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The Phytoestrogen Genistein Affects Zebrafish Development through Two Different Pathways  [PDF]
Sana Sassi-Messai, Yann Gibert, Laure Bernard, Shin-Ichi Nishio, Karine F. Ferri Lagneau, José Molina, Monika Andersson-Lendahl, Gérard Benoit, Patrick Balaguer, Vincent Laudet
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0004935
Abstract: Background Endocrine disrupting chemicals are widely distributed in the environment and derive from many different human activities or can also be natural products synthesized by plants or microorganisms. The phytoestrogen, genistein (4′, 5, 7-trihydroxy-isoflavone), is a naturally occurring compound found in soy products. Genistein has been the subject of numerous studies because of its known estrogenic activity. Methodology/Principal Findings We report that genistein exposure of zebrafish embryos induces apoptosis, mainly in the hindbrain and the anterior spinal cord. Timing experiments demonstrate that apoptosis is induced during a precise developmental window. Since adding ICI 182,780, an ER antagonist, does not rescue the genistein-induced apoptosis and since there is no synergistic effect between genistein and estradiol, we conclude that this apoptotic effect elicited by genistein is estrogen-receptors independent. However, we show in vitro, that genistein binds and activates the three zebrafish estrogen receptors ERα, ERβ-A and ERβ-B. Furthermore using transgenic ERE-Luciferase fish we show that genistein is able to activate the estrogen pathway in vivo during larval stages. Finally we show that genistein is able to induce ectopic expression of the aromatase-B gene in an ER-dependent manner in the anterior brain in pattern highly similar to the one resulting from estrogen treatment at low concentration. Conclusion/Significance Taken together these results indicate that genistein acts through at least two different pathways in zebrafish embryos: (i) it induces apoptosis in an ER-independent manner and (ii) it regulates aromatase-B expression in the brain in an ER-dependent manner. Our results thus highlight the multiplicity of possible actions of phytoestrogens, such as genistein. This suggests that the use of standardized endpoints to study the effect of a given compound, even when this compound has well known targets, may carry the risk of overlooking interesting effects of this compound.
The Bone-Protective Effect of Genistein in the Animal Model of Bilateral Ovariectomy: Roles of Phytoestrogens and PTH/PTHR1 Against Post-Menopausal Osteoporosis  [PDF]
Qing Miao,Jing-Ge Li,Shan Miao,Nan Hu,Jin Zhang,Song Zhang,Yan-Hua Xie,Jian-Bo Wang,Si-Wang Wang
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13010056
Abstract: Genistein, a major phytoestrogen of soy, is considered a potential drug for the prevention and treatment of post-menopausal osteoporosis. Mounting evidence suggested a positive correlation between genistein consumption and bone health both in vivo and in vitro. Earlier studies have revealed that genistein acted as a natural estrogen analogue which activated estrogen receptor and exerted anti-osteoporotic effect. However, it remains unclear whether PTH, the most crucial hormone that regulates mineral homeostasis, participates in the process of genistein-mediated bone protection. In the present study, we compared the therapeutic effects between genistein and nilestriol and investigated whether PTH and its specific receptor PTHR1 altered in response to genistein-containing diet in the animal model of ovariectomy. Our results showed that genistein administration significantly improved femoral mechanical properties and alleviates femoral turnover. Genistein at all doses (4.5 mg/kg, 9.0 mg/kg and 18.0 mg/kg per day, respectively) exerted improved bending strength and b-ALP limiting effects than nilestriol in the present study. However, genistein administration did not exert superior effects on bone protection than nilestriol. We also observed circulating PTH restoration in ovariectomized rats receiving genistein at the dose of 18 mg/kg per day. Meanwhile, PTHR1 abnormalities were attenuated in the presence of genistein as confirmed by RT-PCR, Western blot and immunohistochemistry. These findings strongly support the idea that besides serving as an estrogen, genistein could interact with PTH/PTHR1, causing a superior mineral restoring effect than nilestriol on certain circumstance. In conclusion, our study reported for the first time that the anti-osteoporotic effect of genistein is partly PTH/PTHR1-dependent. Genistein might be a potential option in the prevention and treatment of post-menopausal osteoporosis with good tolerance, more clinical benefits and few undesirable side effects.
Inhibitory effects of genistein and resveratrol on guinea pig gallbladder contractility in vitro  [cached]
Long-De Wang, Xiao-Qing Qiu, Zhi-Feng Tian, Ying-Fu Zhang, Hong-Fang Li
World Journal of Gastroenterology , 2008,
Abstract: AIM: To observe and compare the effects of phytoestrogen genistein, resveratrol and 17β-estradiol on the tonic contraction and the phasic contraction of isolated gallbladder muscle strips and to study the underlying mechanisms.METHODS: Isolated strips of gallbladder muscle from guinea pigs were suspended in organ baths containing Kreb’s solution, and the contractilities of strips were measured before and after incubation with genistein, resveratrol and 17β-estradiol respectively.RESULTS: Similar to 17β-estradiol, genistein and resveratrol could dose-dependently inhibit the phasic contractile activities, they decreased the mean contractile amplitude and the contractile frequencies of gallbladder muscle strips, and also produced a marked reduction in resting tone. The blocker of estrogen receptor ICI 182780 failed to alter the inhibitory effects induced by genistein and resveratrol, but potassium bisperoxo (1, 10 phenanthroline) oxovanadate bpV (phen), a potent protein tyrosine phosphatase inhibitor, markedly attenuated the inhibitory effects induced by genistein and resveratrol. In calcium-free Kreb’s solution containing 0.01 mmol/L egtazic acid (EGTA), genistein and resveratrol inhibited the first phasic contraction induced by acetylcholine (ACh), but did not affect the second contraction induced by CaCl2. In addition, genistein, resveratrol and 17β-estradiol also could reduce the contractile responses of ACh and KCl, and shift their cumulative concentration-response curves rightward.CONCLUSION: Phytoestrogen genistein and resveratrol can directly inhibit the contractile activity of isolated gallbladder muscle both at rest and in response to stimulation. The mechanisms responsible for the inhibitory effects probably due mainly to inhibition of tyrosine kinase, Ca2+ influx through potential-dependent calcium channels (PDCs) and Ca2+ release from sarcoplasmic reticulum (SR), but were not related to the estrogen receptors.
Genistein chemoprevention of prostate cancer in TRAMP mice
Wang Jun,Eltoum Isam-Eldin,Lamartiniere Coral A
Journal of Carcinogenesis , 2007, DOI: 10.1186/1477-3163-6-3
Abstract: Epidemiological studies suggest an inverse association between soy intake and prostate cancer risk. Genistein, the predominant phytoestrogen in soy food, has been proposed as a potential chemopreventive agent due to its anti-estrogen and tyrosine kinase inhibitory effects. To determine the most effective period for genistein chemoprevention, the Transgenic adenocarcinoma mouse prostate (TRAMP) model was used. The treatments were 250 mg genistein/kg AIN-76A diet 1) prepubertally only, 2) in adulthood only or 3) through out life. Controls received AIN-76A diet. By 28 weeks of age, 100% TRAMP mice fed control diet developed prostatic intraepithelial neoplasia (PIN) or adenocarcinomas with 6%, 16%, 44% and 34% developing high grade PIN, well differentiated, moderately differentiated and poorly differentiated prostatic adenocarcinomas, respectively. Prepubertal only (1–35 days postpartum) and adult only genistein treatments (12 – 28 weeks) resulted in 6% and 29% decreases in poorly-differentiated cancerous lesions compared with controls, respectively. The most significant effect was seen in the TRAMP mice exposed to genistein throughout life (1–28 weeks) with a 50% decrease in poorly-differentiated cancerous lesions. In a separate experiment in castrated TRAMP mice, dietary genistein suppressed the development of advanced prostate cancer by 35% compared with controls. Of the tumors that developed in castrated TRAMP mice, 100% were poorly-differentiated in contrast to the 37% of noncastrated TRAMP mice that developed poorly-differentiated tumors. ICI 182,780 (ICI), genistein and estrogen down-regulated androgen receptor (AR), estrogen receptor alpha (ER-α) and progesterone receptor (PR) in the prostates of C57BL/6 mice, and act independently of ER. Our data obtained in intact and castrated transgenic mice suggest that genistein may be a promising chemopreventive agent against androgen-dependent and independent prostate cancers.
Differential binding with ERα and ERβ of the phytoestrogen-rich plant Pueraria mirifica
Boonchird, C.;Mahapanichkul, T.;Cherdshewasart, W.;
Brazilian Journal of Medical and Biological Research , 2010, DOI: 10.1590/S0100-879X2009007500026
Abstract: 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) herα and herβ and human transcriptional intermediary factor 2 (htif2) or human steroid receptor coactivator 1 (hsrc1), respectively, together with the β-galactosidase expression cassette. relative estrogenic potency was expressed by determining the β-galactosidase activity (ec50) of the tuber extracts in relation to 17β-estradiol. twenty-four and 22 of the plant tuber ethanolic extracts interacted with herα and herβ, respectively, with a higher relative estrogenic potency with herβ than with herα. antiestrogenic activity of the plant extracts was also determined by incubation of plant extracts with 17β-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.
Eudragit nanoparticles containing genistein: formulation, development, and bioavailability assessment  [cached]
Tang J,Xu N,Ji H,Liu H
International Journal of Nanomedicine , 2011,
Abstract: Jingling Tang2, Na Xu1,2, Hongyu Ji1, Hongmei Liu1, Zhiyong Wang1, Linhua Wu1,2 1Department of Pharmacy, the Second Affiliated Hospital of Harbin Medical University, Key Laboratory of College in Heilongjiang Province; 2Department of Pharmaceutics, School of Pharmacy, Harbin Medical University, Harbin, China Background: Genistein, one of the major isoflavones, has received great attention as a phytoestrogen and potential cancer chemoprevention agent. However, the dissolution and bioavailability of genistein from solid oral preparations is low due to its poor water solubility. Methods: In order to improve the oral bioavailability of genistein, genistein nanoparticles were prepared by the nanoprecipitation technique using Eudragit E100 as carriers and an optimized formulation of mass ratio (genistein:Eudragit E100, 1:10). The mean particle size of genistein nanoparticles was approximately 120 nm when diluted 100 times with distilled water. The drug-loaded nanoparticles were spherical on observation by transmission electric microscopy. Results: Encapsulation efficiency and drug loading of the genistein nanoparticles were approximately 50.61% and 5.02%, respectively. Release of drug from the genistein nanoparticles was two times greater than that from the conventional capsules. After administration of genistein suspension or genistein nanoparticles at a single dose of 100 mg/kg to fasted rats, the relative bioavailability of genistein from the nanoparticles compared with the reference suspension was 241.8%. Conclusion: These results suggested that a nanoparticle system is a potentially promising formulation for the efficient delivery of poorly water-soluble drugs by oral administration. Keywords: bioavailability, dissolution, genistein, nanoparticles, nanoprecipitation technique
Genome-Wide DNA Methylation Analysis Reveals Phytoestrogen Modification of Promoter Methylation Patterns during Embryonic Stem Cell Differentiation  [PDF]
Noriko Sato,Naomi Yamakawa,Moe Masuda,Katsuko Sudo,Izuho Hatada,Masaaki Muramatsu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0019278
Abstract: Environmental challenges during development affect the fetal epigenome, but the period(s) vulnerable to epigenetic dysregulation is(are) not clear. By employing a soy phytoestrogen, genistein, that is known to alter the epigenetic states of the Avy allele during embryogenesis, we have explored the sensitive period for epigenetic regulation. The post-implantation period, when de novo DNA methylation actively proceeds, is amenable to in vitro analysis using a mouse embryonic stem (ES) cell differentiation system.
ROLE OF PHYTOESTROGEN IN TREATMENT OF CANCER: A REVIEW  [cached]
Ashish Kumar Sharma
International Journal of Pharmaceutical Research and Development , 2010,
Abstract: Phytoestrogens are a group of naturally occurring estrogen-like diphenolic compounds present in legumes, whole grains, fruits and vegetables. These dietary flavonoids have drawn much attention because there are possibilities that they might benefit human health. There are more than 300 foods have been shown to contain phytoestrogens. High consumption of phytoestrogen-rich food has been linked to a reduced incidence of cancers at different sites including breast, prostate, lung and colon. In spite of initial optimism, it is not clear whether eating foods rich in phytoestrogens decreases breast cancer risk. In the United States phytoestrogens appears to lower lung cancer risk in both smokers and non-smokers. Most food phytoestrogens are from one of three chemical classes, the isoflavonoids, the lignans or the coumestans. It is currently unclear whether phytoestrogens from soy foods affect breast cancer risk. Traditional Japanese and Chinese diets are rich in foods containing phytoestrogenic compounds, whereas the Western diet is a poor source of these phytochemicals. This is an active area of research with much work needed to resolve this issue. This review presents the most current information and indicates where more research would be helpful.
Eudragit nanoparticles containing genistein: formulation, development, and bioavailability assessment
Tang J, Xu N, Ji H, Liu H, Wang Z, Wu L
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S24185
Abstract: dragit nanoparticles containing genistein: formulation, development, and bioavailability assessment Original Research (4298) Total Article Views Authors: Tang J, Xu N, Ji H, Liu H, Wang Z, Wu L Published Date October 2011 Volume 2011:6 Pages 2429 - 2435 DOI: http://dx.doi.org/10.2147/IJN.S24185 Jingling Tang2, Na Xu1,2, Hongyu Ji1, Hongmei Liu1, Zhiyong Wang1, Linhua Wu1,2 1Department of Pharmacy, the Second Affiliated Hospital of Harbin Medical University, Key Laboratory of College in Heilongjiang Province; 2Department of Pharmaceutics, School of Pharmacy, Harbin Medical University, Harbin, China Background: Genistein, one of the major isoflavones, has received great attention as a phytoestrogen and potential cancer chemoprevention agent. However, the dissolution and bioavailability of genistein from solid oral preparations is low due to its poor water solubility. Methods: In order to improve the oral bioavailability of genistein, genistein nanoparticles were prepared by the nanoprecipitation technique using Eudragit E100 as carriers and an optimized formulation of mass ratio (genistein:Eudragit E100, 1:10). The mean particle size of genistein nanoparticles was approximately 120 nm when diluted 100 times with distilled water. The drug-loaded nanoparticles were spherical on observation by transmission electric microscopy. Results: Encapsulation efficiency and drug loading of the genistein nanoparticles were approximately 50.61% and 5.02%, respectively. Release of drug from the genistein nanoparticles was two times greater than that from the conventional capsules. After administration of genistein suspension or genistein nanoparticles at a single dose of 100 mg/kg to fasted rats, the relative bioavailability of genistein from the nanoparticles compared with the reference suspension was 241.8%. Conclusion: These results suggested that a nanoparticle system is a potentially promising formulation for the efficient delivery of poorly water-soluble drugs by oral administration.
Breast cancer risk in relation to urinary and serum biomarkers of phytoestrogen exposure in the European Prospective into Cancer-Norfolk cohort study
Heather Ward, Gaelle Chapelais, Gunter GC Kuhnle, Robert Luben, Kay-Tee Khaw, Sheila Bingham
Breast Cancer Research , 2008, DOI: 10.1186/bcr1995
Abstract: Serum and urine samples from 237 incident breast cancer cases and 952 control individuals (aged 45 to 75 years) in the European Prospective into Cancer-Norfolk cohort were analysed for seven phytoestrogens (daidzein, enterodiol, enterolactone, genistein, glycitein, o-desmethylangolensin, and equol) using liquid chromatography/mass spectrometry. Data on participants' diet, demographics, anthropometrics, and medical history were collected upon recruitment. All models were adjusted for weight, fat and energy intake, family history of breast cancer, social class, analytical batch, and factors related to oestrogen exposure.Urinary or serum phytoestrogens were not associated with protection from breast cancer in the European Prospective into Cancer-Norfolk cohort. Breast cancer risk was marginally increased with higher levels of total urinary isoflavones (odds ratio = 1.08 (95% confidence interval = 1.00 to 1.16), P = 0.055); among those with oestrogen receptor-positive tumours, the risk of breast cancer was increased with higher levels of urinary equol (odds ratio = 1.07 (95% confidence interval = 1.01 to 1.12), P = 0.013).There was limited evidence of an association between phytoestrogen biomarkers and breast cancer risk in the present study. There was no indication of decreased likelihood of breast cancer with higher levels of phytoestrogen biomarkers, but the observation that some phytoestrogen biomarkers may be associated with greater risk of breast cancer warrants further study with greater statistical power.It has been proposed that phytoestrogens – dietary compounds that structurally resemble the hormone oestrogen – are associated with the development of breast cancer due to their potential to act as oestrogen agonists or antagonists [1-3]. Phytoestrogens are a complex group of compounds widespread at low levels in most western plant foods. There are two main classes: the isoflavones (daidzein, genistein, and glycitein), present at high levels in soya products [4]
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