Dietary Phytoestrogens Research Articles

Hepatoprotective and Metabolic Effects of Dietary Soy Phytoestrogens against Hyper Caloric Diet in Cyclic Female Wistar Rats is Mediated through Estradiol Receptors

Hepatoprotective and Metabolic Effects of Dietary Soy Phytoestrogens against Hyper Caloric Diet in Cyclic Female Wistar Rats is Mediated through Estradiol Receptors

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.

Molecular docking prediction and in vitro studies elucidate anti-cancer activity of phytoestrogens

AimThe study is aimed at evaluating the chemosensitization and apoptotic effect of aglycone rich extracts of dietary phytoestrogens (derived from soybean and flaxseed) on estrogen receptor positive, MCF-7 and estrogen receptor negative, MDA-MB-231 cells. The extracts show potent activity on both the cell lines, hence, in silico studies have been carried out to find the possible reason for their activity. Main methodsMTT assay was carried to assess chemosensitization effect and activated caspase-3/7 activity was studied using flow-cytometry and western blotting. In silico studies were carried out using PharmMapper and the top hits were taken up for docking using the Schrödinger software. Top molecular targets were subjected to gene expression studies by qPCR and protein expression using Western blot analysis. Key findingsThis study reports the apoptotic activity and chemosensitization effect of the phytoestrogens. Molecular docking studies predict AKR1B1 (aldose reductase), HRAS (Harvey rat sarcoma) and GSTP1 (glutathione s-transferase pi) as potential molecular targets for genistein, daidzein and secoisolariciresinol, respectively. Gene and protein expression studies show down-regulation of AKR1BI, HRAS and GSTP1 by the extracts. SignificanceThe qPCR and western blot analysis results support the computational analyses, and hence genistein, daidzein and secoisolariciresinol may be considered as good candidates for future development into potent inhibitors of the respective protein targets through medicinal chemistry optimization.

Enhanced therapeutic benefit of quercetin-loaded phytosome nanoparticles in ovariectomized rats

Quercetin, a dietary flavonol phytoestrogen, has many health benefits but it is poorly absorbed when administered orally. To improve its bioavailability, we prepared quercetin-loaded phytosome nanoparticles (QP) using the thin film hydration method. The prepared nano-formulations were characterized using different techniques. Transmission electron microscopy revealed the homogeneously spherical, well and uniformly dispersed, nano-sized nature of QP. Dynamic light scattering measurements of QP (70 ± 7.44 nm) also confirmed this. Stability of the formed nanoparticles was established via zeta potential determination. The prepared QP exhibited very high encapsulation efficiency (98.4%). The estrogenic activity of QP, concerning inflammation, oxidative stress, bone, lipid profile, blood glucose level and weight gain, was investigated in ovariectomized rat model using 10 and 50 mg/kg/day oral doses for 4 weeks. Treatment with QP showed significant increase in serum calcium, inorganic phosphorus and glutathione content. Whereas, it significantly decreased serum alkaline phosphatase, acid phosphatase, malondialdehyde level, tumor necrosis factor-alpha and glucose level and improved lipid profile. Consequently, the results obtained confirm the superiority of QP over free quercetin at the same doses as a promising hormone replacement therapy.

Equol, a Dietary Daidzein Gut Metabolite Attenuates Microglial Activation and Potentiates Neuroprotection In Vitro.

Estrogen deficiency has been well characterized in inflammatory disorders including neuroinflammation. Daidzein, a dietary alternative phytoestrogen found in soy (Glycine max) as primary isoflavones, possess anti-inflammatory activity, but the effect of its active metabolite Equol (7-hydroxy-3-(4′-hydroxyphenyl)-chroman) has not been well established. In this study, we investigated the anti-neuroinflammatory and neuroprotective effect of Equol in vitro. To evaluate the potential effects of Equol, three major types of central nervous system (CNS) cells, including microglia (BV-2), astrocytes (C6), and neurons (N2a), were used. Effects of Equol on the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), Mitogen activated protein kinase (MAPK) signaling proteins, and apoptosis-related proteins were measured by western blot analysis. Equol inhibited the lipopolysaccharide (LPS)-induced TLR4 activation, MAPK activation, NF-kB-mediated transcription of inflammatory mediators, production of nitric oxide (NO), release of prostaglandin E2 (PGE-2), secretion of tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6), in Lipopolysaccharide (LPS)-activated murine microglia cells. Additionally, Equol protects neurons from neuroinflammatory injury mediated by LPS-activated microglia through downregulation of neuronal apoptosis, increased neurite outgrowth in N2a cell and neurotrophins like nerve growth factor (NGF) production through astrocytes further supporting its neuroprotective potential. These findings provide novel insight into the anti-neuroinflammatory effects of Equol on microglial cells, which may have clinical significance in cases of neurodegeneration.

Study of dietary phytoestrogens and estrogenic activity in pet animal diets

Study of dietary phytoestrogens and estrogenic activity in pet animal diets

Performance and egg quality of laying hens fed flaxseed: highlights on n-3 fatty acids, cholesterol, lignans and isoflavones

Flaxseed is a rich source of α-linolenic acid and phytoestrogens, mainly lignans, whose metabolites (enterodiol and enterolactone) can affect estrogen functions. The present study evaluated the influence of dietary flaxseed supplementation on reproductive performance and egg characteristics (fatty acids, cholesterol, lignans and isoflavones) of 40 Hy-Line hens (20/group) fed for 23 weeks a control diet or the same diet supplemented with 10% of extruded flaxseed. The flaxseed diet had approximately three times the content of lignans (2608.54 ng/g) as the control diet, mainly secoisolariciresinol diglucoside (1534.24 v. 494.72 ng/g). When compared with the control group, hens fed flaxseed showed a similar deposition rate (72.0% v. 73.9%) and egg yield. Furthermore, there was no effect of flaxseed on the main chemical composition of the egg and on its cholesterol content. Estradiol was higher in the plasma of the control group (1419.00 v. 1077.01 pg/ml) probably due to the effect of flaxseed on phytoestrogen metabolites. The plasma lignans were higher in hens fed flaxseed, whereas isoflavones were lower, mainly due to the lower equol value (50.52 v. 71.01 ng/ml). A similar trend was shown in eggs: the flaxseed group had higher level of enterodiol and enterolactone, whereas the equol was lower (198.31 v. 142.02 ng/g yolk). Secoisolariciresinol was the main lignan in eggs of the flaxseed group and its concentration was three times higher then control eggs. Flaxseed also improved the n-3 long-chain polyunsaturated fatty acids of eggs (3.25 v. 0.92 mg/g egg), mainly DHA, however, its oxidative status (thiobarbituric reactive substances) was negatively affected. In conclusion, 10% dietary flaxseed did not affect the productive performance of hens or the yolk cholesterol concentration, whereas the lignans and n-3 polyunsaturated fatty acid content of eggs improved. Further details on the competition between the different dietary phytoestrogens and their metabolites (estrogen, equol, enterodiol and enterolactone) should be investigated.

Probiotic Bacteria for Healthier Aging: Immunomodulation and Metabolism of Phytoestrogens.

Age-related degeneration gives rise to a number of pathologies, many of them associated with imbalances of the microbiota and the gut-associated immune system. Thus, the intestine is considered a key target organ to improve the quality of life in senescence. Gut microbiota can have a powerful impact in the deterioration linked to aging by its nutritional and immunomodulatory activity. Reduced numbers of beneficial species and low microbial biodiversity in the elderly have been linked with pathogenesis of many diseases. A healthy lifestyle with an elderly customized diet including probiotics can contribute to reducing the chronic proinflammatory status and other age-related pathologies. Beneficial effects of probiotic lactic acid bacteria and bifidobacteria to alleviate some of these disorders based on their immunomodulatory properties as well as their capacity to produce bioactive metabolites from dietary phytoestrogens are summarized. On one hand, the preservation of gut barrier integrity and an increased ability to fight infections are the main reported immune benefits of probiotics. On the other hand, the intake of a diet rich in phytoestrogens along with the presence of selected probiotic bacteria may lead to the production of equol, enterolignans, and urolithins, which are considered protective against chronic diseases related to aging.

Comparison of phytoestrogens dietary intake from vegetables and fruit in selected population in Slovakia

Phytoestrogens are compounds that are naturally present in almost all plant foods to a varying degree. They include several different classes of chemical compounds known as isoflavones, coumestans and lignans. In our work we analyzed intake of phytoestrogens is based upon our answer questionaries' in different ages. Evaluating health effects of phytoestrogens is difficult and depends on numerous factors, including the kind and dose (amount) of phytoestrogens eaten and the age, gender, and health of the person. We are exposed daily to highly variable amounts of phytoestrogens. While adults are eating a vegetarian diet or those taking dietary supplements containing phytoestrogens have high levels of exposure, infants drinking soy-based formula have the highest exposure levels by far. Accurate information about dietary phytoestrogens is therefore important but there is very limited data concerning food contents. In this study, we analyzed the phytoestrogen content in fresh and processed fruits and vegetables. The comprehensive database of phytoestrogen content determined simultaneously in vegetables and fruits foods has been developed. The important source of phytoestrogens in Slovak men and women is garlic. Phytoestrogen intake of fruits in men as an in woman is very low. Slovak populations consume a lot of fruits but the total intake is low due to the lower content of phytoestrogens.

The potential health effects of dietary phytoestrogens.

Phytoestrogens are plant‐derived dietary compounds with structural similarity to 17‐β‐oestradiol (E2), the primary female sex hormone. This structural similarity to E2 enables phytoestrogens to cause (anti)oestrogenic effects by binding to the oestrogen receptors. The aim of the present review is to present a state‐of‐the‐art overview of the potential health effects of dietary phytoestrogens. Various beneficial health effects have been ascribed to phytoestrogens, such as a lowered risk of menopausal symptoms like hot flushes and osteoporosis, lowered risks of cardiovascular disease, obesity, metabolic syndrome and type 2 diabetes, brain function disorders, breast cancer, prostate cancer, bowel cancer and other cancers. In contrast to these beneficial health claims, the (anti)oestrogenic properties of phytoestrogens have also raised concerns since they might act as endocrine disruptors, indicating a potential to cause adverse health effects. The literature overview presented in this paper illustrates that several potential health benefits of phytoestrogens have been reported but that, given the data on potential adverse health effects, the current evidence on these beneficial health effects is not so obvious that they clearly outweigh the possible health risks. Furthermore, the data currently available are not sufficient to support a more refined (semi) quantitative risk–benefit analysis. This implies that a definite conclusion on possible beneficial health effects of phytoestrogens cannot be made.Linked ArticlesThis article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc

1256 WS Effects of dietary phytoestrogens on testicular growth and semen quality characteristics in developing Angus bulls

1256 WS Effects of dietary phytoestrogens on testicular growth and semen quality characteristics in developing Angus bulls

Cardiometabolic risk and gut microbial phytoestrogen metabolite phenotypes.

Recent evidence supports that the gut microbial community, independently and/or interactively with dietary intake, is a target for reducing cardiovascular disease risk through its effects on cardiometabolic risk factors. Dietary phytoestrogens may be a source for interactive effects. Phytoestrogens, such as isoflavones, lignans, and flavonoids, are compounds found in plants that have estrogenic or antiestrogenic activities, as well as antioxidant, antiproliferative, or apoptotic actions. Given these physiological activities, phytoestrogens may have a role in cardiometabolic health. Some phytoestrogens consumed in the diet undergo biotransformation through gut bacterial metabolism to other compounds that may exhibit similar or different physiological activity than the parent compound. There is interindividual variability in the capability to metabolize phytoestrogens to their metabolites, and there is a resulting phenotype that can be evaluated based on urinary metabolite excretion. Evidence suggests that phytoestrogen metabolites and/or phenotypes are associated with cardiometabolic risk factors, such as blood pressure, abdominal obesity, and serum lipids, triglycerides, glucose, and inflammatory markers. The objective of this review was to provide an overview of the observed associations between gut microbial phytoestrogen metabolites and metabolite phenotypes with cardiometabolic risk factors, with focus on the more extensively studied isoflavone metabolites.

Urine and serum biomonitoring of exposure to environmental estrogens II: Soy isoflavones and zearalenone in pregnant women

Urine and serum biomonitoring was used to measure internal exposure to selected dietary estrogens in a cohort of 30 pregnant women. Exposure was measured over a period comprising one-half day in the field (6 h) and one day in a clinic (24 h). Biomonitoring of the dietary phytoestrogens genistein (GEN), daidzein (DDZ) and equol (EQ), as well as the mycoestrogen, zearalenone (ZEN) and its congeners, was conducted using UPLC-MS/MS. Biomonitoring revealed evidence of internal exposure to naturally occurring dietary estrogens during pregnancy. Urinary concentrations of total GEN, DDZ and EQ were similar to levels reported for general adult U.S. population. Measurable concentrations of total (parent and metabolites) GEN, DDZ and EQ were present in 240, 207 and 2 of 270 serum samples, respectively. Six out of 30 subjects had measurable concentrations of unconjugated GEN and/or DDZ in serum between 0.6 and 7.1 nM. Urine to serum total isoflavone ratios for GEN, DDZ and EQ were 13, 47, and 180, respectively. ZEN and its reductive metabolite, α-zearalenol (α-ZEL), were present in pregnant women (11 out of 30 subjects) as conjugates at levels near the limit of quantification. The average total urinary concentration was 0.10 μg/L for ZEN and 0.11 μg/L for α-ZEL.

Roles of Dietary Phytoestrogens on the Regulation of Epithelial-Mesenchymal Transition in Diverse Cancer Metastasis.

Epithelial-mesenchymal transition (EMT) plays a key role in tumor progression. The cells undergoing EMT upregulate the expression of cell motility-related proteins and show enhanced migration and invasion. The hallmarks of EMT in cancer cells include changed cell morphology and increased metastatic capabilities in cell migration and invasion. Therefore, prevention of EMT is an important tool for the inhibition of tumor metastasis. A novel preventive therapy is needed, such as treatment of natural dietary substances that are nontoxic to normal human cells, but effective in inhibiting cancer cells. Phytoestrogens, such as genistein, resveratrol, kaempferol and 3,3′-diindolylmethane (DIM), can be raised as possible candidates. They are plant-derived dietary estrogens, which are found in tea, vegetables and fruits, and are known to have various biological efficacies, including chemopreventive activity against cancers. Specifically, these phytoestrogens may induce not only anti-proliferation, apoptosis and cell cycle arrest, but also anti-metastasis by inhibiting the EMT process in various cancer cells. There have been several signaling pathways found to be associated with the induction of the EMT process in cancer cells. Phytoestrogens were demonstrated to have chemopreventive effects on cancer metastasis by inhibiting EMT-associated pathways, such as Notch-1 and TGF-beta signaling. As a result, phytoestrogens can inhibit or reverse the EMT process by upregulating the expression of epithelial phenotypes, including E-cadherin, and downregulating the expression of mesenchymal phenotypes, including N-cadherin, Snail, Slug, and vimentin. In this review, we focused on the important roles of phytoestrogens in inhibiting EMT in many types of cancer and suggested phytoestrogens as prominent alternative compounds to chemotherapy.

Dietary withdrawal of phytoestrogens resulted in higher gene expression of 3-beta-HSD and ARO but lower 5-alpha-R-1 in male rats

Removing dietary phytoestrogens causes obesity and diabetes in adult male rats. Based on the facts that hypothalamic food intake control is disrupted in phytoestrogen-deprived animals and that several steroids affect food intake, we hypothesized that phytoestrogen withdrawal alters the expression of hypothalamic steroidogenic enzymes. Male Wistar rats fed with a high-phytoestrogen diet from conception to adulthood were subjected to phytoestrogen withdrawal by feeding them a low-phytoestrogen diet or a high-phytoestrogen, high-fat diet. Withdrawal of dietary phytoestrogens increased 3β-hydroxysteroid dehydrogenase and P450 aromatase gene expression and decreased those of 5α-reductase-1. This is a direct effect of the lack of dietary phytoestrogens and not a consequence of obesity, as it was not observed in high-fat–fed rats. Phytoestrogen withdrawal and high-fat diet intake reduced hypothalamic expression of estrogen receptor (ER)α correlated with low levels of ERα-O, ERα-OS, and ERα-OT transcripts. Variations in gene expression of steroidogenic enzymes may affect the content of neurosteroids. As neurosteroids are related to food intake control, the changes observed may be a novel mechanism in the regulation of energy balance in obese phytoestrogen-deprived animals. In rats, steroidogenesis and ER signaling appear to be altered by phytoestrogen withdrawal in the rat. The ubiquity of phytoestrogens in the diet and changing intakes or withdrawal suggest that aspects of human health could be affected based on the rat and warrant further research.

Estrogenicity of captive southern white rhinoceros diets and their association with fertility

The captive southern white rhinoceros (SWR) population is not currently self-sustaining, primarily due to poor or absent reproduction of captive-born (F1+) females. In this study, we investigate the role of dietary phytoestrogens in this reproductive phenomenon by characterizing activation of SWR estrogen receptors (ESRs) 1 and 2 by diet items from nine North American institutions and comparing female SWR fertility to total diet estrogenicity. Of the diet items tested, alfalfa hay and soy and alfalfa-based commercial pellets were found to be the most potent activators of SWR ESRs. In contrast, most grass hays tested were not estrogenic. The estrogenicity of total diets varied across the institutions surveyed and the degree of diet estrogenicity was positively associated with the percentage of the total diet comprised by pellets. Comparisons of fertility records of the institutions surveyed showed no significant relationship between diet estrogenicity and fertility for female SWR conceived or born in the wild (F0). However, for F1+ females, there was a significant negative relationship between institutional diet estrogenicity and fertility. Taken together, these data suggest that developmental exposure to phytoestrogens may be the cause of poor fertility in captive-born female SWR. Whether the low fertility of the current population of captive-born female SWR is permanent or can be reversed by removing phytoestrogens from the diet remains unclear. However, our findings suggest that in order for the SWR population to become self-sustaining, the development and feeding of low phytoestrogen diets should be strongly considered.

The effect of dietary phytoestrogen content on the development of systemic lupus erythematosus in the MRL/lpr mouse.

Abstract Systemic lupus erythematosus is a prototypical autoimmune disease, characterized by the loss of immune cell tolerance to self-antigens, and the subsequent production of autoantibodies leading to multi-organ damage. SLE is an incurable, highly variable autoimmune disease that most often affects women of child-bearing age. We investigated the effects of three standard commercial diets with varying phytoestrogen content on the development of lupus in female MRL/lpr mice. The diets include Harlan 2018 which contains soybean meal, Teklad 7013 which contains both soy and alfalfa, and Research Diets Inc. D11112226 (RD) purified ingredients diet, containing no measurable phytoestrogens. Mice fed the 2018 diet developed severe glomerulonephritis with high levels of complement C3 protein deposition and moderate IgG immune-complex deposition, while mice fed the RD diet developed minimal evidence of renal damage and protein deposition. The mice fed the RD diet, however, had increased levels of multiple pro-inflammatory cytokines, while immune cell populations remained unchanged. Immunofluorescence revealed distinct infiltrating cellular phenotypes in the kidney, dependent on dietary source. Splenocyte miRNA-148a was markedly elevated in mice fed the 2018 and 7013 diets, while circulating miRNA values were not statistically different. Our results suggest that dietary isoflavones can worsen the development of glomerulonephritis due to enhanced immune complex protein deposition and altered cellular infiltration phenotypes. Our results also support that each organ system must be evaluated independently, and that what is measured in circulation does not necessarily reflect what is occurring in disease target organs.

Prospective Study of Dietary Phytoestrogen Intake and the Risk of Colorectal Cancer

ABSTRACTDietary phytoestrogen intake has been inversely associated with the risk of prostate and breast cancer and might also affect the risk of colorectal cancer. We evaluated the associations between dietary lignan intake, dietary isoflavonoid intake, dietary coumestrol intake, and dietary enterolignans and equol intake, and risk of colorectal cancer. Data from the Women's Lifestyle and Health (WLH) Cohort study was used. The WLH study is a prospective population-based cohort study including 48,268 Swedish women aged 30–49 years at the time of enrolment in 1991–92. Follow-up for colorectal cancer incidence, death, and emigration until the end of 2010 was performed through record linkage to the Swedish Cancer Registry and Total Population Register. During follow-up 206 incident colorectal cancer cases were identified. Cox proportional hazards models were fitted to estimate adjusted risk ratios with 95% confidence intervals. We found no statistically significant association between the intake of dietary lignans, dietary isoflavonoids, coumestrol, or enterolignans and equol, and risk of colorectal cancer. We found no association between dietary phytoestrogen intake and the risk of colorectal cancer. However, since the number of cancer cases was small, our results need to be confirmed. Future studies should investigate colon and rectal cancer separately.

Genetic and Dietary Regulation of Glyburide Efflux by the Human Placental Breast Cancer Resistance Protein Transporter.

Glyburide is frequently used to treat gestational diabetes owing to its low fetal accumulation resulting from placental efflux by the breast cancer resistance protein (BCRP)/ABCG2 transporter. Here we sought to determine how exposure to the dietary phytoestrogen genistein and expression of a loss-of-function polymorphism in the ABCG2 gene (C421A) impacted the transport of glyburide by BCRP using stably transfected human embryonic kidney 293 (HEK) cells, human placental choriocarcinoma BeWo cells, and human placental explants. Genistein competitively inhibited the BCRP-mediated transport of (3)H-glyburide in both wild-type (WT) and C421A-BCRP HEK-expressing cells, with greater accumulation of (3)H-glyburide in cells expressing the C421A variant. In BeWo cells, exposure to genistein for 60 minutes increased the accumulation of (3)H-glyburide 30%-70% at concentrations relevant to dietary exposure (IC50 ∼180 nM). Continuous exposure of BeWo cells to genistein for 48 hours reduced the expression of BCRP mRNA and protein by up to 40%, which impaired BCRP transport activity. Pharmacologic antagonism of the estrogen receptor attenuated the genistein-mediated downregulation of BCRP expression, suggesting that phytoestrogens may reduce BCRP levels through this hormone receptor pathway in BeWo cells. Interestingly, genistein treatment for 48 hours did not alter BCRP protein expression in explants dissected from healthy term placentas. These data suggest that whereas genistein can act as a competitive inhibitor of BCRP-mediated transport, its ability to downregulate placental BCRP expression may only occur in choriocarcinoma cells. Overall, this research provides important mechanistic data regarding how the environment (dietary genistein) and a frequent genetic variant (ABCG2, C421A) may alter the maternal-fetal disposition of glyburide.

Dietary phytoestrogens, intestinal microflora and human health

Dietary phytoestrogens, intestinal microflora and human health