Dietary phytoestrogens

The Potential of Plant Phenolics in Prevention and Therapy of Skin Disorders

Phenolic compounds constitute a group of secondary metabolites which have important functions in plants. Besides the beneficial effects on the plant host, phenolic metabolites (polyphenols) exhibit a series of biological properties that influence the human in a health-promoting manner. Evidence suggests that people can benefit from plant phenolics obtained either by the diet or through skin application, because they can alleviate symptoms and inhibit the development of various skin disorders. Due to their natural origin and low toxicity, phenolic compounds are a promising tool in eliminating the causes and effects of skin aging, skin diseases, and skin damage, including wounds and burns. Polyphenols also act protectively and help prevent or attenuate the progression of certain skin disorders, both embarrassing minor problems (e.g., wrinkles, acne) or serious, potentially life-threatening diseases such as cancer. This paper reviews the latest reports on the potential therapy of skin disorders through treatment with phenolic compounds, considering mostly a single specific compound or a combination of compounds in a plant extract.

Flaxseed reduces epithelial proliferation but does not affect basal cells in induced benign prostatic hyperplasia in rats

PURPOSE

This study aimed to quantitatively and qualitatively evaluate the effects of a flaxseed-based diet on the histoarchitecture of the prostate of normal Wistar rats and of rats with induced BPH.

METHODS

The study included four experimental groups of ten animals each: casein control group (CCG), who were fed a casein-based diet; flaxseed control group (FCG), who were fed a flaxseed-based diet; hyperplasia-induced casein group (HICG), who were fed a casein-based diet; and hyperplasia-induced flaxseed group (HIFG), who were fed a flaxseed-based diet. Hyperplasia was induced by the subcutaneous implantation of silicone pellets containing testosterone propionate. After 20 weeks, the rats were euthanized and their prostate fixed in buffered formalin. Tissue sections were stained with HE, picrosirius red and immunostained for nuclear antigen p63. Histomorphometric analysis evaluated the epithelial thickness, epithelial area, individual luminal area, and total area of prostatic alveoli.

RESULTS

The mean epithelial thickness obtained for HIFG and HICG was 16.52 ± 1.65 and 20.58 ± 2.86 µm, respectively. The mean epithelial thickness in HICG was greater than that in the other groups tested. HIFG had a smaller epithelial thickness and lower percentage of papillary projections in the prostatic alveoli. No significant difference was observed between CCG and FCG. The total area and mean alveolar area showed no significant differences between the groups. The number of cells immunostained for p63 was not significantly different between the groups evaluated.

CONCLUSION

These results suggest that flaxseed has a protective effect on the prostate epithelium in BPH-induced animals.

A robust analytical method for measurement of phytoestrogens and related metabolites in serum with liquid chromatography tandem mass spectrometry

A sensitive and robust method using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for quantitation of 13 phytoestrogens and related metabolites in rat serum samples. A new type of column, the Kinetex core-shell C18 column, was applied for rapid separation of the target analytes in 10min. Two enzymes, sulfatase H-1 and gulcuronidase H-5 from Helix pomatia were compared on the efficiency of releasing the conjugated forms of the target analytes to their free forms in serum samples. The method detection limit (MDL) defined as three times the signal to noise ratio in spiked serum matrix-based solutions was in the range of 0.1-3.5ng/mL. The linear dynamic calibration was in the broad range of 0.2-500ng/mL for all target compounds. Thirty-two rat serum samples from the rats that were fed with diets containing either casein or soy protein isolates with various amounts of isoflavones for 8 weeks were analyzed for the target analytes with the developed method. Nine target analytes were detected in the serum samples. Those detectable compounds are all the metabolites of the dietary isoflavones, suggesting that the diet isoflavones were mostly metabolized to their metabolites in rat.

Interaction of Isoflavones and Endophyte-Infected Tall Fescue Seed Extract on Vasoactivity of Bovine Mesenteric Vasculature

It was hypothesized that isoflavones may attenuate ergot alkaloid-induced vasoconstriction and possibly alleviate diminished contractility of vasculature after exposure to ergot alkaloids. The objective of this study was to determine if prior incubation of bovine mesenteric vasculature with the isoflavones formononetin (F), biochanin A (B), or an ergovaline-containing tall fescue seed extract (EXT) and their combinations affect ergotamine (ERT)-induced contractility. Multiple segments of mesenteric artery and vein supporting the ileal flange of the small intestine were collected from Angus heifers at slaughter (n = 5, bodyweight = 639 ± 39 kg). Duplicates of each vessel type were incubated in tissue culture flasks at 37°C with a 50-mL volume of Krebs–Henseleit buffer containing: only buffer (control); or 1 × 10⁻⁶ M EXT; F; or B; and combinations of 1 × 10⁻⁶ M EXT + F; 1 × 10⁻⁶ M EXT + B; 1 × 10⁻⁶ M F + B; or 1 × 10⁻⁶ M EXT + F + B. After incubation for 2 h, sections were mounted in a multimyograph chamber. The ERT dose responses were normalized to 0.12 M KCl. Pretreatment with F, B, and F + B without EXT resulted in similar contractile responses to ERT in mesenteric artery and all incubations containing EXT resulted in a complete loss of vasoactivity to ERT. In mesenteric artery pretreated with EXT, treatments that contained B had higher contractile responses (P < 0.05) at ERT concentrations of 1 × 10⁻⁷ and 5 × 10⁻⁷ M. Also, treatments containing B tended (P < 0.1) to have greater responses than treatments without B at ERT concentrations of 1 × 10⁻⁶, 5 × 10⁻⁶, and 5 × 10⁻⁵ M. In mesenteric vein pretreated with EXT, treatments containing F had greater contractile responses to ERT at 1 × 10⁻⁵, 5 × 10⁻⁵, and 1 × 10⁻⁴ M (P < 0.05). These data indicated that F and B at 1 × 10⁻⁶ M and their combination did not impact the overall contractile response to ERT in mesenteric vasculature. However, F and B may offset some of the vasoconstriction caused by prior exposure to ergot alkaloids.

The effects of aqueous extract of alfalfa on blood glucose and lipids in alloxan-induced diabetic rats

Diabetes is a common metabolic disorder that is specified by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The use of nonpharmacological treatments (herbal agents) is a new approach in the management of diabetes. The aim of this study was to investigate the effect of aqueous extract of alfalfa on blood glucose and serum lipids in alloxan-induced diabetic rats. In this study, 32 female rats (210-250 g) were used which were divided randomly into 4 groups including intact control group, diabetic control group, and 2 diabetic groups which received 250 and 500 mg/kg doses of aqueous extract of alfalfa, respectively. In the diabetic groups, alloxan-monohydrate was injected peritoneally to create diabetic condition. The two last groups orally received aqueous extract of alfalfa for 21 days. At the end of experiment, sugar, cholesterol, triglycerides, high-density and low-density lipoprotein, and aspartate aminotransferase (ALT) and alanine aminotransferase (AST) levels were measured in the samples. Consumption of aqueous alfalfa extract significantly reduced glucose, cholesterol, triglycerides, and low-density lipoprotein (LDL) levels in the diabetic rats but enhanced high-density lipoprotein (HDL) levels. ALT and AST liver enzyme levels were also reduced in blood. Histological examination showed that the aqueous alfalfa extract caused reconstruction of damaged liver and enhanced Langerhans islets' diameter in pancreas. Therefore, all signs of diabetes were improved by oral administration of alfalfa in defined dose.

Pharmacokinetic Comparison of Soy Isoflavone Extracts in Human Plasma

The soy isoflavones daidzein and genistein produce several biological activities related to health benefits. A number of isoflavone extracts are commercially available, but there is little information concerning the specific isoflavone content of these products or differences in their bioavailability and pharmacokinetics. This study describes the development and validation of an analytical method to detect and quantify daidzein, genistein, and equol in human plasma using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method was applied in a crossover, randomized, bioavailability study. Twelve healthy volunteers were administered the same total isoflavones dose from two isoflavone supplement preparations (Super-Absorbable Soy Isoflavones (Life Extension, USA) and Fitoladius (Merck, Spain)). The pharmacokinetic parameters (AUC0-24/dose and Cmax/dose) of the isoflavones from the two preparations differed significantly. Such differences in bioavailability and kinetics may have relevant effects on the health benefits derived from their intake.

In vivo estrogenic-like activities of Gouania longipetala Hemsl. (Rhamnaceae) bark extracts in a post-menopause-like model of ovariectomized Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Gouania longipetala is commonly used in Cameroonian traditional medicine to manage women fertility and menopausal complaints. However, despite this use, the estrogenic properties of G. longipetala have not been studied until now.

AIM OF STUDY

The present study was aimed to assess estrogenic activities of the stem bark aqueous (GLA) and ethanolic (GLE) extracts of G. longipetala in post-menopause-like model of ovariectomized (Ovx) Wistar rats.

MATERIAL AND METHODS

Animals were either sham-operated or Ovx. 84 days after ovariectomy, animals were divided into seven groups of five animals and were daily treated for 28 days with distilled water (10 mL/kg) for group 1, 2% solution of Tween 80 (10 mL/kg) for group 2, estradiol valerate (1 mg/kg) for group 3, GLA (45 or 180 mg/kg) and GLE (40 or 160 mg/kg) for groups 4 to 7 respectively. Sham-operated animals daily received distilled water (10 mL/kg). During the experimental period, the body weight was registered every week. At the day 29, blood pressure was registered by invasive method while uterine and vagina morphometry as well as body, uterine and abdominal fat weights changes were analyzed. Serum levels of total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol were determined. Moreover, oxidative stress markers such as nitrites, reduced glutathione (GSH) and malondialdehyde (MDA) were measured in homogenized liver and aorta.

RESULTS

Compared with the sham control, vagina and uterine dystrophy and elevated blood pressure were observed in Ovx rats treated with vehicles. Biochemical parameters showed a significant increase of total cholesterol, triglycerides, LDL-cholesterol and MDA as well as a significant decrease of nitrites and GSH in Ovx animals treated with vehicle as compared to sham group. GLA and GLE displayed estrogen-like effects on vagina and did not affect uterine wet weight and epithelial height compared with vehicle groups. Both extracts displayed anti-atherogenic properties by reducing AI, AIP and LDL-cholesterol level as compared to vehicles groups. GLA and GLE significantly prevented the increase of MDA induced by ovariectomy as compared to rats treated with vehicles.

CONCLUSION

This study showed that GLA and GLE exhibited estrogenic effects by providing vaginal lubrication, by modulating blood pressure and improving lipid profile, oxidative status and endothelial function and may not have an undesirable influence on the endometrium in ovariectomized rats.

Isoflavones: chemistry, analysis, functions and effects on health and cancer

Isoflavones are phytoestrogens and natural plant compounds which are similar to 17-β-estradiol in chemical structure. It is known that they can act as estrogen agonists or antagonists, depending on endocrine estrogenic levels, but actions of isoflavones are rather complex due to large number of variables such as chemical structures and mechanisms. Some hypotheses on biological mechanisms have not satisfactorily been confirmed to date and human epidemiological and experimental studies have been relatively limited. Nevertheless, isoflavones and isoflavone rich foods have become a focus on interest due to positive health benefits on many diseases, especially prevention of hormone-related cancers, cardiovascular disease, osteoporosis, and adverse postmenopausal symptoms, and improvement of physiological condition such as maintaining cognitive function. This review provides an overview of chemistry, analytical techniques (focused on human biospecimens), functions including biological mechanisms, and effects of isoflavones, on the basis of the available meta-analysis and review articles and some original articles, on health and cancer.

Urinary enterolactone associated with liver enzyme levels in US adults: National Health and Nutrition Examination Survey (NHANES)

Phyto-oestrogens are a family of plant-derived xeno-oestrogens that appear to have beneficial effects on human health. To date, no data are available about phyto-oestrogen consumption affecting liver health in a population. The present study aimed to explore the relationship of urinary phyto-oestrogen metabolites with serum liver enzymes in US adults. A nationally representative sample of US adults in the National Health and Nutrition Examination Survey (NHANES) 2003–10 was analysed. The cross-sectional study sample consisted of 6438 adults with data on urinary phyto-oestrogen levels, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and γ-glutamyl transaminase (GGT) concentrations and data on other potential confounders. Multivariate logistic regression and linear regression were applied to assess associations between urinary phyto-oestrogen levels and ALT, AST, ALP and GGT concentrations. We found a remarkable association between urinary enterolactone and GGT in both adult males (OR 0·37, 95 % CI 0·22, 0·61; P= 0·003) and females (OR 0·37, 95 % CI 0·26, 0·54; P= 0·009). Moreover, elevated enterolactone levels were inversely associated with ALT and AST levels in adult males. However, no association was present between levels of urinary daidzein, O-desmethylangolensin, equol, enterodiol or genistein with liver enzyme levels in this population. The present study results provide epidemiological evidence that urinary enterolactone levels are associated with liver GGT levels in humans. This suggests a potential protective effect of enterolactone on human liver function. However, the underlying mechanisms still need further investigation.

Effects of various pharmacological agents on the function of norepinephrine transporter

The norepinephrine transporter is selectively expressed in noradrenergic nerve terminals, where it can exert spatial and temporal control over the action of norepinephrine. The norepinephrine transporter mediates the termination of neurotransmission via the reuptake of norepinephrine released into the extracellular milieu. In the present brief review, we report our recent studies about the effects of various pharmacological agents such as fasudil, nicotine, pentazocine, ketamine and genistein on norepinephrine transporter function.

Antiosteoporosis Activity of New Oriental Medicine Preparation (Kyungokgo Mixed with Water Extract of Hovenia dulcis) on the Ovariectomized Mice

Protective effect of new oriental medicine (Kyungokgo mixed with water extract of Hovenia dulcis, KOGHD) was assessed on the bone loss induced mice by ovariectomy. In the in vivo experiments, antiosteoporosis effect of KOGHD was investigated using ovariectomized osteoporosis mice model. After 6 weeks of treatment, the mice were euthanized, and the effect of Kyungokgo (KOG) and KOGHD on body weight, spleen weigh, thymus weight, uterine weight, serum biochemical indicators, bone weight and length, immune cell population, bone morphometric parameters, and histological stains was observed. Our results showed that KOGHD prevented the deterioration of trabecular microarchitecture caused by ovariectomy, which were accompanied by the lower levels of bone turnover markers and immune cell population as evidenced by the inhibition of RANKL-mediated osteoclast differentiation without cytotoxic effect on bone marrow derived macrophages (BMMs). Therefore, these results suggest that the Hovenia dulcis (HD) supplementation in the KOG may also prevent and treat bone loss.

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.

Role of herbal bioactives as a potential bioavailability enhancer for Active Pharmaceutical Ingredients

The current review emphasizes on the herbal bioenhancers which themselves do not possess inherent pharmacological activity of their own but when co-administered with Active Pharmaceutical Ingredients (API), enhances their bioavailability and efficacy. Herbal bioenhancers play a crucial role in enhancing the bioavailability and bioefficacy of different classes of drugs, such as antihypertensives, anticancer, antiviral, antitubercular and antifungal drugs at low doses. This paper highlights various natural compounds that can be utilized as an efficient bioenhancer. Several herbal compounds including piperine, quercetin, genistein, naringin, sinomenine, curcumin, and glycyrrhizin have demonstrated capability to improve the pharmacokinetic parameters of several potent API. This article also focuses on various United States patents on herbal bioenhancers, which has proved to be beneficial in improving oral absorption of nutraceuticals like vitamins, minerals, amino acids and certain herbal compounds. The present paper also describes proposed mechanism of action, which mainly includes absorption process, drug metabolism, and action on drug target. The herbal bioenhancers are easily available, safe, free from side effects, minimizes drug toxicity, shortens the duration of treatment, lowers the drug resistance problems and minimizes the cost of treatment. Inspite of the fact that herbal bioenhancers provide an innovative concept for enhancing the bioavailability of several potent drugs, there are numerous bioenhancers of herbal origin that are yet to be explored in several vital areas. These bioenhancers must also be implied to enhance the bioavailability and bioefficacy through routes other than the oral route of drug delivery. There is a vast array of unexploited plants which can be investigated for their drug bioenhancing potency. The toxicity profiles of these herbal bioenhancers must not be overlooked. Researches must be carried out to solve these issues and to deliver a safe and effective dose of drugs to attain desired pharmacological response.

Cytotoxicity and apoptosis induced by alfalfa (Medicago sativa) leaf extracts in sensitive and multidrug-resistant tumor cells

Alfalfa (Medicago sativa) has been used to cure a wide variety of ailments. However, only a few studies have reported its anticancer effects. In this study, extracts were obtained from alfalfa leaves and their cytotoxic effects were assessed on several sensitive and multidrug-resistant tumor cells lines. Using the mouse leukaemia P388 cell line and its doxorubicin-resistant counterpart (P388/DOX), we showed that the inhibition of cell growth induced by alfalfa leaf extracts was mediated through the induction of apoptosis, as evidenced by DNA fragmentation analysis. The execution of programmed cell death was achieved via the activation of caspase-3, leading to PARP cleavage. Fractionation of toluene extract (To-1), the most active extract obtained from crude extract, led to the identification of 3 terpene derivatives and 5 flavonoids. Among them, (-)-medicarpin, (-)-melilotocarpan E, millepurpan, tricin, and chrysoeriol showed cytotoxic effects in P388 as well as P388/DOX cells. These results demonstrate that alfalfa leaf extract may have interesting potential in cancer chemoprevention and therapy.

Phytochemicals as Anticancer and Chemopreventive Topoisomerase II Poisons

Phytochemicals are a rich source of anticancer drugs and chemopreventive agents. Several of these chemicals appear to exert at least some of their effects through interactions with topoisomerase II, an essential enzyme that regulates DNA supercoiling and removes knots and tangles from the genome. Topoisomerase II-active phytochemicals function by stabilizing covalent protein-cleaved DNA complexes that are intermediates in the catalytic cycle of the enzyme. As a result, these compounds convert topoisomerase II to a cellular toxin that fragments the genome. Because of their mode of action, they are referred to as topoisomerase II poisons as opposed to catalytic inhibitors. The first sections of this article discuss DNA topology, the catalytic cycle of topoisomerase II, and the two mechanisms (interfacial vs. covalent) by which different classes of topoisomerase II poisons alter enzyme activity. Subsequent sections discuss the effects of several phytochemicals on the type II enzyme, including demethyl-epipodophyllotoxins (semisynthetic anticancer drugs) as well as flavones, flavonols, isoflavones, catechins, isothiocyanates, and curcumin (dietary chemopreventive agents). Finally, the leukemogenic potential of topoisomerase II-targeted phytochemicals is described.

3D models of human ERα and ERβ complexed with coumestrol

Coumestrol, a phytoestrogen found in alfalfa, clover, and beans, has nM affinity for both estrogen receptor-α [ERα] and ERβ. Recently, a novel activity of coumestrol was reported: coumestrol binding to human ERβ represses microglia-mediated inflammation, which is associated with various neurodegenerative diseases, such as multiple sclerosis. In contrast, estradiol binding to ERβ had little or no effect on repression of microglia-mediated inflammation. Coumestrol and estradiol have several structural differences, which suggest that each ligand could induce different conformations in ERβ and, thus, different transcriptional responses in brain microglia. To begin to understand how coumestrol binds to ERβ and ERα, we constructed 3D models of coumestrol with human ERβ and ERα, which were compared to the structures of these ERs with estradiol. Of four possible orientations of coumestrol in ERα and ERβ, one orientation had the most favorable contacts with both ERs. Other phytochemicals may activate ERβ and inhibit inflammation in brain microglia and be useful therapeutics for inflammatory conditions in the brain.

Feeding soybean meal increases the blood level of isoflavones and reduces the steroidogenic capacity in bovine corpora lutea, without affecting peripheral progesterone concentrations

Thirty-three Holstein-Friesian cows were followed from 14 days pre partum until the fourth ovulation post partum. Housing conditions and basic ration were identical for all animals. Concentrates were individually supplemented according to the daily milk production level, using two different types of protein rich concentrates: soybean meal and rapeseed meal. Soybean and rapeseed meal are known to be respectively high and low in isoflavones. Cows were randomly divided into three groups and blocked for parity. Group I (n=11) was supplemented with soybean meal and acted as control group. Groups II (n=11) and III (n=11) were respectively supplemented with soybean and rapeseed meal and were subjected to a biopsy sampling of the corpus luteum at day 9 of the first three postpartal estrous cycles. Soybean meal supplementation to lactating dairy cows (1.72 kg on average) induced an increase in the blood concentration of equol, dihydrodaidzein, o-desmethylangolensin in both soy groups and resulted in a reduced area occupied by steroidogenic (P=0.012) and endothelial cells (P=0.0007) in the luteal biopsies. Blood concentrations of equol and glycitein were negatively correlated with the areas occupied by steroidogenic (r=-0.410 with P=0.0002, respectively r=-0.351 with P=0.008) and endothelial cells (r=-0.337 with P=0.01, respectively r=-0.233 with P=0.085) in the 3 first estrous cycles. The latter however did not affect the diestrous peripheral blood progesterone concentration.

Management of reproduction and pregnancy complications in maternal obesity: which role for dietary polyphenols?

Obesity is a global and dramatic public health problem; maternal obesity represents one of the main risk factors of infertility and pregnancy complications as it is associated with adverse maternal and offspring outcomes. In the last few years, adipose tissue dysfunction associated with altered adipocytokine secretion has been suggested to play a critical role in all the phases of reproductive process. Obesity is a nutrition-related disorder. In this regard, dietary intervention strategies, such as high intake of fruit and vegetables, have shown significant effects in both preserving health and counteracting obesity-associated diseases. Evidence has been provided that polyphenols, important constituents of plant-derived food, can influence developmental program of oocyte and embryo, as well as pregnancy progression by modulating several cellular pathways. This review will examine the controversial results so far obtained on adipocytokine involvement in fertility impairment and pregnancy complications. Furthermore, the different effects exerted by polyphenols on oocyte, embryo, and pregnancy development will be also taken in account.

Environmental epigenetics and phytoestrogen/phytochemical exposures

One of the most important environmental factors to promote epigenetic alterations in an individual is nutrition and exposure to plant compounds. Phytoestrogens and other phytochemicals have dramatic effects on cellular signaling events, so have the capacity to dramatically alter developmental and physiological events. Epigenetics provides one of the more critical molecular mechanisms for environmental factors such as phytoestrogens/phytochemicals to influence biology. In the event these epigenetic mechanisms become heritable through epigenetic transgenerational mechanisms the impacts on the health of future generations and areas such as evolutionary biology need to be considered. The current review focuses on available information on the environmental epigenetics of phytoestrogen/phytochemical exposures, with impacts on health, disease and evolutionary biology considered. This article is part of a Special Issue entitled 'Phytoestrogens'.

Evidence for a role of proteins, lipids, and phytochemicals in the prevention of polycystic kidney disease progression and severity

Polycystic kidney disease (PKD) is a heritable disease characterized by renal cysts and is a leading cause of end-stage renal disease. Dietary intervention offers a potentially efficacious, cost-effective, and safe therapeutic option for PKD. The aim of this article was to review studies investigating the effect of dietary components on PKD and potential mechanisms of action. Low-protein diets are commonly recommended for PKD patients, but inconsistent findings in human and animal PKD studies suggest that the type rather the amount of protein may be of greater importance. Dietary soy protein has been shown to have renal protective effects in various animal models of PKD. Other than dietary proteins, studies investigating the role of the amount and type of dietary lipids on PKD progression are increasing. The omega-3 polyunsaturated fatty acids can alter multiple steps in PKD pathogenesis. Phytoestrogens and phytochemicals are other dietary compounds shown to attenuate cyst pathogenesis in animal studies. A better understanding of the role of nutrition in PKD can contribute to the development of dietary recommendations and diet-based therapies to reduce PKD progression and severity.

Endocrine disruption: fact or urban legend?

Endocrine disruptors (EDs) are substances that cause adverse health effects via endocrine-mediated mechanisms in an intact organism or its progeny or (sub) populations. Purported EDCs in personal care products include 4-MBC (UV filter) or parabens that showed oestrogenic activity in screening tests, although regulatory toxicity studies showed no adverse effects on reproductive endpoints. Hormonal potency is the key issue of the safety of EDCs. Oestrogen-based drugs, e.g. the contraceptive pill or the synthetic oestrogen DES, possess potencies up to 7 orders of magnitude higher than those of PCP ingredients; yet, in utero exposure to these drugs did not adversely affect fertility or sexual organ development of offspring unless exposed to extreme doses. Additive effects of EDs are unlikely due to the multitude of mechanisms how substances may produce a hormone-like activity; even after uptake of different substances with a similar mode of action, the possibility of additive effects is reduced by different absorption, metabolism and kinetics. This is supported by a number of studies on mixtures of chemical EDCs. Overall, despite of 20 years of research a human health risk from exposure to low concentrations of exogenous chemical substances with weak hormone-like activities remains an unproven and unlikely hypothesis.

Phytoestrogens mediated anti-inflammatory effect through suppression of IRF-1 and pSTAT1 expressions in lipopolysaccharide-activated microglia

Microglial activation has been implicated in various neurological disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and HIV encephalopathy. Phytoestrogens have been shown to be neuroprotective in neurotoxicity models; however, their effect on microglia has not been well established. In the current study, we report that the soy phytoestrogens, genistein, daidzein, and coumestrol, decreased nitric oxide (NO) production induced by lipopolysaccharide (LPS) in the rat microglial cell line (HAPI). The levels of inducible NO synthase (iNOS) mRNA and protein expression were also reduced. Transcription factors known to govern iNOS expression including interferon regulatory factor-1 (IRF-1) and phosphorylated STAT1 were down regulated. These observations explain, at least in part, the inhibitory effect of phytoestrogens on NO production. The levels of monocyte chemoattractant protein-1 and interleukin-6 mRNA, proinflammatory chemokine and cytokine associated with various neurological disorders, were also reduced following LPS stimulation when HAPI cells were pretreated with phytoestrogens. Hence, genistein, daidzein, and coumestrol could serve as anti-inflammatory agents and may have beneficial effects in the treatment of neurodegenerative diseases.

Preliminary investigation of the influence of long-term dietary isoflavone intake on puberty onset and oestrous cycles in domestic cats (Felis catus)

Genistein and daidzein are isoflavones which are reported to influence the reproductive system in a variety of mammalian species. This pilot study aimed to determine if dietary isoflavones could potentially influence reproductive parameters in domestic cats, when consumed during the postnatal development period. Cats (n = 12) were maintained on either a treatment (150 µg/g DM genistein and 150 µg/g DM daidzein, n = 4) or control (isoflavone free, n = 8) diet from weaning, up to 414 (±17.2) days post-weaning. Vaginal smears were taken thrice weekly and examined for oestrogen-induced cellular degradation in all cats. Behavioural indicators of oestrous were routinely scored for the presence or absence of six key behaviours. Genistein and daidzein did not alter puberty onset or oestrous cycle parameters in these cats (P > 0.05). Behavioural scores were higher in cats in the treatment group than control. Incidence of apparent spontaneous ovulation (inferred from extended inter-oestrous periods) was greater in treated cats than control cats, although serum hormone profiles were not available to confirm this observation. Further testing is warranted.

Suppression of erythropoietin induction by diethylstilbestrol in rats

Diethylstilbestrol is an estrogenic endocrine disrupter that has diverse health effects in humans. Bisphenol A is another estrogen-like chemical with possible similar effects to diethylstilbestrol, which has been increasingly used for industry to lead to globally widespread human exposure to it. Hematopoiesis is another of their possible targets, since estrogen suppresses erythropoietin induction to induce anemia. The aim of this study was to clarify the effects of diethylstilbestrol and bisphenol A on erythropoietin induction in rats. We observed the effects of one-shot subcutaneous injection of diethylstilbestrol or bisphenol A on hypoxia-, bleeding-, and cobalt-stimulated erythropoietin induction within 24 h and the hematological outcomes after repeated subcutaneous injection of diethylstilbestrol three times a week for 1 month in rats. Diethylstilbestrol at 10-1,000 μg/kg suppressed stimulus-elevated levels of plasma erythropoietin and its renal mRNA induction. In contrast, bisphenol A at 1,000 μg/kg did not suppress plasma erythropoietin elevated by any stimuli. Repeated injection of diethylstilbestrol at 1,000 μg/kg to rats for 1 month induced an anemic trend due to decelerated erythropoiesis through the insufficient production of erythropoietin, mimicking the effects of estradiol. In conclusion, diethylstilbestrol has a suppressive effect on erythropoietin induction, leading to deceleration of erythropoiesis and the development of anemia.

Adverse influence of coumestrol on secretory function of bovine luteal cells in the first trimester of pregnancy

Coumestrol is one of a few biologically active substances present in leguminous plants, which are widely used as fodder for ruminants. Depending on the doses, coumestrol acts on the reproductive processes as an estrogen-like factor or antiestrogen to evoke a decrease in ovulation frequency, elongation of estrous cycle duration. The aim of the current investigations was to study the influence of coumestrol on secretory function of luteal cells obtained from first trimester of pregnant cows. Luteal cells (2.5 × 10(5) /mL) from 3rd to 5th, 6th to 8th, and 9th to 12th week of pregnancy were preincubated for 24 h and incubated with coumestrol (1 × 10(-6) M) for successive 48 h and the medium concentrations of progesterone (P4), oxytocin (OT), prostaglandin (PG) E2 and F2α were determined. Moreover, the expression of mRNA for neurophysin-I/oxytocin (NP-I/OT; precursor of OT) and peptidyl-glycine-α-amidating mono-oxygenase (PGA, an enzyme responsible for post-translational OT synthesis) was determined after 8 h of treatment. Coumestrol did not affect P4 secretion but increased the secretion of OT from the cells collected at all stages of gestation studied. Hence, the ratio of P4 to OT was markedly decreased. Simultaneously, coumestrol increased the expression of NP-I/OT mRNA during 9th to 12th weeks of pregnancy, and mRNA for PGA during 3rd to 5th and 9th to 12th weeks of gestation. Furthermore, coumestrol decreased PGE2 secretion from luteal cells in all studied stages of pregnancy, while it affected PGF2α metabolite (PGFM) concentration only from week 3 to 5 of pregnancy. Obtained results suggest that coumestrol impairs secretory function of the corpus luteum (CL) and this way it can affect the maintenance of pregnancy in the cow.

Dietary flavonol intake is associated with age of puberty in a longitudinal cohort of girls

Lignans and flavonols are dietary phytoestrogens found at high concentrations in the Western Diet. They have potential to influence the timing of puberty. We hypothesized that greater consumption of these 2 phytoestrogens would be related to later age at pubertal onset among girls. Pubertal assessment and 24-hour diet recall data were available for 1178 girls, ages 6 to 8 years (mean 7.3 years) in the Breast Cancer and Environment Research Project Puberty Study. Lignan and flavonol intakes were mainly derived from fruit and vegetable consumption. Average consumption was 6.5 mg/d for flavonols and 0.6 mg/d for lignans. Highest flavonol consumption (>5 mg/d) was associated with later breast development (adjusted hazards ratio [HR]: 0.74, 95% CI: [0.61-0.91]) compared to 2 to 5 mg/d (adjusted HR: 0.84, 95% CI: [0.70-1.0]) and <2 mg/d (referent group; P-trend = .006). Flavonol intake was not associated with pubic hair development. Lignan intake was not associated with either breast or pubic hair development. Dietary intake was only weakly correlated with urinary enterolactone, a biomarker for lignans (RS = 0.13). Consistent with biologic properties of phytoestrogens that indicate hormonal activity, their consumption may be associated with reproductive end points, even in childhood.

Bioavailability and pharmacokinetics of genistein: mechanistic studies on its ADME

Genistein, one of the most active natural flavonoids, exerts various biological effects including chemoprevention, antioxidation, antiproliferation and anticancer. More than 30 clinical trials of genistein with various disease indications have been conducted to evaluate its clinical efficacy. Based on many animals and human pharmacokinetic studies, it is well known that the most challenge issue for developing genistein as a chemoprevention agent is the low oral bioavailability, which may be the major reason relating to its ambiguous therapeutic effects and large interindividual variations in clinical trials. In order to better correlate pharmacokinetic to pharmacodynamics results in animals and clinical studies, an in-depth understanding of pharmacokinetic behavior of genistein and its ADME properties are needed. Numerous in vitro/in vivo ADME studies had been conducted to reveal the main factors contributing to the low oral bioavailability of genistein. Therefore, this review focuses on summarizing the most recent progress on mechanistic studies of genistein ADME and provides a systemic view of these processes to explain genistein pharmacokinetic behaviors in vivo. The better understanding of genistein ADME property may lead to development of proper strategy to improve genistein oral bioavailability via mechanism-based approaches.

2-heptyl-formononetin increases cholesterol and induces hepatic steatosis in mice

Consumption of isoflavones may prevent adiposity, hepatic steatosis, and dyslipidaemia. However, studies in the area are few and primarily with genistein. This study investigated the effects of formononetin and its synthetic analogue, 2-heptyl-formononetin (C7F), on lipid and cholesterol metabolism in C57BL/6J mice. The mice were fed a cholesterol-enriched diet for five weeks to induce hypercholesterolemia and were then fed either the cholesterol-enriched diet or the cholesterol-enriched diet-supplemented formononetin or C7F for three weeks. Body weight and composition, glucose homeostasis, and plasma lipids were compared. In another experiment, mice were fed the above diets for five weeks, and hepatic triglyceride accumulation and gene expression and histology of adipose tissue and liver were examined. Supplementation with C7F increased plasma HDL-cholesterol thereby increasing the plasma level of total cholesterol. Supplementation with formononetin did not affect plasma cholesterol but increased plasma triglycerides levels. Supplementation with formononetin and C7F induced hepatic steatosis. However, formononetin decreased markers of inflammation and liver injury. The development of hepatic steatosis was associated with deregulated expression of hepatic genes involved in lipid and lipoprotein metabolism. In conclusion, supplementation with formononetin and C7F to a cholesterol-enriched diet adversely affected lipid and lipoprotein metabolism in C57BL/6J mice.

Bioavailability enhancers of herbal origin: an overview

Recently, the use of herbal medicines has been increased all over the world due to their therapeutic effects and fewer adverse effects as compared to the modern medicines. However, many herbal drugs and herbal extracts despite of their impressive in-vitro findings demonstrates less or negligible in-vivo activity due to their poor lipid solubility or improper molecular size, resulting in poor absorption and hence poor bioavailability. Nowadays with the advancement in the technology, novel drug delivery systems open the door towards the development of enhancing bioavailability of herbal drug delivery systems. For last one decade many novel carriers such as liposomes, microspheres, nanoparticles, transferosomes, ethosomes, lipid based systems etc. have been reported for successful modified delivery of various herbal drugs. Many herbal compounds including quercetin, genistein, naringin, sinomenine, piperine, glycyrrhizin and nitrile glycoside have demonstrated capability to enhance the bioavailability. The objective of this review is to summarize various available novel drug delivery technologies which have been developed for delivery of drugs (herbal), and to achieve better therapeutic response. An attempt has also been made to compile a profile on bioavailability enhancers of herbal origin with the mechanism of action (wherever reported) and studies on improvement in drug bioavailability, exhibited particularly by natural compounds.

Isoflavone metabolism in domestic cats (Felis catus): comparison of plasma metabolites detected after ingestion of two different dietary forms of genistein and daidzein

Some felid diets contain isoflavones but the metabolic capacity of cats toward isoflavones is relatively unknown, despite the understanding that isoflavones have divergent biological potential according to their metabolite end products. The objective of this study was to determine the plasma metabolites detectable in domestic cats after exposure to 2 different dietary forms of isoflavones, either as a soy extract tablet (n = 6) or as part of a dietary matrix (n = 4). Serial blood samples were collected after isoflavone exposure to identify the plasma metabolites of each cat. Genistein was detected in its unconjugated form or as a monosulfate. Daidzein was detected as both a mono- and disulfate as well as in its unconjugated form. Other daidzein metabolites detected included equol mono- and disulfate, dihydrodaidzein, and O-desmethylangolensin. No β-glucuronide metabolites of either isoflavone were detected. Equol was produced in markedly fewer cats after ingestion of a soy extract tablet as a single oral bolus compared with cats consuming an isoflavone-containing diet. The detectable metabolites of the isoflavones, genistein and daidzein, in domestic cat plasma after dietary ingestion has been described in the present study for the first time. The metabolic capacity for isoflavones by domestic cats appears to be efficient, with only minimal proportions of the ingested amount detected in their unconjugated forms. This has implications for the potential of isoflavones to exert physiological activity in the domestic cat when consumed at concentrations representative of typical dietary intake.

Antidiabetic effect of secoisolariciresinol diglucoside in streptozotocin-induced diabetic rats

Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycaemia. Its complications such as neuropathy, cardiopathy, nephropathy, and micro and macro vascular diseases are believed to be due to the increase in oxidative stress and decrease in the level of antioxidants. The aim of this study was to determine the antihyperglycemic activity of synthetic Secoisolariciresinol diglucoside (SDG) in streptozotocin (STZ)-induced diabetic rats. The synthetic SDG in a single-dose (20 mg/kg b.w.) two-day study showed dose-dependent reduction in glucose levels with maximum effect of 64.62% at 48 h post drug treatment (p<0.05), which is comparable to that of the standard drug tolbutamide (20 mg/kg b.w.). In a multi-dose fourteen-day study, lower doses of SDG (5 and 10 mg/kg b.w.) exhibited moderate reduction in glucose levels, lipid profile, restoration of antioxidant enzymes and improvement of the insulin and c-peptide levels which shows the regeneration of β-cell which secretes insulin. Altered levels of lipids and enzymatic antioxidants were also restored by the SDG to the considerable levels in diabetic rats. Results of the present investigation suggest that diabetes is associated with an increase in oxidative stress as shown by increase in serum malondialdehyde (MDA), decreased levels of catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH). Also, diabetes is associated with an increase in serum total cholesterol as well as triglycerides levels and decrease in insulin and c-peptide levels. SDG is effective in retarding the development of diabetic complications. We propose that synthetic SDG exerts anti hyperglycemic effect by preventing the liver from peroxidation damage through inhibition of ROS level mediated increased level of enzymatic and non-enzymatic antioxidants. And, also maintaining tissue function which results in improving the sensitivity and response of target cells in STZ-induced diabetic rats to insulin.

Does phytoestrogen supplementation affect cognition differentially in males and females?

Phytoestrogens are plant-derived compounds found mainly in soy with known estrogenic properties and a potential for benefits to human health. Increased intake in phytoestrogens stemmed from the search for safe alternatives to hormone replacement therapies. Based on epidemiologic evidence comparing Western and Asian populations and clinical studies, phytoestrogens show promise to improve health and brain function. This review is focused on the effects of phytoestrogens on cognition by examining clinical and animal studies, with special attention placed on (1) a window of therapeutic opportunity which may explain the discrepancy among studies, and (2) whether a sex/gender difference exists in response to phytoestrogen intake and what the possible underlying mechanisms may be.

Distribution of isoflavones and coumestrol in neglected tropical and subtropical legumes

BACKGROUND

Isoflavones and coumestrol from dietary legumes are plant constituents showing multiple beneficial effects on humans. Owing to their ability to bind with mammalian estrogenic receptors and thereby intervention in several kinds of hormone-related cancers, they have received much attention. Soybean (Glycine max) is currently the major source of isoflavonoids in human diet. However, dozens of tropical and subtropical leguminous species remain unexplored for their isoflavonoids content.

RESULTS

We have analyzed 55 extracts from 41 tropical and subtropical legume species used either in human or animal diet by high-performance liquid chromatography for the content of soy isoflavones, biochanin A, daidzein, daidzin, formononetin, genistein, genistin, sissotrin, ononin and the coumestan coumestrol. Genistein and biochanin A were the most abundant compounds. The highest content of genistein was found in aerial parts of Andira macrothyrsa, seeds of Pachyrhizus tuberosus and aerial parts of Calopogonium mucunoides (598, 250 and 184 µg g(-1), respectively) and biochanin A in aerial parts of Cratylia argentea, C. mucunoides and flowers of A. macrothyrsa (76, 53 and 40 µg g(-1), respectively).

CONCLUSION

None of the samples tested was richer overall source of soy isoflavones and coumestrol than soybean; nevertheless several species (C. mucunoides or A. macrothyrsa) may serve as a promising source of individual compounds.