Phytoestrogens in clinical practice: a review of the literature

Assessing the combined effects of Black Cohosh, Soy Isoflavones, and SDG Lignans on menopausal symptoms: a randomized, double-blind, placebo-controlled clinical trial

OBJECTIVE

This randomized, double-blind, parallel-group clinical trial aimed to evaluate the efficacy of Black Cohosh, Soy Isoflavones, and SDG Lignans in alleviating menopausal symptoms compared to a placebo.

METHODS

Ninety-six postmenopausal women aged 45-60 years were enrolled. Participants were randomized to receive either the study supplements or a placebo for 90 days, with Menopause Rating Scale (MRS) scores collected at baseline and every 4 weeks to monitor symptom changes. Secondary outcomes assessed included hormonal variations and the incidence of adverse symptoms.

RESULTS

Of the initial cohort, 90 participants completed the study with high adherence. Significant improvements were observed in the treatment group across all MRS domains: somatic (- 54.3% difference, p < 0.01), psychological (- 54.3% difference, p < 0.01), urogenital (-37.3% difference, p < 0.01), and total score (- 48.0% difference, p < 0.01). Hormonal changes were modest yet statistically significant for FSH (- 6.7% difference, p < 0.01) and estradiol (12.6% difference, p < 0.01). Adverse events were minimal, transient, and did not require cessation of supplementation.

CONCLUSION

Black Cohosh, Soy Isoflavones, and SDG Lignans significantly reduced menopausal symptoms with a favorable safety profile. These findings support the potential of this supplement combination as a therapeutic option for menopausal symptom management.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06328348.

Genistein Up-Regulates the Expression of EGF and E-Cadherin in the Treatment of Senile Vaginitis

Investigating the therapeutic effect of genistein (Gen) on postmenopausal senile vaginitis (SV) and its mechanism of action. Adult SPF female Wistar rats were selected to establish a bilateral ovariectomized animal model (OVX), which simulated senile vaginitis dominated by estrogen deficiency in ovarian dysfunction. After 14 days of continuous treatment, the morphology of vaginal epithelial tissue was observed and various types of epithelial cells were counted, and the body mass and uterine and vaginal index of rats were measured. the levels of vaginal tissue secretion, microorganism, hormone and glycogen in each group were measured and the reproductive health was evaluated clinically. The protein expression and mRNA expression of epidermal growth factor (EGF) and E-cadherin (E-cadherin) in vaginal tissues were detected by immunohistochemistry and RT-PCR, respectively. Result showed that Genistein lowered vaginal pH, increased vaginal index and vaginal health score, thickened epithelial layers and improved vaginal tissue atrophy after administration. Genistein also increased the contents of glycogen and Lactobacillus in vagina, and promoted the expression of EGF, E-cadherin protein and mRNA. To sum up, there is no significant change in serum E2 and FSH levels, indicating that genistein has no effect on hormone levels in rats. genistein promoted the proliferation of vaginal epithelial cells, thickened epithelial layers and the vaginal wall, which improved the resistance of vaginal epithelium, the recovery of self-cleaning ability and healed the vaginal wound and erosive surface to improve atrophy.

Estrogens and phytoestrogens in body functions

Estrogens are the hormones of reproduction in women as well as of many other important functions in the male and female body. They undergo significant changes in the different phases of life, e.g. during puberty, pregnancy or at menopause/andropause. Phytoestrogens are natural non-steroidal phenolic plant compounds that can mimic the activity of estrogens and their beneficial effects in women and in men. This narrative review summarizes the literature on the physiological role of estrogens and the several potential health benefits of phytoestrogens, with particular attention given to the possible role of phytoestrogens in aging.

Unveiling the Complexity of Red Clover (Trifolium pratense L.) Transcriptome and Transcriptional Regulation of Isoflavonoid Biosynthesis Using Integrated Long- and Short-Read RNAseq

Red clover (Trifolium pratense L.) is used as forage and contains a high level of isoflavonoids. Although isoflavonoids in red clover were discovered a long time ago, the transcriptional regulation of isoflavonoid biosynthesis is virtually unknown because of the lack of accurate and comprehensive characterization of the transcriptome. Here, we used a combination of long-read (PacBio Iso-Seq) and short-read (Illumina) RNAseq sequencing to develop a more comprehensive full-length transcriptome in four tissues (root, stem, leaf, and flower) and to identify transcription factors possibly involved in isoflavonoid biosynthesis in red clover. Overall, we obtained 50,922 isoforms, including 19,860 known genes and 2817 novel isoforms based on the annotation of RefGen Tp_v2.0. We also found 1843 long non-coding RNAs, 1625 fusion genes, and 34,612 alternatively spliced events, with some transcript isoforms validated experimentally. A total of 16,734 differentially expressed genes were identified in the four tissues, including 43 isoflavonoid-biosynthesis-related genes, such as stem-specific expressed TpPAL, TpC4H, and Tp4CL and root-specific expressed TpCHS, TpCHI1, and TpIFS. Further, weighted gene co-expression network analysis and a targeted compound assay were combined to investigate the association between the isoflavonoid content and the transcription factors expression in the four tissues. Twelve transcription factors were identified as key genes for isoflavonoid biosynthesis. Among these transcription factors, the overexpression of TpMYB30 or TpRSM1-2 significantly increased the isoflavonoid content in tobacco. In particular, the glycitin was increased by 50-100 times in the plants overexpressing TpRSM1-2, in comparison to that in the WT plants. Our study provides a comprehensive and accurate annotation of the red clover transcriptome and candidate genes to improve isoflavonoid biosynthesis and accelerate research into molecular breeding in red clover or other crops.

Genistein: Dual Role in Women's Health

Advanced research in recent years has revealed the important role of nutrients in the protection of women's health and in the prevention of women's diseases. Genistein is a phytoestrogen that belongs to a class of compounds known as isoflavones, which structurally resemble endogenous estrogen. Genistein is most often consumed by humans via soybeans or soya products and is, as an auxiliary medicinal, used to treat women's diseases. In this review, we focused on analyzing the geographic distribution of soybean and soya product consumption, global serum concentrations of genistein, and its metabolism and bioactivity. We also explored genistein's dual effects in women's health through gathering, evaluating, and summarizing evidence from current in vivo and in vitro studies, clinical observations, and epidemiological surveys. The dose-dependent effects of genistein, especially when considering its metabolites and factors that vary by individuals, indicate that consumption of genistein may contribute to beneficial effects in women's health and disease prevention and treatment. However, consumption and exposure levels are nuanced because adverse effects have been observed at lower concentrations in in vitro models. Therefore, this points to the duplicity of genistein as a possible therapeutic agent in some instances and as an endocrine disruptor in others.

Moderate Consumption of Beer (with and without Ethanol) and Menopausal Symptoms: Results from a Parallel Clinical Trial in Postmenopausal Women

The menopausal transition can be a challenging period for women’s health and a trigger of uncomfortable symptoms. Beer is the main food source of isoxanthohumol, a precursor of 8-prenylnaringenin, the strongest phytoestrogen identified to date. As phytoestrogens are reported to reduce perimenopausal symptoms, we evaluated if a daily moderate consumption of beer with (AB) and without alcohol (NAB) could improve menopausal symptoms and modify cardiovascular risk factors. A total of 37 postmenopausal women were enrolled in a parallel controlled intervention trial and assigned to three study groups: 16 were administered AB (330 mL/day), 7 NAB (660 mL/day), and 14 were in the control group. After a 6-month follow-up of the 34 participants who finished the trial, both interventions (AB and NAB) significantly reduced the severity of the menopause-related symptoms (p-value AB vs. Control: 0.009; p-value NAB vs. Control: 0.033). Moreover, AB had a beneficial net effect on psychological menopausal discomforts compared to the control group. As the sex hormone profile did not differ significantly between the study groups, the effects of both types of beers (AB and NAB) are attributed to the non-alcoholic fraction of beer. Furthermore, moderate NAB consumption improved the lipid profile and decreased blood pressure in postmenopausal women.

Improved yeast-screening assay for phytoestrogens

A yeast estrogen screening (YES) assay was improved to increase sensitivity for detection of phytoestrogens. New yeast strains minus one or the other of transporters Pdr5 or Snq2 and harboring yEGFP as a reporter gene were developed. The new strains showed 2-100-fold improvement in sensitivity for detection of standard estrogens and antiestrogens. In addition, the assay time (1 h) using the newly developed strains was shorter than that (4 h) previously reported. Furthermore, the snq2-minus strains were most effective for detection of estrogenic activity while the pdr5-minus strains were most effective for detection of antiestrogenic activity. The efficacy of the new methods was evaluated and confirmed by testing with 23 Thai medicinal plant species. The new strains were also tested for detection of xenoestrogens. The results revealed that the newly developed YES methods were specific and rapid and suitable for simple high-throughput screening or detection of estrogen-like compounds.

Is There Such a Thing as "Anti-Nutrients"? A Narrative Review of Perceived Problematic Plant Compounds

Plant-based diets are associated with reduced risk of lifestyle-induced chronic diseases. The thousands of phytochemicals they contain are implicated in cellular-based mechanisms to promote antioxidant defense and reduce inflammation. While recommendations encourage the intake of fruits and vegetables, most people fall short of their target daily intake. Despite the need to increase plant-food consumption, there have been some concerns raised about whether they are beneficial because of the various ‘anti-nutrient’ compounds they contain. Some of these anti-nutrients that have been called into question included lectins, oxalates, goitrogens, phytoestrogens, phytates, and tannins. As a result, there may be select individuals with specific health conditions who elect to decrease their plant food intake despite potential benefits. The purpose of this narrative review is to examine the science of these ‘anti-nutrients’ and weigh the evidence of whether these compounds pose an actual health threat.

Flavonoids and Related Members of the Aromatic Polyketide Group in Human Health and Disease: Do They Really Work?

Some aromatic polyketides such as dietary flavonoids have gained reputation as miraculous molecules with preeminent beneficial effects on human health, for example, as antioxidants. However, there is little conclusive evidence that dietary flavonoids provide significant leads for developing more effective drugs, as the majority appears to be of negligible medicinal importance. Some aromatic polyketides of limited distribution have shown more interesting medicinal properties and additional research should be focused on them. Combretastatins, analogues of phenoxodiol, hepatoactive kavalactones, and silymarin are showing a considerable promise in the advanced phases of clinical trials for the treatment of various pathologies. If their limitations such as adverse side effects, poor water solubility, and oral inactivity are successfully eliminated, they might be prime candidates for the development of more effective and in some case safer drugs. This review highlights some of the newer compounds, where they are in the new drug pipeline and how researchers are searching for additional likely candidates.

Isoflavone-enriched whole soy milk powder stimulates osteoblast differentiation

Functional foods with high nutritive values and potential therapeutic potential is a prerequisite for today's ailing world. Soybeans exert beneficial effects on human health. It contains plentiful polyunsaturated fatty acids and dietary fibers along with several isoflavonoids having bioactivity for improving health. Recent studies have shown that soybean isoflavones can have a positive effect on bone growth. The current study was designed to observe any impact of isoflavone-enriched soy milk powder (I-WSM) on inducing osteogenic properties at cellular and molecular levels. Precisely, we have evaluated the effect of I-WSM on the bone differentiation process. Our results show that I-WSM has the ability to stimulate osteogenic properties in osteoblasts both at the initial and terminal stages of differentiation. Treatment of I-WSM on osteoblasts demonstrates the inductive effect on the expression of osteogenic transcriptional factors like Runx2 and Osterix. Moreover, I-WSM increased the expression of the extracellular matrix protein osteocalcin, required for the formation of scaffold for bone mineralization. The estrogen signaling pathway was utilized by I-WSM to induce osteogenic activity. Taken together, here we report the cellular and molecular events mediated by I-WSM to exert an osteogenic effect in osteoblasts, which will help to understand its mechanism of action and project it as a remedy for the bone-related disease. Taken together, I-WSM has the ability to exert the osteogenic effect in osteoblasts via the estrogen signaling pathway and thus might be projected as a remedy for a bone-related disease like osteoporosis.

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 ARTICLES

This 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.

Ethanolic extract of dandelion (Taraxacum mongolicum) induces estrogenic activity in MCF-7 cells and immature rats

Plants of the genus Taraxacum, commonly known as dandelions, are used to treat breast cancer in traditional folk medicine. However, their use has mainly been based on empirical findings without sufficient scientific evidence. Therefore, we hypothesized that dandelions would behave as a Selective estrogen receptor modulator (SERM) and be effective as hormone replacement therapy (HRT) in the postmenopausal women. In the present study, in vitro assay systems, including cell proliferation assay, reporter gene assay, and RT-PCR to evaluate the mRNA expression of estrogen-related genes (pS2 and progesterone receptor, PR), were performed in human breast cancer cells. Dandelion ethanol extract (DEE) significantly increased cell proliferation and estrogen response element (ERE)-driven luciferase activity. DEE significantly induced the expression of estrogen related genes such as pS2 and PR, which was inhibited by tamoxifen at 1 μmol·L(-1). These results indicated that DEE could induce estrogenic activities mediated by a classical estrogen receptor pathway. In addition, immature rat uterotrophic assay was carried out to identify estrogenic activity of DEE in vivo. The lowest concentration of DEE slightly increased the uterine wet weight, but there was no significant effect with the highest concentration of DEE. The results demonstrate the potential estrogenic activities of DEE, providing scientific evidence supporting their use in traditional medicine.

Bioactivation of Phytoestrogens: Intestinal Bacteria and Health

Phytoestrogens are polyphenols similar to human estrogens found in plants or derived from plant precursors. Phytoestrogens are found in high concentration in soya, flaxseed and other seeds, fruits, vegetables, cereals, tea, chocolate, etc. They comprise several classes of chemical compounds (stilbenes, coumestans, isoflavones, ellagitannins, and lignans) which are structurally similar to endogenous estrogens but which can have both estrogenic and antiestrogenic effects. Although epidemiological and experimental evidence indicates that intake of phytoestrogens in foods may be protective against certain chronic diseases, discrepancies have been observed between in vivo and in vitro experiments. The microbial transformations have not been reported so far in stilbenes and coumestans. However, isoflavones, ellagitanins, and lignans are metabolized by intestinal bacteria to produce equol, urolithins, and enterolignans, respectively. Equol, urolithin, and enterolignans are more bioavailable, and have more estrogenic/antiestrogenic and antioxidant activity than their precursors. Moreover, equol, urolithins and enterolignans have anti-inflammatory effects and induce antiproliferative and apoptosis-inducing activities. The transformation of isoflavones, ellagitanins, and lignans by intestinal microbiota is essential to be protective against certain chronic diseases, as cancer, cardiovascular disease, osteoporosis, and menopausal symptoms. Bioavailability, bioactivity, and health effects of dietary phytoestrogens are strongly determined by the intestinal bacteria of each individual.

Isoflavone Content in Subterranean Clover Germplasm from Sardinia

Subterranean clover (Trifolium subterraneum) is an important pasture legume, and Sardinia is known as a major centre of diversification of this species. As other legumes, this clover produces biologically active flavonoids including the subclass of isoflavones that are natural phytoestrogens with positive health effects. Present sources of isoflavones for medical/nutraceutical treatments are red clover (Trifolium pratense) and soybean (Glycine max). This study assessed the content and composition of flavonoids in 14 subterranean clover genotypes from Sardinia, grown ex-situ in comparison with two red clover ecotypes, to acquire information on the potential of the species as an alternative source of isoflavones for possible exploitation. Twenty compounds were tentatively identified across the two clovers after HPLC and LC/ESI-MS analyses, including clovamide, four flavonols, and 15 isoflavones. Most compounds were present as glucosides or glucosyl malonates. Subterranean clover extracts mainly comprised of derivatives of the isoflavones genistein, biochanin A, and formononetin. Compared to red clover, subterranean clover had higher content of total isoflavones and lower concentration of total flavonols. The isoflavone concentration in subterranean clover was higher than literature data for soybean or red clover. The existing genotypic variation warrants the possibility of selecting varieties with high isoflavone concentration for nutraceutical or pharmaceutical purposes.

The impact of equol-producing status in modifying the effect of soya isoflavones on risk factors for CHD: a systematic review of randomised controlled trials

Recent studies suggest that the ability to produce equol, a metabolite of the soya isoflavone daidzein, is beneficial to coronary health. Equol, generated by bacterial action on isoflavones in the human gut, is biologically more potent than dietary sources of isoflavones. Not all humans are equol producers. We investigated whether equol-producing status is favourably associated with risk factors for CHD following an intervention by dietary soya isoflavones. We systematically reviewed randomised controlled trials (RCT) that evaluated the effect of soya isoflavones on risk factors for CHD and that reported equol-producing status. We searched PubMed, EMBASE, Ovid Medline and the Cochrane Central Register for Controlled Trials published up to April 2015 and hand-searched bibliographies to identify the RCT. Characteristics of participants and outcomes measurements were extracted and qualitatively analysed. From a total of 1671 studies, we identified forty-two articles that satisfied our search criteria. The effects of equol on risk factors for CHD were mainly based on secondary analyses in these studies, thus with inadequate statistical power. Although fourteen out of the forty-two studies found that equol production after a soya isoflavone intervention significantly improved a range of risk factors including cholesterol and other lipids, inflammation and blood pressure variables, these results need further verification by sufficiently powered studies. The other twenty-eight studies primarily reported null results. RCT of equol, which has recently become available as a dietary supplement, on CHD and its risk factors are awaited.

Low-dose isoflavone aglycone alleviates psychological symptoms of menopause in Japanese women: a randomized, double-blind, placebo-controlled study

Purpose

Many studies have demonstrated the effectiveness of isoflavones on menopausal symptoms; however, these mostly used high dosages. Because high-dose isoflavone may result in endometrial hyperplasia, we investigated whether low-dose isoflavone aglycone alleviates menopausal symptoms similarly to high dosages.

Methods

We conducted a randomized, double-blind, placebo-controlled study in 90 healthy women aged 40–60 years who had at least one menopausal symptom on the Menopausal Symptom Scale (MSS). The participants were randomized to receive active tablets containing ultralow-dose (12.5 mg/day; n = 30) or low-dose (25 mg/day; n = 30) isoflavone aglycone, or placebo (n = 30) tablets, for 8 weeks. Their menopausal symptoms were evaluated using MSS, Hospital Anxiety and Depression Scale (HADS), and Athens Insomnia Scale (AIS) before, and 4 and 8 weeks after treatment.

Results

Eighty-seven women (97 %) completed the 8-week treatment. In the low-dose group, significant improvement was observed from baseline, in the following parameters: (1) HADS-depression subscale score, (2) AIS score, (3) MSS-somatic symptom score after 4 and 8 weeks of treatment, and (4) MSS-vasomotor symptom score after 8 weeks of treatment. The changes in scores on HADS-depression subscale and AIS from baseline to 8 weeks were significantly higher in the low-dose group than in the placebo group.

Conclusions

Low-dose (25 mg/day) isoflavone aglycone significantly alleviated symptoms of depression and insomnia in Japanese middle-aged women.

Clinical Trial Registration UMIN-CTR UMIN000011876.

Clovamide and Flavonoids from Leaves of Trifolium pratense and T. pratense subsp. nivale Grown in Italy

The phenolic content and composition in leaves of Trifolium pratense (red clover) and T. pratense subsp. nivale (snow clover) grown in Italy were evaluated by means of ultraperformance liquid chromatography (UPLC) coupled with photodiode array and mass spectrometry detectors. Compound identification was based on UV and MS data comparing results with those of reference compounds. Quantitative evaluation of all detected compounds was based on calibration curves obtained with available standards. Several phenolics were identified in both extracts, including clovamide, flavonols and isoflavones as their glycosilated and malonated derivatives. The total phenolic content was higher in red clover (53.7 ± 2.2 mg/g dry weight) than in snow clover (44.4 ± 4.9 mg/g dry weight). Red clover contained higher amounts of clovamide and isoflavones (15.6 ± 0.6 and 24.6 ± 1.6 mg/g dry weight, respectively) than snow clover (8.2 ± 0.1 mg/g and 16.9 ± 0.4 mg/g dry weight, respectively), while flavonols were quantified almost in the same amount in both extracts (13.2 ± 0.6 mg/g and 15.8 ± 0.6 mg/g dry weight in red clover and snow clover, respectively). Red clover was characterized by the presence of quercetin, formononetin and biochanin A derivatives as the most abundant flavonoids, whereas snow clover was characterized by higher amounts of quercetin and prunetin derivatives. This investigation, conducted for the first time on phenolics from T. pratense subsp. nivale, revealed the presence in this plant of several flavonoid derivatives the same as in T. pratense. The higher amount of prunetin in snow clover suggest a possible role of this isoflavone as a chemotaxonomic marker for this subspecies. Moreover, snow clover may represent an interesting new source of natural isoflavones with a different concentration pattern than in red clover.

Is complementary and alternative therapy effective for women in the climacteric period?

Vasomotor symptoms start about 2 years prior to menopause in women who are approaching menopause, and early menopause symptoms appear including emotional disturbance and anxiety, followed by physical changes such as vaginal dryness, urinary incontinence and skin wrinkles. As time progresses, osteoporosis, cardiovascular diseases, and dementia occur consecutively. Hormone therapy is primarily considered for the relief of menopause symptoms in postmenopausal women. However, as hormone replacement has emerged as a therapy that increases the potential risk of thrombosis, cerebral infarction and breast cancer, complementary and alternative medicine has drawn much attention. This study aimed to examine the types and effects of evidence-based complementary and alternative therapies that are currently used.

Chinese herbal medicine for myelosuppression induced by chemotherapy or radiotherapy: a systematic review of randomized controlled trials

Background. Myelosuppression is one of the major side effects of chemo- and radiotherapy in cancer patients and there are no effective interventions to prevent it currently. Chinese herbal medicine (CHM) may be helpful due to its multidrug targets. Objectives. This study was designed to evaluate effectiveness of CHM on preventing patients from experiencing myelosuppression by chemo- or radiotherapy. Search Methods. Randomized controlled trials (RCTs) were retrieved from seven different databases from the date of database creation to April 2014. We assessed all included studies using Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 and performed statistical analysis using RevMan 5.2.1. Results. Eight RCTs were included (818 patients). Pooled data showed that increase of white blood cells (WBCs) is higher with CHM plus chemotherapy/radiotherapy than with chemotherapy/radiotherapy only. Both CHM compared to placebo and CHM combined with chemotherapy/radiotherapy compared to chemotherapy/radiotherapy lacked significant differences in the peripheral platelets, red blood cells (RBCs), and hemoglobin changes. Conclusions. Our results demonstrated that CHM significantly protected peripheral blood WBCs from a decrease caused by chemotherapy or radiotherapy. There were no significant protective effects on peripheral RBCs, hemoglobin, or platelets, which may be related to low quality and small sample of included studies.

A hypothesis regarding the molecular mechanism underlying dietary soy-induced effects on seizure propensity

Numerous neurological disorders including fragile X syndrome, Down syndrome, autism, and Alzheimer’s disease are co-morbid with epilepsy. We have observed elevated seizure propensity in mouse models of these disorders dependent on diet. Specifically, soy-based diets exacerbate audiogenic-induced seizures in juvenile mice. We have also found potential associations between the consumption of soy-based infant formula and seizure incidence, epilepsy comorbidity, and autism diagnostic scores in autistic children by retrospective analyses of medical record data. In total, these data suggest that consumption of high levels of soy protein during postnatal development may affect neuronal excitability. Herein, we present our theory regarding the molecular mechanism underlying soy-induced effects on seizure propensity. We hypothesize that soy phytoestrogens interfere with metabotropic glutamate receptor signaling through an estrogen receptor-dependent mechanism, which results in elevated production of key synaptic proteins and decreased seizure threshold.

Effects of different doses of soy isoflavones on bone tissue of ovariectomized rats

AIM

Studies report that hormone replacement prevents osteoporosis, but there are doubts whether isoflavones are really efficient in this process. The aim of this study was to evaluate the effects of different doses of soy isoflavones on bone tissue of ovariectomized rats.

METHODS

Forty female rats at the age of 6 months were ovariectomized and, after 3 months, the animals were divided into four groups: GI - Control (treated with drug vehicle); GII - treated with isoflavones (80 mg/kg per day); GIII - treated with isoflavones (200 mg/kg per day) and GIV - treated with isoflavones (350 mg/kg per day). Soy isoflavones were administered by gavage for 90 consecutive days. After treatment, the rats were euthanized and their distal femurs were removed for histological routine, histochemistry and biochemical study. Histological sections were stained with hematoxylin-eosin or subjected to picrosirius red and alcian blue methods. Shafts of femurs were submitted to biochemical assay and tibias were subjected to biophysical and biomechanical tests.

RESULTS

In distal femurs, the trabecular bone volume was higher in the groups treated with isoflavones, being higher in GIV, while the cortical bone width and the presence of mature type I collagen fibers were higher in GII. At the trabecular bone region, the percentage of total glycosaminoglycans (GAGs) was higher in GII and the percentage of only sulfated GAGs was higher in GIII, while the higher content of chondroitin sulfate in shafts of femurs was seen in GIV. Biophysical and biomechanical tests in tibias did not differ among the groups.

CONCLUSION

Our data indicate that soy isoflavones improve bone quality in femurs of rats by increasing histomorphometric parameters, the content of GAGs and mature type I collagen fibers. These positive effects are dose-dependent and it was different in cortical and trabecular bone.

Adding the phytoestrogen Cimicifugae Racemosae to clomiphene induction cycles with timed intercourse in polycystic ovary syndrome improves cycle outcomes and pregnancy rates - a randomized trial

BACKGROUND

Owing to their potential to act as estrogen receptor modulators and interfere with aromatase enzyme in animal studies, phytoestrogens (PE) may be useful as part of ovulation induction for polycystic ovary syndrome (PCOS).

PATIENTS AND METHODS

Patients <35 years, presenting with infertility and PCOS, were included and randomly allocated to either group I (clomiphene citrate; CC) or group II (CC plus Cimicifugae racemosae; CR). Primary outcome was pregnancy rate. Secondary outcomes included ovulation, midcycle serum estradiol and luteinizing hormone (LH) as well as mid-luteal serum progesterone.

RESULTS

Analysis included 98 patients in group I versus 96 patients in group II. Both groups were matched regarding demographics and basic data. Significant differences were elicited when comparing days until HCG injection (15.0 ± 1.7 versus 12.0 ± 1.9, p=0.91), endometrial thickness (mm) (8.5 ± 1.9 versus 12.5 ± 1.9, p<0.001), serum levels of mid-luteal and midcycle estradiol (p<0.001; Figure 2), LH (IU/ml) (p<0.001) as well as mid-luteal progesterone (p<0.001). PE plus CC group had significantly higher clinical pregnancies per cycle (33/192 (17.2%) versus 71/204 (34.8%), p<0.01), compared to the CC only group.

CONCLUSIONS

Adding CR to clomiphene-induction cycles with timed intercourse in polycystic ovarian syndrome improves cycle outcomes and pregnancy rates.

Phytoestrogens for menopausal bone loss and climacteric symptoms

Women have always looked for non-hormonal options to alleviate menopausal vasomotor symptoms and prevent menopausal bone loss. The use of complementary and alternative medicine for these purposes has particularly increased after the publication of the Women's Health Initiative's results suggesting that there might be more risks than benefits with hormone replacement. Phytoestrogens are plant-derived estrogens that, although less potent than estradiol, bind to the estrogen receptor and can function as estrogen agonists or antagonists. Soy isoflavones extracted from soy are the phytoestrogens most commonly used by menopausal women. Because typical Western diets are low in phytoestrogens and taking into account the general difficulty in changing dietary habits, most clinical trials in Western women have used isoflavone-fortified foods or isoflavone tablets. Although some women might experience a reduction in the frequency or severity of hot flashes, most studies point towards the lack of effectiveness of isoflavones derived from soy or red clover, even in large doses, in the prevention of hot flashes and menopausal bone loss. This article is part of a Special Issue entitled 'Phytoestrogens'.

Soy foods: are they useful for optimal bone health?

Numerous studies have investigated the relationship between soy foods, soy protein, or isoflavone extracts and markers of bone health and osteoporosis prevention, and have come to conflicting conclusions. Research on dietary patterns, rather than on specific food ingredients or individual foods, may offer an opportunity for better understanding the role of soy foods in bone health. Evidence is reviewed regarding the question of whether soy foods contribute to a dietary pattern in humans that supports and promotes bone health. Soy foods are associated with improved markers of bone health and improved outcomes, especially among Asian women. Although the optimal amounts and types of soy foods needed to support bone health are not yet clear, dietary pattern evidence suggests that regular consumption of soy foods is likely to be useful for optimal bone health as an integral part of a dietary pattern that is built largely from whole plant foods.

Phytoestrogens for menopausal symptoms: a review

OBJECTIVE

To review the evidence that isoflavones are effective treatments for menopausal symptoms and to present the safety data.

METHODS

The databases Scopus, ScienceDirect and Primo Central Index were searched and preference was given to systematic reviews and meta-analyses.

RESULTS

The available evidence suggests that isoflavones do not relieve menopausal vasomotor symptoms any better than placebo. Long-term safety studies suggest that women who consume a diet high in isoflavones may have a lower risk of endometrial and ovarian cancer.

CONCLUSIONS

Isoflavones cannot be recommended for the relief of hot flushes.

Emerging evidence of the health benefits of S-equol, an estrogen receptor β agonist

Many clinical studies have been carried out to determine the health benefits of soy protein and the isoflavones contained in soy. S-equol is not present in soybeans but is produced naturally in the gut of certain individuals, particularly Asians, by the bacterial biotransformation of daidzein, a soy isoflavone. In those intervention studies in which plasma S-equol levels were determined, a concentration of >5-10 ng/mL has been associated with a positive outcome for vasomotor symptoms, osteoporosis (as measured by an increase in bone mineral density), prostate cancer, and the cardiovascular risk biomarkers low-density lipoprotein cholesterol and C-reactive protein. These studies suggest that S-equol may provide therapeutic benefits for a number of medical needs.

Soy protein diet and exercise training increase relative bone volume and enhance bone microarchitecture in a mouse model of uremia

Soy protein consumption and exercise training have been widely studied for their effects on the vasculature and bone in healthy populations, but little is known about the effectiveness of these interventions in chronic kidney disease (CKD). Cardiovascular disease and bone fracture risk are significantly elevated in CKD, and current pharmacological interventions have been unsuccessful in treating these conditions simultaneously. The purpose of this study was to compare the effects of a soy protein diet and endurance exercise training, alone or in combination, on cardiovascular and bone health in a mouse model of renal insufficiency. At 8 weeks of age, 60 female apolipoprotein E(-/-) mice underwent a two-step surgical procedure to induce uremia. These mice were then randomized at 12 weeks of age to one of four treatment groups for the 16-week intervention period: sedentary, control diet (n = 16); sedentary, soy protein diet (n = 18); exercise, control diet (n = 14); and exercise, soy protein diet (n = 12). There were no significant treatment effects on atherosclerotic lesion areas or aortic calcium deposits. We demonstrated a significant main effect of both diet and exercise on relative bone volume, trabecular number, trabecular separation, and trabecular connective density in the proximal femur as measured by microcomputed tomography. There were no treatment effects on trabecular thickness. We also showed a main effect of diet on plasma urea levels. These data suggest that soy protein intake and exercise training exert beneficial effects on properties of bone and plasma urea levels in mice with surgically induced renal impairment.

Effect of Red Clover Isoflavones over Skin, Appendages, and Mucosal Status in Postmenopausal Women

Objective. Evaluate in postmenopausal women the effect of red clover extract (RCE) isoflavones over subjective status of skin, appendages, and several mucosal sites. Method. Postmenopausal women (n = 109) were randomly assigned to receive either two daily capsules of the active compound (80 mg RCE, Group A) or placebo of equal appearance (Group B) for a 90-day period. After a washout period of 7 days, medication was crossed over and taken for 90 days more. Subjective improvement of skin, appendages, and several mucosal site status was assessed for each studied group at 90 and 187 days using a visual analogue scale (VAS). In addition, libido, tiredness, and urinary, sleep, and mood complaints were also evaluated. Results. Women after RCE intervention (both groups) reported better subjective improvement of scalp hair and skin status, libido, mood, sleep, and tiredness. Improvement of urinary complaints, nail, body hair, and mucosa (oral, nasal, and ocular) status did not differ between treatment phases (intra- and intergroup). Overall satisfaction with treatment was reported higher after RCE intervention (both groups) as compared to placebo. Conclusion. RCE supplementation exerted a subject improvement of scalp hair and skin status as well as libido, mood, sleep, and tiredness in postmenopausal women.

Down regulation of gene related sex hormone synthesis pathway in mouse testes by miroestrol and deoxymiroestrol

Miroestrol and deoxymiroestrol are phytoestrogens isolated from tuberous root of Pueraria candollei var. mirifica. Modulatory effects of miroestrol and deoxymiroestrol on enzymes involved in sex-hormone synthesis pathway in male C57BL/6 mice were investigated using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Miroestrol and deoxymiroestrol suppressed the expressions of 3β-HSD, 17β-HSD1, and CYP17 while CYP19 mRNA expression was slightly decreased. In addition, the expression of 17β-HSD2 was induced in correlation with those did by estradiol. These observations supported that miroestrol and deoxymiroestrol could exhibit the same effect as estradiol regarding regulation of testicular gene related sex hormone synthesis pathway.

Soy isoflavones, diet and physical exercise modify serum cytokines in healthy obese postmenopausal women

OBJECTIVES

Evaluate the effect of diet, physical exercise, and a daily oral intake of a soy isoflavones extract (Fisiogen(®)) contained 200 mg of Glycine max, which corresponded to 80 mg of isoflavone (60.8 mg of genistein, 16 mg of daidzein and 3.2 mg of glicitein) on leptin and other adipokines plasma levels in healthy obese postmenopausal women.

METHODS

A multicentric randomized longitudinal prospective cohort study was conducted in a sample of 87 healthy obese postmenopausal women. Patients were randomly assigned to a 1200 kcal diet and exercise group (control group) or a group of 1200 kcal diet, exercise, and daily oral intake of daily oral intake of a soy isoflavones extract (Fisiogen(®)) contained 200 mg of Glycine max, which corresponded to 80 mg of isoflavone (60.8 mg of genistein, 16 mg of daidzein and 3.2 mg of glicitein) (soy isoflavones group) along 6 months. Main outcome measures were: anthropometric measures, body composition, leptin, adiponectin, TNF-alpha, homocysteine, C-reactive protein, glucose, insulin, lipid profile and oestradiol serum levels, Kupperman index and Cervantes Scale.

RESULTS

Mean serum leptin and TNF-alpha levels declined after 6 months in both groups of the study, but only women in the soy isoflavones group showed a significant increase of mean serum levels of adiponectin.

CONCLUSIONS

Diet, physical exercise and daily oral intake of a soy isoflavones extract (Fisiogen(®)) contained 200 mg of Glycine max, which corresponded to 80 mg of isoflavone (60.8 mg of genistein, 16 mg of daidzein and 3.2 mg of glicitein) have a beneficial effect on serum leptin, adiponectin and TNF-α in healthy obese postmenopausal women after 6 months of treatment.

Safety of herbal medicinal products in women with breast cancer

OBJECTIVE

To review and summarise current evidence on the efficacy and safety of herbal medicinal products for the relief of hot flushes in women with previous breast cancer.

METHODS

A literature search was conducted in the databases of Medline, EMBASE, The Cochrane Central Register of Controlled Trials (CENTRAL), PSYCHINFO, AMED (Allied and Complementary Medicine), NCCAM (The National Centre for Complementary and Alternative Medicine).

RESULTS

Black cohosh and phytoestrogens have received the most research attention but there is currently insufficient evidence to recommend either for relief of flushes. Black cohosh use appears safe in women with previous breast cancer. Opposing advice has been given regarding the safety of dietary phytoestrogen use for women with previous breast cancer, but there is emerging data that soyfood phytoestrogen intake may have a beneficial effect on tumour recurrence.

CONCLUSIONS

The majority of studies, regarding the efficacy of herbal treatments for hot flushes, have not been conducted in women with breast cancer and many are of short duration. Increased pharmacovigilance practices for herbal medicines are required with initiatives to stimulate reporting of suspected adverse reactions.

A randomized, double-blind, placebo-controlled, cross-over pilot study on the use of a standardized hop extract to alleviate menopausal discomforts

OBJECTIVES

To examine the efficacy of a hop extract (standardized at 100mug 8-prenylnaringenin per day) for relief of menopausal discomforts.

METHODS

A 16-week randomized, double-blind, placebo-controlled, cross-over study was conducted with 36 menopausal women. The participants were randomly allocated to either placebo or active treatment (hop extract) for a period of eight weeks after which treatments were switched for another eight weeks. The Kupperman Index (KI), the Menopause Rating Scale (MRS) and a multifactorial Visual Analogue Scale (VAS) were assessed at baseline, and after eight and sixteen weeks.

RESULTS

After 8 weeks, both active treatment and placebo significantly improved all outcome measures when compared to baseline with somewhat higher average reductions for placebo than for the active treatment. After 16 weeks only the active treatment after placebo further reduced all outcome measures, whereas placebo after active treatment resulted in an increase for all outcome measures. Although, the overall estimates of treatment efficacy (active treatment-placebo) based on linear mixed models do not show a significant effect, time-specific estimates of treatment efficacy indicate significant reductions for KI (P = 0.02) and VAS (P = 0.03) and a marginally significant reduction (P = 0.06) for MRS after 16 weeks.

CONCLUSIONS

Whereas the first treatment period resulted in similar reductions in menopausal discomforts in both treatment groups, results from the second treatment period suggest superiority of the standardized hop extract over placebo. Thus, phytoestrogen preparations containing this standardized hop extract may provide an interesting alternative to women seeking relief of mild vasomotor symptoms.

Phytoestrogens and post reproductive health

The use of phytoestrogens for various perceived health benefits is widespread. Despite 20 years of research the evidence for any significant health benefits remains inconclusive. Pre clinical trials have demonstrated both non-genomic and genomic actions of constituents of phytoestrogens including selective, but weak, binding to estrogen receptors, with a preference for ER B over ER A. Evidence of clinically relevant biological effects from observational studies and randomized trials has, in general, been lacking. Despite many trials there remains little evidence that phytoestrogens, whether dietary or supplemented, significantly relieve menopausal vasomotor symptoms or cognition. Several potential mechanisms for a positive effect on bone and cardiovascular health have been demonstrated however no fracture prevention data or cardiovascular end point benefit has yet been demonstrated. In vitro effects of phytoestrogens on breast cells have been both stimulatory and inhibitory however net effects appear neutral with observational studies finding no change in breast cancer risk. No effect has been seen on endometrial or other cancers and side effect profiles have, in general, been mild.

Soy isoflavones, Mediterranean diet, and physical exercise in postmenopausal women with insulin resistance

OBJECTIVE

The aim of this study was to evaluate whether a standard dose of 40 mg of soy isoflavones prescribed in routine clinical practice for treatment of menopausal symptoms has some influence on glucose homeostasis in postmenopausal women with insulin resistance (IR).

METHODS

A total of 116 postmenopausal women with IR were randomly assigned to a group of Mediterranean diet and physical exercise (control group) or a group of Mediterranean diet, physical exercise, and daily oral ingestion of 40 mg of soy isoflavones (soy isoflavones group). Anthropometric measures, Kupperman Index values, Cervantes Scale score, and blood samples for glucose, insulin, lipid profile, creatinine, uric acid, homocysteine, folic acid, vitamin B12, selenium, and estradiol were determined at baseline and at intervals of 6, 12, 18, and 24 months.

RESULTS

Mean homeostasis model assessment of IR (HOMA-IR) values remained unchanged from the baseline in the control group but steadily decreased in the soy isoflavones group at 6 months (P = 0.042). There were no statistically significant differences between both groups in mean HOMA-IR scores at baseline, but statistically significantly lower values were found in the soy isoflavones group at 6 months (P = 0.009), 12 months (P = 0.011), 18 months (P = 0.018), and 24 months (P = 0.012). Changes in HOMA-IR values were also clearly related to body mass index (P < 0.001), abdominal circumference (P < 0.001), and treatment (P = 0.044) when a linear regression analysis was carried out.

CONCLUSIONS

Daily intake of 40 mg of soy isoflavones together with a Mediterranean diet and exercise reduced IR in postmenopausal women who had IR in the first place. It was significantly better than lifestyle changes alone. If corroborated, this may be a useful intervention for these women.

Effect of St John's wort on severity, frequency, and duration of hot flashes in premenopausal, perimenopausal and postmenopausal women: a randomized, double-blind, placebo-controlled study

OBJECTIVE

Because of a decline in estradiol levels, premenopausal, perimenopausal, and postmenopausal women experience symptoms related to vasomotor instability. Certain plants have been found to have molecular components that are identical in structure and function to human hormones. We conducted this study to compare the efficacy of St John's wort with that of placebo in women with hot flashes.

METHODS

A total of 100 women participated in a clinical trial conducted in an academic medical center in Shiraz-Iran. Women were treated with St John's wort extract or placebo for 8 weeks. Climacteric complaints were evaluated by using the Blatt-Kupperman Index at two follow-up visits. Statistical analysis was carried out by using descriptive statistics and multivariate analysis.

RESULTS

The mean age of the participants was 50.4 years. Both groups responded to the interventions, and the within-group differences in frequency, duration, and severity of hot flashes were statistically significant (P < 0.05). The difference in duration of hot flashes between groups was not significant on the 4th week of intervention (P = 0.27); however, it was statistically significant between the two groups on the 8th week of treatment (P < 0.001). The fall-off in frequency of hot flashes on the 4th and 8th weeks of intervention was more evident in women receiving St John's wort, and the differences between groups were statistically significant (P = 0.005 and P < 0.001, respectively). Furthermore, comparing both study groups, we showed that the decrease in the severity of flashes in women who received St John's wort was more evident on the 4th and 8th weeks (P = 0.004 and P < 0.001, respectively).

CONCLUSIONS

St John's wort can be used as an effective treatment for the vasomotor symptoms of perimenopausal or postmenopausal women.

Estrogenic activity of xanthorrhizol isolated from curcuma xanthorrhiza ROXB

Plant-derived estrogen-like compounds, or phytoestrogens, are given much attention due to their potential therapeutic use. In this study, xanthorrhizol, a natural sesquiterpenoid isolated from the rhizome of Curcuma xanthorrhiza ROXB. (Zingiberaceae), was evaluated for its estrogenic activity. It has been known that compounds acting as ligands for estrogen receptors (ERs) are considered to possess estrogenic activity. Therefore, the Gal-4/ER transactivation assay in transiently transfected African green monkey kidney (COS-7) cells was used to examine the estrogenic activity of xanthorrhizol. Both subtypes of ERs, ERalpha and ERbeta, were involved in this assay. Further transactivation assays and pS2 mRNA analysis were also conducted in estrogen receptor-positive human breast cancer (MCF-7). Our results showed that xanthorrhizol significantly increased Gal-4/ER luciferase activity in a dose-dependent manner and induced the endogenous ER-estrogen response element (ERE) interaction in MCF-7 cells. Xanthorrhizol also significantly enhanced the expression of the pS2 gene in MCF-7 cells. In contrast, treatment using ICI 182780, an ER antagonist, suppressed all activities induced by xanthorrhizol, indicating ER-dependant activities were involved. These results suggest that xanthorrhizol possesses estrogenic activity and its estrogenic effects are mediated by estrogen-induced gene expression.

Inhibition of angiogenesis and inflammation by an extract of red clover (Trifolium pratense L.)

Antiangiogenic compounds are gaining more and more interest as a new approach in the prevention and treatment of cancer and inflammatory diseases. The objective of this study was the evaluation of the antiangiogenic effect of a red clover extract (RCE) used in food supplements for menopausal complaints as well as of its main isoflavones in an in vivo system, the chorioallantoic membrane assay of fertilized hen's eggs. At a dosage of 250 microg/pellet the red clover extract showed excellent inhibition of angiogenesis. The antiangiogenic activity of the non-methylated isoflavones daidzein and genistein was higher than that of the methylated compounds formononentin and biochanin A. The results demonstrate that RCE is not only suitable for menopausal complaints, but might also be a powerful chemopreventive agent against chronic diseases e.g. which have a high incidence especially in elderly female.