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Phytoestrogens as Alternative to the Hormone Replacement Therapy in Menopause: Cellular and Mitochondrial Interactions

Moreira, Ana Carolina dos Santos
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
37.27%
Os sintomas associados à menopausa, que são na maioria dos casos desconfortáveis para as mulheres. As alterações hormonais observadas neste período podem aumentar a incidência de condições patológicas tais como doenças cardiovasculares, osteoporose, afrontamentos, entre outros. A terapia de substituição hormonal (TSH), baseada em 17β-estradiol (E2), é normalmente administrada às mulheres na menopausa para ultrapassar os sintomas associados a este período. Contudo, a TSH tem alguns efeitos secundários, nomeadamente o risco aumentado de cancro da mama. Fitoestrogénios (FE), compostos naturais que são estruturalmente semelhantes a E2, têm sido sugeridos como alternativa à TSH. Devido à sua semelhança com E2, os FE podem ter actividade estrogénica ou anti-estrogénica. Não obstante, os riscos e benefícios dos FE na saúde da mulher não estão ainda bem estabelecidos. O principal objectivo deste projecto foi identificar FE com baixa toxicidade mas, simultaneamente, capaz (es) de atenuar alguns sintomas conhecidos da menopausa, com especial enfase para os afrontamentos. Um screening inicial foi efectuado com os FE seleccionados (enterolactona, enterodiol, resveratrol e coumestrol) usando fracções mitocondriais de cérebro e fígado...

Effects of phytoestrogens derived from soy bean on expression of adhesion molecules on HUVEC

de Andrade, C. M.; Silva de Sa, M. F.; Toloi, M. R. Torqueti
Fonte: INFORMA HEALTHCARE; LONDON Publicador: INFORMA HEALTHCARE; LONDON
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.57%
Background The risks of hormone replacement therapy have led to a search for new alternatives such as phytoestrogens, plant compounds with estrogen-like biological activity. Isoflavones are the phytoestrogens most extensively studied and can be found in soybean, red clover and other plants. Due to this estrogen-like activity, phytoestrogens can have some effect on atherosclerosis. Human umbilical vein endothelial cells (HUVEC) have been extensively used to study the biology and pathobiology of human endothelial cells and most of the knowledge acquired is due to experiments with cultures of these cells. Objective To evaluate the effects of the phytoestrogen extracts from Glycine max soy bean, genistein, formononetin, biochanin A and daidzein, as well as a mixture of these extracts (Mix), on expression of adhesion molecules, VCAM-1, ICAM-1 and E-selectin, by endothelial cell HUVEC, stimulated with lipopolysaccharide. Methods HUVEC were cultured in medium EBM2, pretreated with isoflavones for 24 and 48 h and then stimulated with lipopolysaccharide; in addition, isoflavones were added, after stimulation by lipopolysaccharide, to HUVEC. We evaluated the production of VCAM-1, ICAM-1 and E-selectin on cell surface, by cell-based enzyme immunoassay...

Avaliação do efeito anti-aterogênico dos fitoestrógenos na expressão de moléculas de adesão em células andoteliais Humanas; Phytoestrogens antiatherogenic effect on adhesion molecules expression on endothelial cells.

Andrade, Camila Marques de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/11/2009 PT
Relevância na Pesquisa
37.93%
Os riscos provocados pela Terapia de Reposição Hormonal, levaram à busca de novas terapias, como os fitoestrógenos. São substâncias com ação estrogênica e propriedades que podem retardar a formação de placas ateroscleróticas. Isoflavonas são os fitoestrógenos mais estudados e são encontradas na soja, no red clover e em outras plantas. Avaliamos os efeitos dos fitoestrógenos extraídos da soja Glycine max: genisteína, formononetina, biocanina A e daidzeína; a mistura entre eles (Mix1); o extrato padronizado de red clover (Menoflavon 40mg) e uma segunda mistura com os fitoestrógenos extraídos da Glycine max nas concentrações encontradas no Menoflavon (Mix2), na expressão de moléculas de adesão de leucócitos, VCAM-1, ICAM-1 e E-selectina, em cultura de células endoteliais de cordão umbilical humano (HUVEC), assim como na linhagem modificada de célula endotelial, ECV304, estimuladas com LPS. Resultados: foram padronizados os tempos e concentrações de exposição ao LPS no cultivo de HUVEC de 1ug durante 12 horas de exposição para as três moléculas de adesão; e no cultivo de ECV304 para a expressão de VCAM-1, de 500ng durante 12 horas, para ICAM-1 de 1ug durante 18 horas, para E-selectina 100ng durante 18 horas na superfície celular e 200ng durante 24 horas no sobrenadante de culturas de ECV304...

Fitoestrogênios : posicionamento do Departamento de Endocrinologia Feminina da Sociedade Brasileira de Endocrinologia e Metabologia (SBEM); Phytoestrogens : position of the Department of Female Endocrinology of the Brazilian Society of Endocrinology and Metabolism

Clapauch, Ruth; Meirelles, Ricardo Martins da Rocha; Julião, Maria Amélia S.G.; Loureiro, Claudia Kohler C.; Giarogoli, Paola B.; Pinheiro, Solange Alves; Harrigan, Albemar Roberts; Spritzer, Poli Mara; Pardini, Dolores Perovano; Weiss, Rita Vasconcello
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
37.27%
Para avaliar a utilidade dos fitoestrogênios (FE) na terapia de reposição hormonal da menopausa (TRHM), o Departamento de Endocrinologia Feminina da SBEM reuniu um grupo de especialistas para fazer uma revisão bibliográfica e selecionar trabalhos nos quais a metodologia adotada demonstrasse rigor científico. Os FE têm ações estrogênicas e antiestrogênicas, predominantemente sobre os receptores de estrogênios (E) b, com potência estrogênica muito inferior à do estradiol. O conteúdo de FE nas suas fontes vegetais é variável, dependendo da forma de cultivo, safra, armazenamento e industrialização. Também a conversão dos precursores em fitormônios ativos no organismo humano tem grande variabilidade individual. A maior parte das pesquisas com FE é realizada in vitro ou com animais de laboratório, nem sempre podendo ser extrapoladas para humanos. Com relação à síndrome do climatério, alguns estudos sugerem discreta melhora dos fogachos, sem modificação do ressecamento vaginal ou das alterações do humor. No metabolismo lipídico, alimentação rica em soja, mas não isoflavonas isoladamente, promove redução do colesterol total, do LDL-col e dos triglicerídeos, mas não elevam o HDL-col, como os E, e podem causar aumento da lipoproteína (a)...

Dual effects of phytoestrogens result in u-shaped dose-response curves.

Almstrup, Kristian; Fernández, Mariana F; Petersen, Jørgen H; Olea, Nicolas; Skakkebaek, Niels E; Leffers, Henrik
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/2002 EN
Relevância na Pesquisa
27.65%
Endocrine disruptors can affect the endocrine system without directly interacting with receptors, for example, by interfering with the synthesis or metabolism of steroid hormones. The aromatase that converts testosterone to 17beta-estradiol is a possible target. In this paper we describe an assay that simultaneously detects aromatase inhibition and estrogenicity. The principle is similar to that of other MCF-7 estrogenicity assays, but with a fixed amount of testosterone added. The endogenous aromatase activity in MCF-7 cells converts some of the testosterone to 17beta-estradiol, which is assayed by quantifying differences in the expression level of the estrogen-induced pS2 mRNA. Potential aromatase inhibitors can be identified by a dose-dependent reduction in the pS2 mRNA expression level after exposure to testosterone and the test compound. Using this assay, we have investigated several compounds, including synthetic chemicals and phytoestrogens, for aromatase inhibition. The phytoestrogens, except genistein, were aromatase inhibitors at low concentrations (< 1 micro M) but estrogenic at higher concentrations (greater than or equal to 1 micro M), resulting in U-shaped dose-response curves. None of the tested synthetic chemicals were aromatase inhibitors. The low-dose aromatase inhibition distinguished phytoestrogens from other estrogenic compounds and may partly explain reports about antiestrogenic properties of phytoestrogens. Aromatase inhibition may play an important role in the protective effects of phytoestrogens against breast cancer.

Phytoestrogens are partial estrogen agonists in the adult male mouse.

Mäkelä, S; Santti, R; Salo, L; McLachlan, J A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1995 EN
Relevância na Pesquisa
27.72%
The intake, as well as serum and urinary concentrations, of phytoestrogens is high in countries where incidence of prostate cancer is low, suggesting a chemopreventive role for phytoestrogens. Their significance could be explained by the ability to antagonize the action of more potent endogenous estrogens in initiation or promotion of tumor formation. We have studied estrogenicity and antiestrogenicity of dietary soy and two phytoestrogens, coumestrol and daidzein, in our neoDES mouse model for the study or prostatic neoplasia. Soy was chosen because it is rich in phytoestrogens, is widely used in Oriental diets, and has antiestrogenic and anticarcinogenic properties in the neoDES mouse when given from fertilization onward. In short-term tests with adult animals, no evidence for estrogenicity or antiestrogenicity (capability to antagonize the action of 17 beta-estradiol) of soy was found when development of epithelial metaplasia and expression of c-fos protooncogene in prostate were used as end points of estrogen action. Estrogenic activity of coumestrol and daidzein on c-fos expression was subtle. Coumestrol, either given alone or in combination with 17 beta-estradiol, had no effect on development of epithelial metaplasia. These marginal or missing effects in adult males could be interpreted by assuming that the neonatal period is more critical for estrogenic or antiestrogenic action of soy and phytoestrogens. Once initiated...

Dietary soy phytoestrogens and ERα signalling modulate interferon gamma production in response to bacterial infection

CURRAN, E M; JUDY, B M; NEWTON, L G; LUBAHN, D B; ROTTINGHAUS, G E; MACDONALD, R S; FRANKLIN, C; ESTES, D M
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /02/2004 EN
Relevância na Pesquisa
27.65%
Diets rich in soy phytoestrogens have many potential health benefits but isoflavones such as genistein may suppress cell mediated immune function. The effect of dietary phytoestrogens on the host response to infection has not been extensively examined. Mice were fed a diet containing soy phytoestrogens and infected with Mycobacterium avium to establish a chronic infection and inflammatory response. As phytoestrogens may act through classical oestrogen receptors (ER), mice deficient in ERα signalling and wild type mice were evaluated for a panel of Type 1-associated cytokines (IFNγ, IL-12 and IL-18) in the spleen. IFNγ production in the spleen was increased approximately 4-fold in ERα-deficient mice fed a casein-based diet over wild type mice fed a casein-based diet (P < 0·05), suggesting a role for ERα in suppressing IFNγ production. IL-18 levels in spleens of wild type mice were decreased compared to ERα-deficient mice on a casein diet. Splenic IL-12 and IL-18 levels were not affected in wild type and ERα-deficient mice on the phytoestrogen containing diets, with the exception that whole soy increased IL-12 levels in the tissues of ERα deficient mice. We conclude that ERα and dietary phytoestrogens can influence production of key regulatory cytokines in response to chronic bacterial infection.

Soy phytoestrogens are neuroprotective against stroke-like injury in vitro

Schreihofer, Derek A.; Redmond, Lori
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.65%
Diets high in soy are neuroprotective in experimental stroke. This protective effect is hypothesized to be mediated by phytoestrogens contained in soy, because some of these compounds have neuroprotective effects in in vitro models of cell death. We tested the ability of the soy phytoestrogens genistein, daidzein, and the daidzein metabolite equol to protect primary cortical neurons from ischemic-like injury in vitro at doses typical of circulating concentrations in human populations (0.1-1 μM). All three phytoestrogens inhibited LDH release from cells exposed to glutamate toxicity or the calcium-ATPase inhibitor, thapsigargin. In cells exposed to hypoxia or oxygen-glucose deprivation (OGD), pretreatement with the phytoestrogens inhibited cell death in an estrogen receptor (ER) dependent manner. Although OGD results in multiple modes of cell death, examination of α-spectrin cleavage and caspase-3 activation revealed that the phyoestrogens were able to inhibit apoptotic cell death in this model. In addition, blockade of phosphoinositide 3-kinase prevented the protective effects of genistein and daidzein, and blockade of mitogen-activated protein kinase prevented genistein-dependent neuroprotection. These results suggest that pretreatment with dietary levels of soy phytoestrogens can mimic neuroptotective effects observed with estrogen and appear to use the same ER-kinase pathways to inhibit apoptotic cell death.

Regulation of Progestin Receptors in Medial Amygdala: Estradiol, Phytoestrogens and Sex

Kudwa, AE; Harada, N; Honda, S-I; Rissman, EF
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.65%
PHYSIOL BEH Exposure to estrogens during critical developmental periods and in adulthood affects sex differences in the brain. We examined the roles of estradiol (E2) and phytoestrogens, and their interactions, on potential sex differences in brain. We used aromatase knockout (ArKO) mice, which cannot produce endogenous estrogens, along with wild type (WT) littermates. Mice were gestated, raised and maintained on a diet either rich in phytoestrogens or a diet virtually void of soy-derived phytoestrogens. Adult males and females were gonadectomized and received implants filled with 17-β-estradiol to induce progestin receptors (PR), while controls received empty implants. Mice were sacrificed five days later and brain sections containing the posterodorsal medial amygdala (MePD) were processed for PR immunoreactivity. Activation of sex differences in PR required adult E2 treatment. A diet high in phytoestrogens was required for expression of sex differences in PR after E2 treatment. Our data underscore the important contribution of dietary phytoestrogens for the development of sex differences in PR-ir in the adult mouse medial amygdala. We hypothesize that both aromatization of androgens to estrogens and dietary sources of additional estrogens are part of the normal requirement for sex differences in the rodent brain.

The pros and cons of phytoestrogens

Patisaul, Heather B.; Jefferson, Wendy
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.72%
Phytoestrogens are plant derived compounds found in a wide variety of foods, most notably soy. A litany of health benefits including a lowered risk of osteoporosis, heart disease, breast cancer, and menopausal symptoms, are frequently attributed to phytoestrogens but many are also considered endocrine disruptors, indicating that they have the potential to cause adverse health effects as well. Consequently, the question of whether or not phytoestrogens are beneficial or harmful to human health remains unresolved. The answer is likely complex and may depend on age, health status, and even the presence or absence of specific gut microflora. Clarity on this issue is needed because global consumption is rapidly increasing. Phytoestrogens are present in numerous dietary supplements and widely marketed as a natural alternative to estrogen replacement therapy. Soy infant formula now constitutes up to a third of the US market, and soy protein is now added to many processed foods. As weak estrogen agonists/antagonists with molecular and cellular properties similar to synthetic endocrine disruptors such as Bisphenol A (BPA), the phytoestrogens provide a useful model to comprehensively investigate the biological impact of endocrine disruptors in general. This review weighs the evidence for and against the purported health benefits and adverse effects of phytoestrogens.

Prevention of bone resorption by intake of phytoestrogens in postmenopausal women: a meta-analysis

Salari Sharif, Pooneh; Nikfar, Shekoufeh; Abdollahi, Mohammad
Fonte: Springer Netherlands Publicador: Springer Netherlands
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.77%
Phytoestrogens as selective estrogen receptor modulators like compounds may consider as a therapeutic option in osteoporosis. In this regard, the effect of phytoestrogens on bone biomarkers was examined in several trials which their results are controversial. We aimed this meta-analysis to evaluate the net effect of phytoestrogens on bone markers. A thorough search was conducted from 2000 to 2010 in English articles. All randomized clinical trials were reviewed, and finally, 11 eligible randomized clinical trials were selected for meta-analysis. Totally 1,252 postmenopausal women were enrolled in the study by considering the changes of pyridinoline (Pyd), desoxypyridinoline (Dpyd), bone alkaline phosphatase, and osteocalcin concentrations in urine and serum after phytoestrogens consumption. The urine Pyd and Dpyd levels decreased significantly in phytoestrogens consumers. Effect size and effect size for weighted mean difference of urine Pyd levels showed −1.229171 (95% confidence interval (CI) = −1.927639 to −0.530703) and −9.780623 (95% CI = −14.240401 to −5.320845), respectively, a significant results in comparison to control group and significant results for Dpyd −0.520132 (95% CI = −0.871988 to −0.168275) and −0.818582 (95% CI = −1.247758 to −0.389407)...

Activation of Southern White Rhinoceros (Ceratotherium simum simum) Estrogen Receptors by Phytoestrogens: Potential Role in the Reproductive Failure of Captive-Born Females?

Tubbs, Christopher; Hartig, Phillip; Cardon, Mary; Varga, Nicole; Milnes, Matthew
Fonte: Endocrine Society Publicador: Endocrine Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.72%
The captive southern white rhinoceros (SWR; Ceratotherium simum simum) population serves as an important genetic reservoir critical to the conservation of this vulnerable species. Unfortunately, captive populations are declining due to the poor reproductive success of captive-born females. Captive female SWR exhibit reproductive problems suggested to result from continual ovarian follicular activity and prolonged exposure to endogenous estrogen. However, we investigated the potential role of exogenous dietary phytoestrogens in the reproductive failure of SWR by cloning and characterizing in vitro phytoestrogen binding and activation of recombinant SWR estrogen receptors (ESR). We compared those characteristics with recombinant greater one-horned rhinoceros (GOHR; Rhinoceros unicornis) ESR, a species that receives similar captive diets yet reproduces relatively well. Our results indicate that phytoestrogens bind rhino ESR in a manner similar to other vertebrate species, but there are no differences found in phytoestrogen binding affinity of SWR ESR compared with GOHR ESR. However, species-specific differences in ESR activation by phytoestrogens were detected. The phytoestrogen coumestrol stimulated greater maximal activation of SWR ESR1 than GOHR ESR1. SWR ESR2 were also more sensitive to phytoestrogens and were activated to a greater extent by both coumestrol and daidzein. The concentrations in which significant differences in ESR activation occurred (10−7 to 10−5 m) are consistent with circulating concentrations measured in other vertebrate species. Taken together...

Vascular Effects of Phytoestrogens and Alternative Menopausal Hormone Therapy in Cardiovascular Disease

Gencel, Vahide B.; Benjamin, Mina M.; Bahou, Shafik N.; Khalil, Raouf A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/02/2012 EN
Relevância na Pesquisa
27.93%
Phytoestrogens are estrogenic compounds of plant origin classified into different groups including isoflavones, lignans, coumestans and stilbenes. Isoflavones such as genistein and daidzein are the most studied and most potent phytoestrogens, and are found mainly in soy based foods. The effects of phytoestrogens are partly mediated via estrogen receptors (ERs): ERα, ERβ and possibly GPER. The interaction of phytoestrogens with ERs is thought to induce both genomic and non-genomic effects in many tissues including the vasculature. Some phytoestrogens such as genistein have additional non-ER-mediated effects involving signaling pathways such as tyrosine kinase. Experimental studies have shown beneficial effects of phytoestrogens on endothelial cells, vascular smooth muscle, and extracellular matrix. Phytoestrogens may also affect other pathophysiologic vascular processes such as lipid profile, angiogenesis, inflammation, tissue damage by reactive oxygen species, and these effects could delay the progression of atherosclerosis. As recent clinical trials showed no vascular benefits or even increased risk of cardiovascular disease (CVD) and CV events with conventional menopausal hormone therapy (MHT), phytoestrogens are being considered as alternatives to pharmacologic MHT. Epidemiological studies in the Far East population suggest that dietary intake of phytoestrogens may contribute to the decreased incidence of postmenopausal CVD and thromboembolic events. Also...

Tools to evaluate estrogenic potency of dietary phytoestrogens:A consensus paper from the EU Thematic Network “Phytohealth” (QLKI-2002-2453)

Saarinen, N. M.; Bingham, C.; Lorenzetti, S.; Mortensen, A.; Mäkelä, S.; Penttinen, P.; SØrensen, I. K.; Valsta, L. M.; Virgili, F.; Vollmer, G.; Wärri, A.; Zierau, O.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Publicado em /09/2006 EN
Relevância na Pesquisa
27.72%
Phytoestrogens are naturally occurring plantderived polyphenols with estrogenic potency. They are ubiquitous in diet and therefore, generally consumed. Among Europeans, the diet is rich in multiple putative phytoestrogens including flavonoids, tannins, stilbenoids, and lignans. These compounds have been suggested to provide beneficial effects on multiple menopause-related conditions as well as on development of hormone-dependent cancers, which has increased the interest in products and foods with high phytoestrogen content. However, phytoestrogens may as well have adverse estrogenicity related effects similar to any estrogen. Therefore, the assessment of estrogenic potency of dietary compounds is of critical importance. Due to the complex nature of estrogenicity, no single comprehensive test approach is available. Instead, several in vitro and in vivo assays are applied to evaluate estrogenic potency. In vitro estrogen receptor (ER) binding assays provide information on the ability of the compound to I) interact with ERs, II) bind to estrogen responsive element on promoter of the target gene as ligand-ER complex, and III) interact between the co-activator and ERs in ligand-dependent manner. In addition, transactivation assays in cells screen for ligand-induced ERmediated gene activation. Biochemical in vitro analysis can be used to test for possible effects on protein activities and E-screen assays to measure (anti)proliferative response in estrogen responsive cells. However...

Relationships between urinary biomarkers of phytoestrogens, phthalates, phenols, and pubertal stages in girls

Chakraborty, Tandra R; Alicea, Eilliut; Chakraborty, Sanjoy
Fonte: Dove Medical Press Publicador: Dove Medical Press
Tipo: Artigo de Revista Científica
Publicado em 06/01/2012 EN
Relevância na Pesquisa
27.72%
Phytoestrogens, phthalates, and phenols are estrogen-disrupting chemicals that have a pronounced effect at puberty. They are exogenous chemicals that are either plant-derived or man-made, and can alter the functions of the endocrine system and cause various health defects by interfering with the synthesis, metabolism, binding, or cellular responses of natural estrogens. Phytoestrogens, phthalates, and phenols are some of the potent estrogens detectable in urine. Phytoestrogens are plant-derived xenestrogens found in a wide variety of food products, like soy-based food, beverages, several fruits, and vegetables. Exposure to phytoestrogens can delay breast development and further lead to precocious puberty. The effect of phytoestrogens is mediated through estrogen receptors α and β or by binding with early immediate genes, such as jun and fos. Phthalates are multifunctional synthetic chemicals used in plastics, polyvinyl chloride products, cosmetics, hair spray, and children’s toys. Phthalates have been shown to cause defeminization, thelarche, precocious puberty, and an increase in breast and pubic hair in pubertal girls. However, reports are also available that show no association of phthalates with precocious puberty in girls. Phthalates can act through a receptor-mediated signaling pathway or affect the production of luteinizing hormone and follicle-stimulating hormone that has a direct effect on estrogen formation. Phenols like bisphenol A are industrial chemicals used mainly in the manufacture of polycarbonates and plastic materials. Bisphenol A has been shown to cause precocious puberty and earlier menarche in pubertal girls. Reports suggest that the neurotoxic effect of bisphenol A can be mediated either by competing with estradiol for binding with estrogen receptors or via the ERK/NK-kappa or ERRγ pathway. This review demonstrates the effects of phytoestrogens...

Phytoestrogens in Postmenopause: The State of the Art from a Chemical, Pharmacological and Regulatory Perspective

Poluzzi, Elisabetta; Piccinni, Carlo; Raschi, Emanuel; Rampa, Angela; Recanatini, Maurizio; Ponti, Fabrizio De
Fonte: Bentham Science Publishers Publicador: Bentham Science Publishers
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.65%
Phytoestrogens represent a diverse group of non-steroidal natural products, which seem to have some oestrogenic effects and are often marketed as food supplements. Population exposed to phytoestrogens is potentially increasing, in part because an unfavourable risk-benefit profile of Hormone Replacement Therapy (HRT) for prolonged treatments (e.g., osteoporosis prevention) highlighted by the publication of the Women Health Initiative (WHI) trial in 2002, but also because many post-menopausal women often perceived phytoestrogens in food supplements as a safer alternative than HRT. Despite of increasing preclinical and clinical studies in the past decade, appealing evidence is still lacking to support the overall positive risk-benefit profile of phytoestrogens. Their status as food supplements seems to discourage studies to obtain new evidence, and the chance to buy them by user’s initiative make it difficult to survey their prevalence and pattern of use. The aim of the present review is to: (a) outline the clinical scenario underlying the increased interest on phytoestrogens, by overviewing the evolution of the evidence on HRT and its main therapeutic goals (e.g., menopausal symptoms relief, chemoprevention, osteoporosis prevention); (b) address the chemical and pharmacological features (e.g. chemical structure...

Phytoestrogens and prevention of breast cancer: The contentious debate

Bilal, Iqra; Chowdhury, Avidyuti; Davidson, Juliet; Whitehead, Saffron
Fonte: Baishideng Publishing Group Inc Publicador: Baishideng Publishing Group Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.84%
Phytoestrogens have multiple actions within target cells, including the epigenome, which could be beneficial to the development and progression of breast cancer. In this brief review the action of phytoestrogens on oestrogen receptors, cell signalling pathways, regulation of the cell cycle, apoptosis, steroid synthesis and epigenetic events in relation to breast cancer are discussed. Phytoestrogens can bind weakly to oestrogen receptors (ERs) and some have a preferential affinity for ERβ which can inhibit the transcriptional growth-promoting activity of ERα. However only saturating doses of phytoestrogens, stimulating both ERα and β, exert growth inhibitory effects. Such effects on growth may be through phytoestrogens inhibiting cell signalling pathways. Phytoestrogens have also been shown to inhibit cyclin D1 expression but increase the expression of cyclin-dependent kinase inhibitors (p21 and p27) and the tumour suppressor gene p53. Again these effects are only observed at high (> 10) µmol/L doses of phytoestrogens. Finally the effects of phytoestrogens on breast cancer may be mediated by their ability to inhibit local oestrogen synthesis and induce epigenetic changes. There are, though, difficulties in reconciling epidemiological and experimental data due to the fact experimental doses...

Phytoestrogens and Their Metabolites in Bulk-Tank Milk: Effects of Farm Management and Season

Adler, Steffen A.; Purup, Stig; Hansen-Møller, Jens; Thuen, Erling; Steinshamn, Håvard
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 21/05/2015 EN
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27.65%
Phytoestrogens have structures similar to endogenous steroids and may induce or inhibit the response of hormone receptors. The objectives of the present study were to compare the effects of long-term vs. short-term grassland management in organic and conventional dairy production systems, compare organic and conventional production systems and assess seasonal variation on phytoestrogen concentrations in bulk-tank milk. The concentrations of phytoestrogens were analyzed in bulk-tank milk sampled three times in two subsequent years from 28 dairy farms: Fourteen organic (ORG) dairy farms with either short-term or long-term grassland management were paired with 14 conventional (CON) farms with respect to grassland management. Grassland management varied in terms of time since establishment. Short-term grassland management (SG) was defined as establishment or reseeding every fourth year or more often, and long-term grassland management (LG) was defined as less frequent establishment or reseeding. The proportion of red clover (Trifolium pretense L.) in the herbage was positively correlated with milk concentrations of the mammalian isoflavone equol. Therefore, organically produced bulk-tank milk contained more equol than conventionally produced milk...

Estimaci??n de la ingesta de fitoestr??genos en poblaci??n femenina

Hern??ndez-Elizondo, J.; Mariscal Arcas, Miguel; Rivas, A.; Feriche, Bel??n; Velasco, Javier; Olea Serrano, F??tima
Fonte: Aula M??dica; Sociedad Espa??ola de Nutrici??n Parenteral y Enteral (SENPE) Publicador: Aula M??dica; Sociedad Espa??ola de Nutrici??n Parenteral y Enteral (SENPE)
Tipo: Artigo de Revista Científica
SPA
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Introducci??n: Los fitoestr??genos son compuestos naturales que forman parte de numerosos alimentos de origen vegetal y que podr??an modular tanto aspectos relacionados con hormonas, como reacciones de tipo antioxidante, por lo que conocer las ingestas de estos compuestos en diferentes poblaciones aclarar??a aspectos importantes sobre sus respuestas en el organismo. Objetivo: Valorar la exposici??n de fitoestr??genos por medio de la dieta, en una muestra de mujeres de todas las edades pertenecientes a la comunidad universitaria (docentes, administrativas y estudiantes), residentes en la provincia de Granada, Espa??a. Material y m??todo: 52 mujeres adultas, con edades entre 20 y 63 a??os completaron individualmente un cuestionario de frecuencia de consumo de alimentos (FFQ) compuesto por un total de 144 alimentos. Se ponder?? el consumo diario de fitoestr??genos totales estandarizando los valores refiriendo estos a la daidze??na como sustancia patr??n (mg/d??a). El an??lisis estad??stico se realiz?? con SPSS 15.0 (SPSS Inc., Chicago, IL, USA), con un nivel de significancia de p < 0,05. Resultados: Muestran que la ingesta total de fitoestr??genos referidos a la daizde??na fue de 0,89 mg/d??a, y la mayor parte de fitoestrogenos fue consumido en forma de lignanos. El consumo total de isoflavonas...

Dual effects of phytoestrogens result in u-shaped dose-response curves

Almstrup, Kristian; Fern??ndez, Mariana F.; Petersen, J??rgen; Olea, Nicol??s; Skakkeb??k, Niels; Leffers, Henrik
Fonte: National Institute of Environmental Health Sciences Publicador: National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
ENG
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'Reproduced with permission from Environmental Health Perspectives'; Endocrine disruptors can affect the endocrine system without directly interacting with receptors, for example, by interfering with the synthesis or metabolism of steroid hormones. The aromatase that converts testosterone to 17??-estradiol is a possible target. In this paper we describe an assay that simultaneously detects aromatase inhibition and estrogenicity. The principle is similar to that of other MCF-7 estrogenicity assays, but with a fixed amount of testosterone added. The endogenous aromatase activity in MCF-7 cells converts some of the testosterone to 17??-estradiol, which is assayed by quantifying differences in the expression level of the estrogen-induced pS2 mRNA. Potential aromatase inhibitors can be identified by a dose-dependent reduction in the pS2 mRNA expression level after exposure to testosterone and the test compound. Using this assay, we have investigated several compounds, including synthetic chemicals and phytoestrogens, for aromatase inhibition. The phytoestrogens, except genistein, were aromatase inhibitors at low concentrations (< 1 ??M) but estrogenic at higher concentrations (??? 1 ??M), resulting in U-shaped dose???response curves. None of the tested synthetic chemicals were aromatase inhibitors. The lowdose aromatase inhibition distinguished phytoestrogens from other estrogenic compounds and may partly explain reports about antiestrogenic properties of phytoestrogens. Aromatase inhibition may play an important role in the protective effects of phytoestrogens against breast cancer.