Phyto-oestrogens, their mechanism of action: current evidence for a role in breast and prostate cancer

Natural Compounds Derived from Plants on Prevention and Treatment of Renal Cell Carcinoma: A Literature Review

Renal cell carcinoma (RCC) accounts for roughly 85% of all malignant kidney cancer. Therapeutic options for RCC have expanded rapidly over the past decade. Targeted therapy and immunotherapy have ushered in a new era of the treatment of RCC, which has facilitated the outcomes of RCC. However, the related adverse effects and drug resistance remain an urgent issue. Natural compounds are optional strategies to reduce mobility. Natural compounds are favored by clinicians and researchers due to their good tolerance and low economic burden. Many studies have explored the anti-RCC activity of natural products and revealed relevant mechanisms. In this article, the chemoprevention and therapeutic potential of natural compounds is reviewed and the mechanisms regarding natural compounds are explored.

Metabolite interactions between host and microbiota during health and disease: Which feeds the other?

Metabolites produced by the host and microbiota play a crucial role in how human bodies develop and remain healthy. Most of these metabolites are produced by microbiota and hosts in the digestive tract. Metabolites in the gut have important roles in energy metabolism, cellular communication, and host immunity, among other physiological activities. Although numerous host metabolites, such as free fatty acids, amino acids, and vitamins, are found in the intestine, metabolites generated by gut microbiota are equally vital for intestinal homeostasis. Furthermore, microbiota in the gut is the sole source of some metabolites, including short-chain fatty acids (SCFAs). Metabolites produced by microbiota, such as neurotransmitters and hormones, may modulate and significantly affect host metabolism. The gut microbiota is becoming recognized as a second endocrine system. A variety of chronic inflammatory disorders have been linked to aberrant host-microbiota interplays, but the precise mechanisms underpinning these disturbances and how they might lead to diseases remain to be fully elucidated. Microbiome-modulated metabolites are promising targets for new drug discovery due to their endocrine function in various complex disorders. In humans, metabolotherapy for the prevention or treatment of various disorders will be possible if we better understand the metabolic preferences of bacteria and the host in specific tissues and organs. Better disease treatments may be possible with the help of novel complementary therapies that target host or bacterial metabolism. The metabolites, their physiological consequences, and functional mechanisms of the host-microbiota interplays will be highlighted, summarized, and discussed in this overview.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

Exploring the recent trends in perturbing the cellular signaling pathways in cancer by natural products

Cancer is commonly thought to be the product of irregular cell division. According to the World Health Organization (WHO), cancer is the major cause of death globally. Nature offers an abundant supply of bioactive compounds with high therapeutic efficacy. Anticancer effects have been studied in a variety of phytochemicals found in nature. When Food and Drug Administration (FDA)-approved anticancer drugs are combined with natural compounds, the effectiveness improves. Several agents have already progressed to clinical trials based on these promising results of natural compounds against various cancer forms. Natural compounds prevent cancer cell proliferation, development, and metastasis by inducing cell cycle arrest, activating intrinsic and extrinsic apoptosis pathways, generating reactive oxygen species (ROS), and down-regulating activated signaling pathways. These natural chemicals are known to affect numerous important cellular signaling pathways, such as NF-B, MAPK, Wnt, Notch, Akt, p53, AR, ER, and many others, to cause cell death signals and induce apoptosis in pre-cancerous or cancer cells without harming normal cells. As a result, non-toxic “natural drugs” taken from nature’s bounty could be effective for the prevention of tumor progression and/or therapy of human malignancies, either alone or in combination with conventional treatments. Natural compounds have also been shown in preclinical studies to improve the sensitivity of resistant cancers to currently available chemotherapy agents. To summarize, preclinical and clinical findings against cancer indicate that natural-sourced compounds have promising anticancer efficacy. The vital purpose of these studies is to target cellular signaling pathways in cancer by natural compounds.

Intake of isoflavones reduces the risk of all-cause mortality in middle-aged Japanese

BACKGROUND/OBJECTIVES

To clarify the effects of intake of legumes and isoflavones on all-cause mortality in middle-aged and older Japanese.

SUBJECT/METHODS

The subjects were 2136 randomly chosen community-dwelling Japanese men and women aged 40-79 years who participated in a first-wave survey (1997-2000; baseline). The subjects were followed from baseline to December 31, 2017 (mean period of 16.6 ± 4.2 years). Intake of legumes, soybeans, and isoflavones at baseline was assessed using a 3-day dietary record with photographs. The relationships of intake amounts of legumes and isoflavones to mortality were assessed using Cox proportional hazards regression controlling for age, sex, education, employment, body mass index, smoking habits, medical histories, drinking, and energy intake.

RESULTS

There were 491 deaths during the follow-up period. We found inverse associations of the intake of total soy products and intake of each of the isoflavones with all-cause mortality (p for trend < 0.05) in subjects aged < 60 years: the multivariate-adjusted hazard ratios (95% confidence intervals) for all-cause mortality in the highest intake group (third tertile) of total soy products and total isoflavones were 0.32 (0.13-0.78) and 0.35 (0.17-0.73), respectively, compared with the reference group (first tertile). In contrast, there were no significant associations of intake amounts of legumes, soybeans, and isoflavones with all-cause mortality in subjects aged 60 years or older.

CONCLUSIONS

The findings suggest that a higher intake of isoflavones might decrease the risk of all-cause mortality, especially in middle-aged Japanese.

Serum isoflavones and lignans and odds of breast cancer in pre- and postmenopausal Chinese women

OBJECTIVE

Isoflavones and lignans are phytoestrogens present in plant-based foods, which have a potential preventive effect on breast carcinogenesis. The effects of phytoestrogens on breast cancer may differ according to the hormonal environment. This case-control study aimed to investigate the association between serum phytoestrogens and odds of breast cancer among Chinese pre- and postmenopausal women.

METHODS

A total of 792 cases and 813 age-matched controls were included. Serum isoflavone (daidzein, genistein, glycitein, equol, and formononetin) and lignan (enterodiol and enterolactone) concentrations were measured using a liquid chromatography-tandem mass spectrometry method.

RESULTS

Significant inverse associations were found between serum total soy isoflavone precursors, daidzein, genistein, formononetin, total lignans, enterodiol, enterolactone, and the odds of breast cancer in premenopausal but not postmenopausal women. For premenopausal women, the adjusted odds ratios (95% confidence intervals) for the highest versus the lowest serum concentration groups were 0.60 (0.41-0.87) for total soy isoflavones precursors, 0.64 (0.44-0.93) for daidzein, 0.62 (0.43-0.90) for genistein, 0.49 (0.35-0.68) for formononetin, 0.38 (0.25-0.57) for total lignans, 0.49 (0.33-0.73) for enterodiol, and 0.49 (0.33-0.74) for enterolactone. However, the interaction between serum phytoestrogens and menopausal status on odds of breast cancer was statistically significant only for daidzein. No significant association was found between serum equol or gycitein and the odds of breast cancer among either pre- or postmenopausal women.

CONCLUSIONS

Higher levels of certain serum isoflavones and lignans were associated with reduced odds of breast cancer in premenopausal women, but the interaction was statistically significant only for daidzein.

A practical nutritional guide for the management of sleep disturbances in menopause

Sleep disturbances (SD) represent one of the main symptoms of menopause and they are caused by several factors. Hormonal changes such as the reduction of oestrogen levels and the consequent vasomotor symptoms (VMS) along with psychiatric disorders such as depression and anxiety could contribute to the onset of SD. Furthermore, obesity per sè or through the obstructive sleep apnoea (OSA) could blunt sleep. Moreover, in menopause is usual a reduction in melatonin, that could contribute to SD. Nutritional strategies are paramount because they could contribute to manage menopause-related SD, in particular tackling obesity and overweight. Furthermore, some foods, such as soy, fish, whole grains, vegetables and fruit could decrease symptoms like depression and VMS, correlated with SD in postmenopausal women. Therefore, the aim of this review is to provide an overview of the current evidence on SD in menopause and to provide nutritional strategies for managing SD in this context.

Effects of Soy Foods in Postmenopausal Women: A Focus on Osteosarcopenia and Obesity

Chronic diseases in postmenopausal women are caused by rapid changes in hormones and are accompanied by rapid changes in body composition (muscle, bone, and fat). In an aging society, the health of postmenopausal women is a social issue, and people’s interest in ingesting high-quality protein is increasing in order to maintain a healthy body composition. This review aims to summarize the efficacy of soy foods and their impact on body composition. The soy protein and isoflavones contained in soy foods can improve muscle and bone density quality and reduce body weight. It is considered a breakthrough in preventing osteosarcopenia and obesity that may occur after menopause.

Habitual dietary intake of flavonoids and all-cause and cause-specific mortality: Golestan cohort study

BACKGROUND AND OBJECTIVES

Flavonoids are the most important group of polyphenols with well-known beneficial effects on health. However; the association of intake of total flavonoid or their subclasses with all-cause or cause-specific mortality is not fully understood. The present study aims to evaluate the association between intake of total flavonoid, flavonoid subclasses, and total and cause-specific mortality in a developing country.

METHODS

A total number of 49,173 participants from the Golestan cohort study, who completed a validated food frequency questionnaire at recruitment, were followed from 2004 till 2018. Phenol-Explorer database was applied to estimate dietary intakes of total flavonoid and different flavonoid subclasses. Associations were examined using adjusted Cox proportional hazards models.

RESULTS

During a mean follow-up of 10.63 years, 5104 deaths were reported. After adjusting for several potential confounders, the hazard ratios (HRs) of all-cause mortality for the highest versus the lowest quintile of dietary flavanones, flavones, isoflavonoids, and dihydrochalcones were 0.81 (95% confidence interval = 0.73-0.89), 0.83(0.76-0.92), 0.88(0.80-0.96) and 0.83(0.77-0.90), respectively. However, there was no association between total flavonoid intake or other flavonoid subclasses with all-cause mortality. In cause-specific mortality analyses, flavanones and flavones intakes were inversely associated with CVD mortality [HRs: 0.86(0.73-1.00) and 0.85(0.72-1.00)] and isoflavonoids and dihydrochalcones were the only flavonoid subclasses that showed a protective association against cancer mortality [HR: 0.82(0.68-0.98)].

CONCLUSION

The results of our study suggest that certain subclasses of flavonoids can reduce all-cause mortality and mortality rate from CVD and cancer.

The Connection between Urinary Equol Levels and the Prevalence of Atopic Dermatitis

BACKGROUND

Soy isoflavones and their metabolites such as equol have been associated with a reduced risk of hormone-sensitive tumors and metabolic syndromes. However, individual soy isoflavones and equol levels in atopic dermatitis remain uninvestigated.

OBJECTIVE

The aim of this study is to compare the levels of urinary daidzein, genistein, and equol between atopic dermatitis patients and normal subjects and to examine the correlation between equol concentration and the severity of clinical symptoms.

METHODS

A cross-sectional study was conducted at Akita University Hospital and Aso Iizuka Hospital in Japan. Fifty patients with confirmed atopic dermatitis diagnosis and 67 healthy controls were recruited. Daidzein, genistein, and equol in urine were measured by using a high-performance liquid chromatography-mass spectrometry system.

RESULTS

Urinary equol levels were significantly lower in the atopic dermatitis patients than in the healthy controls (p = 0.002). The difference was particularly noticeable in young people (6-19 years, p < 0.001). No correlations were found between urinary equol levels and the severity of clinical symptoms and laboratory data in the atopic dermatitis patients.

CONCLUSION

Equol levels in childhood might be involved in the development of atopic dermatitis.

Type 5 17-hydroxysteroid dehydrogenase/prostaglandin F synthase (AKR1C3) inhibition and potential anti-proliferative activity of cholest-4-ene-3,6-dione in MCF-7 breast cancer cells

Cholest-4-ene-3,6-dione (KS) is a cholesterol oxidation product which exhibits anti-proliferative activity. However, its precise mechanism of action remains unknown. In this study, the effects of KS on AKR1C3 inhibition and anti-proliferative activities were investigated in the hormone-dependent MCF-7 breast cancer cells. We identified that KS arrested the enzymatic conversion of estrone to 17-β estradiol, by inhibiting AKR1C3 in intact MCF-7 cells. The anti-proliferative effects of KS were evaluated by MTT assay, acridine orange and ethidium bromide dual staining, cell cycle analysis and Western blotting. KS arrested the cell cycle progression in the G1 phase with a concomitant increase of the Sub-G0 population to increase in concentration and time. It also enhanced the p53 and NFkB expression and induced caspase-12, 9 and 3 processing and down-regulated the Bcl-2 expression. Molecular docking studies performed to understand the inhibition mechanism of KS on AKR1C3 revealed that KS occupied the binding region of AKR1C3 with almost similar orientation as indomethacin (IM), thereby acting as an antagonistic agent for AKR1C3. Based on the results it is identified that KS induces inhibition of AKR1C3 and cell death in MCF-7 cells. These results indicate that KS can be used as a molecular scaffold for further development of novel small-molecules with better specificity towards AKR1C3.

Non-'classical' MEKs: A review of MEK3-7 inhibitors

The MAPK pathways are an enduring area of interest due to their essential roles in cell processes. Increased expression and activity can lead to a multitude of diseases, sparking research efforts in developing inhibitors against these kinases. Though great strides have been made in developing MEK1/2 inhibitors, there is a notable lack of chemical probes for MEK3-7, given their central role in stimuli response, cell growth, and development. This review summarizes the progress that has been made on developing small molecule probes for MEK3-7, the specific disease states in which they have been studied, and their potential to become novel therapeutics.

Targeting Abdominal Obesity and Its Complications with Dietary Phytoestrogens

In the assessment of the health risk of an obese individual, both the amount of adipose tissue and its distribution and metabolic activity are essential. In adults, the distribution of adipose tissue differs in a gender-dependent manner and is regulated by sex steroids, especially estrogens. Estrogens affect adipocyte differentiation but are also involved in the regulation of the lipid metabolism, insulin resistance, and inflammatory activity of the adipose tissue. Their deficiency results in unfavorable changes in body composition and increases the risk of metabolic complications, which can be partially reversed by hormone replacement therapy. Therefore, the idea of the supplementation of estrogen-like compounds to counteract obesity and related complications is compelling. Phytoestrogens are natural plant-derived dietary compounds that resemble human estrogens in their chemical structure and biological activity. Supplementation with phytoestrogens may confer a range of beneficial effects. However, results of studies on the influence of phytoestrogens on body composition and prevalence of obesity are inconsistent. In this review, we present data from in vitro, animal, and human studies regarding the role of phytoestrogens in adipose tissue development and function in the context of their potential application in the prevention of visceral obesity and related complications.

Isolation and identification of an isoflavone reducing bacterium from feces from a pregnant horse

The aim of this research was to isolate bacteria capable of biotransforming daidzein from fresh feces from pregnant horses. A Hungate anaerobic roller tube was used for anaerobic culture. Single colonies were picked at random and incubated with daidzein. High performance liquid chromatography was used to detect whether the isolated bacteria were able to biotransform the substrate. A strain capable of reducing daidzein was selected and characterized using sequence analysis of 16S rDNA, and a phylogenetic tree was constructed. The morphological physiological and biochemical characteristics of the strain were investigated. A facultative anaerobic, Gram-positive bacterium capable of converting daidzein to dihydrodaidzein was isolated and named HXBM408 (MF992210). A BLAST search of HXBM408's 16S rDNA sequence against the GenBank database suggested that the strain has 99% similarity with Pediococcus acidilactici strain DSM (NR042057). The morphological, physiological, and biochemical characteristics of HXBM408 are very similar to those of Pediococcus. Based on these characteristics, the strain was identified as Pediococcus acidilactici. The bacterial strain HXBM408 isolated from the feces of pregnant horses was able to reduce the isoflavone daidzein to dihydrodaidzein.

The Effects of the Dietary and Nutrient Intake on Gynecologic Cancers

The contribution of diet to cancer risk has been considered to be higher in advanced countries than in developing countries. In this paper, I review the current issues (a review of the relevant literature), and the effects of the dietary and nutrient intake on three types of gynecologic cancer (cervical, endometrial and ovarian cancers). In cervical cancer, the most important roles of diet/nutrition in relation to cancer are prophylaxis and countermeasures against human papillomavirus (HPV) infection. The main preventive and reductive factors of cervical cancer are antioxidants, such as vitamin A, C, D and E, carotenoids, vegetables and fruits. These antioxidants may have different abilities to intervene in the natural history of diseases associated with HPV infection. For endometrial cancer, the increase in peripheral estrogens as a result of the aromatization of androgens to estrogens in adipose tissue in obese women and insulin resistance are risk factors. Thus, we must mainly take care to avoid the continuous intake of fat energy and sugar. In ovarian cancer, the etiology has not been fully understood. To the best of our knowledge, the long-term consumption of pro-inflammatory foods, including saturated fat, carbohydrates and animal proteins is a risk factor. The intake of acrylamide is also a risk factor for both endometrial and ovarian cancer. Most papers have been epidemiological studies. Thus, further research using in vitro and in vivo approaches is needed to clarify the effects of the dietary and nutrient intake in detail.

A variable loop involved in the substrate selectivity of pinoresinol/lariciresinol reductase from Camellia sinensis

Pinoresinol/lariciresinol reductase (PLR), an NADPH-dependent reductase that catalyzes the sequential reduction of pinoresinol into secoisolariciresinol via Lariciresinol, can lead to the structural and stereochemical diversity of lignans. The relationship between substrate-selective reaction of PLR and sequence homology still remains unclear. In this study, we focused on the contribution of the variable region between PLRs in determining substrate selectivity. Here, two CsPLRs (CsPLR1 and CsPLR2) were identified in the tea plant (Camellia sinensis var. sinensis cv. Shuchazao). In vitro enzymatic assays showed that CsPLR1 could convert (+)- and (-)-pinoresinol into lariciresinol or secoisolariciresinol, whereas CsPLR2 catalyzed (+)-pinoresinol enantioselectively into (-)-secoisolariciresinol. Homology modeling and site-directed mutagenesis were used to examine the role of a variable loop in catalysis and substrate selectivity. The L174I mutant in CsPLR1 lost the capacity to reduce either (+)- or (-)-pinoresinol but retained the ability to catalyze the reduction of (-)-lariciresinol. These findings provide a basis for better understanding of the substrate-selective reaction of PLR.

Protective effect of Glycyrrhiza glabra roots extract on bone mineral density of ovariectomized rats

Objective: The aim of this study was to evaluate the potential effect of the methanolic extract of plant Glycyrrhiza glabra roots on bone mineral density and femoral bone strength of ovariectomized rats.

Methods: Thirty 10-month-old Wistar rats were randomly separated into three groups of ten, Control, Ovariectomy and Ovariectomy-plus-Glycyrrhiza in their drinking water. Total and proximal tibial bone mineral density was measured in all groups before ovariectomy (baseline) and after 3 and 6 months post ovariectomy. Three-point-bending of the femurs and uterine weight and histology were examined at the end of the study.

Results: No significant difference was noted in bone density percentage change of total tibia from baseline to 3 months between Control and Ovariectomy-plus-Glycyrrhiza groups (+5.31% ± 4.75 and +3.30% ± 6.31 respectively, P = non significant), and of proximal tibia accordingly (+5.58% ± 6.92 and +2.61% ± 13.62, P = non significant) demonstrating a strong osteoprotective effect. There was notable difference in percentage change of total tibia from baseline to 6 months between groups Ovariectomy and Ovariectomy-plus-Glycyrrhiza (−13.03% ± 5.11 and −0.84% ± 7.63 respectively, P < 0.005), and of proximal tibia accordingly (−27.9% ± 3.69 and −0.81% ± 14.85 respectively, P < 0.001), confirming the protective effect of Glycyrrhiza glabra extract in preserving bone density of the Ovariectomy-plus-Glycyrrhiza group. Three-point-bending did not reveal any statistically significant difference between Ovariectomy and Ovariectomy-plus-Glycyrrhiza groups. Uterine weights of the Ovariectomy-plus-Glycyrrhiza group ranged between the other two groups with no statistically significant difference to each.

Conclusions: Glycyrrhiza glabra root extract notably protected tibial bone mineral density loss in Ovariectomy-plus-Glycyrrhiza rats in comparison with ovariectomized rats, but did not improve biomechanical strength.

Effects of phytoestrogens on the activity and growth of primary breast cancer cells ex vivo

AIM

To explore the ex vivo effects of phytoestrogens on primary human breast cancer cells.

METHODS

Breast cancer cells were obtained from patients who underwent primary breast cancer surgery, which were treated with 10^-8  M 17β-estradiol (E₂ ), one of three phytoestrogens (genistein, resveratrol and quercetin, 10^-7  M), and a combination of E₂ and one of the three phytoestrogens for 48 h. These cells were then extracted for viability and apoptosis assay. The proteins involved in the proliferative and apoptotic pathways were evaluated by western blot analysis.

RESULTS

Human breast cancer cell viability was inhibited by all phytoestrogens but induced by E₂ with or without phytoestrogen. Apoptotic cells, as well as the proteins involved in apoptotic pathway and estrogen receptor (ER) β, were significantly increased in the cells treated with phytoestrogen alone. The use of E₂ with or without a phytoestrogen revealed completely opposite results. The proteins involved in the proliferative pathway and ER α expression were all increased in the cultures with E₂ with or without phytoestrogens.

CONCLUSION

In the presence of E₂ , these phytoestrogens lose the effects of suppressing breast cancer cells; contrastingly, induce growth stimulatory effects by inhibiting apoptosis and stimulating proliferation in primary breast cancer cells. Thus, the effects of phytoestrogens on breast cancer should be considered as E₂ still present in breast cancer tissue.

Genistein increases the thermogenic program of subcutaneous WAT and increases energy expenditure in mice

White adipose tissue (WAT) can differentiate into beige adipose tissue by the browning process. Some polyphenols, including isoflavones, particularly genistein, are suggested to increase the expression of browning markers. There is evidence that consumption of genistein can attenuate body weight gain and improve glucose tolerance and blood lipid levels. The aim of the present study was to investigate the potential mechanisms of stimulation by which genistein activates the browning of WAT. We studied the stimulation of the expression of browning markers in the following models: mice fed genistein; preadipocytes from 3 T3-L1 cells; and the stromal vascular fraction (SVF) from the inguinal adipose tissue of mice. The results indicated that genistein can stimulate the browning process by at least two mechanisms. An indirect mechanism was involved in the induction of PGC-1α/FNDC5 in skeletal muscle leading to an increase in the myokine irisin. In preadipocytes, irisin was able to increase the expression of Ucp1 and Tmem26, markers of browning, to increase energy expenditure. Interestingly, genistein was also able to activate browning by a direct mechanism. Incubation of preadipocytes with genistein increased UCP1 expression as well as some biomarkers of browning in a concentration-dependent manner, possibly via phosphorylation of AMPK. The effect of genistein was accompanied by an increase in the number of mitochondria as well as in the maximum respiration rate of the adipocytes. In conclusion, this study indicated that genistein can increase energy expenditure by stimulating the browning process directly in preadipocytes and indirectly by increasing the circulating levels of irisin.

The Impact of Antioxidants from the Diet on Breast Cancer Cells Monitored by Raman Microspectroscopy

Background:

The impact of the ubiquitous dietary phenolic compound p-coumaric acid on human breast cancer cells was assessed, through a multidisciplinary approach: Combined biological assays for cytotoxicity evaluation and biochemical profiling by Raman microspectroscopic analysis in cells. </P><P> Methods: Para-coumaric acid was shown to exert in vitro chemoprotective and antitumor activities, depending on the concentration and cell line probed: a significant anti-invasive ability was detected for the triple-negative MDA-MB-231 cells, while a high pro-oxidant effect was found for the estrogen- dependent MCF-7 cells. A striking cell selectivity was obtained, with a more noticeable outcome on the triple-negative MDA-MB-231 cell line.

Results:

The main impact on the cellular biochemical profile was verified to be on proteins and lipids, thus justifying the compound´s anti-invasive effect and chemoprotective ability.

Conclusion:

p-Coumaric acid was thus shown to be a promising chemoprotective/chemotherapeutic agent, particularly against the low prognosis triple-negative human breast adenocarcinoma.

Formononetin and metformin act synergistically to inhibit growth of MCF-7 breast cancer cells in vitro

Many breast cancer patients suffer from obvious side effects induced by chemotherapy. Formononetin (FM), one kind ingredient of Chinese herbal medicine, has been suggested to inhibit MCF-7 breast cancer cells. And recently metformin (MET) has gained more attention as a potential anti-cancer drug. The aim of this study was to investigate the synergistic effects of FM and MET on the proliferation of MCF-7 cells and to clarify the possible molecular mechanism involved. MCF-7 cells were treated with various concentrations of FM (40 and 80 μM) or FM (40 and 80 μM) combined with MET (150 μM) for 48 h. Cell proliferation was tested by an methyl tetrazolium (MTT) (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay. The percentage of apoptotic cells was measured by flow cytometry. The expression level of b-cell lymphoma/leukemia-2 (bcl-2) mRNA was examined by RT-PCR, while the expression levels of phosphorylated extracellular signal-regulated kinases (p-ERK1/2) and bcl-2 protein were detected by Western blotting. Compared with untreated cells, 40 μM and 80 μM FM efficiently inhibited proliferation and increased apoptosis in MCF-7 cells. Additionally, 40 μM and 80 μM FM greatly downregulated bcl-2 mRNA expression when compared with untreated cells. Furthermore, the protein expression of bcl-2 and p-ERK1/2 was significantly reduced by 40 μM and 80 μM FM. The cytotoxic effect of FM was more remarkable when 150 μM MET was added. Taken together, the combinational use of FM and MET enhanced cell growth inhibition, and the induction of apoptosis in MCF-7 cells mediated by the ERK1/2 signaling pathway.

Hydroxypropyl-β-cyclodextrin-containing hydrogel enhances skin formononetin permeation/retention

OBJECTIVES

This study was aimed to investigate the in vitro permeation potential of hydrogel formulations containing the isoflavones formononetin and biochanin A and cyclodextrins in different combinations.

METHODS

The permeation assay was performed using porcine skin discs on Franz diffusion cells model. The isoflavone contents of the formulations were quantified in the different layers of the skin using a validated HPLC-PDA method.

KEY FINDINGS

The isoflavones individually incorporated into the formulations showed high permeation potential, especially formononetin, after the incorporation of hydroxypropyl-β-cyclodextrin that enhanced its permeation in the epidermis and dermis. Biochanin A showed 2.7 times of permeation capacity in the epidermis and dermis mainly after incorporation of cyclodextrins in the formulations. Formononetin showed reduction in its permeation when incorporated in the formulations together to biochanin A, showing the absence of synergism.

CONCLUSIONS

Our results indicated a noticeable skin permeation promoting effect of HPβCD in formononetin formulation. Furthermore, formononetin and biochanin A can permeate the skin being mostly retained in the epidermis and dermis, revealing its potential use in cosmetic preparations intended to prevent skin aging.

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.

Effect of combined endurance-resistance training and soy extract supplementation on expression of eNOS gene in ovariectomized rats

Introduction

Menopause is an independent risk factor for cardiovascular disease (CVD). Physical exercise and soybean diets have been suggested to reduce the risk of CVD in postmenopausal women. The purpose of this study was to investigate the effects of combined resistance and endurance (RE) training and soy extract (SOY) supplementation, both known to improve endothelial function, on expression of the eNOS gene in the heart of ovariectomized (OVX) rats.

Material and methods

Fifty female Wistar rats were divided into five groups: 1) sham (SHAM); 2) ovariectomy (OVX); 3) ovariectomy with soy extract supplementation (OVX + SOY); 4) OVX with RE training (OVX + RE); 5) and ovariectomy plus RE training with soy extract supplementation (OVX + RE + SOY). RE training and soy extract supplementation were administered alone or in combination for 6 weeks. The effects of these treatments on cardiac eNOS expression were measured using real-time PCR.

Results

Ovariectomy down-regulated cardiac eNOS gene expression; however, 6 weeks of SOY treatment or RE training reversed this effect (p ≤ 0.05). The combination of SOY plus RE was greater than RE or SOY alone in reversing estrogen-deficiency-caused eNOS down-regulation (p ≤ 0.05).

Conclusions

Our data suggest that the combinatory regimen of soy extract supplementation and regular RE training may be more beneficial to cardiovascular disease risk in a menopause rat model than either exercise or soy supplementation alone.

The Role of Secondary Metabolites on Gynecologic Cancer Therapy: Some Pathways and Mechanisms

Gynecologic cancers are among the most common cancers in humans and animals. Treatment success depends on several factors including stage at diagnosis, tumor type, origin and metastasis. Currently, surgery, chemotherapy, and radiotherapy are preferred in the treatment of these cancers. However, many anticarcinogenic drugs can cause severe adverse effects and also the expected response to treatment may not be obtained. In recent studies, the importance of the relationship between cancer and inflammation has been emphasized. Therefore, several phytochemicals that exhibit beneficial bioactive effects towards inflammatory pathways were proven to have anticarcinogenic potential for gynecologic cancer therapy. This review summarizes the role of inflammatory pathways in gynecologic cancers and effective secondary metabolites for cancer therapy.

Lannea acida A. Rich. (Anacardiaceae) Ethanol Extract Exhibits Estrogenic Effects and Prevents Bone Loss in an Ovariectomized Rat Model of Osteoporosis

Phytoestrogens have been shown to prevent postmenopausal osteoporosis. Lannea acida is a medicinal plant traditionally used in Cameroon to treat infertility, gynaecological complaints, and rheumatism. These uses prompted us to evaluate estrogenic activity of Lannea acida bark ethanolic extract and its antiosteoporotic potential in ovariectomized Wistar rats. In vitro, the E-screen assay was used to assess the ability of L. acida extract to induce MCF-7 cells proliferation. In vivo, a 3-day uterotrophic assay and a 12-week oral treatment in ovariectomized adult rats were carried out to evaluate the ability of L. acida extract to prevent bone mass loss. L. acida extract induced MCF-7 cell proliferation. In vivo, it significantly increased the uterine wet weight, uterine and vaginal epithelial heights, and mammary glands differentiation. At 200 mg/kg, a long-term treatment with the extract prevented body weight gain (p < 0.05) and loss of bone mass and/or density (p < 0.05) induced by ovariectomy. Also, a significant (p < 0.001) decrease of alkaline phosphatase activity was observed with 50 mg/kg. L. acida extract improved bone microarchitecture and could restore normal bone mineralization by increasing the inorganic phosphorus and calcium level in bone. These findings provide evidence that Lannea acida is a potential alternative for the prevention of postmenopausal osteoporosis.

In vitro antioxidant/prooxidant effects of combined use of flavonoids

The present study was undertaken to investigate the individual and combined antioxidant or prooxidant effects of genistein, daidzein and quercetin in human erythrocytes and rat microsomes in vitro. Their reducing potential against oxidation of a redox sensitive fluorescent probe, their protective effect against H₂O₂-induced membrane lipid peroxidation and their inhibitory effect on AAPH-induced hemolysis were evaluated. Genistein and daidzein were prooxidant in erythrocytes but antioxidant in microsomes where their metabolites might have been formed which suggests the importance of metabolic capacity in in vitro models to predict the physiological situation. Quercetin showed antioxidant effects in all models and conditions. Prooxidant effect of 'genistein-daidzein mixture', at their concentrations reflecting the real life, was suppressed by addition of quercetin to the mixture. Our study shows that flavonoids can exert prooxidant effects depending on the conditions, but the mixture effect should be considered while assessing their effects and safety in humans.

Therapeutic Role of Punica Granatum (Pomegranate) Seed Oil Extract on Bone Turnover and Resorption Induced in Ovariectomized Rats

CONTEXT

Postmenopausal osteoporosis is mostly caused by increased bone remodeling resulting from estrogen deficiency. Hormone replacement therapy (HRT) is used to prevent osteoporosis, but it increases the risk for breast cancer, thromboembolism, strokes, and heart attacks. Pomegranate seed oil extract (SOE) is rich in phytoestrogen and antioxidant compounds.

OBJECTIVES

To evaluate the therapeutic role of SOE against bone turnover, resorption and osteoporosis induced in ovariectomized rats as a postmenopausal model and comparing the results with those from Generic CycloProgynova drug (D).

DESIGN

The study used western albino rats undergo bilaterally ovariectomization as a model for postmenopausal.

SETTING

The study took part in a laboratory setting.

ANIMALS

Forty female western albino rats (age: 3-4 months) weighing 150-180 gm.

MEASUREMENTS

Rats were divided into four groups, 10 rats each; SC-group: Sham control = untreated and unovariectomized rats; OVX-group = ovariectomized rats; (OVX-SOE) and (OVX-D) groups = OVX rats were treated with SOE and D, respectively. Bone markers (BMs) especially osteocalcin (BGP), alkaline phosphatase (ALP), tartarate resistance acid phosphatase (TRAcP), bone weight, bone calcium concentration, serum electrolytes (calcium, sodium and potassium) and serum estradiol (E2) level and histopathological examination of bones were determined. Also lipid profile, uric acid, prothrombin time (INR) and liver and kidney functions were measured to evaluate the adverse effects of SOE and D.

RESULTS

In OVX group the activities of ALP and TRAcP and the levels of BGP, serum calcium, sodium and body weight were significantly higher (p≤0.05) than SC-group, while bone calcium concentration, bone mass, serum E2 and potassium level as well as uterus mass were significantly lower (p≤0.05). Also histopathological results revealed that the outer cortical bone became thinner, while the cancellous bone trabeculae lost their normal architecture. Moreover in OVX group lipid profile and uric acid levels were significantly higher (p≤0.05) than SC group, but there were no significant changes (p≤0.05) in INR level, liver and kidney functions. Treatment of OVX rats with SOE or D for 12 weeks improved both the architecture of bones as shown from the histopathological results and BMs, serum electrolytes and E2 levels (p≤0.05) which approached SC-group. Moreover after treatment of OVX rats with SOE the levels of lipid profile and uric acid were improved and approached SC-group, while liver function became significant lower (p≤0.05) than SC-group. Also there were no significant changes (p≤0.05) in kidney functions and INR of (OVX-SOE), OVX and SC groups. In contrast in (OVX-D) group the levels of lipid profile, liver and kidney functions, uric acid and INR were significantly higher (p≤0.05) than those of OVX and SC groups.

CONCLUSION

The results of this study show that SOE has therapeutic effects on osteoporosis, while it has no adverse effects on lipid profile, uric acid, liver and kidney functions when compared to HRT. SOE offers a promising alternative in the design of new strategies in nutritional management of age-related bone complications.

Phytoestrogens Induce Differential Estrogen Receptor Alpha- or Beta-Mediated Responses in Transfected Breast Cancer Cells

Increased intake of phytoestrogens may be associated with a lower risk of cancer in the breast and several other sites, although there is controversy surrounding this activity. One of the mechanisms proposed to explain the activity of phytoestrogens is their ability to bind and activate human estrogen receptor a (ERα) and human estrogen receptor β (ERβ). Nine phytoestrogens were tested for their ability to transactivate ERα or ERβ at a range of doses. Mammary adenocarcinoma (MCF-7) cells were co-transfected with either ERα or ERβ, and an estrogen-response element was linked to a luciferase reporter gene. Dose-dependent responses were compared with the endogenous ligand 17β-estradiol. Purified genistein, daidzein, apigenin, and coumestrol showed differential and robust transactivation of ERα- and ERβ-induced transcription, with an up to 100-fold stronger activation of ERβ. Equol, naringenin, and kaempferol were weaker agonists. When activity was evaluated against a background of 0.5 nM 17β-estradiol, the addition of genistein, daidzein, and resveratrol superstimulated the system, while kaempferol and quercetin were antagonists at the highest doses. This transfection assay provides an excellent model to evaluate the activation of ERα and ERβ by different phytoestrogens in a breast cancer context and can be used as a screening bioassay tool to evaluate the estrogenic activity of extracts of herbs and foods.

Hydrolysis of isoflavone in black soy milk using cellulose bead as enzyme immobilizer

The establishment of a catalytic system to enrich isoflavone aglycones in black soybean milk was investigated in this study. Beta-glucosidase, which was covalently immobilized onto cellulose beads, exhibited a significant efficiency for the conversion of 4-nitrophenyl β-d-glucuronide to p-nitrophenol over the sol–gel method. The Michaelis constant (K_m) of the cellulose bead enzymatic system was determined to be 1.50 ± 0.10 mM. Operational reusability of the cellulose bead enzymatic system was justified for more than 10 batch reactions in black soy milk. Moreover, the storage stability verification indicated that the cellulose bead catalytic system was able to sustain its highest catalytic activity for 10 days. High-performance liquid chromatography results demonstrated that this enzymatic system required only 30 minutes to achieve complete isoflavone deglycosylation, and the aglycone content in the total isoflavones in black soy milk was enriched by 67% within 30 minutes by the cellulose bead enzymatic system.

Estrogenic properties of spices of the traditional Cameroonian dish "Nkui" in ovariectomized Wistar rats

BACKGROUND

Besides the basic role to flavor and color foods, several health benefits have been attributed to spices. The traditional Cameroonian food "Nkui" is prepared using several spices (Afrostyrax lepidophyllus Mildbr., Capsicum frutescens Linn., Fagara leprieurii Guill. et Perr., Fagara tessmannii Engl., Mondia whitei Hook. F. Skell., Pentadiplandra brazzeana Baill., Solanum gilo Raddi., Tetrapleura tetraptera Taub. and Xylopia parviflora A. Rich. Benthane) that are believed to have a positive impact on the female reproductive physiology. Aiming to determine the potential effect of this food on the female reproductive tract, we evaluated the estrogenic properties of aqueous and ethanol extracts of Nkui using a 3-day uterotrophic assay in ovariectomized (OVX) rats.

METHODS

OVX female Wistar rats were randomly separated in several groups of five animals each and submitted to a 3-day uterotrophic assay (per os). At the end of treatment, animals were sacrificed and uterus, vagina and mammary gland collected and fixed in 10 % formalin for histological analysis.

RESULTS

These extracts increased the uterine wet weight, the uterine and vaginal epithelial heights, and the lumen and diameter of alveoli in the mammary glands. They also altered the estradiol-induced increase of uterine wet weight. The dichloromethane and methanol fractions of the ethanol extract exhibited estrogenic properties as well by increasing uterine and vaginal endpoints.

CONCLUSIONS

These results suggest that the spices of "Nkui" contain estrogenic phytoconstituents and this traditional food may be considered as functional.

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.

Structure activity relationship studies on cytotoxicity and the effects on steroid receptors of AB-functionalized cholestanes

Structure-activity relationship analysis and profiling of a library of AB-functionalized cholestane derivatives closely related to brassinosteroids (BRs) were performed to examine their antiproliferative activities and activities on steroid hormone receptors. Some of the compounds were found to have strong cytotoxic activity in several human normal and cancer cell lines. The presence of a 3-hydroxy or 3-oxo group and 2,3-vicinal diol or 3,4-vicinal diol moiety were found to be necessary for optimum biological activity, as well as a six-membered B ring. According to the profiling of all steroid receptors in both agonist and antagonist mode, the majority of the cholestanes were weakly active or inactive compared to the natural ligands. Estrogenic activity was detected for two compounds, two compounds possessed antagonistic properties on estrogen receptors and seven compounds showed agonistic activity. Two active cholestane derivatives were shown to strongly influence cell viability, proliferation, cell cycle distribution, apoptosis and molecular pathways responsible for these processes in hormone-sensitive/insensitive (MCF7/MDA-MB-468) breast cancer cell lines.

Treatment with kaempferol suppresses breast cancer cell growth caused by estrogen and triclosan in cellular and xenograft breast cancer models

As a phytoestrogen, kaempferol (Kaem) is one of bioflavonoids, which are found in a variety of vegetables including broccoli, tea and tomato. In this study, the antiproliferative effects of Kaem in triclosn (TCS)-induced cell growth were examined in MCF-7 breast cancer cells. TCS promoted the cell viability of MCF-7 cells via estrogen receptor α (ERα) as did 17β-estradiol (E2), a positive control. On the other hand, Kaem significantly suppressed E2 or TCS-induced cell growth. To elucidate the molecular mechanisms of TCS and Kaem, alterations in the expressions of cell cycle, apoptosis and metastasis-related genes were identified using western blot assay. The treatment of the cells with TCS up-regulated the protein expressions of cyclin D1, cyclin E and cathepsin D, while down-regulated p21 and bax expressions. Kaem reversed TCS-induced gene expressions in an opposite manner. The phosphorylation of IRS-1, AKT, MEK1/2 and ERK was increased by TCS, indicating that TCS induced MCF-7 cell proliferation via nongenomic ER signaling pathway associated with IGF-1R. Kaem presented an antagonistic activity on this signaling by down-regulating the protein expression of pIRS-1, pAkt and pMEK1/2 promoted by E2 or TCS. In an in vivo xenografted mouse model, tumor growth was induced by treatment with E2 or TCS, which was identified in the measurement of tumor volume, hematoxylin and eosin staining, bromodeoxyuridine and immunohistochemistry assay. On the contrary, E2 or TCS-induced breast tumor growth was inhibited by co-treatment with Kaem, which is consistent with in vitro results. Taken together, these results revealed that Kaem has an anticancer effect against procancer activity of E2 or TCS, a xenoestrogen, in breast cancer and may be suggested as a prominent agent to neutralize breast cancer risk caused by TCS.

The impact of low-dose carcinogens and environmental disruptors on tissue invasion and metastasis

The purpose of this review is to stimulate new ideas regarding low-dose environmental mixtures and carcinogens and their potential to promote invasion and metastasis. Whereas a number of chapters in this review are devoted to the role of low-dose environmental mixtures and carcinogens in the promotion of invasion and metastasis in specific tumors such as breast and prostate, the overarching theme is the role of low-dose carcinogens in the progression of cancer stem cells. It is becoming clearer that cancer stem cells in a tumor are the ones that assume invasive properties and colonize distant organs. Therefore, low-dose contaminants that trigger epithelial-mesenchymal transition, for example, in these cells are of particular interest in this review. This we hope will lead to the collaboration between scientists who have dedicated their professional life to the study of carcinogens and those whose interests are exclusively in the arena of tissue invasion and metastasis.

Wedelolactone induces growth of breast cancer cells by stimulation of estrogen receptor signalling

Wedelolactone, a plant coumestan, was shown to act as anti-cancer agent for breast and prostate carcinomas in vitro and in vivo targeting multiple cellular proteins including androgen receptors, 5-lipoxygenase and topoisomerase IIα. It is cytotoxic to breast, prostate, pituitary and myeloma cancer cell lines in vitro at μM concentrations. In this study, however, a novel biological activity of nM dose of wedelolactone was demonstrated. Wedelolactone acts as agonist of estrogen receptors (ER) α and β as demonstrated by transactivation of estrogen response element (ERE) in cells transiently expressing either ERα or ERβ and by molecular docking of this coumestan into ligand binding pocket of both ERα and ERβ. In breast cancer cells, wedelolactone stimulates growth of estrogen receptor-positive cells, expression of estrogen-responsive genes and activates rapid non-genomic estrogen signalling. All these effects can be inhibited by pretreatment with pure ER antagonist ICI 182,780 and they are not observed in ER-negative breast cancer cells. We conclude that wedelolactone acts as phytoestrogen in breast cancer cells by stimulating ER genomic and non-genomic signalling pathways.

Phytoestrogens and risk of prostate cancer: a meta-analysis of observational studies

Background

Epidemiologic studies have reported various results relating phytoestrogens to prostate cancer (PCa). The aim of this study was to provide a comprehensive meta-analysis on the extent of the possible association between phytoestrogens (including consumption and serum concentration) and the risk of PCa.

Methods

Eligible studies were retrieved via both computer searches and review of references. The summary relative risk ratio (RR) or odds ratio (OR) and 95 % confidence interval (CI) were calculated with random effects models.

Results

A total of 11 studies (2 cohort and 9 case–control studies) on phytoestrogen intake and 8 studies on serum concentration were included in the meta-analysis. The pooled odds ratio (OR) showed a significant influence of the highest phytoestrogens consumption (OR 0.80, 95 % CI 0.70–0.91) and serum concentration (OR 0.83, 95 % CI 0.70–0.99) on the risk of PCa. In stratified analysis, high genistein and daidzein intake and increased serum concentration of enterolactone were associated with a significant reduced risk of PCa. However, no significant associations were observed for isoflavone intake, lignans intake, or serum concentrations of genistein, daidzein, or equol.

Conclusions

The overall current literature suggests that phytoestrogen intake is associated with a decreased risk of PCa, especially genistein and daidzein intake. Increased serum concentration of enterolactone was also associated with a significant reduced risk of PCa. Further efforts should be made to clarify the underlying biological mechanisms.

Equol, a Metabolite of Daidzein, Is More Efficient than Daidzein for Bone Formation in Growing Female Rats

Few studies have examined the effects of isoflavones and particularly equol, a metabolite of the isoflavone daidzein, on bone formation during the growth period in animals. The present study investigated the effects of orally administered daidzein or equol on bone formation and bone mineral density in growing female rats. Female Sprague-Dawley rats, aged 3 weeks, were divided into four groups (n = 8 per group) as follows: rats were orally administered a corn oil, 8 mg/day of daidzein, 4 mg/day of equol or 8 mg/day of equol in corn oil for 4 weeks. Daidzein and equol increased the bone mineral density of growing female rats by stimulating bone formation without exhibiting a substantial effect on the weight of their reproductive organs. Bone growth caused by increased bone mineralizing surface and bone formation rate in rats administered with equol was approximately twice that of rats administered with daidzein. These results suggest that equol might be more efficient than daidzein for bone formation in growing female rats. Copyright © 2015 John Wiley & Sons, Ltd.

Red clover isoflavone metabolite bioavailability is decreased after fructooligosaccharide supplementation

BACKGROUND

Red clover is an important source of isoflavones; which has been made commercially available as dietary supplements for the treatment of menopausal symptoms. Bioavailability and metabolism of these red clover isoflavones (RCI) have not been studied in detail. Fructooligosaccharides (FOS) stimulate the growth of intestinal bacteria and play an important role in the formation of certain isoflavone metabolites, such as equol and O-desmethylangolensin.

OBJECTIVE

To determine the bioavailability of RCI metabolites and analyse whether FOS supplementation could influence their bioavailability.

METHODS

Seventeen healthy adults were enrolled in the study carried out in two periods. In the first, compound bioavailability was determined after consumption of 80 mg of RCI (MF11RCE). In the second, a 6-day supplementation of 2×3000 mg/day of FOS was administered before isoflavone consumption.

RESULTS

Biochanin A and formononetin were rapidly absorbed and both reached maximum concentrations at an average of 5-7h. Demethylation was a major reaction in the metabolic pathway. Daidzein serum level peaked after about 12.6h. Supplementation with FOS led to a significant decrease in the bioavailability of daidzein, dihydroformononetin, dihydrogenistein and dihydrodaidzein. An increase in equol production was also observed which did not reach statistical significance (p>0.05).

CONCLUSION

This study is the first to provide detailed data on RCI bioavailability in humans and determine no influence of FOS yet a trend toward increased equol production. More research is warranted involving a greater sample size.

Urinary phytoestrogens and cancer, cardiovascular, and all-cause mortality in the continuous National Health and Nutrition Examination Survey

PURPOSE

Experimental studies suggest that phytoestrogen intake alters cancer and cardiovascular risk. This study investigated the associations of urinary phytoestrogens with total cancer (n = 79), cardiovascular (n = 108), and all-cause (n = 290) mortality among 5179 participants in the continuous National Health and Nutrition Examination Survey (1999-2004).

METHODS

Urinary phytoestrogens were measured using high-performance liquid chromatography with tandem mass spectrometric detection. Survival analysis was performed to evaluate hazard ratios (HRs) and 95 % confidence intervals (CIs) for each of the three outcomes in relation to urinary phytoestrogens.

RESULTS

After adjustment for confounders, higher urinary concentrations of total enterolignans were associated with a reduced risk of death from cardiovascular disease (HR for tertile 3 vs. tertile 1 0.48; 95 % CI 0.24, 0.97), whereas higher urinary concentrations of total isoflavones (HR for tertile 3 vs. tertile 1 2.14; 95 % CI 1.03, 4.47) and daidzein (HR for tertile 3 vs. tertile 1 2.05; 95 % CI 1.02, 4.11) were associated with an increased risk. A reduction in all-cause mortality was observed for elevated urinary concentrations of total enterolignans (HR for tertile 3 vs. tertile 1 0.65; 95 % CI 0.43, 0.96) and enterolactone (HR for tertile 3 vs. tertile 1 0.65; 95 % CI 0.44, 0.97).

CONCLUSIONS

Some urinary phytoestrogens were associated with cardiovascular and all-cause mortality in a representative sample of the US population. This is one of the first studies that used urinary phytoestrogens as biomarkers of their dietary intake to evaluate the effect of these bioactive compounds on the risk of death from cancer and cardiovascular disease.