Embora seja uma das áreas mais ameaçadas na Terra, há poucos estudos sobre o potencial farmacológico da Caatinga. Este bioma é exclusivamente brasileiro e as plantas encontradas na região apresentam características únicas que as tornam fontes imensuráveis de compostos ativos. O parasito Trichomonas vaginalis é o agente etiológico da tricomoníase, a doença sexualmente transmissível não viral mais comum no mundo. A infecção está associada a sérias consequências em saúde e casos de resistência ao fármaco de escolha, metronidazol, estão em constante crescimento. Desta forma, a necessidade por alternativas para o tratamento da tricomoníase é evidente. O objetivo desta tese foi avaliar o potencial anti-T. vaginalis de plantas oriundas da Caatinga. A planta Manilkara rufula apresentou a mais potente atividade frente ao parasito e um fracionamento bioguiado foi realizado. Triterpenos pentacíclicos (caproato de α- e β-amirina, acetato de β-amirina e lupeol) foram identificados nas frações apolares de M. rufula, porém com baixa atividade antiparasitária. Derivados triterpênicos semissintéticos, frações contendo flavonoides, taninos e saponinas também foram testados. Nossos resultados demonstraram que o ácido ursólico e a fração H100 apresentaram potente atividade anti-T. vaginalis e ambos afetaram o crescimento e viabilidade dos trofozoítos. Além disso, o ácido ursólico e a fração H100 induziram importantes alterações na ultraestrutura dos organismos, indicando que o mecanismo de morte do parasito ocorreu por danos na membrana. A fração H100 induziu a lise total de eritrócitos e reduziu a adesão dos parasitos às células epiteliais, sugerindo, novamente, a ação sobre membrana. A fração H100 não apresentou citotoxicidade às células epiteliais. Os resultados apresentados demonstraram o potencial da planta M. rufula contra T. vaginalis e contribuem para o entendimento das propriedades farmacológicas das plantas da Caatinga, bem como para o desenvolvimento racional de alternativas para o tratamento da tricomoníase. / Although it is one of the most endangered areas on Earth, there are few studies on the pharmacological potential of the Caatinga. This is an exclusively Brazilian biome and its plants present unique characteristic that make them an immeasurable source of active compounds. The parasite Trichomonas vaginalis is the etiologic agent of trichomoniasis, the most common non-viral sexually transmitted disease worldwide. The infection has been associated with serious consequences in health and cases of resistance to metronidazole are constantly increasing. Then, the necessity of new alternatives to the treatment of trichomoniasis is evident. The aim of this thesis was to evaluate the anti-T. vaginalis potential of plants from Caatinga. The Manilkara rufula plant showed the most potent activity against the parasite and bioguided fractionation was performed. Pentacyclic triterpenes (α- and β-amyrin caproate and β-amyrin and lupeol acetate) were identified in the nonpolar fractions of M. rufula, however, low antiparasitic activity was observed. Triterpenic semisynthetic derivatives, fractions containing flavonoids, tannins and saponins were also tested. Our results showed that ursolic acid and H100 fraction exhibited potent anti-T. vaginalis activity and both affect growth and viability of trophozoites. In addition, ursolic acid and H100 fraction induced significant alterations in the ultrastructure of the parasite, indicating that the mechanism of death is by membrane damage. The H100 fraction induced complete lysis of erythrocytes and reduced the parasites adhesion to epithelial cells, once again, suggesting that the H100 action was on parasite membrane. The fraction H100 showed no cytotoxicity to epithelial cells. The results demonstrated the potential of the plant M. rufula against T. vaginalis and contributed to the understanding of the pharmacological properties of the Caatinga plants, as well as for the rational development of alternatives for trichomoniasis treatment.

Alicyclobacillus acidoterrestris são bactérias termoacidófilas esporofórmicas não patogênicas e estão comumente presentes em sucos de frutas ácidas, podendo deteriorá-los. Tendo em vista a importância da atividade agrícola e seus derivados no país, como suco de laranja industrializado, o interesse no desenvolvimento de técnicas bioanalíticas que propiciem uma detecção rápida, sensível e confiável, bem como alternativas para inativação desse microrganismo, é elevado. Neste trabalho foi testado o uso de saponina como agente inibidor de esporos e células vegetativas de A. acidoterrestris, em sucos de laranja concentrado e reconstituído. Entretanto, à temperatura ambiente a inibição é lenta, especialmente para esporos (cerca de 10 dias para inibição total), inviabilizando o seu uso na indústria de cítricos. A combinação de tratamento térmico e saponinas potencializaram a inibição da bactéria, o que torna possível sua aplicação industrial. A potencialização com temperatura alcançou 20% para esporos em suco concentrado, 28,5% para esporos em suco reconstituído e 45,1% para células vegetativas em sucos reconstituídos. A detecção da viabilidade celular foi realizada pela reação em cadeia da polimerase por transcrição reversa (RT-PCR), que se mostrou uma técnica rápida, sensível, e quantitativamente equivalente ao método padrão de detecção, o plaqueamento de culturas, sendo o coeficiente de correlação (r) entre as técnicas de 0,9977 para esporos e 0,9987 para células vegetativas. A quantificação dos produtos da RT-PCR foi realizada por eletroforese capilar em microchip com o equipamento Bioanalyzer 2100. O equipamento forneceu resultados confiáveis e reprodutíveis para diagnóstico de DNA transcrito de A. acidoterrestris. Além da alta sensibilidade, o equipamento permitiu um mínimo consumo de amostra (1 μL), praticidade e rapidez. / Alicyclobacillus acidoterrestris are termoacidophilic sporeforming nonpathogenic bacteria who are commonly present in acidic fruit juices and can deteriorate them. In view of the importance of agricultural activities in the country and its derivatives, such as industrialized orange juice the interest in the development of bioanalitycal techniques that provide early, sensitive, and reliable detection, as well as alternatives to inactivate the microorganism is elevated. This study tested the use of saponins as an inhibitor of spores and vegetative cells of A. acidoterrestris in both concentrate and reconstituted orange juices. At room temperature, however, the inhibition is slow, especially for spores (about 10 days for a total inhibition), preventing its use in the citrus industry. The combination of heat treatment and saponins potentiated the inhibition of bacteria, which makes possible their industrial application. Optimizing the temperature reached 20% for spores in juice concentrate, 28.5% for spores in reconstituted juice and 45.1% for vegetative cells in reconstituted juices. Detection of cell viability was performed by reverse transcription polymerase chain reaction (RT-PCR), which showed to be a fast, sensitive, and quantitative equivalent to the traditional plating technique, and the correlation coefficient (r) between the techniques were 0.9977 and 0.9987 for spores and vegetative cells, respectively. The quantification of the products of RT-PCR was performed by capillary electrophoresis on microchip with Bioanalyzer 2100 equipment. The equipment provided reliable and reproducible results for the diagnosis of DNA transcript of A. acidoterrestris. Besides of high sensitivity, the equipment allowed minimal consumption of sample (1 μL) and provided convenience and speed of analysis.

no / Candidiasis is one of the most frequent opportunistic infections in individuals with severe immunosupression and further development of resistance against the available antifungal drugs has created an alarming situation. This requires intensive drug discovery to develop new, more effective, affordable and accessible antifungal agents possessing novel modes of action. Albizia anthelmintica, which is ethno medically used to treat vaginal candidiasis in the Morogoro and coastal regions of Tanzania, on activity guided fractionation and subsequent purification resulted in the isolation and characterization of an isomer of methyl cyclitol (1) and six echinocystic acid saponins (2–7). Saponins 6 and 7 are new and being reported for the first time from nature. Among all the isolated compounds, 3-O-[α-L-arabinopyranosyl (1[RIGHTWARDS ARROW]2)][α-L-arabinopyranosyl (1[RIGHTWARDS ARROW]6)]-2-acetamido-2-deoxy-β-D-glucopyranosyl echinocystic acid (4), 3-O-[α-L-arabinopyranosyl (1[RIGHTWARDS ARROW]2)] [α-L-arabinopyranosyl (1[RIGHTWARDS ARROW]6)]-2-amino-2-deoxy-β-D-glucopyranosyl echinocystic acid (6) and 3-O-[β-D-glucopyranosyl (1[RIGHTWARDS ARROW]3)] [α-L-arabinopyranosyl (1[RIGHTWARDS ARROW]2)] [α-L-arabinopyranosyl (1[RIGHTWARDS ARROW]6)]-2-amino-2-deoxy-β-D-glucopyranosyl echinocystic acid (7) and their combinations were active against the various strains of C. albicans with MICs ranging from 12.5 to 125 μg/ml.

No description available.

No description available.

Orientador: Wagner Vilegas / Resumo: Apesar dos diversos relatos do uso de Rhipsalis Gaërtn (Cactaceae) por populações tradicionais no tratamento de uma gama de enfermidades, há pouquíssimos estudos fitoquímicos com esse grupo de cactos e por vezes estes são superficiais, apenas indicando a possível presença de algumas classes de produtos naturais. Ademais, estudos avaliando a atividade biológica de Rhipsalis são escassos. Neste viés, este trabalho objetivou investigar a composição química do gênero Rhipsalis e avaliar possíveis atividades ligadas à sua composição, subsidiando desta forma seu uso popular. Esta dissertação foi dividida e organizada da seguinte forma: a primeira parte apresenta uma introdução geral sobre plantas medicinais e sua importância, assim como uma revisão sobre estudos fitoquímicos em Cactaceae. Em seguida, foram redigidas três seções: na primeira, investigamos a composição química de Rhipsalis teres (Vell.) Steud identificando 5 saponinas derivadas do ácido oleanólico, 2 flavonoides C-glicosilados derivados da apigenina e 2 ácidos fenólicos; na segunda, investigamos a composição química do gênero Rhipsalis identificando 28 saponinas cujo core é o ácido oleanólico e 8 flavonoides, também sugerimos fingerprints para cada espécie avaliada com base nas substâncias majoritárias, os resultados quantitativos obtidos por UPLC-MS foram eficientes na identificação das espécies com base na filogenia; na terceira, avaliamos as atividades antioxidante, antifúngica e anti-inflamatória de espécies de R... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Despite the several reports of the use of Rhipsalis Gaërtn (Cactaceae) by traditional populations in the treatment of a range of diseases, there are very few phytochemical studies with this group and sometimes these are superficial, only indicating the possible presence of some classes of natural products. In addition, there are very few studies evaluating the biological activity of Rhipsalis. Therefore, this work aimed to investigate the chemical composition of the genus Rhipsalis and to evaluate possible activities related to its composition, thus subsidizing its popular use. This dissertation was divided and organized as follows: the first part presents a general introduction on medicinal plants and their importance as well as a review on phytochemical studies in Cactaceae. Then, three sections were written: in the first one, we investigated the chemical composition of Rhipsalis teres, identifying 5 saponins derived from oleanolic acid, 2 C-glycosilated flavonoids derived from apigenin and 2 phenolic acids; in the second section, we investigate the chemical composition of the genus Rhipsalis identifying 28 saponins whose core is oleanolic acid and 8 flavonoids, we also suggested fingerprints for each species evaluated on the basis of the majority compounds, the quantitative results obtained by UPLC-MS were efficient in the identification of the species based on the phylogeny; in the third, we evaluated the antioxidant, antifungal and anti-inflammatory activities of Rhipsal... (Complete abstract click electronic access below) / Mestre

by Koo Po Lan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 120-130). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / Abstract (Chinese version) --- p.iv / Content --- p.vii / List of Abbreviations --- p.xi / List of Figures and Tables --- p.xiii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Saponins --- p.1 / Chapter 1.2 --- Structure of Saponin --- p.2 / Chapter 1.2.1 --- Triterpene Class --- p.2 / Chapter 1.2.2 --- Steroid Class --- p.3 / Chapter 1.2.2.1 --- Spirostanol Glycoside --- p.4 / Chapter 1.2.2.2 --- Furostanol Glycoside --- p.4 / Chapter 1.2.3 --- Steroid Alkaloid Class --- p.5 / Chapter 1.3 --- Steroidal Saponin as Anti-Tumor Drug --- p.5 / Chapter 1.4 --- Possible Anti-Tumor Action Mechanisms of Steroid Saponin --- p.6 / Chapter 1.4.1 --- Direct Cytotoxic and Growth Inhibitory Effects --- p.7 / Chapter 1.4.2 --- Immune-Modulatory Effects --- p.8 / Chapter 1.5 --- Possible Anti-Carcinogenicity Action Mechanism of Saponin --- p.9 / Chapter 1.5.1 --- Saponin Binding to Bile Acids --- p.9 / Chapter 1.6 --- Saponin as Cardioactive Drug --- p.9 / Chapter 1.7 --- Liver Cancer --- p.10 / Chapter 1.7.1 --- Prevalence of Hepatocellular Carcinoma (HCC) --- p.11 / Chapter 1.8 --- Coronary Heart Disease (CHD) --- p.12 / Chapter 1.8.1 --- Prevalence and Risk Factors of CHD --- p.12 / Chapter 1.9 --- Diosgenin --- p.14 / Chapter 1.10 --- Hong Kong (HK) Products --- p.15 / Chapter 1.10.1 --- HK-18 (Polyphyllin D) --- p.15 / Chapter 1.11 --- DI AO XIN XUE KANG (DI AO) --- p.17 / Chapter 1.12 --- Aims of My Project --- p.20 / Chapter 1.12.1 --- In Vitro Study of the Effect of HK-18 on Human Hepatocellular Carcinoma Cell Line (HepG2) --- p.21 / Chapter 1.12.2 --- In Vivo Study of the Effect of HK-18 by Human Liver Tumor HepG2 Cells-Bearing Nude Mice Model --- p.21 / Chapter 1.12.3 --- In Vitro Study of the Effect of HK-18 on Multidrug- Resistant Human Hepatocellular Carcinoma Cell Line (R-HepG2) --- p.22 / Chapter 1.12.4 --- Myocardial Ischemia-Reperfusion (IR) Injury in Isolated- Perfused Rat Heart Model --- p.23 / Chapter 1.12.5 --- Effect of DI AO Pretreatment on Global IR Injury --- p.26 / Chapter 1.12.6 --- Effect of DI AO Pretreatment on Isoproterenol-Induced Myocardial Injury in Rats --- p.26 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Materials --- p.28 / Chapter 2.1.1 --- Cell Lines and Culture Medium / Chapter 2.1.1.1 --- Cell Lines --- p.28 / Chapter 2.1.1.2 --- Culture Medium --- p.29 / Chapter 2.1.2 --- Chemicals --- p.30 / Chapter 2.1.3 --- Buffers and Reagents --- p.31 / Chapter 2.2 --- Methods / Chapter 2.2.1 --- In Vitro Studies --- p.33 / Chapter 2.2.1.1 --- In Vitro Cytotoxicity --- p.33 / Chapter 2.2.1.2 --- Cell Cycle Analysis by Flow Cytometry --- p.34 / Chapter 2.2.1.3 --- Maintenance of P-glycoprotein in R-HepG2 cells by Doxorubicin and HK-18 --- p.35 / Chapter 2.2.1.4 --- Assessment of DNA Fragmentation --- p.36 / Chapter 2.2.2 --- In Vivo Assessment of the Anti-Tumor Activity of HK-18 --- p.37 / Chapter 2.2.2.1 --- Animals and Tumor Inoculation --- p.37 / Chapter 2.2.2.2 --- Drug Administration --- p.37 / Chapter 2.2.2.3 --- Assessment of the Tumor Size and Tumor Weight --- p.38 / Chapter 2.2.2.4 --- Plasma Preparation --- p.38 / Chapter 2.2.2.5 --- Measurement of the Plasma Enzyme Activity --- p.39 / Chapter 2.2.3 --- Isoproterenol (ISO)-Induced Myocardial Injury (Rat Model) --- p.40 / Chapter 2.2.3.1 --- Animals --- p.40 / Chapter 2.2.3.2 --- Drug Preparations --- p.40 / Chapter 2.2.3.3 --- Animal Treatment --- p.41 / Chapter 2.2.3.4 --- Preparation of Myocardial Tissue Homogenate --- p.41 / Chapter 2.2.3.5 --- Preparation of Cytosolic Fraction of Heart Homogenates --- p.42 / Chapter 2.2.3.6 --- Myocardial Antioxidant Enzyme Activity --- p.42 / Chapter 2.2.3.6.1 --- Glutathione Reductase (GRD) --- p.42 / Chapter 2.2.3.6.2 --- Glutathione S-Transferases (GST) --- p.43 / Chapter 2.2.3.7 --- Myocardial Antioxidant Capacity --- p.43 / Chapter 2.2.3.7.1 --- Myocardial Malondialdehyde (MDA) Content --- p.43 / Chapter 2.2.3.7.2 --- Myocardial Thiol Content --- p.44 / Chapter 2.2.3.7.3 --- Tert-Butylhydroperoxide (tBHP)-Induced Thiol Depletion --- p.45 / Chapter 2.2.3.7.4 --- TBHP-Induced Thiobarbituric Acid-Reactive Substances (TBARS) Formation --- p.45 / Chapter 2.2.4 --- Myocardial Ischemia-Reperfusion (IR) Injury --- p.46 / Chapter 2.2.4.1 --- Langendorff Isolated Perfused Rat Heart --- p.46 / Chapter 2.2.4.1.1 --- Preparation of Perfusion Buffer --- p.46 / Chapter 2.2.4.1.2 --- Preparation of Isolated Rat Heart --- p.47 / Chapter 2.2.4.1.3 --- Myocardial Global Ischemia-Reperfusion Injury --- p.49 / Chapter 2.2.4.1.4 --- Contractile Force Recovery --- p.49 / Chapter 2.2.5 --- Statistical Analysis --- p.50 / Chapter Chapter 3 --- Study of HK-18 on Anti-Tumor Effect / Chapter 3.1 --- In Vitro Study of HK-18 on Human Hepatoma Carcinoma Cell Line (HepG2) --- p.51 / Chapter 3.1.1 --- The Effect of HK-18 on Cell Proliferation of HepG2 Cells by MTT Assay --- p.52 / Chapter 3.1.2 --- DNA Fragmentation Assay --- p.54 / Chapter 3.1.3 --- The Effect of HK-18 on Cell Cycle Phase Distribution --- p.57 / Chapter 3.2 --- In Vivo Study of HK-18 on HepG2-Inoculated Nude Mice --- p.61 / Chapter 3.2.1 --- Assessment of the Anti-Tumor Activity of HK-18 --- p.61 / Chapter 3.2.2 --- The Effect of HK-18 Towards Heart Tissue --- p.65 / Chapter 3.2.3 --- In Vitro Study of HK-18 on Multidrug Resistant Cell Line (R-HepG2) --- p.68 / Chapter 3.2.4 --- The Comparison of the Cytotoxicity of DOX on the Parental Cells and Resistant Cells of HepG2 --- p.69 / Chapter 3.2.5 --- The Effect of HK-18 on Cell Proliferation of R-HepG2 Cells by MTT Assay --- p.72 / Chapter 3.2.6 --- DNA Fragmentation Assay --- p.74 / Chapter 3.2.7 --- The Effect of HK-18 on Cell Cycle Phase Distribution --- p.77 / Chapter 3.2.8 --- The Relationship Between HK-18 and P-glycoprotein --- p.80 / Chapter Chapter 4 --- Study of the Cardioprotective Effect of DI AO / Chapter 4.1 --- Myocardial Ischemia-Reperfusion (IR) Injury in Isolated- Perfused Rat Heart --- p.82 / Chapter 4.1.1 --- Time Course of Global Ischemia-Reperfusion-Induced LDH Leakage --- p.82 / Chapter 4.1.2 --- Effect of DI AO Pretreatment on Global IR Injury --- p.85 / Chapter 4.1.2.1 --- LDH Leakage --- p.85 / Chapter 4.1.2.2 --- Contractile Force --- p.87 / Chapter 4.2 --- Isoproterenol-Induced Myocardial Injury in Rats --- p.89 / Chapter 4.2.1 --- Effect of DI AO Pretreatment --- p.89 / Chapter 4.2.2 --- Alternations in the Activity of Myocardial Antioxidant Enzymes --- p.91 / Chapter 4.2.3 --- Alternations in Myocardial Antioxidant Capacity --- p.94 / Chapter Chapter 5 --- Discussion / Chapter 5.1 --- The Significance of the Study of Saponin in the Treatment of Liver Cancer and Heart Injury --- p.96 / Chapter 5.2 --- Effect of HK-18 on Human Hepatocellular Carcinoma Cell --- p.101 / Chapter 5.3 --- Mechanism Study of Anti-Tumor Effect of HK-18 --- p.102 / Chapter 5.4 --- Cytotoxicity of HK-18 Toward Normal Tissue --- p.105 / Chapter 5.5 --- Effect of HK-18 on Multidrug Resistant Human Hepatocellular Carcinoma / Chapter 5.6 --- Protective Effect of DI AO Against Isoproterenol (ISO)- Induced Myocardial Injury --- p.110 / Chapter 5.7 --- Cardioprotective Effect of DI AO Against Ischemia- Reperfusion (IR) Injury --- p.111 / Chapter 5.8 --- Effect of DI AO Pretreatment on Myocardial Antioxidant Enzymes Activities and Antioxidant Capacity --- p.113 / Chapter 5.9 --- Conclusion and Future Prospect --- p.117 / Chapter Chapter 6 --- References --- p.121

Os frutos de S. saponaria, espécie bastante abundante em São Carlos e outras regiões do Brasil são ricos em glicosídeos anfifílicos, ou seja, compostos por uma parte polar e outra apolar. Devido a esta peculiaridade tendem a formar espuma mostrando propriedades químicas semelhantes às dos tensoativos. Alguns destes glicosídeos pertencem à classe das saponinas e são constituídos por uma aglicona de estrutura carbônica a qual está ligada a uma ou duas cadeias de açúcar. O interesse pelas propriedades tensoativas deste glicosídeos motivou o estudo destas substâncias para uso em eletroforese capilar. Os frutos foram extraídos com metanol e fracionados em coluna cromatográfica preparativa utilizando sephadex LH-20 como fase estacionária. Após a eluição, as frações foram analisadas por espectrometria de massas e estudadas por eletroforese capilar. A eletroforese capilar de zona mostrou-se uma técnica viável para o estudo das frações obtidas. Embora um grau de pureza elevado não tenha sido alcançado, a fração B foi utilizada como aditivo para tampão em cromatografia eletrocinética micelar (MEKC) e uma interação diferenciada foi observada do nitrobenzeno com o tampão aditivado em relação ao tampão com SDS puro. / Sapindus saponaria is a very abundant species in São Carlos and others regions of Brazil. Fruits of S. saponaria have a high content of glycosides which possess well-defined regions of hydrophobic and hydrophilic feature denominated amphiphilic molecule. Thus, this can form a foam showing chemical proprieties equals to surfactants. Some glycosides belong to class of saponins and are composed of carbonic structure designates aglycone, which is linked in one or two sugar chains. The purpose of the present study was the use of glycosides due to their surfactants properties in further applications of capillary electrophoresis. The extraction of crude fruits was carried out with methanol and this extract was fractionated in Sephadex LH-20. The fractions were analyzed for mass spectrometry and studied in capillary electrophoresis (CE). This is a feasible technique for the study of fractions obtained. Although a high degree of purity was not reached, the fraction B were used as additive for the electrolyte background in MEKC. The nitrobenzene showed different interaction with micellar system in the electrolyte background with fraction B.

The influence of primary compounds (energy, protein, minerals, and vitamins) in animal nutrition and foraging behavior has been studied for years. The roles of secondary compounds (terpenes, alkaloids, and phenolic compounds) are equally important, yet they have been ignored until recently. Where secondary compounds were once considered toxic by-products of plant metabolism, we now know they are actively involved in plant and animal behavior, health, and productivity. Though often appreciated historically for their negative impacts on food intake and animal production, we are becoming increasingly aware of their beneficial roles in the health of plants, animals, and humans. When animals can ingest an array of plants that contain different kinds and amounts of secondary compounds, they can mix different foods in their diet to better use both primary and secondary compounds, enhancing their health and production, as well as economic and ecological characteristics of landscapes. Endophyte-infected tall fescue contains the alkaloids perlolidine, perloline, ergotamine, and ergovaline, which are all steroidal or protein-like in nature. Tannins and saponins have a high affinity for binding proteins and lipids in the gastro-intestinal tract of animals, and facilitating their excretion from the body. These findings suggest animals may increase their use of forages with alkaloids when they are also provided forages that contain tannins or saponins. The sequence in which forages with different secondary compounds are ingested may influence any potential interactions because different compounds have different residence times in the gastrointestinal tract. I tested the hypothesis that cattle and sheep foraging behavior is influenced by eating different combinations of forages containing secondary compounds in different sequences. In pen and pasture trials, I showed that 1) cattle grazing pastures of endophyte-infected tall fescue (TF) grazed more often on TF when first allowed to graze legumes containing either tannins or saponins, and they grazed TF much more when they first grazed legumes as opposed to the reverse sequence; 2) sheep fed basal diets high in the alkaloid ergotamine d tartrate (EDT) ate more when supplemented with food containing either tannins or saponins, but in contrast to the trials on pasture with cattle, their behavior was not dramatically influenced by sequence; 3) cattle fed fresh cut endophyte-infected tall fescue were not influenced by the addition of tannin to their drinking water, as tannins limited both water and forage intake; 4) sheep fed food containing EDT ate more when supplemented with food containing tannins or when given a choice of foods containing tannins or saponins, than sheep supplemented with food containing saponins or no additional secondary compound. Results from these studies suggest that secondary compounds interact with one another to influence foraging behavior, and that sequence of food ingestion can be influential when animals graze on pastures.

La vigne (Vitis vinifera) est sensible à un grand nombre de maladies. Les politiques de limitation des traitements phytosanitaires font qu'aujourd'hui, les viticulteurs ne disposent d'aucun moyen de lutte contre certains bioagresseurs. C'est le cas des maladies du bois causées par des complexes fongiques nécrosant les ceps et du court noué, maladie virale transmise par des nématodes. La vigne est une espèce végétale connue pour sa production particulière de métabolites secondaires en réponse à des infections. Dans le cadre de cette thèse, nous nous sommes intéressés aux phytoanticipines, préformées dans les plantes et dont le potentiel de toxicité envers des agents pathogènes est intéressant, c’est le cas des triterpénoïdes. Les objectifs de cette thèse ont donc été dans un premier temps d'estimer la capacité de la vigne à produire de tels composés. Pour cela, la composition en triterpénoïdes de différents organes et de différents cépages a été analysée. Nous avons pu montrer que la composition générale en triterpénoïdes est caractéristique de chaque cépage et de chaque organe. Dans une deuxième partie, 9 gènes impliqués dans la synthèse de triterpènes chez la vigne ont été identifiés et leur expression a été évaluée dans différents organes, chez différents cépages et sous différentes conditions de stress biotique et abiotique. Cette étude exploratoire nous donne des pistes pour mettre en corrélation l'expression de certaines triterpène synthases avec la production différentielle de certains triterpènes à la surface des feuilles de différents cépages. Enfin, nous nous sommes intéressés aux triterpènes glycosylés, les saponines, afin d'évaluer leur potentiel dans la lutte contre certaines maladies majeures de la vigne pour lesquelles aucun traitement n'est actuellement disponible. Pour cela, l'efficacité de saponines issues de la gypsophile et du quillaja a été testée contre certains champignons associés aux maladies du bois ainsi que contre les nématodes vecteurs des virus du court noué. Nous avons pu mettre en évidence que les souches de champignons testées étaient capables de contourner la toxicité des saponines, tandis qu'un tel traitement était rapidement efficace pour lutter contre les nématodes. Afin de vérifier l'innocuité de ce traitement pour l'environnement, les doses efficaces ont été testées et n'ont pas eu d'impact significatif sur différents bioindicateurs. / Vitis vinifera is susceptible to many pathogens. These past few years, treatment policies led to the withdrawal of many pesticides. Renee, no chemical treatments are available to treat some grapevine diseases such as the grapevine trunk diseases caused by fungi complexes and the grapevine fanleaf degeneration, a viral disease transmitted from grapevine to grapevine by vector nematodes. Grapevine is known for the production of secondary metabolites as a response to pathogen infections. In this work, we focused on phytoanticipins such as triterpenoids, that are found as preformed compounds and that confer a basal resistance level to plants. First, a chemical analysis was made on the triterpenoid composition of some grapevine cultivars and organs. This study revealed that the triterpenoid composition is specific to the V. vinifera cultivar and the organ. In a genomic approach, 9 candidate genes involved in the triterpene biosynthesis were identified and their expression was studied in different organs, varieties and biotic or abiotic stress conditions. This explorative study shows correlations between gene expression and differential triterpene production at the leaf surface of the different varieties. In the last part of this study, the use of glycosylated triterpenes, also called saponins, as a substitution solution to withdrawed treattnents against major grapevine diseases was tested. Therefore, the efficiency of saponins extracted from gypsophila and quillaja was tested against fungi associated to grapevine trunk diseases and some nematodes vector of the grapevine fanleaf degeneration. These tests evidenced that the fungi were able to avoid saponins toxicity, whereas such treatment was efficient to kill nematodes. In order to evaluate the effect of the treatment on the environment, the efficient doses were tested and bad no significant impact on some bioindicators.