocyte proliferation at a concentration of 100 gg.m1:1, and is therefore chosen for characterization and quantification of the major compounds present. The NMR spectral analysis of the fraction in chloroform, including 1D experiments (1H, 13C, DEPT 90 °, DEPT135 °) and 2D (J-Resolved, HSQC and HMBC) allowed the detailed structural elucidation of two major compounds, ursolic and oleanolic acids, both identified for the first time in this species. Due to the importance of these acids in the treatment of skin diseases and various cancers, measurements were determined for these triterpenes in ethanol extract (ZTB), fraction in chloroform (ZTP2) and the subfractions, using techniques for this purpose NMR and chemometric tools (Matlab programs, AMIX and SIMCA). All spectra were processed and analyzed using the program topspin (BRUKER). The qualitative and quantitative results of the chemometrics analysis for NMR of the ethanol extract, fraction in chloroform and subfractions of Zeyheria tuberculosa showed that fractions ZTF3 (evaluated in MTT as being non-cytotoxic at concentrations of 10, 50 and 100 pg.mL-1) and ZTF6 (measured in MTT as being non-cytotoxic at the concentration of 10 pg.mL-1 and cytotoxic at concentrations of 50 and 100 pg.mL-1) are the richest of oleanolic and ursolic acids, respectively, and so are more promising for the isolation of these triterpenes. The fraction ZTF4 was second richer fraction both as oleanolic acid and ursolic acid, the most promising for the isolation of these two acids together, also considering that this fraction was evaluated in MTT as non-cytotoxic at concentrations of 10 and 50 g .mL-1, and only the cytotoxic concentration of 100 pg.mL-1. The ursolic and oleanolic acids have a range of therapeutic properties and a high commercial value, being highly relevant the qualitative and quantitative results obtained in this study, referring to these triterpenes found in the leaves of the species Zeyheria tuberculosa. The model proposed in this work was efficient, as indicated by the values of the Q parameter, and suitable for the classification of samples into groups and subgroups according to the presence of ursolic and oleanolic acids (chemical composition) and the concentration of these in the samples, and it may be useful in the identification of potentially promising extracts, serving as a guide for subsequent isolation of the substance of interest. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Desde os tempos antigos, os produtos naturais são utilizados como fonte de medicamentos, para prevenir e tratar doenças. Atualmente, o alto custo e o tempo despendido para as análises de produtos naturais têm sido significativamente reduzidos pelo uso de abordagens modernas, como a análise quimiométrica, que dão agilidade ao processo de desenvolvimento de novos produtos. Este trabalho teve como objetivo a análise quimiométrica do extrato etanólico, da fração em clorofórmio e subfrações do extrato bruto das folhas de Zeyheria tuberculosa (Vell) Bureau (Bignoniaceae), por Ressonância Magnética Nuclear, com a caracterização e quantificação dos compostos majoritários presentes nestes, além da construção de um modelo capaz de selecionar extratos potencialmente promissores, servindo como guia para um posterior isolamento das substâncias de interesse, viabilizando a descoberta de compostos bioativos. A fração em clorofórmio que concentrou a quase totalidade dos metabólitos do extrato bruto, apresentou 100 % de atividade inibitória da linfoproliferação, sendo por isso escolhida para caracterização e quantificação dos compostos majoritários presentes. A análise espectral de RMN da fração em clorofórmio, incluindo experimentos 1D (1H, 13C, DEPT 90°, DEPT 135°) e 2D (J-Resolvido, HSQC e HMBC) permitiu a elucidação estrutural detalhada de dois compostos majoritários, os Ácidos Ursólico e Oleanólico, ambos identificados pela primeira vez nesta espécie. Devido à importância desses ácidos no tratamento de doenças da pele e vários tipos de câncer, foram determinadas as quantificações relativas destes triterpenos no extrato bruto (ZTB), na fração em clorofórmio (ZTP2) e nas subfrações, utilizando-se para este fim técnicas de RMN e ferramentas quimiométricas (programas Matlab, AMIX e SIMCA). Todos os espectros foram processados e analisados utilizando o programa TOPSPIN (BRUKER). Os resultados quantitativos e qualitativos da análise quimiométrica por RMN do extrato bruto, fração clorofórmica e subfrações de Z. tuberculosa mostraram que as frações ZTF3 (avaliada no teste MTT como sendo átoxica nas concentrações de 10, 50 e 100 pg.mL-1) e ZTF6 (avaliada no teste MTT como sendo atóxica na concentração de 10 pg.mL-1 e citotóxica nas concentrações de 50 e 100 pg.mL-1) são as mais ricas dos ácidos oleanólico e ursólico, respectivamente, e por isso são as mais promissoras para o isolamento destes triterpenos. Já a fração ZTF4 foi a segunda fração mais rica tanto em ácido ursólico como em ácido oleanólico, sendo a mais promissora para o isolamento destes dois ácidos juntos, considerando ainda que esta fração foi avaliada no teste MTT como atóxica nas concentrações de 10 e 50 pg.mL-1, e citotóxica apenas na concentração de 100 pg.mL-1. Os ácidos ursólico e oleanólico possuem uma gama de propriedades terapêuticas e um alto valor comercial, sendo de grande relevância os resultados qualitativos e quantitativos, obtidos neste trabalho, referentes a esses triterpenos encontrados nas folhas da espécie Zeyheria tuberculosa. O modelo proposto neste trabalho foi eficiente, conforme indicado pelos valores do parâmetro Q, e satisfatório para a classificação das amostras em grupos e subgrupos, segundo a presença dos ácidos ursólico e oleanólico (composição química) e a concentração destes nas amostras, podendo ser de grande utilidade na identificação de extratos potencialmente promissores, servindo como guia para um posterior isolamento da(s) substância(s) de interesse.

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