Genistein Alleviates High-Fat Diet-Induced Obesity by Inhibiting the Process of Gluconeogenesis in Mice.

Genistein is an isoflavone phytoestrogen that has been shown to improve obesity; however, the underlying molecular mechanisms involved therein have not been clearly elucidated. In this study, we administered genistein to high-fat diet-induced obese mice to investigate its effect on hepatic gluconeogenesis. The results showed that genistein treatment significantly inhibited body weight gain, hyperglycemia, and adipose and hepatic lipid deposition in high-fat diet-induced obese mice. Glucose tolerance test (GTT), insulin tolerance test (ITT) and pyruvate tolerance test (PTT) showed that genistein treatment significantly inhibited gluconeogenesis and improved insulin resistance in obese mice. In addition, this study also found that genistein could promote the expression of miR-451 in vitro and in vivo, and the dual-luciferase reporter system showed that G6pc (glucose-6-phosphatase) may be a target gene of miR-451. Both genistein treatment and in vivo injection of miR-451 agomir significantly inhibited gluconeogenesis and inhibited the expression of G6pc and Gk (glycerol kinase, a known target gene of miR-451). In conclusion, genistein may inhibit gluconeogenesis in obese mice by regulating the expression of Gk and G6pc through miR-451. These results may provide insights into the functions of miR-451 and food-derived phytoestrogens in ameliorating and preventing gluconeogenesis-related diseases.

Uterine Patterning, Endometrial Gland Development, and Implantation Failure in Mice Exposed Neonatally to Genistein.

BACKGROUND: Embryo implantation relies on precise hormonal regulation, associated gene expression changes, and appropriate female reproductive tract tissue architecture. Female mice exposed neonatally to the phytoestrogen genistein (GEN) at doses similar to those in infants consuming soy-based infant formulas are infertile due in part to uterine implantation defects. OBJECTIVES: Our goal was to determine the mechanisms by which neonatal GEN exposure causes implantation defects. METHODS: Female mice were exposed to GEN on postnatal days (PND)1-5 and uterine tissues collected on PND5, PND22-26, and during pregnancy. Analysis of tissue weights, morphology, and gene expression was performed using standard histology, confocal imaging with three-dimensional analysis, real-time reverse transcription polymerase chain reaction (real-time RT-PCR), and microarrays. The response of ovariectomized adults to 17ß-estradiol (E2) and artificial decidualization were measured. Leukemia inhibitory factor (LIF) injections were given intraperitoneally and implantation sites visualized. Gene expression patterns were compared with curated data sets to identify upstream regulators. RESULTS: GEN-exposed mice exhibited reduced uterine weight gain in response to E2 treatment or artificial decidualization compared with controls; however, expression of select hormone responsive genes remained similar between the two groups. Uteri from pregnant GEN-exposed mice were posteriorized and had reduced glandular epithelium. Implantation failure was not rescued by LIF administration. Microarray analysis of GEN-exposed uteri during early pregnancy revealed significant overlap with several conditional uterine knockout mouse models, including Foxa2, Wnt4, and Sox17. These models exhibit reduced endometrial glands, features of posteriorization and implantation failure. Expression of Foxa2, Wnt4, and Sox17, as well as genes important for neonatal uterine differentiation (Wnt7a, Hoxa10, and Msx2), were severely disrupted on PND5 in GEN-exposed mice. DISCUSSION: Our findings suggest that neonatal GEN exposure in mice disrupts expression of genes important for uterine development, causing posteriorization and diminished gland function during pregnancy that contribute to implantation failure. These findings could have implications for women who consumed soy-based formulas as infants. https://doi.org/10.1289/EHP6336.

Retrospective analysis of phytoSERM for management of menopause-associated vasomotor symptoms and cognitive decline: a pilot study on pharmacogenomic effects of mitochondrial haplogroup and APOE genotype on therapeutic efficacy.

OBJECTIVE: PhytoSERM is a selective estrogen receptor beta (ERß) modulator comprised of three phytoestrogens: genistein, daidzein, and S-equol. The PhytoSERM formulation promotes estrogenic action in the brain while largely inactive or inhibitory in reproductive tissue. A phase Ib/IIa clinical trial (ClinicalTrial.gov ID: NCT01723917) of PhytoSERM demonstrated safety and pharmacokinetics profile of PhytoSERM. While this study was not powered for efficacy analysis, we conducted a pilot, retrospective analysis to identify potential responders to PhytoSERM treatment, and to determine the optimal populations to pursue in a phase II clinical trial of efficacy of the PhytoSERM formulation. METHODS: In this retrospective analysis involving 46 participants (n = 16, placebo; n = 18, 50 mg/d PhytoSERM; and n = 12, 100 mg/d PhytoSERM), the therapeutic effect of PhytoSERM was stratified by 2 genetic risk modulators for Alzheimer's disease: mitochondrial haplogroup and APOE genotype. RESULTS: Our retrospective responder analysis indicated that participants on 50 mg of daily PhytoSERM (PS50) for 12 weeks significantly reduced hot flash frequency compared with their baseline (mean [95% CI])-1.61, [-2.79, -0.42], P = 0.007). Participants on 50 mg of PhytoSERM also had significantly greater reduction in hot flash frequency at 12 weeks compared with the placebo group (-1.38, -0.17 [median PS50, median placebo], P = 0.04). Fifty milligrams of daily PhytoSERM also preserved cognitive function in certain aspects of verbal learning and executive function. Our analysis further suggests that mitochondrial haplogroup and APOE genotype can modify PhytoSERM response. CONCLUSION: Our data support a precision medicine approach for further development of PhytoSERM as a safe and effective alternative to hormone therapy for menopause-associated hot flash and cognitive decline. While definitive determination of PhytoSERM efficacy is limited by the small sample size, these data provide a reasonable rationale to extend analyses to a larger study set powered to address statistical significance.

Phytoestrogens and Thyroid Cancer Risk: A Population-Based Case-Control Study in Connecticut.

BACKGROUND: Very few previous studies have examined the relationship between thyroid cancer risk and intake of phytoestrogens (PE); furthermore, these studies have reached inconsistent results. METHODS: We analyzed data from a population-based case-control study in Connecticut from 2010 to 2011, including 387 histologically confirmed thyroid cancer cases and 433 population-based controls, with compound data available concerning specific PEs. Multivariate unconditional logistic regression models were used to estimate the associations between specific PEs and the risk of thyroid cancer, adjusting for potential confounders. RESULTS: An elevated risk of thyroid cancer was associated with moderate to high levels of coumestrol intake [OR = 2.48, 95% confidence interval (CI), 1.39-4.43 for 40-80 µg/day; OR = 2.41, 95% CI, 1.32-4.40 for 80-130 µg/day; and OR = 2.38, 95% CI, 1.26-4.50 for >200 µg/day compared with <40 µg/day], and the main elevation in risk appeared among microcarcinomas (≤1 cm). A decreased risk of papillary macrocarcinomas (>1 cm; OR = 0.26, 95% CI, 0.08-0.85 for 1,860-3,110 µg/day compared with <760 µg/day) was associated with moderate genistein intake among women. CONCLUSIONS: Our study suggests that high coumestrol intake increases the risk of thyroid cancer, especially microcarcinomas, whereas moderate amounts of genistein intake appear to be protective for females with thyroid macrocarcinomas. IMPACT: The study highlights the importance of distinguishing between microcarcinomas and macrocarcinomas in future research on the etiology of thyroid cancer.

Effects of High-Dose Genistein on the Hypothalamic RNA Profile and Intestinal Health of Female Chicks.

Genistein is abundant in animal feed. In this study, the side effects of high-dose genistein on intestinal health and hypothalamic RNA profile were evaluated. Chicks exposed to high-dose genistein by intraperitoneal injection (416 ± 21, 34.5 ± 2.5) and feed supplementation (308 ± 19, 27.2 ± 2.1) both showed a reduced body weight gain and feed intake in comparison with the control group (261 ± 16, 22.7 ± 1.6, P < 0.01). In comparison with the control (22.4 ± 0.5, 33.3 ± 2.4), serum levels of albumin and total protein were decreased after high-dose genistein injection (21.6 ± 0.5, 31.8 ± 1.6) and diet supplementation (20.6 ± 0.9, 29.9 ± 2.5, P < 0.001). Interestingly, the genistein diet presented the chick hypothalamus with downregulated expression of bitter receptors (TAS1R3, P < 0.05). Meanwhile, it upregulated the expressions of TAS2R1 (P < 0.05) and downstream genes (PLCB2 and IP3R3) in the ileum (P < 0.05). Accordingly, high-dose dietary genistein reduced villus height and the abundance of Lactobacillus, along with the increased abundance of pathogenic bacteria in the ileum (P < 0.05). Furthermore, transcriptomic analysis identified 348 differently expressed genes (168 upregulated and 224 downregulated) in the high-dose dietary genistein treated group in comparison with the control (P < 0.05, |log2FoldChange| > 0.585). Therefore, high-dose dietary genistein altered the hypothalamic RNA profile and signal processing. Cluster analysis further revealed that high-dose dietary genistein significantly influenced apoptosis, the immune process, and the whole synthesis of steroid hormones in the hypothalamus (P < 0.05). In conclusion, high-dose dietary genistein altered the hypothalamic RNA profile and intestinal health of female chicks.

Postnatal genistein administration selectively abolishes sexual dimorphism in specific hypothalamic dopaminergic system in mice.

As demonstrated in previous studies, early postnatal genistein (GEN) administration to mice pups of both sexes, at doses similar to that of infant soy-based formulas, may affect the development of some steroid-sensitive neuronal circuits (i.e. nitrergic and vasopressinergic systems), causing irreversible alterations in adults. Here, we investigated the hypothalamic and mesencephalic dopaminergic system (identified with tyrosine hydroxylase immunohistochemistry). GEN administration (50 mg/kg) to mice of both sexes during the first week of postnatal life specifically affected tyrosine hydroxylase immunohistochemistry in the hypothalamic subpopulation of neurons, abolishing their sexual dimorphism. On the contrary, we did not observe any effects in the mesencephalic groups. Due to the large involvement of dopamine in circuits controlling rodent sexual behavior and food intake, these results clearly indicate that the early postnatal administration of GEN may irreversibly alter the control of reproduction, of energetic metabolism, and other behaviors. These results suggest the need for a careful evaluation of the use of soy products in both human and animal newborns.

Biomarker Identification of Maternal Genistein Exposure Induced Obesity by Metabonomics Analysis.

The objective of this study was to confirm the effect of maternal genistein exposure on body weight of male offspring and the metabolic alterations associated with maternal genistein-induced obesity. Pregnant female Sprague-Dawley (SD) rats were supplemented with 300 mg/kg diet of genistein (GEN) or no genistein (CON) throughout pregnancy and lactation. The growth of male offspring was investigated until 12 week age and the mechanism of obesity was studied using metabonomics by ultra performance liquid chromatography and quadrupole time-of-flight (UPLC Q-TOF) MS with electrospray ionization in positive ESI mode (ESI+). Compared with the CON group, body weight, fat pad and food intake of male offspring in GEN group were increased significantly at the age of weeks 10 to 12 (p<0.05). Ten urine principal metabolites contributing to the clusters were identified, including increased 8-Isoprostaglandin F2a, and decreased L-Proline, Betaine, L-Acetylcarnitine, Norsalsolinol, Indoleacrylic acid, L-Tryptophan, Lysophosphatidylcholines (LysoPC) (20 : 4), Lysophosphatidylethanolamines (LysoPE) (18 : 1) and LysoPC (O-18 : 0). Our results confirmed weight-increasing effects of maternal genistein exposure, accompanied by favorable changes in metabolites in the male offspring' urine. Therefore, this research enables us to better understand obesity and predict risk of obesity-related disease by studying metabolites present in the urine.

Toxicity and non-harmful effects of the soya isoflavones, genistein and daidzein, in embryos of the zebrafish, Danio rerio.

Based on the assumed oestrogenic and apoptotic properties of soya isoflavones (genistein, daidzein), and following the current OECD test-guidelines and principle of 3Rs, we have studied the potential toxicity of phytochemicals on the zebrafish embryos test (ZFET). For this purpose, zebrafish embryos at 2-3 h post-fertilisation (hpf) were exposed to both soya isoflavones (from 1.25 mg/L to 20 mg/L) and assayed until 96 hpf. Lethal and sub-lethal endpoints (mortality, hatching rates and malformations) were estimated in the ZFET, which was expanded to potential gene expression markers, determining the lowest observed effect (and transcriptional) concentrations (LOEC, LOTEC), and the no-observable effect (and transcriptional) concentrations (NOEC, NOTEC). The results revealed that genistein is more toxic (LC50-96 hpf: 4.41 mg/L) than daidzein (over 65.15 mg/L). Both isoflavones up-regulated the oestrogen (esrrb) and death receptors (fas) and cyp1a transcript levels. Most thyroid transcript signals were up-regulated by genistein (except for thyroid peroxidase/tpo), and the hatching enzyme (he1a1) was exclusively up-regulated by daidzein (from 1.25 mg/L onwards). The ZFET proved suitable for assessing toxicant effects of both isoflavones and potential disruptions (i.e. oestrogenic, apoptotic, thyroid, enzymatic) during the embryogenesis and the endotrophic larval period.

Neonatal Genistein Exposure and Glucocorticoid Signaling in the Adult Mouse Uterus.

BACKGROUND: Female reproductive tract development is sensitive to the endocrine-disrupting potential of environmental estrogens. Early-life exposure to the dietary phytoestrogen genistein impairs fertility and persistently alters the transcriptome in the oviduct and uterus of rodents. Glucocorticoid signaling, which has recently been shown to be essential for normal fertility in the female mouse uterus, is antagonized by genistein. OBJECTIVE: Our goal was to determine whether early-life exposure to genistein disrupts glucocorticoid signaling in the mouse uterus, which may contribute to infertility. METHODS: Female C57Bl/6 mice were exposed to either 50 mg/kg per day genistein, 10 µg/kg per day estradiol, or vehicle (corn oil) on postnatal days 1-5 (PND1-5), and then treated with the synthetic glucocorticoid dexamethasone (Dex: 1 mg/kg) or vehicle (saline) on PND5, at weaning on PND21, or as adults on PND56 following adrenalectomy and ovariectomy to evaluate glucocorticoid responsiveness. Uteri were isolated following treatment for gene expression or chromatin immunoprecipitation. RESULTS: Neonatal exposure to genistein altered the uterine transcriptome of adult mice and caused substantial changes to the transcriptional response to glucocorticoids. Although expression of the glucocorticoid receptor was not affected, genistein exposure disrupted glucocorticoid receptor recruitment to specific regulatory sites in target genes. Many genes involved in chromatin remodeling were dysregulated in genistein-exposed mice, suggesting that epigenetic reprograming may contribute to the altered glucocorticoid response of the uterus following early-life exposure to genistein. These changes affected the biological activity of glucocorticoids within the uterus, as glucocorticoids antagonized the proliferative effects of estradiol in the uterus of control mice but not genistein-exposed mice. CONCLUSIONS: Our findings suggest that disruption of glucocorticoid signaling due to early-life exposure to environmental estrogens may in part render the uterus unable to support implantation. https://doi.org/10.1289/EHP1575.

Association between dietary phytoestrogens intakes and prostate cancer risk in Sicily.

OBJECTIVE: In this study we aimed to investigate the association between dietary phytoestrogen consumption and prostate cancer in a sample of southern Italian individuals. METHODS: A population-based case-control study on the association between prostate cancer and dietary factors was conducted from January 2015 to December 2016 in a single institution of the municipality of Catania, southern Italy (Registration number: 41/2015). A total of 118 histopathological-verified prostate cancer (PCa) cases and a total of 222 controls were collected. Dietary data was collected by using two food frequency questionnaires. RESULTS: Patients with PCa consumed significantly higher levels of phytoestrogens. Multivariate logistic regression showed that lignans (Q[quartile]4 vs. Q1, OR [odds ratio] = 4.72; p < .05) and specifically, lariciresinol (Q4 vs. Q1, OR = 4.60; p < .05), pinoresinol (Q4 vs. Q1, OR = 5.62; p < .05), matairesinol (Q4 vs. Q1, OR = 3.63; p < .05), secoisolariciresinol (Q4 vs. Q1, OR = 4.10; p < .05) were associated with increased risk of PCa. Furthermore, we found that isoflavones (Q3 vs. Q1, OR = 0.28; p < .05) and specifically, genistein (Q4 vs. Q1, OR = 0.40; p < .05) were associated with reduced risk of PCa. CONCLUSION: We found of an inverse association between dietary isoflavone intake and PCa, while a positive association was found with lignans intake.

Protective Effect of Genistein against Neuronal Degeneration in ApoE-/- Mice Fed a High-Fat Diet.

Altered cholesterol metabolism is believed to play a causal role in major pathophysiological changes in neurodegeneration. Several studies have demonstrated that the absence of apolipoprotein E (ApoE), a predominant apolipoprotein in the brain, leads to an increased susceptibility to neurodegeneration. Previously, we observed that genistein, a soy isoflavone, significantly alleviated apoptosis and tau hyperphosphorylation in SH-SY5Y cells. Therefore, we investigated the neuroprotective effects of dietary genistein supplementation (0.5 g/kg diet) in the cortex and hippocampus of wild-type C57BL/6 (WT) and ApoE knockout (ApoE-/-) mice fed a high-fat diet (HFD) for 24 weeks. Genistein supplementation alleviated neuroinflammation and peripheral and brain insulin resistance. Reductions in oxidative and endoplasmic reticulum stress were also observed in ApoE-/- mice fed a genistein-supplemented diet. Beta-secretase 1 and presenilin 1 mRNA levels and beta-amyloid peptide (Aß) protein levels were reduced in response to genistein supplementation in ApoE-/- mice but not in WT mice. Although the absence of ApoE did not increase tau hyperphosphorylation, genistein supplementation reduced tau hyperphosphorylation in both WT and ApoE-/- mice. Consistent with this result, we also observed that genistein alleviated activity of c-Jun N-terminal kinase and glycogen synthase kinase 3ß, which are involved in tau hyperphosphorylation. Taken together, these results demonstrate that genistein alleviated neuroinflammation, Aß deposition, and hyperphosphorylation in ApoE-/- mice fed an HFD.

Risks and benefits of phytoestrogens: where are we now?

PURPOSE OF REVIEW: The estrogenic effects of genistein, as reconfirmed by the American National Toxicology Program (USA-NTP), have led to several new clinical studies being undertaken. Here, we highlight the most relevant recent data, reporting either beneficial or adverse effects. RECENT FINDINGS: Phytoestrogens are natural molecules from edible plants exhibiting estrogenic activities. Post-USA-NTP studies investigated both human and animal reproductive and other physiological issues. These studies showed that estrogens can be either deleterious for reproduction and estrogen-dependent diseases, or beneficial for those with steroid deficiencies, that is more than 50. The specific outcome depends on exposure level and on the estrogenic status of the patients exposed. Recently, it was reported that, with the industrialization of soybean process, phytoestrogen exposure dramatically increased in both humans and cattle, whereas traditional Asian soy-food-processing empirically removed isoflavones. Phytoestrogen exposure has also become more widespread with the progressive internationalization of soybean use in human and cattle food. SUMMARY: Phytoestrogens should be considered as modern endocrine disruptors and studied as such.

Genistein supplementation prevents weight gain but promotes oxidative stress and inflammation in the vasculature of female obese ob/ob mice.

Obesity, a state of chronic low-grade inflammation, is strongly associated with the development of hypertension and diabetes. Superoxide, a free radical elevated in obese individuals, promotes hypertension through scavenging the endogenous vasodilator nitric oxide. The hypothesis was a genistein-enriched diet would promote weight loss and reduce oxidative stress and inflammation in the vasculature of intact female ob/ob mice. Aortas and mesenteric arteries were isolated from female ob/ob mice fed genistein-free (0mg genistein/kg diet; n=6), standard chow (200-300mg genistein/kg diet; n=11) or genistein-enriched (600mg genistein/kg diet; n=9) diets for 4weeks. Sections of isolated vessels were labeled with the superoxide indicator dihydroethidium and fluorescence was measured by confocal microscopy. Protein expression of the inflammatory marker inducible nitric oxide synthase (iNOS) was measured in the perivascular adipose tissue (PVAT) surrounding each vessel and plasma concentrations of superoxide dismutase (SOD) were quantified. Genistein-enriched diet promoted less weight gain compared to animals fed standard chow (P=.008). Standard chow promoted increased superoxide in the aorta (P=.030) and mesenteric arteries (P=.024) compared to a diet devoid of genistein. At all tested concentrations, genistein significantly increased iNOS expression in mesenteric artery PVAT (vs. standard chow, P<.001; vs. genistein-enriched, P=.002) and tended to increase iNOS within the aortic PVAT (standard chow, P=.075) compared to the genistein-free group. Plasma SOD activity was significantly downregulated in genistein-enriched animals as compared to those fed a genistein-free diet (P=.028). In summary, although genistein prevents weight gain, it promotes vascular oxidative stress and inflammation in obese ovarian-intact female mice.

Changes of growth hormone-releasing hormone and somatostatin neurons in the rat hypothalamus induced by genistein: a stereological study.

OBJECTIVES: Genistein is a plant-derived estrogenic isoflavone commonly found in dietary and therapeutic supplements, due to its potential health benefits. Growth hormone-releasing hormone (GHRH) and somatostatin (SS) are neurosecretory peptides synthesized in neurons of the hypothalamus and regulate the growth hormone secretion. Early reports indicate that estrogens have highly involved in the regulation of GHRH and SS secretions. Since little is known about the potential effects of genistein on GHRH and SS neurons, we exposed rats to genistein. METHODS: Genistein were administered to adult rats in dose of 30 mg/kg, for 3 weeks. The estradiol-dipropionate treatment was used as the adequate controls to genistein. Using applied stereology on histological sections of hypothalamus, we obtained the quantitative information on arcuate (Arc) and periventricular (Pe) nucleus volume and volume density of GHRH neurons and SS neurons. Image analyses were used to obtain GHRH and SS contents in the median eminence (ME). RESULTS: Administration of estradiol-dipropionate caused the increase of Arc and Pe nucleus volume, SS neuron volume density, GHRH and SS staining intensity in the ME, when compared with control. Genistein treatment increased: Arc nucleus volume and the volume density of GHRH neurons (by 26%) and SS neurons (1.5 fold), accompanied by higher GHRH and SS staining intensity in the ME, when compared to the orhidectomized group. DISCUSSION: These results suggest that genistein has a significant effect on hypothalamic region, involved in the regulation of somatotropic system function, and could contribute to the understanding of genistein as substance that alter the hormonal balance.

Bioactivity of genistein: A review of in vitro and in vivo studies.

Genistein is a soy derived isoflavanoid compound with multitude of health benefits. This compound is found to be a potent agent in both prophylaxis and treatment of cancer and various other chronic diseases. Ranging from its antioxidant activity to its effect on various cancer types, genistein has been a compound of interest in a number of studies carried out so far. The great interest that has focused on genistein led to the identification of numerous intracellular targets of its action in the live cells. Retardation of atherogenic activity and increasing the antioxidant defense of a cell has been attributed to genistein while as it has also been reported that genistein possesses suppressive effects on both the cell-mediated and humoral components of the adaptive immune system. At the molecular level, genistein reduces the number of developing CD4(+) and CD8(+) thymocytes suggesting a possible mechanism for genistein effects on cell-mediated immunity. Genistein may inhibit cancer progression by inducing apoptosis or inhibiting proliferation. In addition, genistein has its prominent role in preventing the DNA damage. Apolipoprotein B secretion gets reduced when the subjects are administered with genistein. Genistein confers a better protection to ischemic conditions thereby giving a significant cardioprotection. At cellular level adipocyte differentiation is another property of genistein which makes it a better neutraceutical which can reduce the atherogenic condition and hypercholesterolemia. Expression of human endothelial nitric oxide synthase is associated with genistein supplementation. The advantage of using genistein is its multidirectional action and its lesser toxicity.

An insight into the harmful effects of soy protein: A review.

Soy protein (SP) is a protein derived from soybean meal. SP is obtained from the removal of the outer shell of soybean and the fatty acid. The dietary supplementation of SP was was reported to have positive effects on human health. Therefore, the attention towards SP is increasing among the consumers, industrialist and researchers. However, the side effects and toxicity related to SP was not summarized, to date. This review summarized the toxic effects such as hormonal disturbances, carcinogenic and organotoxicity of SP based on the clinical and experimental studies. The review mainly focused on the effect of soy isoflavone-genistein on various organs. The main aim of the present review is to increase the public awareness on the harmful effect of SP on the various health aspects and draw the attention of the health care personnel and researchers.

Determination of the isoflavone composition and estrogenic activity of commercial dietary supplements based on soy or red clover.

Dietary supplements high in isolated isoflavones are commercially available for human consumption primarily to alleviate menopausal symptoms in women. The isoflavone composition, quantity and importantly their estrogenic potency are poorly standardised and can vary considerably between different products. The aim of this study was to analyse the isoflavone composition of 11 dietary supplements based on soy or red clover using the HPLC/MS/MS technique. Furthermore, we investigated the transactivational potential of the supplements on the estrogen receptors (ER), ERα and ERß, performing luciferase reporter gene assays. As expected, we found that the isoflavone composition varies between different products. The measured total isoflavone contents in various supplements were mostly comparable to those claimed by the manufacturers in their product information. However expressing the isoflavone content as isoflavone aglycone equivalents, soy-based supplements had a clearly lower quantity compared to the manufacturer information. All supplements transactivated more or less ERα and ERß with a preference for ERß. The transactivational efficiency exceeded partly the maximal 17ß-estradiol induced ER activation. While the different soy-based supplements revealed similar transactivation potential to both ERs, red clover-based supplements differed considerably. We conclude that different commercial dietary supplements based on soy or red clover vary in their isoflavone composition and quantity. They are estrogenically active, although especially the red clover-based supplements show considerable differences in their estrogenic potential to ERα and ERß. Thus, different isoflavone-rich products cannot be necessarily compared regarding possible biological effects.

Detection of a negative correlation between prescription of Chinese herbal products containing coumestrol, genistein or daidzein and risk of subsequent endometrial cancer among tamoxifen-treated female breast cancer survivors in Taiwan between 1998 and 2008: A population-based study.

ETHNOPHARMACOLOGICAL RELEVANCE: Tamoxifen users sometimes seek complementary and alternative medicine advice for treatment of a variety of illness and co-administer with phytoestrogen-containing herbs, resulting in an increasing concern of its influence in subsequent endometrial cancer risk. Our study aims to determine the prevalence of Chinese herbal products containing coumestrol, genistein, or daidzein and their association with subsequent endometrial cancer risk among tamoxifen-treated breast cancer survivors in Taiwan. METHODS: We selected all patients who were newly diagnosed with invasive breast cancer and received tamoxifen treatment between January 1, 1998, and December 31, 2008, from the National Health Insurance Research Database. Among the 26,656 tamoxifen-treated breast cancer survivors, we evaluated the usage, frequency of service, and prescription of Chinese herbal products containing coumestrol, genistein, or daidzein. The logistic regression method was employed to calculate the odds ratios for utilization of those herbal products. Cox proportional hazard regression was set to calculate the hazard ratios of endometrial cancer associated with such usage. RESULTS: Of the patients surveyed, 36.2% (n=9652) of the tamoxifen-treated breast cancer survivors examined in the study had consumed Chinese herbal products containing coumestrol, genistein, or daidzein during the study period. Exposure to Ge Gen(Puerariae Radix) specifically was the most extensive. For it, the population consumed an average cumulative dose of above 180g. Compared to those who had never used Chinese herbal products, breast cancer survivors who had taken Chinese herbal products containing coumestrol, genistein, or daidzein concurrently with tamoxifen treatment did not have a higher hazard ratio for subsequent development of endometrial cancer. CONCLUSION: Among those tamoxifen-treated female breast cancer survivors in Taiwan, consumption of Chinese herbal products containing coumestrol, genistein, or daidzein is negatively correlated with subsequent endometrial cancer risk.

Effects of genistein in combination with conjugated estrogens on endometrial hyperplasia and metabolic dysfunction in ovariectomized mice.

Tissue-selective estrogen complex (TSEC), which combines a selective estrogen receptor modulator (SERM) with one or more estrogens, is a novel approach to menopausal therapy. It has been demonstrated that the phytoestrogen genistein (GEN) exhibits mixed estrogen receptor agonist and antagonist activity, suggesting that GEN may have potential for use as a natural SERM. We evaluated, for the first time, the effects of GEN, conjugated estrogens (CE), and their pairing effects as a TSEC treatment on estrogen-induced endometrial hyperplasia and metabolic dysfunction in ovariectomized (OVX) mice fed a high-fat diet. CE replacement prevented fat accumulation in the adipose tissue and liver, improved glucose homeostasis, and induced endometrial hyperplasia in OVX mice. GEN at 100 mg/kg showed CE mimetic effects in preventing ovariectomy-induced metabolic dysfunctions without endometrial stimulation. Combination treatments with CE and GEN prevented metabolic dysfunctions more strongly than CE alone, but at both low and high doses, GEN did not reverse CE-induced endometrial hyperplasia. In addition, we found that in a TSEC regimen, a typical SERM raloxifene maintains the metabolic benefits of CE while simultaneously protecting the endometrium in OVX mice. These findings indicate that GEN acts as an estrogen agonist in metabolic regulation, but has no SERM function in the uteri of OVX mice.

Isoflavones in soy flour diet have different effects on whole-genome expression patterns than purified isoflavone mix in human MCF-7 breast tumors in ovariectomized athymic nude mice.

SCOPE: Soy flour diet (MS) prevented isoflavones from stimulating MCF-7 tumor growth in athymic nude mice, indicating that other bioactive compounds in soy can negate the estrogenic properties of isoflavones. The underlying signal transduction pathways to explain the protective effects of soy flour consumption were studied here. METHODS AND RESULTS: Ovariectomized athymic nude mice inoculated with MCF-7 human breast cancer cells were fed either Soy flour diet (MS) or purified isoflavone mix diet (MI), both with equivalent amounts of genistein. Positive controls received estradiol pellets and negative controls received sham pellets. GeneChip Human Genome U133 Plus 2.0 Array platform was used to evaluate gene expressions, and results were analyzed using bioinformatics approaches. Tumors in MS-fed mice exhibited higher expression of tumor growth suppressing genes ATP2A3 and BLNK and lower expression of oncogene MYC. Tumors in MI-fed mice expressed a higher level of oncogene MYB and a lower level of MHC-I and MHC-II, allowing tumor cells to escape immunosurveillance. MS-induced gene expression alterations were predictive of prolonged survival among estrogen-receptor-positive breast cancer patients, whilst MI-induced gene changes were predictive of shortened survival. CONCLUSION: Our findings suggest that dietary soy flour affects gene expression differently than purified isoflavones, which may explain why soy foods prevent isoflavones-induced stimulation of MCF-7 tumor growth in athymic nude mice.