Introdução. O câncer é responsável por uma das principais causas de morte entre mulheres e nota-se um aumento na sua incidência. A linhaça tem sido preconizada como capaz de reduzir o risco do câncer de mama. Objetivo. Verificar o efeito de dietas ricas em linhaça marrom e dourada na evolução do câncer de mama. Métodos. Células cancerosas mamárias humanas (tipo MCF-7) foram inseridas no tecido subcutâneo de camundongos fêmeas nude. Quando os tumores já puderam ser claramente identificados, após 7 semanas, os animais constituíram 3 grupos, um com dieta controle e os outros dois com as variedades de linhaça marrom e dourada. As sementes de linhaça foram moídas para produção de farinhas que foram utilizadas na suplementação das dietas oferecidas aos animais. O crescimento dos tumores implantados nos animais foi acompanhado por oito semanas. Resultados. As linhaças das variedades marrom e dourada mostraram-se eficazes na diminuição da taxa de crescimento dos tumores MCF-7, não sendo verificada nenhuma diferença entre elas. Conclusão. Ambas variedades de linhaça reduziram o crescimento dos tumores. Assim, o consumo de linhaça deve ser estimulado a fim de diminuir a incidência do câncer de mama. / Introduction. Breast cancer is one of the main causes of death among women and an increase in its incidence has been noticed. There is evidence that flaxseed intake could reduce breast cancer risk. Objective. To verify the effect of brown and golden flaxseed rich diets on breast cancer. Methods. Cancer cells of the MCF-7 line were injected subcutaneously into athymic mice. After seven weeks, when tumors were already established, the animals were randomly divided in three groups: (1) control, fed on a basal diet; (2) and (3) mice fed on the basal diet supplemented with 10% brown and with 10% golden flaxseed, respectively. Flaxseed was freshly ground for production of the diets offered to the animals. Tumor growth was monitored weekly for eight weeks. Results. The two varieties of flaxseed inhibited tumor growth, without any difference between them. Conclusion. Both flaxseed varieties were able to reduce tumor growth. Therefore, their intake should be stimulated with the aim to reduce breast cancer incidence.

Introdução. O câncer é responsável por uma das principais causas de morte entre mulheres e nota-se um aumento na sua incidência. A linhaça tem sido preconizada como capaz de reduzir o risco do câncer de mama. Objetivo. Verificar o efeito de dietas ricas em linhaça marrom e dourada na evolução do câncer de mama. Métodos. Células cancerosas mamárias humanas (tipo MCF-7) foram inseridas no tecido subcutâneo de camundongos fêmeas nude. Quando os tumores já puderam ser claramente identificados, após 7 semanas, os animais constituíram 3 grupos, um com dieta controle e os outros dois com as variedades de linhaça marrom e dourada. As sementes de linhaça foram moídas para produção de farinhas que foram utilizadas na suplementação das dietas oferecidas aos animais. O crescimento dos tumores implantados nos animais foi acompanhado por oito semanas. Resultados. As linhaças das variedades marrom e dourada mostraram-se eficazes na diminuição da taxa de crescimento dos tumores MCF-7, não sendo verificada nenhuma diferença entre elas. Conclusão. Ambas variedades de linhaça reduziram o crescimento dos tumores. Assim, o consumo de linhaça deve ser estimulado a fim de diminuir a incidência do câncer de mama. / Introduction. Breast cancer is one of the main causes of death among women and an increase in its incidence has been noticed. There is evidence that flaxseed intake could reduce breast cancer risk. Objective. To verify the effect of brown and golden flaxseed rich diets on breast cancer. Methods. Cancer cells of the MCF-7 line were injected subcutaneously into athymic mice. After seven weeks, when tumors were already established, the animals were randomly divided in three groups: (1) control, fed on a basal diet; (2) and (3) mice fed on the basal diet supplemented with 10% brown and with 10% golden flaxseed, respectively. Flaxseed was freshly ground for production of the diets offered to the animals. Tumor growth was monitored weekly for eight weeks. Results. The two varieties of flaxseed inhibited tumor growth, without any difference between them. Conclusion. Both flaxseed varieties were able to reduce tumor growth. Therefore, their intake should be stimulated with the aim to reduce breast cancer incidence.

Dans la famille des protéines dirigeantes, AtDIR6, oriente le couplage de radicaux phénoxyles afin de former un lignane optiquement pur : le (-)-pinorésinol. Comme de nombreux lignanes, le pinorésinol est un produit d’intérêt avec des propriétés anti-cancéreuse et anti-fongique. Avec pour objectif à long terme de mettre au point de nouveaux biocatalyseurs énantiosélectifs, nous nous sommes intéressés au mécanisme d’action d’AtDIR6.Dans un premier temps, la production d’AtDIR6 et les conditions de bioconversion ont été optimisées. L’effet dose-dépendant de la protéine sur la formation du (-)-pinorésinol a été confirmé. Les études spectroscopiques entreprises afin de préciser la nature du « substrat » pris en charge par AtDIR6 ont permis de confirmer que l’alcool coniférylique est un mauvais substrat. De plus, par RPE nous avons pu mettre en évidence pour la première fois qu’AtDIR6 augmente la durée de vie de la forme radicalaire de l’AC. Par ailleurs, le greffage covalent d’une sonde radicalaire sur AtDIR6 nous a permis de marquer une tyrosine localisée dans la cavité. Avec AtDIR6 marquée la régiosélectivité de la réaction est affectée. Par ailleurs, la reconnaissance de molécules substrats par AtDIR6 semble être naturellement limitée à un motif 2-methoxy-phénol. Nous montrons pour la première fois que le motif propényle peut être modifié comme en témoigne les produits de bioconversion de l’acétate d’AC pour lesquels une régiosélectivité dépendante de la présence d’AtDIR6 est observée. L’ensemble de nos résultats ouvre des perspectives dans l’utilisation de protéines dirigeantes pour la formation contrôlée de nouveaux produits de couplage. / The family of the leading proteins gathers proteins widely spread within the plant world. In this family, AtDIR6, one of the first characterized proteins, directs the coupling of phenoxyl radicals to form an optically pure lignan: the (-)-pinoresinol. Like many lignans, pinoresinol is a product of interest with anti-cancer and anti-fungal properties. With the long-term goal of developing new enantioselective biocatalysts, we are interested in the mechanism of action of AtDIR6.At first, AtDIR6 production and bioconversion conditions were optimized. The dose-dependent effect of the protein on (-)-pinoresinol formation was confirmed. Spectroscopic studies undertaken to clarify the nature of the "substrate" accommodated by AtDIR6 have confirmed that coniferyl alcohol is a poor substrate. Furthermore, by EPR we have been able to highlight for the first time that AtDIR6 increases the life of the radical form of coniferyl alcohol. Moreover, the covalent grafting of a radical probe on AtDIR6 allowed us to tag a tyrosine located in the cavity. With the tagged protein the regioselectivity of the reaction is affected. On the other hand, the recognition of substrate molecules by AtDIR6 seems to be naturally limited to AC or its radical, apparently recognized because of the 2-methoxyphenol motif. We show for the first time that the propenyl unit can be modified as evidenced by the bioconversion products of AC acetate for which a regioselectivity dependent on the presence of AtDIR6 is observed. All of our results open up prospects for the use of dirigent proteins for the controlled formation of new coupling products.

The rising use of natural products creates an imperative need for an enhanced awareness of the safety of current and new products making their way into the marketplace. An important example is natural products containing lignans as the principal active component. Despite their structural similarity the lignan of creosote bush can cause hepato- and renal toxicity while the lignans of flaxseed have no reported serious toxicity. This dissertation aimed to investigate the oxidative metabolism of such lignans to determine whether reversible, competitive interactions and/or bioactivation may explain the differences in their apparent toxicity.<p> The first objective was to study the metabolism and bioactivation of nordihydroguaiaretic acid (creosote bush) and secoisolariciresinol (flaxseed). Nordihydroguaiaretic acid metabolism in rat liver microsomes led to the production of three glutathione adducts formed via ortho¬-quinone reactive intermediates. This metabolism was independent of NADPH and thus attributed to autoxidation. Secoisolariciresinol metabolism yielded lariciresinol and no glutathione adducts suggesting an absence of bioactivation to reactive quinone intermediates.<p> The second objective was to study the autoxidation of nordihydroguaiaretic acid. The major autoxidation product was a unique, stable schisandrin-like cyclolignan which was the result of nordihydroguaiaretic acid cyclization. The half-life of nordihydroguaiaretic acid in aqueous solution, pH 7.4, 37ºC is 3.14 hours suggesting the cyclolignan may be responsible for some of the biological effects of nordihydroguaiaretic acid.<p> The third objective was to study the inhibition of cytochrome P450 isoforms 1A2, 2B, 2C11 and 3A by lignans derived from creosote bush and flaxseed. None of the lignans caused irreversible inhibition. Both creosote bush and flaxseed lignans caused reversible inhibition of P450 enzyme activity that involved competitive or mixed-type inhibition, however the inhibition was present at nonphysiologically relevant concentrations. Activation of cytochrome P450 isoforms was also observed at low lignan concentrations. The results suggest that P450-mediated bioactivation or reversible inhibition cannot explain the differences in toxicity noted between the lignans of creosote bush and flaxseed.<p> This work suggests a minimal risk for drug-lignan interactions at P450 enzymes. Further studies are warranted to determine the presence and biological and toxicological role of the nordihydroguaiaretic acid cyclolignan in herbal preparations.

The rising use of natural products creates an imperative need for an enhanced awareness of the safety of current and new products making their way into the marketplace. An important example is natural products containing lignans as the principal active component. Despite their structural similarity the lignan of creosote bush can cause hepato- and renal toxicity while the lignans of flaxseed have no reported serious toxicity. This dissertation aimed to investigate the oxidative metabolism of such lignans to determine whether reversible, competitive interactions and/or bioactivation may explain the differences in their apparent toxicity.<p> The first objective was to study the metabolism and bioactivation of nordihydroguaiaretic acid (creosote bush) and secoisolariciresinol (flaxseed). Nordihydroguaiaretic acid metabolism in rat liver microsomes led to the production of three glutathione adducts formed via ortho¬-quinone reactive intermediates. This metabolism was independent of NADPH and thus attributed to autoxidation. Secoisolariciresinol metabolism yielded lariciresinol and no glutathione adducts suggesting an absence of bioactivation to reactive quinone intermediates.<p> The second objective was to study the autoxidation of nordihydroguaiaretic acid. The major autoxidation product was a unique, stable schisandrin-like cyclolignan which was the result of nordihydroguaiaretic acid cyclization. The half-life of nordihydroguaiaretic acid in aqueous solution, pH 7.4, 37ºC is 3.14 hours suggesting the cyclolignan may be responsible for some of the biological effects of nordihydroguaiaretic acid.<p> The third objective was to study the inhibition of cytochrome P450 isoforms 1A2, 2B, 2C11 and 3A by lignans derived from creosote bush and flaxseed. None of the lignans caused irreversible inhibition. Both creosote bush and flaxseed lignans caused reversible inhibition of P450 enzyme activity that involved competitive or mixed-type inhibition, however the inhibition was present at nonphysiologically relevant concentrations. Activation of cytochrome P450 isoforms was also observed at low lignan concentrations. The results suggest that P450-mediated bioactivation or reversible inhibition cannot explain the differences in toxicity noted between the lignans of creosote bush and flaxseed.<p> This work suggests a minimal risk for drug-lignan interactions at P450 enzymes. Further studies are warranted to determine the presence and biological and toxicological role of the nordihydroguaiaretic acid cyclolignan in herbal preparations.

Made available in DSpace on 2016-06-02T20:36:48Z (GMT). No. of bitstreams: 1 5580.pdf: 12897921 bytes, checksum: 7de4b9e632d7de714eb77bf5afad7e21 (MD5) Previous issue date: 2013-03-27 / Universidade Federal de Sao Carlos / The leaf-cutting ants are social species, living in permanent colonies. The genera of the greater importance, Atta (saúvas) and Acromyrmex (quenquéns), are the major plagues of Brazilian agriculture, to cause serious damages by its large and uncontrolled grazing, which leads to serious economic losses for many agrosystems. In the same way, the corn maize weevil, Sitophilus zeamais, belonging to the family Curculionidae, is the major pest species of stored corn. The corn grains are drilled and damaged by larvae and adults, causing numerous qualitative and quantitative losses of corn grains disabling its marketing. As the consequence, the effective control of these plagues is extremely important for agriculture and economy that aims to provide the nacional and international market quality products with high commercial value. In this context, the phytochemistry study of Annona sylvatica provides an alternative way to control these plagues, since that studies of these species showed a wide variety of natural products with promising activities, including, insecticide and fungicide, due to the large presence of acetogenins and lignans as secondary metabolites. This study allowed the isolation of fourteen compounds (four lignans, four acetogenins, three alkaloids and three steroids), however were identified eleven compounds due to the high structural complexity presented for the acetogenins. The identification techniques employed have been using single and two-dimensional spectra of 1H and 13C NMR and Mass Spectrometry (HPLC/NMR; HPLC/ESI-MS/MS e HPLC/APCI-MS/MS). For the biological tests, the ethanolic extract of the seeds stood out as potentially toxic to three bioassays cited above. The leaves and branches dichlorometanic fractions obtained by liquid-liquid partitioning of the extracts were toxic for leaf-cutting ants and their symbiotic fungus. Among the acetogenins isolated, only one of them showed a significant activity against corn maize weevil. / As formigas cortadeiras são espécies sociais, vivendo em colônias permanentes. Os gêneros de maior importância econômica, Atta (saúvas) e Acromyrmex (quenquéns), são as principais pragas da agricultura brasileira, por causarem sérios danos pela sua grande e descontrolada herbivoria, o que gera sérios prejuízos econômicos para muitos agroecossitemas. Nessa mesma vertente, o gorgulho do milho, Sitophilus zeamais, pertencente à família Curculionídea, é a principal espécie praga do milho armazenado. Os grãos são perfurados e danificados pelas larvas e adultos, inutilizando sua comercialização. Como consequência, o controle eficaz de tais pragas é de extrema importância para a agricultura e economia do país que visa oferecer ao mercado nacional e internacional produtos de qualidade e alto valor comercial. Nesse contexto, o estudo fitoquímico de Annona sylvatica fornece uma forma alternativa de controle a estas pragas, uma vez que estudos destas espécies mostraram uma ampla variedade de produtos naturais com atividades promissoras, entre elas, inseticida e fungicida, devido à ampla presença de acetogeninas e lignanas como metabólitos secundários. Este estudo resultou no isolamento de 14 compostos (quatro lignanas, quatro acetogeninas, três alcaloides e três esteroides), no entanto, foram identificados 11 compostos, devido à alta complexidade estrutural apresentada para as acetogeninas. As técnicas de identificação utilizadas foram através dos espectros uni e bidimensionais de RMN 1H e 13C e por Espectrometria de Massas (HPLC/NMR; HPLC/ESI-MS/MS e HPLC/APCI-MS/MS). Para os ensaios biológicos, o extrato etanólico das sementes destacou-se como potencial tóxico frente aos três bioensaios citados acima. As frações diclorometânicas das folhas e ramos obtidas através do particionamento líquido-líquido dos extratos foram tóxicas para as formigas cortadeiras e seu fungo simbionte. Dentre as acetogeninas isoladas, apenas uma apresentou uma atividade significativa frente ao gorgulho do milho.

Plante de grande culture aux multiples applications, le lin accumule dans ses graines des métabolites spécialisés appelés lignanes aux propriétés phytooestrogène et antioxydante, bénéfiques en santé humaine et, dans ses feuilles, des lignanes de nature toxique. Pour l’utilisation et l’étude de ces composés phénoliques issus de la voie des monolignols, une technique d’éco-extraction assistée par les ultrasons a été développée et appliquée à un criblage de différentes variétés pour leur contenu en lignanes conférant une haute valeur ajoutée aux extraits et produits. Les potentiels verrous métaboliques de la voie de biosynthèse de ces composés ont fait l’objet d’investigations au niveau de la régulation transcriptionnelle des gènes responsables de la formation des énantiomères opposés de sécoisolaricirésinol dans la graine et les parties aériennes. La famille multigénique des protéines dirigeantes (DIR) du lin, premiers acteurs de cette voie, a été criblée au niveau génomique et transcriptionnel afin de déterminer des candidates pour fonctionner avec les pinorésinol laricirésinol réductases (PLR), enzymes bifonctionnelles catalysant la formation du sécoisolaricirésinol. L’étude de la régulation fine de l’expression des deux isoformes des gènes PLR a mis en évidence des profils d’inductibilité très contrastés et a conduit à l’identification d’éléments cis-régulateurs ainsi que de facteurs de transcription impliqués dans ces voies de régulation. L’ensemble des résultats convergent vers un rôle de défense des lignanes in planta et a permis de construire une vue d’ensemble des mécanismes complexes de régulation de leur biosynthèse et enfin de proposer des pistes pour l’amélioration de la production de ces molécules naturelles par une stimulation de leur accumulation et l’augmentation des rendements d’extraction par chimie verte. / As a crop with multiple purposes, flax accumulates lignans, specialized metabolites with health benefits, known for their phytoestrogenic and antioxidant properties in its seed, and toxic lignans in its leaves. In order to use and study these phenolic compounds derived from monolignols, an eco-friendly method based on ultrasound-assisted extraction was developed and applied to the screening of cultivars for their lignan content which confers high value to extracts and flaxseed by-product. Regulation of the lignan biosynthetic pathway was investigated at the transcriptional level for the genes responsible for the formation of secoisolariciresinol in seeds and aerial parts. The multigene family of dirigent proteins (DIR), first actors of this pathway, was explored by genomic and transcriptional approaches in order to select candidates to operate with pinoresinol lariciresinol reductases (PLR), bifunctional enzymes catalyzing secoisolariciresinol biosynthesis. The study of the transcriptional regulation of PLR genes evidenced very contrasting expression profiles and led to the identification of transcription factors acting as master regulators of this biosynthesis and their cis-regulatory target elements. Results allowed first to reinforce the hypothesis of the lignans defensive role in planta, second to afford an overall view of complex mechanisms occurring in the regulation of lignan natural production and finally to suggest leads to improve lignan yield by a stimulation of natural production and an enhancement of extraction yield using green chemistry methods.

No description available.

Cardiovascular diseases are the leading cause of death in most industrialised countries and in developing countries the trend in cardiovascular-related deaths is increasing. World-wide, type 2 diabetes mellitus (T2DM) is an emerging cause of disability and premature death. Both these conditions are closely associated with the consumption of energy-dense foods and food products that are poor in nutrients, as well as with a sedentary lifestyle. Pharmacological and surgical interventions can improve the outcome and delay the progression of the disease, but in terms of population-level prevention there is no substitute for the adoption of a healthy lifestyle. SETTING The underlying studies were conducted in Västerbotten (the VIP study), and in Norrbotten and Västerbotten combined (the MONICA Project). Norrbotten andVästerbotten are the two northernmost counties in Sweden. Since the mid-1980sthe prevalence of cardiovascular disease has decreased and diabetes rates haveremained stable in this region, despite of an unbroken trend of increasing body weight. OBJECTIVE The aim of this thesis is to describe changes in reported dietary habits, estimatetheir relative importance as risk factors for diabetes and cardiovascular disease, and finally to identify lifestyle components as potential targets for intervention. RESULTS The first paper describes changes in self-reported food consumption between 1986 and 1999. During this period, the population in question switched from products with high saturated fatty acid content (e.g. milk containing 3% fat, butter) to foods containing less saturated fat (e.g. milk containing 1.5% fat, vegetable oil, low-fat margarine); pasta and rice were consumed more often, and potatoes were consumed less. Convenience foods (e.g. hamburgers, snacks, sweets) became more popular, whilst traditional dishes (e.g. potato dumplings, black pudding, blöta) decreased in popularity. Fruit and vegetable intake remained low. In paper two we study the effects of these changes in food intake on the risk of developing T2DM using body fat distribution as an early indicator. Increased consumption of convenience foods was associated with unfavourable changes (smaller hip circumference and larger waist circumference), whereas the increased consumption of vegetable oil and pasta was associated with low-risk fat distribution. In the third paper we report studies on the association between fat consumption and T2DM. We used the pattern of fatty acids in the membranes of red blood cells as a marker of fat intake. In addition to confirming earlier findings (markers of the intake of saturated fat are associated with increased risk of T2DM and markers of unsaturated fat are associated with reduced T2DM risk), we also identified associations between two markers of milk-derived saturated fat intake and enterolactone, a biomarker of dietary fibre intake, and the risk of developing myocardial infarction. Our results indicate that moderately high levels of enterolactone intake in men are associated with lower risk of experiencing myocardial infarction. Manuscript 5 ranks education level, physical activity, smoking status, and self-reported intake of dietary fibre and fatty acids according to their effects on body fat distribution. Increased levels of physical activity, a higher education level and a reduced intake of saturated fat from meat were ranked as the most strongly associated factors in both men and women. Increased intake of dietary fibre from grains in women, and increased intake of dietary fibre from fruits and vegetables in men, was also inversely associated with average waist circumference. CONCLUSION Both questionnaire-based and biological markers of the risk of developing diabetes or cardiovascular disease have been identified. Based on available population level measurements, reduced consumption of convenience foods, increased consumption of whole-grain products, fruits and vegetables, vegetable oil and pasta as well as increased physical activity are potential goals for interventions in northern Sweden.