Phytoestrogen content of foods--a compendium of literature values

Mechanistic insights into the potential role of dietary polyphenols and their nanoformulation in the management of Alzheimer's disease

Alzheimer's disease (AD) is a very common neurodegenerative disorder associated with memory loss and a progressive decline in cognitive activity. The two major pathophysiological factors responsible for AD are amyloid plaques (comprising amyloid-beta aggregates) and neurofibrillary tangles (consisting of hyperphosphorylated tau protein). Polyphenols, a class of naturally occurring compounds, are immensely beneficial for the treatment or management of various disorders and illnesses. Naturally occurring sources of polyphenols include plants and plant-based foods, such as fruits, herbs, tea, vegetables, coffee, red wine, and dark chocolate. Polyphenols have unique properties, such as being the major source of anti-oxidants and possessing anti-aging and anti-cancerous properties. Currently, dietary polyphenols have become a potential therapeutic approach for the management of AD, depending on various research findings. Dietary polyphenols can be an effective strategy to tackle multifactorial events that occur with AD. For instance, naturally occurring polyphenols have been reported to exhibit neuroprotection by modulating the Aβ biogenesis pathway in AD. Many nanoformulations have been established to enhance the bioavailability of polyphenols, with nanonization being the most promising. This review comprehensively provides mechanistic insights into the neuroprotective potential of dietary polyphenols in treating AD. It also reviews the usability of dietary polyphenol as nanoformulation for AD treatment.

Role of Flavonoids in Modulation of Mitochondria Dynamics during Oxidative Stress

BACKGROUND

Flavonoids are a widespread category of naturally occurring polyphenols distinguished by the flavan nucleus in plant-based foods and beverages, known for their various health benefits. Studies have suggested that consuming 150-500 mg of flavonoids daily is beneficial for health. Recent studies suggest that flavonoids are involved in maintaining mitochondrial activity and preventing impairment of mitochondrial dynamics by oxidative stress.

OBJECTIVE

This review emphasized the significance of studying the impact of flavonoids on mitochondrial dynamics, oxidative stress, and inflammatory response.

METHODS

This review analysed and summarised the findings related to the impact of flavonoids on mitochondria from publicly available search engines namely Pubmed, Scopus, and Web of Science.

DESCRIPTION

Any disruption in mitochondrial dynamics can contribute to cellular dysfunction and diseases, including cancer, cardiac conditions, and neurodegeneration. Flavonoids have been shown to modulate mitochondrial dynamics by regulating protein expression involved in fission and fusion events. Furthermore, flavonoids exhibit potent antioxidant properties by lowering the production of ROS and boosting the performance of antioxidant enzymes. Persistent inflammation is a characteristic of many different disorders. This is because flavonoids also alter the inflammatory response by controlling the expression of numerous cytokines and chemokines involved in the inflammatory process. Flavonoids exhibit an impressive array of significant health effects, making them an effective therapeutic agent for managing various disorders. Further this review summarised available mechanisms underlying flavonoids' actions on mitochondrial dynamics and oxidative stress to recognize the optimal dose and duration of flavonoid intake for therapeutic purposes.

CONCLUSION

This review may provide a solid foundation for developing targeted therapeutic interventions utilizing flavonoids, ultimately benefiting individuals afflicted with various disorders.

Application of Ultrafiltration for Recovery of Polyphenols from Rose Petal Byproduct

One main objective of this study was to increase the utilization of raw material in the rose (Rosa damascena Mill.) essential oil industry by the application of membrane technologies. In this research, distilled (dearomatized) rose petals, the primary byproduct in essential oil production, were subjected to an enzyme-assisted extraction and subsequent membrane separation for partial concentration at different levels using UF1-PAN and UF10-PAN membranes. The results show that the permeate flux decreased with a rise in volume reduction ratio and increased with a rise in transmembrane pressure and feed flow rate. At the beginning of the process, the highest flux was with the UF1-PAN membrane, but at the end of the process, it was with the UF10-PAN membrane. Total polyphenols of the retentates increased by 27-39% and 26-67% during ultrafiltration with the UF1-PAN and UF10-PAN membranes, respectively, with the highest value obtained for the UF10-PAN membrane at VRR 6. The highest concentration factor and rejection of total solids, total polyphenols, redox-active antioxidants, and radical scavenging antioxidants were obtained at VRR 6 with the UF10-PAN membrane. The use of green technology based on enzyme-assisted extraction and ultrafiltration for recovery and concentration of polyphenols from rose petal byproduct solves practical environmental problems for the treatment and utilization of byproducts from the rose oil industry. The retentate obtained could be used in the food production, cosmetic, and pharmaceutical industries.

Understanding the Phytoestrogen Genistein Actions on Breast Cancer: Insights on Estrogen Receptor Equivalence, Pleiotropic Essence and Emerging Paradigms in Bioavailability Modulation

Prevalent as a major phenolic ingredient of soy and soy products, genistein is recognized as an eminent phytoestrogen owing to its interacting ability with estrogen receptors (ERs). The metabolic conversion of plant-derived genistin to genistein by gut microbes and intestinal enzymes enhances its absorption at intestinal pH of ~7.5-7.8. Genistein interferes in breast cancer (BC) development via pleiotropic actions on cell proliferation, survival, angiogenesis, and apoptosis. Though multiple investigations have demonstrated genistein intake-driven reduced BC risk, similar efficacy has not been replicated in clinical trials. Furthermore, multiple studies have structurally and functionally equated genistein extents with 17-β-estradiol (E2), the most available physiological estrogen in females, culminating in aggravated BC growth. Of note, both genistein and E2 function via interacting with ERs (ERα and ERβ). However, although E2 shows almost equal affinity towards both ERα and ERβ, genistein shows more affinity towards ERβ than ERα. Our cautious literature survey revealed typical intake mode, ER expression pattern and the ratio of ERα and ERβ, transactivators/ regulators of ERα and ERβ expression and activities, patient age, and menopausal status as decisive factors affecting genistein BC activities. Of further interest are the mechanisms by which genistein inhibits triple-negative breast cancers (TNBCs), which lack ERs, progesterone receptors (PRs), and human epidermal growth factor receptors (HER2). Herein, we attempt to understand the dosage-specific genistein actions in BC cells and patients with an insight into its better response via derivative development, nanocarrier-assisted, and combinatorial delivery with chemotherapeutic drugs.

Polyphenol Supplementation and Antioxidant Status in Athletes: A Narrative Review

Antioxidants in sports exercise training remain a debated research topic. Plant-derived polyphenol supplements are frequently used by athletes to reduce the negative effects of exercise-induced oxidative stress, accelerate the recovery of muscular function, and enhance performance. These processes can be efficiently modulated by antioxidant supplementation. The existing literature has failed to provide unequivocal evidence that dietary polyphenols should be promoted specifically among athletes. This narrative review summarizes the current knowledge regarding polyphenols' bioavailability, their role in exercise-induced oxidative stress, antioxidant status, and supplementation strategies in athletes. Overall, we draw attention to the paucity of available evidence suggesting that most antioxidant substances are beneficial to athletes. Additional research is necessary to reveal more fully their impact on exercise-induced oxidative stress and athletes' antioxidant status, as well as optimal dosing methods.

Benefits of dietary polyphenols in Alzheimer's disease

Alzheimer's disease (AD) is an irreversible progressive neurodegenerative disease affecting approximately 50 million people worldwide. It is estimated to reach 152 million by the year 2050. AD is the fifth leading cause of death among Americans age 65 and older. In spite of the significant burden the disease imposes upon patients, their families, our society, and our healthcare system, there is currently no cure for AD. The existing approved therapies only temporarily alleviate some of the disease's symptoms, but are unable to modulate the onset and/or progression of the disease. Our failure in developing a cure for AD is attributable, in part, to the multifactorial complexity underlying AD pathophysiology. Nonetheless, the lack of successful pharmacological approaches has led to the consideration of alternative strategies that may help delay the onset and progression of AD. There is increasing recognition that certain dietary and nutrition factors may play important roles in protecting against select key AD pathologies. Consistent with this, select nutraceuticals and phytochemical compounds have demonstrated anti-amyloidogenic, antioxidative, anti-inflammatory, and neurotrophic properties and as such, could serve as lead candidates for further novel AD therapeutic developments. Here we summarize some of the more promising dietary phytochemicals, particularly polyphenols that have been shown to positively modulate some of the important AD pathogenesis aspects, such as reducing β-amyloid plaques and neurofibrillary tangles formation, AD-induced oxidative stress, neuroinflammation, and synapse loss. We also discuss the recent development of potential contribution of gut microbiome in dietary polyphenol function.

Therapeutic roles of plants for 15 hypothesised causal bases of Alzheimer's disease

Alzheimer's disease (AD) is progressive and ultimately fatal, with current drugs failing to reverse and cure it. This study aimed to find plant species which may provide therapeutic bioactivities targeted to causal agents proposed to be driving AD. A novel toolkit methodology was employed, whereby clinical symptoms were translated into categories recognized in ethnomedicine. These categories were applied to find plant species with therapeutic effects, mined from ethnomedical surveys. Survey locations were mapped to assess how this data is at risk. Bioactivities were found of therapeutic relevance to 15 hypothesised causal bases for AD. 107 species with an ethnological report of memory improvement demonstrated therapeutic activity for all these 15 causal bases. The majority of the surveys were found to reside within biodiversity hotspots (centres of high biodiversity under threat), with loss of traditional knowledge the most common threat. Our findings suggest that the documented plants provide a large resource of AD therapeutic potential. In demonstrating bioactivities targeted to these causal bases, such plants may have the capacity to reduce or reverse AD, with promise as drug leads to target multiple AD hallmarks. However, there is a need to preserve ethnomedical knowledge, and the habitats on which this knowledge depends.

Targeting Breast Cancer-Derived Stem Cells by Dietary Phytochemicals: A Strategy for Cancer Prevention and Treatment

Breast cancer is heterogeneous disease with variable prognosis and therapeutic response. Approximately, 70% of diagnosed breast cancer represents the luminal A subtype. This subpopulation has a fair prognosis with a lower rate of relapse than the other clinical subtypes. Acquisition of stemness in luminal A subtype modifies the phenotype plasticity to accomplish increased aggressiveness and therapeutic resistance. Therefore, targeting luminal A-derived breast cancer stem cells (BCSCs) could be a promising strategy for its prevention and treatment. Extensive studies reveal that dietary phytochemicals have the potential to target BCSCs by modulating the molecular and signal transduction pathways. Dietary phytochemicals alone or in combination with standard therapeutic modalities exert higher efficacy in targeting BCSCs through changes in stemness, self-renewal properties and hypoxia-related factors. These combinations offer achieving higher radio- and chemo- sensitization through alteration in the key signaling pathways such as AMPK, STAT3, NF-ĸB, Hedgehog, PI3K/Akt/mTOR, Notch, GSK3β, and Wnt related to cancer stemness and drug resistance. In this review, we highlight the concept of targeting luminal A-derived BCSCs with dietary phytochemicals by summarizing the pathways and underlying mechanism(s) involved during therapeutic resistance.

Bio-active components in medicinal plants: A mechanistic review of their effects on fish growth and physiological parameters

World population is increasing at a tremendous rate so is the demand for animal-based protein. Aquaculture is a promising industry that has the potential to supply high quality protein for mankind with minimum environmental impact. In the past decade, aquaculture practices have been shifting from extensive to intensive culture. To achieve maximum production per unit area, high stocking densities are maintained in intensive aquaculture. If not managed properly, this may lead to stress in fish. Fish under stress condition show decreased growth, suppressed appetite, weakened immunity and increased susceptibility to infections. Chemicals, vaccines and antibiotics are used for the treatment of diseased fish. Use of synthetic chemicals, vaccines and antibiotics is not sustainable because pathogens develop resistance against them and they have high residues. Moreover, certain chemicals used for the treatment of fish diseases are not safe for humans therefore, are banned in some countries. Plant parts and their extracts are used in traditional medicines to cure many diseases and to improve health of mankind. In aquaculture industry, use of plants and their derivatives in fish feed to improve health status of fish is increasing. Several plants improve growth and overall health status of fish, some provide protection against pathogens by improving the immune system while others increase appetite by direct action on neuro-endocrine axis of fish. This review provides an in depth and up to date information about use of medicinal plants and their derivatives to improve growth and physiological status of fish and their possible mechanism of action.

Structural, dynamic, and hydration properties of quercetin and its aggregates in solution

Quercetin is a flavonoid present in the human diet with multiple health benefits. Quercetin solutions are inhomogeneous even at very low concentrations due to quercetin's tendency to aggregate. We simulate, using molecular dynamics, three systems of quercetin solutions: infinite dilution, 0.22 M, and 0.46 M. The systems at the two highest concentrations represent regions of the quercetin aggregates, in which the concentration of this molecule is unusually high. We study the behavior of this molecule, its aggregates, and the modifications in the surrounding water. In the first three successive layers of quercetin hydration, the density of water and the hydrogen bonds formations between water molecules are smaller than that of bulk. Quercetin has a hydrophilic surface region that preferentially establishes donor hydrogen bonds with water molecules with relative frequencies from 0.12 to 0.46 at infinite dilution. Also, it has two hydrophobic regions above and below the planes of its rings, whose first hydration layers are further out from quercetin (≈0.3 Å) and their water molecules do not establish hydrogen bonds with it. Water density around the hydrophobic regions is smaller than that of the hydrophilic. Quercetin molecules aggregate inπ-stacking configurations, with a distance of ≈0.37 nm between the planes of their rings, and form bonds between their hydroxyl groups. The formation of quercetin aggregates decreases the hydrogen bonds between quercetin and the surrounding water and produces a subdiffusive behavior in water molecules. Quercetin has a subdiffusive behavior even at infinite dilution, which increases with the number of molecules within the aggregates and the time they remain within them.

Neuroimmunomodulatory Properties of Flavonoids and Derivates: A Potential Action as Adjuvants for the Treatment of Glioblastoma

Glioblastomas (GBMs) are tumors that have a high ability to migrate, invade and proliferate in the healthy tissue, what greatly impairs their treatment. These characteristics are associated with the complex microenvironment, formed by the perivascular niche, which is also composed of several stromal cells including astrocytes, microglia, fibroblasts, pericytes and endothelial cells, supporting tumor progression. Further microglia and macrophages associated with GBMs infiltrate the tumor. These innate immune cells are meant to participate in tumor surveillance and eradication, but they become compromised by GBM cells and exploited in the process. In this review we discuss the context of the GBM microenvironment together with the actions of flavonoids, which have attracted scientific attention due to their pharmacological properties as possible anti-tumor agents. Flavonoids act on a variety of signaling pathways, counteracting the invasion process. Luteolin and rutin inhibit NFκB activation, reducing IL-6 production. Fisetin promotes tumor apoptosis, while inhibiting ADAM expression, reducing invasion. Naringenin reduces tumor invasion by down-regulating metalloproteinases expression. Apigenin and rutin induce apoptosis in C6 cells increasing TNFα, while decreasing IL-10 production, denoting a shift from the immunosuppressive Th2 to the Th1 profile. Overall, flavonoids should be further exploited for glioma therapy.

Flavonoids as natural phenolic compounds and their role in therapeutics: an overview

Background

Natural plants and plant-derived formulations have been used by mankind from the ancient period of time. For the past few years, many investigations elaborated the therapeutic potential of various secondary chemicals present in the plants. Literature revealed that the various secondary metabolites, viz. phenolics and flavonoids, are responsible for a variety of therapeutic action in humans.

Main body

In the present review, an attempt has been made to compile the exploration of natural phenolic compounds with major emphasis on flavonoids and their therapeutic potential too. Interestingly, long-term intake of many dietary foods (rich in phenolics) proved to be protective against the development and management of diabetes, cancer, osteoporosis, cardiovascular diseases and neurodegenerative diseases, etc.

Conclusion

This review presents an overview of flavonoid compounds to use them as a potential therapeutic alternative in various diseases and disorders. In addition, the present understanding of phenolics and flavonoids will serve as the basis for the next scientific studies.

Selectivity of Current Extraction Techniques for Flavonoids from Plant Materials

Flavonoids have a broad spectrum of established positive effects on human and animal health. They find an application in medicine for disease therapy and chemoprevention, whence the interest in flavonoids increases. In addition, they are used in food and cosmetic industries as pigments and biopreservatives. Plants are an inexhaustible source of flavonoids. The most important step of plant raw material processing is extraction and isolation of target compounds. The quality of an extract and efficiency of a procedure are influenced by several factors: Plant material and pre-extracting sample preparation, type of solvent, extraction technique, physicochemical conditions, etc. The present overview discusses the common problems and key challenges of the extraction procedures and the different mechanisms for selective extraction of flavonoids from different plant sources. In summary, there is no universal extraction method and each optimized procedure is individual for the respective plants. For an extraction technique to be selective, it must combine an optimal solvent or mixture of solvents with an appropriate technique. Last but not least, its optimization is important for a variety of applications. Moreover, when the selected method needs to be standardized, it must achieve acceptable degree of repeatability and reproducibility.

Effect of Ultraviolet C Irradiation on Isoflavone Concentrations in Different Cultivars of Soybean (Glycine max)

Phytoestrogens are naturally occurring plant polyphenolic compounds present in high concentrations in soybean products. Phytoestrogens are divided into three classes: lignans, isoflavones, and coumestans. Nine types of glycoside isoflavones and three types of aglycoside isoflavones are reported in soybean. Soy isoflavones can reduce the risk of a certain type of cancer, cardiovascular problems, osteoporosis, and menopausal symptoms. We irradiated the leaves of five cultivars of soybean with UV-C (260 nm) and determined the effect on concentrations of isoflavone compounds using liquid chromatography–mass spectrometry (LC–MS). Isoflavone concentrations were significantly higher following irradiation, particularly in the cultivar Daepung, which was selected as the best cultivar for high isoflavone induction with UV-C irradiation. Further experimentation with the cultivar Daepung revealed that 20 min UV-C irradiation was the best treatment for the induction of aglycone compounds, and 5 min with the dorsal surface facing the UV-C irradiation source was the best treatment for the induction of glycoside isoflavone compounds.

Phytoestrogen intake and other dietary risk factors for low motile sperm count and poor sperm morphology

BACKGROUND

Few potentially modifiable risk factors of male infertility have been identified, and while different diets and food groups have been associated with male infertility, evidence linking dietary factors including phytoestrogens and semen quality is limited and contradictory.

OBJECTIVES

To study the associations between phytoestrogen intake and other dietary factors and semen quality.

MATERIALS AND METHODS

A case-referent study was undertaken of the male partners, of couples attempting conception with unprotected intercourse for 12 months or more without success, recruited from 14 UK assisted reproduction clinics. A total of 1907 participants completed occupational, lifestyle and dietary questionnaires before semen quality (concentration, motility and morphology) were assessed. Food intake was estimated by a 65-item food frequency questionnaire (FFQ) covering the 12 months prior to recruitment. Analyses of dietary risk factors for low motile sperm concentration (MSC: <4.8 × 10⁶ /mL) and poor sperm morphology (PM: <4% normal morphology) used unconditional logistic regression, accounting for clustering of subjects within the clinics, first without, and then with, adjustment for confounders associated with that outcome.

RESULTS

High consumption of daidzein (≥13.74 μg/d), a phytoestrogen found in soy products, was a protective factor for MSC with an odds ratio (95%CI) of 0.58 (0.42-0.82) after adjustment for clustering and potential confounding. Dietary risk factors for PM after similar adjustment showed that drinking whole milk (OR 0.67, 95%CI 0.47-0.96) and eating red meat were protective with an OR 0.67 (0.46-0.99) for eating red meat >3 times/wk.

DISCUSSION

In this case-referent study of men attending an infertility clinic for fertility diagnosis, we have identified that low MSC is inversely associated with daidzein intake. In contrast, daidzein intake was not associated with PM but eating red milk and drinking whole milk were protective.

CONCLUSIONS

Dietary factors associated with semen quality were identified, suggesting that male fertility might be improved by dietary changes.

Effect of porcine reproductive and respiratory syndrome virus infection and soy isoflavone supplementation on carcass cutability and meat quality of pigs

The objective was to evaluate the effects of porcine reproductive and respiratory syndrome virus (PRRSV) infection and dietary soy isoflavone (ISF) supplementation on carcass cutability and meat quality of commercial pigs. Barrows (21 d of age) were randomly allotted to experimental treatments that were maintained throughout the study: noninfected pigs received an ISF-devoid control diet (CON, n = 22) and infected pigs received either the control diet (PRRSV-CON, n = 20) or that supplemented with total ISF in excess of 1,500 mg/kg (PRRSV-ISF, n = 25). Pigs were penned by treatment, with six pigs within a pen. Following a 7-d adaptation, weanling pigs were inoculated once intranasally with either a sham-control (phosphate buffered saline [PBS]) or live PRRSV (1 × 105 tissue culture infective dose [TCID]50/mL, strain NADC20). Pigs were maintained on experimental diets for 166 d after inoculation and then slaughtered (192 or 194 d of age; approximately 120 kg body weight [BW]). At 1-d postmortem, left sides were separated between the 10th and 11th rib for the determination of loin eye area (LEA), backfat (BF) thickness, and loin quality (ultimate pH, instrumental color, drip loss, visual color, marbling, and firmness). Loin chops were aged 14 d postmortem prior to Warner-Bratzler shear force (WBSF) determination. Belly width, length, thickness, and flop distance were determined. Data were analyzed as a one-way ANOVA with pig as the experimental unit. Carcass yield, LEA, BF, and estimated lean percentage did not differ (P > 0.26) among treatments. Loins from CON pigs had increased ultimate pH (P = 0.01), reduced L* scores (P = 0.005) coupled with darker visual color scores (P = 0.004), were firmer (P < 0.0001), and exhibited reduced drip loss (P = 0.01) compared with PRRSV-CON and PRRSV-ISF pigs. However, WBSF did not differ (P = 0.51) among treatments after 14 d of aging. Bellies from CON pigs were more firm compared with bellies from PRRSV-CON and ISF pigs (P < 0.01). These data suggest PRRSV infection did not alter carcass characteristics but may have marginally reduced loin and belly quality. Supplementation with dietary soy isoflavones did nothing to mitigate the detrimental effects of PRRSV infection.

Detection of Phytoestrogen Metabolites in Breastfed Infants' Urine and the Corresponding Breast Milk by Liquid Chromatography-Tandem Mass Spectrometry

To date, there has been limited information on phytoestrogen (PE) exposure and metabolism in breastfed infants. In the present work, 50 sample pairs of Chinese breastfed infants' urine and the corresponding breast milk were collected. The contents of the relevant PE metabolites in the biosamples were detected via liquid chromatography-tandem mass spectrometry. The correlations between the PE metabolite contents in breastfed infants' urine and those in the corresponding breast milk were analyzed. The average concentrations of total PE metabolites in breast milk and urine were 0.27 and 0.23 nmol/mL, respectively. Genistein and enterolactone levels in the infant urine were positively correlated with their concentrations in the corresponding breast milk samples, which implies that urine excretion can be utilized as a noninvasive parameter for precise genistein and enterolactone intake assessment. Additionally, the efficiency of PE urine excretion showed significant differences across infants with different ages, genders, and durations of pregnancy.

Propolis Reduces the Expression of Autophagy-Related Proteins in Chondrocytes under Interleukin-1β Stimulus

Background: Osteoarthritis (OA) is a progressive and multifactorial disease that is associated with aging. A number of changes occur in aged cartilage, such as increased oxidative stress, decreased markers of healthy cartilage, and alterations in the autophagy pathway. Propolis extracts contain a mixture of polyphenols and it has been proved that they have high antioxidant capacity and could regulate the autophagic pathway. Our objective was to evaluate the effect of ethanolic extract of propolis (EEP) on chondrocytes that were stimulated with IL-1β. Methods: Rabbit chondrocytes were isolated and stimulated with IL-1β and treated with EEP. We evaluated cell viability, nitric oxide production, healthy cartilage, and OA markers, and the expression of three proteins associated with the autophagy pathway LC3, ATG5, and AKT1. Results: The EEP treatment reduces the expression of LC3, ATG5, and AKT1, reduces the production of nitric oxide, increases the expression of healthy markers, and reduces OA markers. Conclusions: These results suggest that treatment with EEP in chondrocytes that were stimulated with IL-1β has beneficial effects, such as a decrease in the expression of proteins associated with autophagy, MMP13, and production of nitric oxide, and also increased collagen II.

Establishment and depletion of the ovarian reserve: physiology and impact of environmental chemicals

The reproductive life span in women starts at puberty and ends at menopause, following the exhaustion of the follicle stockpile termed the ovarian reserve. Increasing data from experimental animal models and epidemiological studies indicate that exposure to a number of ubiquitously distributed reproductively toxic environmental chemicals (RTECs) can contribute to earlier menopause and even premature ovarian failure. However, the causative relationship between environmental chemical exposure and earlier menopause in women remains poorly understood. The present work, is an attempt to review the current evidence regarding the effects of RTECs on the main ovarian activities in mammals, focusing on how such compounds can affect the ovarian reserve at any stages of ovarian development. We found that in rodents, strong evidence exists that in utero, neonatal, prepubescent and even adult exposure to RTECs leads to impaired functioning of the ovary and a shortening of the reproductive lifespan. Regarding human, data from cross-sectional surveys suggest that human exposure to certain environmental chemicals can compromise a woman's reproductive health and in some cases, correlate with earlier menopause. In conclusion, evidences exist that exposure to RTECs can compromise a woman's reproductive health. However, human exposures may date back to the developmental stage, while the adverse effects are usually diagnosed decades later, thus making it difficult to determine the association between RTECs exposure and human reproductive health. Therefore, epidemiological surveys and more experimental investigation on humans, or alternatively primates, are needed to determine the direct and indirect effects caused by RTECs exposure on the ovary function, and to characterize their action mechanisms.

Food components and environmental chemicals of inhibiting human placental aromatase

Human placental CYP19A1 catalyzes the estrogen synthesis from androgens. The enzyme is encoded by CYP19A1 gene located in chromosome 15q21. This enzyme is a monooxygenase in the smooth endoplasmic reticulum. The various promoters of the CYP19A1 gene determine its expression in different tissues and the distal promoter I.1 controls its expression in the placenta and retinoids can regulate the expression. Many food components and environmental chemicals inhibit CYP19A1 activity via different modes of action. These chemicals include gossypol, flavones, flavanones, chalconoids, resveratrol, and tobacco alkaloids derived from foods as well as phthalates, insecticides, fungicides, and biocides in the contaminated foods. The inhibition of placental CYP19A1 could impair pregnancy.

Oestrogenic Isoflavone Content in Natural Strains of Subterranean Clover (Trifolium subterraneum L.) from Sardinia

A collection of subterranean clover (Trifolium subterraneum L.) genotypes from Sardinia was evaluated for the content of oestrogenic isoflavones to assess differences in total and individual compounds. Daidzein, genistein, and their respective 4′-methoxy derivatives biochanin A and formononetin, were detected in leaves and quantified by GC/FID and GC/MS methods. A large variation among genotypes for individual compounds and for the total isoflavone concentration was observed. Total isoflavones were measured in the range 0.8-13.4 mg/g fresh weight (0.3-4.5% dry matter). Daidzein was usually present in lower amount compared to the other isoflavones. Genistein and biochanin A were found in most cases in higher concentration than formononetin. Phyto-oestrogens have been shown to have both oestrogenic and anti-oestrogenic properties, and their effects entail a positive role for the human health. T. subterraneum revealed the presence of higher concentration of isoflavones compared to other sources of these compounds, e.g. soybean (Glycine max (L.) Merrill) and red clover (Trifolium pratense L.). This study provided information on the biodiversity of the natural strains from Sardinia, emphasizing the importance of these genetic resources for their variation in the amount of total and individual isoflavones.

Soy, Soy Foods and Their Role in Vegetarian Diets

Soy is a basic food ingredient of traditional Asian cuisine used for thousands of years. In Western countries, soybeans have been introduced about a hundred years ago and recently they are mainly used for surrogate foods production. Soy and soy foods are common nutritional solutions for vegetarians, due to their high protein content and versatility in the production of meat analogues and milk substitutes. However, there are some doubts about the potential effects on health, such as the effectiveness on cardiovascular risk reduction or, conversely, on the possible disruption of thyroid function and sexual hormones. The soy components that have stimulated the most research interest are isoflavones, which are polyphenols with estrogenic properties highly contained in soybeans. In this review, we discuss the characteristics of soy and soy foods, focusing on their nutrient content, including phytoestrogens and other bioactive substances that are noteworthy for vegetarians, the largest soy consumers in the Western countries. The safety of use will also be discussed, given the growing trend in adoption of vegetarian styles and the new soy-based foods availability.

Is vegetarian diet associated with a lower risk of breast cancer in Taiwanese women?

Background

Studies on the relationship between vegetarian diet and breast cancer in Asian populations are limited. This study aimed to investigate the relationship between vegetarian diet, dietary patterns, and breast cancer in Taiwanese women.

Methods

This case-control study compared the dietary patterns of 233 breast cancer patients and 236 age-matched controls. A questionnaire about vegetarian diets and 28 frequently-consumed food items was administered to these 469 patients in the surgical department of Taipei Tzu Chi Hospital. Serum biochemical status was also examined.

Results

There were no significant differences between the two groups for age, education, family history, oral contraceptive usage, or regular exercise. However, the cancer group presented with both a higher body mass index and an older age of primiparity (P < 0.05). Two food items (shellfish and seafood) were highly correlated (correlation coefficient = 0.77), so shellfish was excluded to avoid multicollinearity. A factor analysis of 27 food items produced five dietary patterns: meat, processed meat, fruit/vegetable/soybean, dessert/sugar, and fermented food. Multivariate logistic regression showed that meat/fat and processed meat dietary patterns were associated with breast cancer risk (odds ratio (OR): 2.22, 95% CI 1.67–2.94, P < 0.001; OR: 1.49, 95% CI 1.09–2.04, P = 0.013, respectively). Vegetarian diet, high isoflavone intake, and high albumin levels were inversely associated with breast cancer risk (P < 0.05). Vegetarians had a higher daily soy isoflavone intake than non-vegetarians (25.9 ± 25.6 mg vs. 18.1 ± 15.6 mg, P < 0.001).

Conclusions

Vegetarian diets show as protective role against breast cancer risk, while meat and processed meat dietary patterns are associated with a higher breast cancer risk.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4819-1) contains supplementary material, which is available to authorized users.

Degradation of sulfadimethoxine catalyzed by laccase with soybean meal extract as natural mediator: Mechanism and reaction pathway

Natural laccase-mediator systems have been well recognized as an eco-friendly and energy-saving approach in environmental remediation, whose further application is however limited by the high cost of natural mediators and relatively long treatment time span. This study evaluated the water extract of soybean meal, a low-cost compound system, in mediating the laccase catalyzed degradation of a model contaminant of emerging concern, sulfadimethoxine (SDM), and demonstrated it as a promising alternative mediator for soil and water remediation. Removal of 73.3% and 65.6% was achieved in 9 h using soybean meal extract (SBE) as the mediating system for laccase-catalyzed degradation of sulfadimethoxine at the concentration of 1 ppm and 10 ppm, respectively. Further degradation of sulfadimethoxine was observed with multiple SBE additions. Using SBE as mediator increased the 9-h removal of SDM at 1 ppm initial concentration by 52.9%, 49.4%, and 36.3% in comparison to the system mediated by 1-Hydroxybenzotriazole (HBT), p-Coumaric acid (COU) and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS), respectively. With the detection of stable coupling products formed with radical scavenger (5,5-Dimethyl-1-pyrroline N-oxide, DMPO), three phenolic compounds (vanillin, apocynin, and daidzein) in SBE were confirmed to serve as mediators for Trametes versicolor laccase. Reaction pathways were proposed based on the results of High Resolution Mass Spectrometry. SO2 excursion happened during SDM transformation, leading to elimination of antimicrobial activity. Therefore, as a natural, phenol rich, and affordable compound system, the future application of SBE in wastewater and soil remediation is worth exploring.

Effects of genistein supplementation on genome‑wide DNA methylation and gene expression in patients with localized prostate cancer

Epidemiological studies have shown that dietary compounds have significant effects on prostate carcinogenesis. Among dietary agents, genistein, the major isoflavone in soybean, is of particular interest because high consumption of soy products has been associated with a low incidence of prostate cancer, suggesting a preventive role of genistein in prostate cancer. In spite of numerous studies to understand the effects of genistein on prostate cancer, the mechanisms of action have not been fully elucidated. We investigated the differences in methylation and gene expression levels of prostate specimens from a clinical trial of genistein supplementation prior to prostatectomy using Illumina HumanMethylation450 and Illumina HumanHT-12 v4 Expression BeadChip Microarrays. The present study was a randomized, placebo-controlled, double-blind clinical trial on Norwegian patients who received 30 mg genistein or placebo capsules daily for 3–6 weeks before prostatectomy. Gene expression changes were validated by quantitative PCR (qPCR). Whole genome methylation and expression profiling identified differentially methylated sites and expressed genes between placebo and genistein groups. Differentially regulated genes were involved in developmental processes, stem cell markers, proliferation and transcriptional regulation. Enrichment analysis suggested overall reduction in MYC activity and increased PTEN activity in genistein-treated patients. These findings highlight the effects of genistein on global changes in gene expression in prostate cancer and its effects on molecular pathways involved in prostate tumorigenesis.

Edible Plants and Their Influence on the Gut Microbiome and Acne

Acne vulgaris affects most people at some point in their lives. Due to unclear etiology, likely with multiple factors, targeted and low-risk treatments have yet to be developed. In this review, we explore the multiple causes of acne and how plant-based foods and supplements can control these. The proposed causative factors include insulin resistance, sex hormone imbalances, inflammation and microbial dysbiosis. There is an emerging body of work on the human gut microbiome and how it mediates feedback between the foods we eat and our bodies. The gut microbiome is also an important mediator of inflammation in the gut and systemically. A low-glycemic load diet, one rich in plant fibers and low in processed foods, has been linked to an improvement in acne, possibly through gut changes or attenuation of insulin levels. Though there is much interest in the human microbiome, there is much more unknown, especially along the gut-skin axis. Collectively, the evidence suggests that approaches such as plant-based foods and supplements may be a viable alternative to the current first line standard of care for moderate acne, which typically includes antibiotics. Though patient compliance with major dietary changes is likely much lower than with medications, it is a treatment avenue that warrants further study and development.

An updated review of dietary isoflavones: Nutrition, processing, bioavailability and impacts on human health

Isoflavones (genistein, daidzein, and glycitein) are bioactive compounds with mildly estrogenic properties and often referred to as phytoestrogen. These are present in significant quantities (up to 4-5 mg·g^-1 on dry basis) in legumes mainly soybeans, green beans, mung beans. In grains (raw materials) they are present mostly as glycosides, which are poorly absorbed on consumption. Thus, soybeans are processed into various food products for digestibility, taste and bioavailability of nutrients and bioactives. Main processing steps include steaming, cooking, roasting, microbial fermentation that destroy protease inhibitors and also cleaves the glycoside bond to yield absorbable aglycone in the processed soy products, such as miso, natto, soy milk, tofu; and increase shelf lives. Processed soy food products have been an integral part of regular diets in many Asia-Pacific countries for centuries, e.g. China, Japan and Korea. However, in the last two decades, there have been concerted efforts to introduce soy products in western diets for their health benefits with some success. Isoflavones were hailed as magical natural component that attribute to prevent some major prevailing health concerns. Consumption of soy products have been linked to reduction in incidence or severity of chronic diseases such as cardiovascular, breast and prostate cancers, menopausal symptoms, bone loss, etc. Overall, consuming moderate amounts of traditionally prepared and minimally processed soy foods may offer modest health benefits while minimizing potential for any adverse health effects.

Effects of dietary soybean isoflavones (SI) on reproduction in the young breeder rooster

Soybean isoflavones (SIs) are phytoestrogens that competitive with estrogens in body. Although SIs play an important role in reproduction, their role in testicular development in roosters is unknown. This study was conducted to investigate the effect of SIs on testicular development and serum reproductive hormone profiles in young breeder roosters (70-133days old). Gene expression of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD), which are related to testosterone synthesis, in rooster testis were also evaluated after treatment with different SI doses. Although SIs had no significant effect on body weight, 5mg/kg SIs significantly increased the testis index and serum levels of reproductive hormones (gonadotropin releasing hormone, follicle- stimulating hormone, luteinizing hormone, and testosterone).To further investigate whether SIs regulate hormone synthesis via StAR, p450scc, 3β-HSD, real time-PCR was performed to measure the mRNA levels of the corresponding genes. The results showed that 5mg/kg of SIs significantly increased StAR mRNA levels. However, there were no significant effects on p450scc or 3β-HSD mRNA levels. Moreover, the spermatogonial development and the number of germ cell layers were increased by treatment with 5mg/kg of SIs. These results suggest that SIs promote testicular growth by increasing reproductive hormone secretion, which is closely related to StAR expression, to positively regulate reproduction in young roosters.

Targeting Nitric Oxide with Natural Derived Compounds as a Therapeutic Strategy in Vascular Diseases

Within the family of endogenous gasotransmitters, nitric oxide (NO) is the smallest gaseous intercellular messenger involved in the modulation of several processes, such as blood flow and platelet aggregation control, essential to maintain vascular homeostasis. NO is produced by nitric oxide synthases (NOS) and its effects are mediated by cGMP-dependent or cGMP-independent mechanisms. Growing evidence suggests a crosstalk between the NO signaling and the occurrence of oxidative stress in the onset and progression of vascular diseases, such as hypertension, heart failure, ischemia, and stroke. For these reasons, NO is considered as an emerging molecular target for developing therapeutic strategies for cardio- and cerebrovascular pathologies. Several natural derived compounds, such as polyphenols, are now proposed as modulators of NO-mediated pathways. The aim of this review is to highlight the experimental evidence on the involvement of nitric oxide in vascular homeostasis focusing on the therapeutic potential of targeting NO with some natural compounds in patients with vascular diseases.

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.

Estrogenic and Anti-estrogenic Constituents of Erythrina caffra

Utilizing the pER8:GUS transgenic plant bioassay system to monitor estrogenic activity-guided fractionation, one new constituent, erycaffrain A, together with 11 known compounds were isolated from the ethanolic extract of Erythrina caffra. The structures of the isolated compounds were identified in combination with spectroscopic analyses. This is the first study reporting the estrogenic activity of E. caffra. The new compound exhibited as a SREM, but also showed both estrogenic and anti-estrogenic activities in the MCF-7 cancer cell model. Several known phytoestrogens in this plant also revealed possible new functions for E. caffra stem.

Plasma equol concentration is not associated with breast cancer and fibrocystic breast conditions among women in Shanghai, China

Equol (a bacterial metabolite of the soy isoflavone daidzein) is produced by 30% to 50% of humans and may be associated with health outcomes. We hypothesized that plasma equol would be inversely associated with risks of fibrocystic breast conditions (FBC) and breast cancer (BC). Plasma from women in a breast self-examination trial in Shanghai with BC (n=269) or FBC (n=443), and age-matched controls (n=1027) was analyzed for isoflavones. Equol was grouped into categories (<20, 20-<45, and ≥45nmol/L) and, among women with daidzein ≥20nmol/L, the log10 equol:daidzein ratio was grouped into tertiles. Where available, non-cancerous tissue (NCT) adjacent to the carcinomas from women with BC were classified as non-proliferative or proliferative (n=130 and 172, respectively). The lesions from women with FBC were similarly classified (n=99 and 92, respectively). Odds ratios (OR) and 95% confidence intervals (CI) were calculated across equol categories and tertiles of log10 equol:daidzein ratio. Equol categories were not associated with FBC or BC (P>.05). For log10 equol:daidzein, compared to controls there were positive associations in the mid tertile for proliferative FBC (OR 2.06, 95% CI 1.08-3.93), BC with proliferative NCT (OR 2.95, 95% CI 1.37-6.35), and all BC regardless of histology (OR 2.37, 95% CI 1.43-3.95). However, trends in ORs with increasing plasma equol values or equol:daidzein ratios were not observed (P>.05). The results of this study do not provide evidence that equol plays a role in the etiology of these breast conditions. However, further work is needed to confirm or refute this conclusion.

Genistein exposure inhibits growth and alters steroidogenesis in adult mouse antral follicles

Genistein is a naturally occurring isoflavone phytoestrogen commonly found in plant products such as soybeans, lentils, and chickpeas. Genistein, like other phytoestrogens, has the potential to mimic, enhance, or impair the estradiol biosynthesis pathway, thereby potentially altering ovarian follicle growth. Previous studies have inconsistently indicated that genistein exposure may alter granulosa cell proliferation and hormone production, but no studies have examined the effects of genistein on intact antral follicles. Thus, this study was designed to test the hypothesis that genistein exposure inhibits follicle growth and steroidogenesis in intact antral follicles. To test this hypothesis, antral follicles isolated from CD-1 mice were cultured with vehicle (dimethyl sulfoxide; DMSO) or genistein (6.0 and 36μM) for 18-96h. Every 24h, follicle diameters were measured to assess growth. At the end of each culture period, the media were pooled to measure hormone levels, and the cultured follicles were collected to measure expression of cell cycle regulators and steroidogenic enzymes. The results indicate that genistein (36μM) inhibits growth of mouse antral follicles. Additionally, genistein (6.0 and 36μM) increases progesterone, testosterone, and dehydroepiandrosterone (DHEA) levels, but decreases estrone and estradiol levels. The results also indicate that genistein alters the expression of steroidogenic enzymes at 24, 72 and 96h, and the expression of cell cycle regulators at 18h. These data indicate that genistein exposure inhibits antral follicle growth by inhibiting the cell cycle, alters sex steroid hormone levels, and dysregulates steroidogenic enzymes in cultured mouse antral follicles.

The Role of Soy Phytoestrogens on Genetic and Epigenetic Mechanisms of Prostate Cancer

Soy phytoestrogens are dietary components with considerable effects on reducing the incidence of prostate cancer. Epidemiological studies demonstrated that occurrence of prostate cancer is relatively low in Asia and Southern Europe, a status associated with consuming of soy isoflavones, such as genistein, daidzein, and glycitein. Soy phytoestrogens exert their activity on molecular mechanisms, including cell-cycle control, induction of apoptosis, inhibition of angiogenesis, and metastasis. In addition, they have antioxidant activity and show regulatory effect on the expression of genes involved in DNA damage and repair. Furthermore, the epigenetic regulation of gene expression can be modified by soy phytoestrogens. They show regulatory effects on gene activity by altering DNA methylation and/or histone modification patterns. In this chapter, we discuss the role of soy phytoestrogens on the genetic and epigenetic mechanisms of prostate cancer. We attempt to provide further insight in order to understand the underlying mechanisms of protective effects of soy phytoestrogens in preventing prostate cancer.

Effects of Endocrine-Disrupting Chemicals on the Ovary

Endocrine-disrupting chemicals (EDCs) are found abundantly in the environment, resulting in daily human exposure. This is of concern because many EDCs are known to target the female reproductive system and, more specifically, the ovary. In the female, the ovary is the key organ responsible for reproductive and endocrine functions. Exposure to EDCs is known to cause many reproductive health problems such as infertility, premature ovarian failure, and abnormal sex steroid hormone levels. Some EDCs and their effects on adult ovarian function have been studied extensively over the years, whereas the effects of others remain unclear. This review covers what is currently known about the effects of selected EDCs (bisphenol A, methoxychlor, 2,3,7,8-tetrachlorodibenzo-p-dioxin, phthalates, and genistein) on the adult ovary and the mechanisms by which they act upon the ovary, focusing primarily on their effects on folliculogenesis and steroidogenesis. Furthermore, this review discusses future directions needed to better understand the effects of EDCs, including the need to examine the effects of multiple and more consistent doses and to study different mechanisms of action.

Modulation of glucose transporter protein by dietary flavonoids in type 2 diabetes mellitus

Diabetes mellitus (DM) is a metabolic diseases characterized by hyperglycemia due to insufficient or inefficient insulin secretory response. This chronic disease is a global problem and there is a need for greater emphasis on therapeutic strategies in the health system. Phytochemicals such as flavonoids have recently attracted attention as source materials for the development of new antidiabetic drugs or alternative therapy for the management of diabetes and its related complications. The antidiabetic potential of flavonoids are mainly through their modulatory effects on glucose transporter by enhancing GLUT-2 expression in pancreatic β cells and increasing expression and promoting translocation of GLUT-4 via PI3K/AKT, CAP/Cb1/TC10 and AMPK pathways. This review highlights the recent findings on beneficial effects of flavonoids in the management of diabetes with particular emphasis on the investigations that explore the role of these compounds in modulating glucose transporter proteins at cellular and molecular level.

Dietary isoflavones and bone mineral density during midlife and the menopausal transition: cross-sectional and longitudinal results from the Study of Women's Health Across the Nation Phytoestrogen Study

OBJECTIVE

This study aims to examine cross-sectional and longitudinal relations between dietary intake of isoflavones and bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN) in black, white, Chinese, and Japanese women during the menopausal transition.

METHODS

We tested whether tertiles of isoflavone intake were associated with baseline BMD when all women were premenopausal or early perimenopausal. To analyze whether isoflavone intake was associated with longitudinal BMD, we fitted piecewise linear models to repeated measurements of baseline-normalized LS or FN BMD as functions of time before or after the final menstrual period (FMP) date.

RESULTS

Multiply adjusted mean FN BMD values of premenopausal Japanese women were monotonically positively related to isoflavone consumption (P for trend = 0.0003). Otherwise, no statistically significant baseline associations were observed. During the period of 1 year before the FMP through 5 years after the FMP, all participants lost LS and FN BMD. Loss was unrelated to isoflavone intake, except for Japanese women during the period of 1 year before the FMP to 2 years after the FMP: higher tertiles of isoflavone intake were associated with greater annual LS BMD loss rates (P for trend = 0.01) and FN loss rates (P for trend = 0.04).

CONCLUSIONS

In Japanese women, higher isoflavone intake is associated with higher peak FN BMD but also with greater rates of LS and FN BMD loss during the menopausal transition. Results for the other racial/ethnic groups did not support a relation between dietary intake of isoflavones and either peak BMD or BMD loss during the menopausal transition.

Therapeutic effects of isoflavones on impaired salivary secretion

Dry mouth, which is characterized by decreased salivation, has a number of causes; the involvement of estrogen has been suggested as symptoms typically develop in middle-aged females. However, there is a lack of consensus regarding the treatment of this condition. Soy isoflavones, a subgroup of flavonoids, are abundantly found in the soy germ. They are thought to exert a number of effects by specifically binding to estrogen receptors due to their structural similarity to estrogen. Recently, soy isoflavones have been found to exert antioxidant effects, ameliorating disorders caused by reactive oxygen/free radicals. Based on these observations, the effects of soybean isoflavones on impaired salivary secretion were studied in patients with dry mouth. Soy isoflavone aglycones were administered at 25 mg per day to 15 subjects with an average age of 67.9 ± 8.0 years for 2 months, and salivary secretion was analyzed. The results showed a significant improvement based on the saliva flow rate and self-completed questionnaire, thus suggesting the usefulness of isoflavones in improving the symptoms of salivary gland hypofunction.

Phytoestrogens in postmenopause: the state of the art from a chemical, pharmacological and regulatory perspective

Phytoestrogens represent a diverse group of non-steroidal natural products, which seem to have some oestrogenic effects and are often marketed as food supplements. Population exposed to phytoestrogens is potentially increasing, in part because an unfavourable risk-benefit profile of Hormone Replacement Therapy (HRT) for prolonged treatments (e.g., osteoporosis prevention) highlighted by the publication of the Women Health Initiative (WHI) trial in 2002, but also because many post-menopausal women often perceived phytoestrogens in food supplements as a safer alternative than HRT. Despite of increasing preclinical and clinical studies in the past decade, appealing evidence is still lacking to support the overall positive risk-benefit profile of phytoestrogens. Their status as food supplements seems to discourage studies to obtain new evidence, and the chance to buy them by user's initiative make it difficult to survey their prevalence and pattern of use. The aim of the present review is to: (a) outline the clinical scenario underlying the increased interest on phytoestrogens, by overviewing the evolution of the evidence on HRT and its main therapeutic goals (e.g., menopausal symptoms relief, chemoprevention, osteoporosis prevention); (b) address the chemical and pharmacological features (e.g. chemical structure, botanical sources, mechanism of action) of the main compounds (e.g., isoflavones, lignans, coumestans); (c) describe the clinical evidence on potential therapeutic applications; (d) put available evidence on their riskbenefit profile in a regulatory perspective, in light of the recent regulation on health claims of food supplements.

A Critical Appraisal of Solubility Enhancement Techniques of Polyphenols

Polyphenols constitute a family of natural substances distributed widely in plant kingdom. These are produced as secondary metabolites by plants and so far 8000 representatives of this family have been identified. Recently, there is an increased interest in the polyphenols because of the evidence of their role in prevention of degenerative diseases such as neurodegenerative diseases, cancer, and cardiovascular diseases. Although a large number of drugs are available in the market for treatment of these diseases, however, the emphasis these days is on the exploitation of natural principles derived from plants. Most polyphenols show low in vivo bioavailability thus limiting their application for oral drug delivery. This low bioavailability could be associated with low aqueous solubility, first pass effect, metabolism in GIT, or irreversible binding to cellular DNA and proteins. Therefore, there is a need to devise strategies to improve oral bioavailability of polyphenols. Various approaches like nanosizing, self-microemulsifying drug delivery systems (SMEDDS), microencapsulation, complexation, and solid dispersion can be used to increase the bioavailability. This paper will highlight the various methods that have been employed till date for the solubility enhancement of various polyphenols so that a suitable drug delivery system can be formulated.