Differential binding with ERá and ERâ of the phytoestrogen-rich plant Pueraria mirifica

Variations in the estrogenic activity of the phytoestrogen-rich plant, Pueraria mirifica, were determined with yeast estrogen screen (YES) consisting of human estrogen receptors (hER) hERá and hERâ and human transcriptional intermediary factor 2 (hTIF2) or human steroid receptor coactivator 1 (hSRC1), respectively, together with the â-galactosidase expression cassette. Relative estrogenic potency was expressed by determining the â-galactosidase activity (EC50) of the tuber extracts in relation to 17â-estradiol. Twenty-four and 22 of the plant tuber ethanolic extracts interacted with hERá and hERâ, respectively, with a higher relative estrogenic potency with hERâ than with hERá. Antiestrogenic activity of the plant extracts was also determined by incubation of plant extracts with 17â-estradiol prior to YES assay. The plant extracts tested exhibited antiestrogenic activity. Both the estrogenic and the antiestrogenic activity of the tuber extracts were metabolically activated with the rat liver S9-fraction prior to the assay indicating the positive influence of liver enzymes. Correlation analysis between estrogenic potency and the five major isoflavonoid contents within the previously HPLC-analyzed tuberous samples namely puerarin, daidzin, genistin, daidzein, and genistein revealed a negative result.

Isoflavonas na pós-menopausa: uma revisão / Isoflavones in post-menopause: a review

Este artigo de revisão abordou os efeitos das isoflavonas na prevenção dos sintomas decorrentes da pós-menopausa na mulher. Isoflavonas são fenóis heterocíclicos com estrutura semelhante à do 17-beta-estradiol, atuando como modulador seletivo dos receptores de estrogênio (SERM). As ações na célula dependem do tecido-alvo, do status do receptor tecidual e dos níveis de estrogênios endógenos. As isoflavonas são produtos naturais que podem ser utilizados como uma alternativa à terapia hormonal na menopausa. Estudos in vitro e em modelos animais mostraram que agem de várias maneiras para exercer seus efeitos, podem atuar nas células através de vias genômicas e não-genômicas. Estudos epidemiológicos sugerem um efeito protetor das isoflavonas sobre o tecido mamário como é evidenciado pelas menores taxas de câncer de mama nos países do Leste Asiático, onde a soja é uma parte predominante da dieta. Os produtos que contêm isoflavonas também aliviam os sintomas da menopausa, reduzindo fogachos. No entanto ainda há necessidade de novos estudos relacionando a segurança em longo prazo de suplementos de isoflavonasna mulher na pós-menopausa.

This article review was designed to address the effects of isoflavones in postmenopausal women and their place in the prevention and treatment of postmenopausal symptoms. Isoflavones are heterocyclic phenols with structural similarity to estradiol-17 beta and selective estrogen receptor modulators (SERM). Actions at the cellular level depend on the target tissue, receptor status of the tissue, and the level of endogenous estrogen. Isoflavones are natural products that could be used as an alternative to menopausal hormone therapy. In vitro and animal studies have shown that they act in multiple ways to exert their postmenopausal effects. They act on both cells of through genomic and nongenomic pathways. Epidemiological studies suggest a protective effect of isoflavone on breast tissue as evidenced by the lower rates of breast cancer in East Asian countries where soy is a predominant part of the diet. Soy products also alleviate menopausal symptoms by reducing hot flashes. However there is still need for further studies relating to long-term safety of isoflavone supplements in postmenopausal women.

Estudo das interações isoflavonas e proteínas da soja: efeitos sobre a digestibilidade e capacidade antioxidante / Study of interactions between isoflavones and soy protein: effect on the digestibility and antioxidant capacity

Embora a soja em grão seja pouco consumida pela população brasileira, seus derivados protéicos são utilizados como ingredientes em diversos alimentos e a tendência é um aumento significativo do seu uso com a aprovação pela FDA e pela ANVISA da alegação funcional referente ao consumo de proteína de soja. Em paralelo, um número crescente de pesquisas sobre as isoflavonas, fitoestrógenos presentes em quantidades significativas na soja, vem demonstrando diversos efeitos benéficos destes compostos, entre os quais a sua ação antioxidante, anticarcinogênica e hipocolesterolêmica. O objetivo foi estudar as interações entre isoflavonas e proteínas da soja, seu efeito na biodisponibilidade in vitro e in vivo e o status antioxidante das isoflavonas. Os resultados sugerem que a presença da proteína reduz a quantidade e leva a um retardo no tempo de absorção das isoflavonas em relação à administração na forma livre. O efeito sobre a capacidade antioxidante do plasma e sobre a atividade e expressão gênica das enzimas CAT, GPx e SOD divergiu para a suplementação de isoflavonas ou proteínas separadamente ou em associação...

Effect of chemical factors on production of isoflavonoids in Pueraria tuberosa (Roxb.ex.Willd.) DC suspension culture.

Suspension cultures of Pueraria tuberosa, a woody legume, have been established and using different concentrations of growth regulators, sucrose, ammonium and nitrate nitrogen, attempts have been made to improve their isoflavonoid content. The cell cultures grew well on all the treatments. Up to approximately 8 folds increased isoflavonoids content was recorded in the cultures grown in MS medium modified with nitrogen and supplemented with 1 mg 1(-1) of kinetin.

Nutrient consumption and production of isoflavones in bioreactor cultures of Pueraria lobata (Willd).

This paper reports the successful culture of Pueraria lobata (Willd.) suspension cells in a bioreactor. In vitro culture of this Chinese herb has potential as an alternative production method for industrial applications. Calli of P. lobata obtained from leaf explants were cultured in a 5.0 L bioreactor for two weeks. During this period, the pH of the medium declined from 5.8 to 4.5. By the end of the run about 70% of the sugars and reducing sugars and about 50% of nitrate was consumed. Almost 70% of inorganic phosphate and about 80% of the iron was exhausted. The bioreactor results indicated an isoflavone yield of 328.9 microg/ml, with an increase of about 1.77 fold. The yield of puerarin increased about 2.42 fold and reached 73.4 microg/ml in the bioreactor culture.

Comparative Study of Concentration of Isoflavones and Lignans in Plasma and Prostatic Tissues of Normal Control and Benign Prostatic Hyperplasia

Objective: Isoflavones and lignans are phytoestrogens that have recently gained interest as dietary factors related to prostatic diseases. However, no data on the concentrations in prostate tissue in humans is available. Therefore, the concentrations of isoflavones and lignans in plasma and prostatic tissues according to the prostate volume were compared to determine their possible effect on the benign prostatic growth. Methods: Fasting plasma and prostatic tissue specimens were acquired from 25 men over 50 years of age with similar normal dietary habits and no previous history of drug intake that could affect the isoflavones and lignans levels. The tissue was acquired either during a transurethral resection of the prostate in 15 patients with benign prostatic hyperplasia (BPH) with prostate volume over 40 ml or during a radical cystoprostatectomy in 10 patients with bladder cancer with a prostate volume < 25 ml, who were used as the controls. Quantitative analysis of the isoflavones, specifically equol, daidzein and genistein and lignans, particularly enterodiol and enterolactone, was performed by gas chromatography-mass spectrometry. Results: The mean prostatic concentrations of enterodiol, enterolactone, equol and daidzein in the BPH and the control groups were similar. However, the mean prostatic concentration of genistein was significantly lower in the BPH group than in the control group (65.43 +/- 17.05 vs 86.96 +/- 37.75 ng/ ml, respectively, p=0.032). The plasma concentration of isoflavones and lignans in the two groups were comparable. Conclusion: Isoflavones, but not lignans, have some influence the benign prostatic growth, and the prostatic concentration of genistein possibly has the closest association among them. More studies to further clarify the roles and mechanisms of isoflavone action on BPH including pharmacokinetic studies are recommended.

Development of Rat Prostatitis Model by Oral Administration of Isoflavone and Its Characteristics

Inflammation of the prostate can be induced experimentally in rats by the subcutaneous administration of estrogen. However, it is usually achieved at the price of some alteration in the sex steroid hormone balance and morphological changes in the prostate. In this study, a soy-extracted isoflavone mixture with weak estrogenic activity was administered orally in an attempt to induce prostatitis in a more physiologic way and to characterize the inflammation induced. A total of 36 male Sprague-Dawley rats, 8 weeks old, were divided into 2 groups. The control group was fed with only an AIN-76A diet containing no detectable phytoestrogen and the experimental group was fed with AIN-76A and a soy- extracted isoflavone mixture (genistein 60.0% and daidzein 19.6%), 300mg/kg body weight for 9 weeks. The sequential body weight and prostate weight at necropsy were measured. A histologic examination and histomorphometry assessed the changes in the prostate. The serum concentrations of testosterone and dihydrotestosterone were measured to estimate the effects on the androgen level. Intraprostatic concentrations of genistein and daidzein were measured by gas chromatography/ mass spectroscopy (GC/MS). While no sign of prostate inflammation was apparent in the control group, severe inflammatory changes in the stroma, increased epithelial detachment and inflammatory exudates within the glandular lumen of the dorsolateral prostate were observed in more than 80%(15/18) of the experimental group. However, there was no significant difference in the ventral prostate between the two groups. The daidzein and genistein concentrations in both the lateral and ventral prostates were significantly higher in the experimental group than in the control group where no isoflavone was detectable. In addition, the concentrations were much higher in the dorsolateral than in the ventral prostate. Although the body weight gain was not consistent in the experimental group, there were no significant differences in the prostate weight and serum androgen level between groups. In summary, when a soy-extracted genistein and daidzein-rich isoflavone mixture was administered orally into rats, prostatic inflammation with characteristic lobe specificity developed. The present method of inducing prostatitis seems to be a more physiologic than an estrogen-induced experimental model, and sequential pharmacokinetic studies might help in establishing this model as a more valuable tool in assisting future research in this field.

Fitoestrógenos: una nueva preocupación en la alimentación infantil / Phytoestrogens: a new preoccupation in paediatric nutrition

Los fitoestrógenos son sustancias ambientales naturales, producidas por plantas, que a pesar de su estructura química distinta de los estrógenos, actúan como tales. Estudios en adultos sugieren que tendrían efectos protectores para cánceres hormonodependientes (de próstata y mama), dislipidemias y de la mineralización ósea. Se clasifican en isoflavonas, cumestanos y lignanos, y se encuentran principalmente en legumbres y poroto de soya, brotes de poroto, forraje y granos, y en cereales de grano entero y semillas, respectivamente. Estudios recientes han demostrado que los alimentos infantiles, incluyendo algunas fórmulas lácteas, yogur y alimentos de soya, contienen cantidades considerables de fitoestrógenos. Los efectos de estos sobre la salud infantil no han sido del todo aclarados. Existen evidencias epidemiológicas y clínicas de que al actuar como estrógenos débiles prodrían determinar adelanto de los eventos puberales y telarquia en la niña y ginecomastia en el varón. Se hace una revisión del tema y se plantea la necesidad de realizar estudios destinados a aclarar los efectos de los estrógenos ambientales sobre la salud infantil

Estrógeno de origen vegetal: actualización / Vegetal origin estrogens: actualization

Los estrógenos de origen vegetal han adquirido en los años recientes cierta importancia que justifica actualizar los conocimientos de que se dispone. Los compuestos con efecto estrogénico disponibles a través de vegetales de consumo alimenticio incluyen a las isoflavonas, las ligninas y las lactonas. Esta revisión comprende su estructura química, su metabolismo, su excreción y su efecto sobre los niveles plasmáticos de estrógenos, FSH, LH y SHBG así como su actividad sobre las lipoproteínas y, desde luego, su acción sobre los síntomas del climaterio y sobre el cáncer mamario