This thesis aims to assess the human health impact of exposure to estrogenic compounds from the diet. A multi-disciplinary approach is taken to address various aspects of this issue. An introduction to xenoestrogens, including international research priorities, wildlife and human health effects, mechanisms of action, structure activity relationships and additivity of estrogenic effects is provided as background information. An assessment of exposure to a range of naturally occurring and synthetic estrogenic compounds found in food is derived in Chapter 2. The assessment combines new and existing data on food concentration, food consumption and serum levels for each xenoestrogen. Exposure is combined with relative estrogenic potency data from published bioassasy data to estimate risk relative to normal circulating levels of estradiol. Assuming additivity of xenoestrogens, for an average New Zealand male and for post-menopausal women, xenoestrogens in the diet contribute an additional 12-90% of estrogenicity above normal circulating levels. For a pre-menopausal female, the contribution from the diet represents in the order of an additional 2%. The level of exposure determined in this thesis would seem to be of pharmacological relevance, especially for men with low levels of estrogen and for post-menopausal women. Bisphenol A (BPA) is an important monomer used in the manufacture of epoxy resins for internal food can linings. A survey of the BPA content of a range of 80 canned foods available to the New Zealand consumer was undertaken and the results used in the exposure and risk assessments. BPA was detected in all foods analysed except soft drinks, at concentrations ranging from <10-29 µg/kg, except for individual samples of tuna, corned beef and coconut cream that were 109, 98 and 191 µg/kg respectively. None, of over 4000 individual exposure scenarios, exceeded the temporary Tolerable Daily Intake (TDI) of 10 µg/kg body weight per day set by the Scientific Committee on Food in 2002. Intestinal microflora influence the bioavailability of the naturally occurring xenoestrogens genistein and daidzein that contribute significantly to total estrogenicity from the diet. The degradation of genistein and daidzein by the faecal microfloral of 5 human subjects was variable and unpredictable between individuals and within an individual. These findings have important implications for the promotion and prescription of soy foods and supplements for disease prevention and health benefits. The "yeast assay" is one of a number of methods available to measure estrogenicity. This assay was established and validated. In utero exposure to estrogenic compounds at critical periods of sexual differentiation and endocrine development may imprint for health effects observed later in life. Placental transfer of estrogenicity, from 17β-estradiol was studied using the human placental perfusion model and the yeast assay. The placenta provides a protective barrier to the transfer of estrogenicity. Experiments with genistein showed that 5-15% placental transfer occurred, suggesting that in utero exposure might be in the order of 10% of maternal exposure. The thesis concludes with consideration of a genomic approach to substantiate, or refute, the mechanistic link between exposure to xenoestrogens and claimed human health effect. Such an approach offers exciting opportunity to clarify the mode of action of the synthetic versus the naturally occurring xenoestrogens, to confirm or dispute additivity of effect that is an important premise of the exposure assessment, to identify key genes involved in the many possible health effects and thence risk to the individual from dietary exposure to xenoestrogens.

Com o crescente aumento do mercado cosmético e com o consequente aumento da exposição da população às diversas moléculas que os compõem, se faz fundamental os cuidados no desenvolvimento e na avaliação da segurança de produtos cosméticos. Diferentes ferramentas estão disponíveis para compor a estratégia de avaliação de segurança, sendo uma delas a avaliação da retenção e permeação cutânea in vitro, técnica que não apenas fornece dados para a avaliação da eficácia de princípios ativos, como também permite um aprofundamento na avaliação toxicológica dos ingredientes e produtos cosméticos. Assim como cresce o interesse da população por produtos cosméticos, observa-se também um aumento considerável na procura por produtos contendo ingredientes botânicos, o que torna ainda mais desafiadora a avaliação de segurança. Sendo as isoflavonas de soja bastante consumidas na alimentação e, em alguns casos, aplicadas a cosméticos, e tendo elas propriedades dérmicas interessantes, este trabalho teve como objetivo estudar o perfil de retenção e permeação cutânea in vitro da daidzeína, umas das mais importantes isoflavonas já descritas e estudadas. Para tal, desenvolveu-se uma nanoemulsão cosmética e aplicou-se um extrato botânico de soja rico em daidzeína. Desenvolveu-se e validou-se um método analítico por cromatografia líquida acoplada a detector de arranjo de diodos, e ainda procedeu-se a caracterização da nanoemulsão, a avaliação teórica de segurança de todos os seus ingredientes, além dos estudos de retenção e permeação cutânea in vitro, foco central deste trabalho. Como resultados, teve-se que a técnica de emulsificação à quente seguida de sonicação adotada para o preparo da nanoemulsão foi eficiente, possibilitando a obtenção de uma nanoemulsão pouco polidispersa e com tamanho de partícula médio abaixo de 200 nm. A retenção e permeação cutânea foram dependentes do tempo de aplicação, sendo que a nanoemulsão proporcionou uma maior retenção e menor permeação cutâneas da daidzeína comparado com solução controle no tempo de 6 h. A nanoemulsão desenvolvida mostrou-se adequada para a liberação tópica da daidzeína presente em extrato vegetal. Os testes in vitro de retenção e permeação cutânea são cruciais para esta etapa de desenvolvimento das formulações, quando os aspectos liberação tópica e possível toxicidade sistêmica são avaliados. / With the continuous growth of the cosmetic market, and so the increase in the exposure of the population to the different molecules present on these products, the care in the development and the safety assessment of cosmetics plays an important role. Different tools are available to compose the safety assessment strategy, one of which is the dermal absorption in vitro assay. This technique does not only give information regarding the efficacy of active ingredients, but also allow a deep toxicological evaluation of cosmetic ingredients and products. As the interest of the population on cosmetic products grows, also grows people\'s search for products containing botanical ingredients, fact that turns the safety assessment more challenger. As the soy isoflavones are part of the diet and sometimes used in cosmetic products, and as they present interesting dermal properties, this work aimed to study the profile of skin retention and dermal absorption of the daidzein, one of the most important isoflavones ever described and studied. For that, a cosmetic nanoemulsion was developed, in which a soy botanical extract rich in daidzein was added. An analytical method was developed and validated, based in liquid chromatography coupled with a diode array detector. Besides the in vitro studies of skin retention and dermal absorption, main focus of this project, the characterization of the nanoemulsion and the theoretical safety assessment of all of its ingredients were also performed. Regarding the results, the technique of hot emulsification followed by sonication used for the preparation of the nanoemulsion could be considered efficient based on the fact that it was less polidisperse and with a medium particle size below 200 nm. The skin retention and permeation were dependent on the time of application, and, it was observed that the nanoemulsion has led to greater retention and lesser skin permeation of daidzein incorporated into the nanoemulsion when compared to the control solution after 6 h of application. The nanoemulsion developed showed to be adequate to topical delivery of daidzein that is present in plant extract. In vitro skin retention and skin permeation are critical for this stage of development of the formulations, considering that aspects of topical delivery and systemic toxicity are evaluated.

Inflammation is a major contributor to postmenopausal bone loss. Various long chain polyunsaturated fatty acids (LCPUFAs), particularly those of the n-3 family, are known to have anti-inflammatory activity and may have a role in minimising postmenopausal bone loss. The objectives of this thesis were to determine whether some LCPUFAs have greater bone-protective effects than others; to identify some of the mechanisms of action of LCPUFAs in bone and to explore the possibility that combined treatment with LCPUFAs and phytoestrogens offers greater bone-protective effects than either treatment alone. Using the ovariectomised rat model for postmenopausal bone loss, the relative effectiveness of eicosapentaenoic acid (EPA, 20:5n-3), docosahexaenoic acid (DHA, 22:6n-3) and gamma-linolenic acid (GLA, 18:3n-6) in minimising bone loss post-ovariectomy was investigated. GLA exacerbated bone loss post ovariectomy in rats. In vitro, treatment of MC3T3-E1/4 osteoblast-like cells with GLA resulted in greater membrane-bound RANKL expression suggesting a possible stimulatory effect of GLA on osteoclastogenesis and osteoclast activity. EPA had no effect on overall bone mass in vivo. DHA significantly ameliorated ovariectomy-induced bone loss possibly by increasing plasma IGF-1 concentration, modulating vitamin D metabolism and, as observed in a second study, by increasing the concentration of gamma-carboxylated osteocalcin. In vitro both EPA and DHA reduced the prostaglandin E2 (PGE2)-induced increase in membrane-bound RANKL expression in MC3T3-E1/4 osteoblast-like cells. However as RANKL-independent pathways are believed to be largely responsible for the ovariectomy-induced increase in osteoclastogenesis in vivo, inhibition of RANKL expression may not significantly contribute to the prevention of ovariectomy-induced bone loss. In a second study in ovariectomised rats, combined treatment with DHA and 17β-oestradiol was associated with significantly higher femur bone mineral content than either treatment alone. However, no beneficial effects of combined treatment with DHA and either of the phytoestrogens genistein or daidzein, on bone mass were apparent. In vitro, co-treatment of TNF-α - exposed MC3T3-E1/4 cells with DHA and 17β-oestradiol was associated with a higher cell number compared to either treatment alone indicating a protective effect of combined treatment against the cytotoxic and/or anti-proliferative effects of TNF-α. In contrast, combined treatment of MC3T3-E1/4 cells with DHA and genistein, but not daidzein, was associated with significantly lower cell number than either treatment alone. As genistein, but not daidzein, is a tyrosine kinase inhibitor, this may indicate that DHA requires tyrosine kinase activity for its protective effect on cell number in TNF-α - exposed osteoblasts. Whether DHA itself is bioactive in bone cells or whether lipid mediators formed from DHA are responsible for the observed bone-protective effects is unknown. Using lipid mediator lipidomic analysis, the presence of DHA-derived lipid mediators in bone marrow in quantities known to be physiologically significant in other tissues was confirmed. Further research into the effects of these lipid mediators in bone and confirmation of the mechanisms of action of DHA in bone cells is required. This thesis demonstrates that consumption of DHA provides some protection against ovariectomy-induced bone loss in vivo and mitigates the effects of inflammation on RANKL signalling and osteoblast cell number in vitro. The bone-protective effects of DHA are complemented by co-treatment with 17β-oestradiol but may be inhibited by co-treatment with the phytoestrogens daidzein or genistein.

This thesis aims to assess the human health impact of exposure to estrogenic compounds from the diet. A multi-disciplinary approach is taken to address various aspects of this issue. An introduction to xenoestrogens, including international research priorities, wildlife and human health effects, mechanisms of action, structure activity relationships and additivity of estrogenic effects is provided as background information. An assessment of exposure to a range of naturally occurring and synthetic estrogenic compounds found in food is derived in Chapter 2. The assessment combines new and existing data on food concentration, food consumption and serum levels for each xenoestrogen. Exposure is combined with relative estrogenic potency data from published bioassasy data to estimate risk relative to normal circulating levels of estradiol. Assuming additivity of xenoestrogens, for an average New Zealand male and for post-menopausal women, xenoestrogens in the diet contribute an additional 12-90% of estrogenicity above normal circulating levels. For a pre-menopausal female, the contribution from the diet represents in the order of an additional 2%. The level of exposure determined in this thesis would seem to be of pharmacological relevance, especially for men with low levels of estrogen and for post-menopausal women. Bisphenol A (BPA) is an important monomer used in the manufacture of epoxy resins for internal food can linings. A survey of the BPA content of a range of 80 canned foods available to the New Zealand consumer was undertaken and the results used in the exposure and risk assessments. BPA was detected in all foods analysed except soft drinks, at concentrations ranging from <10-29 µg/kg, except for individual samples of tuna, corned beef and coconut cream that were 109, 98 and 191 µg/kg respectively. None, of over 4000 individual exposure scenarios, exceeded the temporary Tolerable Daily Intake (TDI) of 10 µg/kg body weight per day set by the Scientific Committee on Food in 2002. Intestinal microflora influence the bioavailability of the naturally occurring xenoestrogens genistein and daidzein that contribute significantly to total estrogenicity from the diet. The degradation of genistein and daidzein by the faecal microfloral of 5 human subjects was variable and unpredictable between individuals and within an individual. These findings have important implications for the promotion and prescription of soy foods and supplements for disease prevention and health benefits. The "yeast assay" is one of a number of methods available to measure estrogenicity. This assay was established and validated. In utero exposure to estrogenic compounds at critical periods of sexual differentiation and endocrine development may imprint for health effects observed later in life. Placental transfer of estrogenicity, from 17β-estradiol was studied using the human placental perfusion model and the yeast assay. The placenta provides a protective barrier to the transfer of estrogenicity. Experiments with genistein showed that 5-15% placental transfer occurred, suggesting that in utero exposure might be in the order of 10% of maternal exposure. The thesis concludes with consideration of a genomic approach to substantiate, or refute, the mechanistic link between exposure to xenoestrogens and claimed human health effect. Such an approach offers exciting opportunity to clarify the mode of action of the synthetic versus the naturally occurring xenoestrogens, to confirm or dispute additivity of effect that is an important premise of the exposure assessment, to identify key genes involved in the many possible health effects and thence risk to the individual from dietary exposure to xenoestrogens.

Com o crescente aumento do mercado cosmético e com o consequente aumento da exposição da população às diversas moléculas que os compõem, se faz fundamental os cuidados no desenvolvimento e na avaliação da segurança de produtos cosméticos. Diferentes ferramentas estão disponíveis para compor a estratégia de avaliação de segurança, sendo uma delas a avaliação da retenção e permeação cutânea in vitro, técnica que não apenas fornece dados para a avaliação da eficácia de princípios ativos, como também permite um aprofundamento na avaliação toxicológica dos ingredientes e produtos cosméticos. Assim como cresce o interesse da população por produtos cosméticos, observa-se também um aumento considerável na procura por produtos contendo ingredientes botânicos, o que torna ainda mais desafiadora a avaliação de segurança. Sendo as isoflavonas de soja bastante consumidas na alimentação e, em alguns casos, aplicadas a cosméticos, e tendo elas propriedades dérmicas interessantes, este trabalho teve como objetivo estudar o perfil de retenção e permeação cutânea in vitro da daidzeína, umas das mais importantes isoflavonas já descritas e estudadas. Para tal, desenvolveu-se uma nanoemulsão cosmética e aplicou-se um extrato botânico de soja rico em daidzeína. Desenvolveu-se e validou-se um método analítico por cromatografia líquida acoplada a detector de arranjo de diodos, e ainda procedeu-se a caracterização da nanoemulsão, a avaliação teórica de segurança de todos os seus ingredientes, além dos estudos de retenção e permeação cutânea in vitro, foco central deste trabalho. Como resultados, teve-se que a técnica de emulsificação à quente seguida de sonicação adotada para o preparo da nanoemulsão foi eficiente, possibilitando a obtenção de uma nanoemulsão pouco polidispersa e com tamanho de partícula médio abaixo de 200 nm. A retenção e permeação cutânea foram dependentes do tempo de aplicação, sendo que a nanoemulsão proporcionou uma maior retenção e menor permeação cutâneas da daidzeína comparado com solução controle no tempo de 6 h. A nanoemulsão desenvolvida mostrou-se adequada para a liberação tópica da daidzeína presente em extrato vegetal. Os testes in vitro de retenção e permeação cutânea são cruciais para esta etapa de desenvolvimento das formulações, quando os aspectos liberação tópica e possível toxicidade sistêmica são avaliados. / With the continuous growth of the cosmetic market, and so the increase in the exposure of the population to the different molecules present on these products, the care in the development and the safety assessment of cosmetics plays an important role. Different tools are available to compose the safety assessment strategy, one of which is the dermal absorption in vitro assay. This technique does not only give information regarding the efficacy of active ingredients, but also allow a deep toxicological evaluation of cosmetic ingredients and products. As the interest of the population on cosmetic products grows, also grows people\'s search for products containing botanical ingredients, fact that turns the safety assessment more challenger. As the soy isoflavones are part of the diet and sometimes used in cosmetic products, and as they present interesting dermal properties, this work aimed to study the profile of skin retention and dermal absorption of the daidzein, one of the most important isoflavones ever described and studied. For that, a cosmetic nanoemulsion was developed, in which a soy botanical extract rich in daidzein was added. An analytical method was developed and validated, based in liquid chromatography coupled with a diode array detector. Besides the in vitro studies of skin retention and dermal absorption, main focus of this project, the characterization of the nanoemulsion and the theoretical safety assessment of all of its ingredients were also performed. Regarding the results, the technique of hot emulsification followed by sonication used for the preparation of the nanoemulsion could be considered efficient based on the fact that it was less polidisperse and with a medium particle size below 200 nm. The skin retention and permeation were dependent on the time of application, and, it was observed that the nanoemulsion has led to greater retention and lesser skin permeation of daidzein incorporated into the nanoemulsion when compared to the control solution after 6 h of application. The nanoemulsion developed showed to be adequate to topical delivery of daidzein that is present in plant extract. In vitro skin retention and skin permeation are critical for this stage of development of the formulations, considering that aspects of topical delivery and systemic toxicity are evaluated.

No description available.

Dietary soy isoflavones have been shown to ameliorate insulin resistance and Type 2 diabetes. However, many in vitro studies used supra-physiological concentrations of individual isoflavones that make it difficult to interpret the results as potential mechanisms in vivo. Since the insulin-sensitizing effects of thiazolidinediones, anti-diabetic drugs, have been shown to be mediated through activation of peroxisome proliferators-activated receptor gamma (PPARγ), the key transcription factor for adipocyte differentiation, we examined the effects of the two main soy isoflavones genistein and daidzein either as individual compound or combined on adipocyte differentiation and PPARγ expression, as well as whether the Wnt/β-catenin signaling pathway is the underlying molecular mechanism. In 3T3-L1 cells, genistein and daidzein significantly enhanced adipocyte differentiation. Similarly the expression of PPARγ increased particularly at 20 µmol/L. The stimulatory effect is greater when the two isoflavones are combined, indicating a synergistic effect. Genistein and daidzein also increased the relative abundance of insulin-responsive glucose transporter 4 (GLUT4) mRNA with a greater effect when combined. Wnt10b expression was not affected by soy isoflavones treatments, while Wnt5b expression was only increased by the combination of genistein and daidzein. Our results suggest, that the combination of soy isoflavones has a greater effect in increasing the newly formation of adipocytes that are highly insulin-sensitive via an increase in PPARγ expression as well as increasing the expression of GLUT4. However, genistein and daidzein actions on Wnt signaling remain unclear. These data further support the epidemiological findings for the beneficial effect of soy consumption on insulin sensitivity.

Made available in DSpace on 2014-07-29T16:11:45Z (GMT). No. of bitstreams: 1 Dissertacao Stela.pdf: 754626 bytes, checksum: 312169c0104b8d6d919af0eb6ee8cf69 (MD5) Previous issue date: 2010-03-05 / Isoflavones are flavonoids found in abundance in grains of soy (Glycine max L.) and its derivatives. These substances have estrogen like structure and weakly estrogenic action. They are used for treatment of menopause symptoms as an alternative to conventional hormone replacement therapies, because they cause fewer side effects. Soy isoflavones are amongst herbal products of great interest to obtain solid dosage forms. High assay variability of isoflavones in commercially available capsules and tablets shows the need of appropriate drug development and quality control for this herbal product. The aim of this work was drug development and quality control of soy isoflavone solid dosage forms, using standardized dry extract of soy. To evaluate the quality of the extract microbiologic and assay analysis of this drug s markers were performed. Results obtained from microbiological test did not show microbiologic contamination of the extract, as Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus niger did not grow. To evaluate assay and dissolution percentage of both markers analytical methodology for quantification of daidzein and genistein by high performance liquid chromatography was developed, and also a method to analyze dissolution profile of the obtained tablets. Isocratic method was used for chromatographic analysis of the markers, with mobil phase of methanol with 0.1% of acetic acid, water with 0.1% of acetic acid and acetonitrile in proportion 64:32:4, flow of 0.7 mL/min and temperature of 30°C. At this condition, peaks were symmetric, had resolution lower than 2, with retention times of 3,13 and 3,72 for daidzein and genistein, respectively. Assay evaluation of the markers daidzein and genistein showed that concentrations in the extract were 27,8% and 11,1%, respectively. To accomplish preformulation study, thermal analysis and powder and granules flow evaluation were made. Six formulations of isoflavone tablets were developed, one by direct compression and five by wet granulation. Results of thermal analysis showed no possible extract interactions between tested excipients and extract. Wet granulation was the best method to obatain tablets, because it presented the best compressional properties with flow velocity between 4,5 and 6,7 s/100g and compressibility between 16,85% and 26,06%. GU3 formulation, which presented the best performance according to evaluated parameters, made by wet granulation, showed 92,66% and 92,76% of daidzein and genistein, respectively, disintegration of 15 minutes, and its flow was categorized as excellent. In analytical dissolution method development of isoflavone tablets solubility test was performed to define the best medium, and water with 3% of sodium lauryl sulfate dissolved the greatest amount of daidzein and genistein at tested temperature, 37°C, in comparison with the other medium. Other parameters defined through method development were paddle apparatus, stirring speed of 100 rpm and 900 mL of medium volume. Results showed the possibility to obtain promising solid dosage forms to deliver isoflavone, and optimized quality control methodologies to analyze raw material and finished product. / Isoflavonas são flavonóides encontrados em abundância nos grãos de soja (Glycine max L.). Essas substâncias têm estrutura semelhante ao estrógeno e possuem uma ação fracamente estrogênica. São utilizadas no tratamento dos sintomas da menopausa como alternativa às terapias de reposição hormonal convencionais, por provocarem menor número de efeitos colaterais. As isoflavonas de soja estão entre as matérias-primas vegetais com ações de interesse para obtenção de formas farmacêuticas sólidas. A alta variabilidade de teores de isoflavonas em cápsulas e comprimidos disponíveis comercialmente demonstra a necessidade de desenvolvimento farmacotécnico e controle de qualidade adequados para este fitoterápico. O objetivo deste trabalho foi o desenvolvimento analítico e farmacotécnico de formas farmacêuticas sólidas de isoflavona de soja, utilizando como matéria-prima extrato seco de soja padronizado. Para verificar a qualidade do extrato foi realizada análise microbiológica e análise do teor dos marcadores. Os resultados obtidos através do ensaio microbiológico não demonstrou contaminação microbiológica do extrato, não tendo crescimento de Escherichia coli, Staphylococcus aureus, Candida albicans e Aspergillus niger. Para avaliação do teor e da porcentagem dissolvida de ambos os marcadores foram desenvolvidas e validadas tanto metodologia analítica de quantificação de daidzeína e genisteína por cromatografia líquida de alta eficiência quanto metodologia para avaliar o perfil de dissolução dos comprimidos obtidos. Para análise cromatográfica dos marcadores foi utilizado método isocrático, com fase móvel constituída por metanol com 0,1% de ácido acético, água com 0,1% de ácido acético e acetonitrila na proporção 64:32:4 , fluxo de 0,7 mL/min e temperatura de 30ºC. Nesta condição os picos foram simétricos, tiveram resolução maior que 2, com tempos de retenção de 3,13 e 3,72 da daidzeína e genisteína, respectivamente. A avaliação do teor dos marcadores daidzeína e genisteína, demonstrou que as concentrações no extrato foram 27,8% e 11,1%, respectivamente. Em relação ao estudo de pré-formulação foi feita análise térmica e a avaliação das propriedades dos pós e grânulos. Foram desenvolvidas seis formulações de comprimidos de isoflavona, sendo uma por compressão direta e cinco por granulação úmida. Nos resultados da análise térmica não foram observadas possíveis interações dos excipientes com o extrato. O melhor método de obtenção dos comprimidos foi por granulação úmida, pois apresentou melhores propriedades compressionais com velocidade de escoamento variando entre 4,5 e 6,7 s/100g e compressibilidade entre 16,85% e 26,06%. A formulação por granulação úmida 3 foi a que apresentou melhor desempenho segundo os parâmetros analisados, apresentando teor de 92,66% e 92,76% de daidzeína e genisteína, respectivamente, desintegração de 15 minutos, e seu fluxo foi caracterizado como excelente. No desenvolvimento do método analítico para dissolução dos comprimidos de isoflavona foi feito o teste de solubilidade para definir o melhor meio, sendo o meio água com 3% de lauril sulfato de sódio o que dissolveu maior quantidade de daidzeína e genisteína na temperatura de 37ºC em comparação com os outros meios. Os demais parâmetros definidos através do desenvolvimento do método foram aparato pá, velocidade de rotação de 100 rpm e 900 mL de volume de meio. Os resultados mostraram a possibilidade de obtenção de formas farmacêuticas sólidas promissoras para veiculação de isoflavona, além de metodologias otimizadas para controle de qualidade para análise da matéria-prima e do produto acabado.