Effects of phyto-oestrogens on tissues

In ovo injection of soy isoflavones on hatching performance and intestinal development of newly hatched chicks

This study aimed to evaluate the effects of in ovo injection of soy isoflavones (ISF) on hatchability, body weight, antioxidant status and intestinal development of newly hatched broiler chicks. One hundred and eighty fertile eggs were divided as follows: the control group, 3 mg/egg ISF (low dose) and 6 mg/egg ISF (high dose) on the 18th day of incubation. The results demonstrated that in ovo inclusion of 6 mg of ISF significantly increased hatchability and hatch weight. Both doses of ISF inclusion elevated the serum glutathione peroxidase and slightly decreased malondialdehyde compared to the control group. The high dose of ISF brings higher villus height and a higher villus/crypt ratio in chicks. Moreover, the mRNA levels of tumour necrosis factor- α and interferon-gamma in the spleen were significantly decreased. The ISF treatments showed an improvement in intestinal enzyme expression levels of sucrose isomaltase and mucin 2  as well as tight junction protein (TJ) mRNA expression of claudin-1 at high doses of ISF (p < 0.05) when compared with the other groups. Furthermore, the mRNA level of IGF-1 was increased in the high doses of ISF compared to the control. Overall, these findings indicate that in ovo administration of ISF on the 18th day of incubation enhances hatchability, antioxidant status and intestinal morphometrics in hatched chicks and modulates the expression of proinflammatory cytokines, TJs and insulin-like growth factor. In addition, the sustainability of antioxidants and other positive effects of ISF may increase chick viability and growth performance.

Profile and content of isoflavones on flaked and extruded soybeans and okara submitted to different drying methods

Isoflavones (IFs) are biocompounds found in considerable amounts in soybean grains. However, to originate soybean-based materials, the grains must be subjected to numerous thermal and mechanical treatments, which can impair the IFs content. The influence of these treatments was investigated and a protocol for IFs extraction and quantification is proposed. Sequential extractions were performed on industrially pretreated soybean samples (broken, flakes, and collets), on okara submitted to different drying methods (freeze-drying, forced convection, and under vacuum), and on soybean oils extracted with hexane and ethanol. β-glucosides levels were decreased by the thermal processes of lamination, expansion, and drying, while the aglycone forms were not affected. Lyophilization was identified as the most viable drying method for the quantification of IFs in okara. Soybean oils extracted with ethanol presented significant amounts of aglycone. Furthermore, two stages of extraction were sufficient for the recovery of the IFs from different matrices.

Genistein improves the reproductive performance and bone status of breeder hens during the late egg-laying period

Genistein (GEN), a type of soy isoflavones, is similar to estrogen structurally and functionally. The effects of dietary gen on the reproductive performance and bone status of breeder hens were investigated. A total pf 720 laying broiler breeder (LBB) hens were randomly allocated into 3 groups with supplemental dietary GEN doses (0, 40, 400 mg/kg). Each treatment has 8 replicates of 30 birds. The results indicated that supplemental GEN significantly improved the egg production and eggshell strength of LBB hens. Dietary GEN was deposited into the egg yolk, which decreased malonaldehyde in the follicle and egg yolk. The levels of vitellogenin (VTG), progesterone, and follicle-stimulating hormone in the serum of GEN-treated groups were elevated compared with the control group. Furthermore, GEN treatment downregulated the mRNA expression of insulin-like growth factor binding protein in the fallopian tube, whereas 40 mg/kg GEN treatment upregulated estrogen receptor α expression. Both the mRNA expression of VTG-II in the liver and mRNA expression of amphiregulin in the fallopian tube were upregulated after 40 and 400 mg/kg GEN treatment. In the 400 mg/kg GEN-treated group, the levels of calcitonin and alkaline phosphatase in the serum were increased compared with the control group, which was consistent with the increased levels of calcium and phosphorus in the tibia. Supplemental GEN (400 mg/kg) improved the tibia strength of LBB hens, whereas 40 mg/kg GEN had better effects on laying performance. In summary, dietary GEN could improve the egg production and quality, as well as the bone status of LBB hens during the late egg-laying period.

The association between soy isoflavone intake and menopausal symptoms after breast cancer diagnosis: a prospective longitudinal cohort study on Chinese breast cancer patients

PURPOSE

This study investigated the association between soy isoflavone intake and menopausal symptoms (MPS) among Chinese women with early stage breast cancer in a prospective cohort study.

METHODS

In an on-going prospective cohort study that involved 1462 Chinese women with early stage breast cancer, MPS were assessed at 18, 36 and 60 months after cancer diagnosis using the validated menopausal rating scale (MRS) questionnaire. Daily soy food intake for the previous 12 months was assessed at the same time using a validated food frequency questionnaire. The associations between MPS and soy isoflavone intake were evaluated in multivariable logistic regression analyses.

RESULTS

The prevalence of MPS was almost the same during the first 60 months after cancer diagnosis, which were 64.5%, 65.2%, and 63.9% at 18, 36, and 60 months, respectively. Patients with MPS tended to be younger than those without MPS. The intake of soy isoflavones was not associated with the total score of MRS at 18-month follow-up [highest vs lowest tertile, odds ratio (OR) = 1.00, 95% CI 0.75-1.34]. Similarly, no significant association was noted at 36-month (OR = 1.25, 95% CI 0.92-1.69) and 60-month (OR = 1.21, 95% CI 0.84-1.74) follow-up. With regards to specific domain within MRS, the risk of symptoms presenting in somatic domain was higher among breast cancer patients who were in the highest tertile of soy isoflavone intake at 36 months post-diagnosis (OR = 1.44, 95% CI 1.07-1.94, P-trend = 0.02), compared with the lowest tertile, where a stronger significant association was noted among patients who were younger than 60 years (OR = 1.52, 95% CI 1.05-2.20, P-trend = 0.03) and pre-menopausal (OR = 3.81, 95% CI 1.85-8.11, P-trend < 0.01).

CONCLUSION

The present study provided further evidence that soy isoflavone consumption was not associated with MPS among Chinese breast cancer patients. In fact, patients with higher intake of soy isoflavone have increased risk of experiencing somatic symptoms.

Female Mice Exhibit Abdominal Aortic Aneurysm Protection in an Established Rupture Model

BACKGROUND

Male gender is a well-established risk factor for abdominal aortic aneurysm (AAA), whereas estrogen is hypothesized to play a protective role. Although rupture rates are higher in women, these reasons remain unknown. In the present study, we sought to determine if female mice are protected from AAA rupture.

MATERIALS AND METHODS

Apolipoprotein E-deficient male and female mice (aged 7 wk; n = 25 per group) were infused with angiotensin II (AngII; 2000 ng/kg/min) plus β-aminopropionitrile (BAPN) in the drinking water for 28 d to test the effects of gender on AAA rupture. Separately, a second group of male apolipoprotein E-deficient mice underwent AngII infusion + BAPN while being fed high-fat phytoestrogen free or a high-fat phytoestrogen diet to assess effects of phytoestrogens on rupture. In a third group, female mice either underwent oophorectomy or sham operation 4 wk before infusion of AngII and BAPN to further test the effects of female hormones on AA rupture. Surviving mice abdominal aorta were collected for histology, cytokine array, and gelatin zymography on postoperative day 28.

RESULTS

Female mice had decreased AAA rupture rates (16% versus 46%; P = 0.029). Female mice expressed fewer elastin breaks (P = 0.0079) and decreased smooth muscle cell degradation (P = 0.0057). Multiple cytokines were also decreased in the female group. Gelatin zymography demonstrated significantly decreased pro-matrix metalloproteinase 2 in female mice (P = 0.001). Male mice fed a high dose phytoestrogen diet failed to decrease AAA rupture. Female mice undergoing oophorectomy did not have accelerated aortic rupture.

CONCLUSIONS

These data are the first to attempt to tease out hormonal effects on AAA rupture and the possible role of gender in rupture.

Acute Soy Supplementation Improves 20-km Time Trial Performance, Power, and Speed

INTRODUCTION

Isoflavones, a chemical class of phytoestrogens found in soybeans and soy products, may have biological functions similar to estradiol. After binding with ERβ or perhaps independently of estrogen receptors, isoflavones may augment vascular endothelial relaxation, contributing to improved limb blood flow.

PURPOSE

To determine if acute fermented soy extract supplementation influences 20-km time trial cycling performance and cardiac hemodynamics compared with a placebo.

METHODS

Subjects included 25 cyclists and triathletes (31 ± 8 yr, V˙O2peak: 55.1 ± 8.4 mL·kg·min). Each subject completed a V˙O2peak assessment, familiarization, and two 20-km time trials in randomized order after ingestion of a fermented soy extract supplement or placebo. The fermented soy extract consisted of 30 g powdered supplement in 16 fl. ounces of water. The placebo contained the same quantities of organic cocoa powder and water. Each trial consisted of 60 min of rest, 30 min at 55% Wpeak, and a self-paced 20-km time trial.

RESULTS

Soy supplementation elicited a faster time to 20-km completion (-0.22 ± 0.51 min; -13 s), lower average HR (-5 ± 7 bpm), and significantly greater power (7 ± 3 W) and speed (0.42 ± 0.16 km·h) during the last 5 km of the time trial compared with placebo. Analysis of the results by relative fitness level (<57 vs ≥ 57 mL⋅kg⋅min) indicated that those with a higher level of fitness reaped the largest performance improvement alongside a reduced HR (-5 ± 7 bpm).

CONCLUSIONS

Ingestion of a fermented soy extract supplement improved sprint-distance performance through improvements in both power and speed. For those with great aerobic fitness, soy supplementation may help to decrease cardiac demand alongside performance improvement.

Novel Drug Targets with Traditional Herbal Medicines for Overcoming Endometriosis

Endometriosis is a disease in which the lining of the endometrium is found outside of the uterus. Recent medical treatments for endometriosis have adverse effects, limiting their long-term use. Furthermore, the recurrence of the disease after the cessation of therapy is quite common, and most patients need to continue treatment to maintain a hypoestrogenic environment till conception. Notwithstanding recent advances in computational and chemical practices, traditional medicines are considered the most consistent sources for the discovery of new drugs. Numerous medicinal plants and plantderived compounds have been tested against gynecological disorders, mainly endometriosis. This review aimed to describe the pharmacological activity profile of the medicinal plants and their active ingredients and draw attention to the discovery of multitargeted drug molecules for rational therapy.

Diet and risk of breast cancer

Diet may play a role in both promoting and inhibiting human breast cancer development. In this review, nutritional risk factors such as consumption of dietary fat, meat, fiber, and alcohol, and intake of phytoestrogen, vitamin D, iron, and folate associated with breast cancer are reviewed. These nutritional factors have a variety of associations with breast cancer risk. Type of fat consumed has different effects on risk of breast cancer: consumption of meat is associated with heterocyclic amine (HCA) exposure; different types of plant fiber have various effects on breast cancer risk; alcohol consumption may increase the risk of breast cancer by producing acetaldehyde and reactive oxygen species (ROS); intake of phytoestrogen may reduce risk of breast cancer through genomic and non-genomic action; vitamin D can reduce the risk of breast cancer by inhibiting the process of cancer invasion and metastasis; intake of dietary iron may lead to oxidative stress, DNA damage, and lipid peroxidation; and lower intake of folate may be linked to a higher risk of breast cancer.

Antioxidant activity of phytoestrogen type isoflavones in biomimetic environments

Oxidation of phytoestrogen type isoflavones in lecithin lipidic bi-layers and in silver nanoparticle complexes by the chemiluminescence method.

Time and dose-dependent effects of Labisia pumila on bone oxidative status of postmenopausal osteoporosis rat model

Postmenopausal osteoporosis can be associated with oxidative stress and deterioration of antioxidant enzymes. It is mainly treated with estrogen replacement therapy (ERT). Although effective, ERT may cause adverse effects such as breast cancer and pulmonary embolism. Labisia pumila var. alata (LP), a herb used traditionally for women’s health was found to protect against estrogen-deficient osteoporosis. An extensive study was conducted in a postmenopausal osteoporosis rat model using several LP doses and duration of treatments to determine if anti-oxidative mechanisms were involved in its bone protective effects. Ninety-six female Sprague-Dawley rats were randomly divided into six groups; baseline group (BL), sham-operated (Sham), ovariectomised control (OVXC), ovariectomised (OVX) and given 64.5 μg/kg of Premarin (ERT), ovariectomised and given 20 mg/kg of LP (LP20) and ovariectomised and given 100 mg/kg of LP (LP100). The groups were further subdivided to receive their respective treatments via daily oral gavages for three, six or nine weeks of treatment periods. Following euthanization, the femora were dissected out for bone oxidative measurements which include superoxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA) levels. Results: The SOD levels of the sham-operated and all the treatment groups were significantly higher than the OVX groups at all treatment periods. The GPx level of ERT and LP100 groups at the 9th week of treatment were significantly higher than the baseline and OVX groups. MDA level of the OVX group was significantly higher than all the other groups at weeks 6 and 9. The LP20 and LP100 groups at the 9th week of treatment had significantly lower MDA levels than the ERT group. There were no significant differences between LP20 and LP100 for all parameters. Thus, LP supplementations at both doses, which showed the best results at 9 weeks, may reduce oxidative stress which in turn may prevent bone loss via its anti-oxidative property.

Pomegranate fruit as a rich source of biologically active compounds

Pomegranate is a widely used plant having medicinal properties. In this review, we have mainly focused on the already published data from our laboratory pertaining to the effect of methanol extract of pericarp of pomegranate (PME) and have compared it with other relevant literatures on Punica. Earlier, we had shown its antiproliferative effect using human breast (MCF-7, MDA MB-231), and endometrial (HEC-1A), cervical (SiHa, HeLa), and ovarian (SKOV3) cancer cell lines, and normal breast fibroblasts (MCF-10A) at concentration of 20-320 μg/mL. The expressions of selected estrogen responsive genes (PR, pS2, and C-Myc) were downregulated by PME. Unlike estradiol, PME did not increase the uterine weight and proliferation in bilaterally ovariectomized Swiss-Albino mice models and its cardioprotective effects were comparable to that of 17 β -estradiol. We had further assessed the protective role of PME on skeletal system, using MC3T3-E1 cells. The results indicated that PME (80 μg/mL) significantly increased ALP (Alkaline Phosphatase) activity, supporting its suggested role in modulating osteoblastic cell differentiation. The antiosteoporotic potential of PME was also evaluated in ovariectomized (OVX) rodent model. The results from our studies and from various other studies support the fact that pomegranate fruit is indeed a source of biologically active compounds.

Features of postmenopausal uterine haemorrhage

Introduction:

Postmenopausal uterine bleeding is a „cancer until proven otherwise”. Endometrial cancer is a typical disease among postmenopause woman, because every bleeding in this age etiology associated with endometrial cancer (10-30%). The lifespan of women today has been extended and post menopause today last one third of a woman’s life. Early diagnosis of endometrial cancer has a very high cure rate. Screening for this cancer has limits in practice and is necessary given the definition of high-risk groups would be subject to primary and secondary prevention.

Goal:

Primary to evaluate the leading causes of postmenopausal uterine bleeding among patients at risk for endometrial cancer (diabetes, obesity, nulliparity, late menopause (after 55 years) and compared them with the causes of postmenopausal uterine bleeding patients without this risk.

Material and methods:

A retrospective, descriptive study with a targeted sample of 50 consecutive patients who had registered postmenopausal uterine bleeding in high-risk groups (cohorts) and the same number of patients with postmenopausal uterine bleeding that does not belong to the risk group (control group). Each patient underwent clinical examination, then fractionated curettements and its histopathological verification and assessment of treated clinical stage of disease with PH analysis of the resected specimens.

Results:

The patients of the studied risk group were significantly affected by endometrial cancer compared with the control group (RR=2.45, 95% CI 1.2 4.6, p=0.005). Endocervical pathology did not differ between groups. Clinical forms of bleeding: for those that are profuse bleeding cancer was present in 54.6% of cases. With intermittent bleeding cancer is verified in the 33.3% of patients. Risk patient groups with cancer frequently suffer from clinically more advanced stages of histologically aggressive endometrial cancer (serous adenocarcinoma–type II, low differentiated cancer).

Dietary phytoestrogens inhibit experimental aneurysm formation in male mice

BACKGROUND

The purpose of these experiments was to test the hypothesis that dietary phytoestrogens would diminish experimental aortic aneurysm formation.

MATERIALS AND METHODS

Six-wk-old C57BL/6 mice were divided into groups, fed either a diet with minimal phytoestrogen content or a regular commercial rodent diet with high phytoestrogen content for 2 wk. At the age of 8 wk, aortic aneurysms were induced by infusing the isolated infrarenal abdominal aorta with 0.4% elastase for 5 min. Mice were recovered and the diameter of the infused aorta was measured at postoperative days 3, 7, and 14. Abdominal aorta samples were collected for histology, cytokine array, and gelatin zymography after aortic diameter measurement. Blood samples were also collected to determine serum phytoestrogens and estradiol levels. Multiple-group comparisons were done using an analysis of variance with post hoc Tukey tests.

RESULTS

Compared with mice on a minimal phytoestrogen diet, mice on a regular rodent diet had higher levels of serum phytoestrogens (male, 1138 ± 846 ng/dL; female, 310 ± 295 ng/dL). These serum phytoestrogen levels were also much higher than their own endogenous estradiol levels (109-fold higher for males and 35.5-fold higher for females). Although aortic diameters of female mice were unaffected by the phytoestrogen concentration in the diets, male mice on the regular rodent diet (M+ group) developed smaller aortic aneurysms than male mice on the minimal phytoestrogen diet (M- group) on postoperative day 14 (M+ 54.8 ± 8.8% versus M- 109.3 ± 37.6%; P < 0.001). During aneurysm development (postoperative days 3 and 7), there were fewer neutrophils, macrophages, and lymphocytes in the aorta from the M+ group than from the M- group. Concentrations of multiple proinflammatory cytokines (matrix metalloproteinases [MMPs]; interleukin 1β [IL-1β]; IL-6; IL-17; IL-23; monocyte chemoattractant protein-1; regulated on activation, normal T cell expressed and secreted; interferon γ; and tumor necrosis factor α) from aortas of the M+ group were also lower than those from the aortas of the M- group. Zymography also demonstrated that the M+ group had lower levels of aortic MMP-9s than the M- group on postoperative day 14 (P < 0.001 for pro-MMP-9, P < 0.001 for active MMP-9).

CONCLUSIONS

These results suggest that dietary phytoestrogens inhibit experimental aortic aneurysm formation in male mice via a reduction of the inflammatory response in the aorta wall. The protective effect of dietary phytoestrogens on aneurysm formation warrants further investigation.

Conformational analysis and vibrational study of daidzein by using FT-IR and FT-Raman spectroscopies and DFT calculations

Daidzein (C15H10O4) is a type of isoflavone. It was isolated from Butea monosperma that belongs to the Fabaceae family. Soybeans and soy products are the abundant source of daidzein. It is the subject of investigation for many reasons, as it has got wide applications, such as anti-tumor, anti-estrogen, weak pro-estrogen and anti-cancer activities. In the present study, a complete vibrational assignment is provided for the observed IR and Raman spectra of daidzein. Electronic properties have been analyzed using TD-DFT method for both gaseous and solvent phase. The optimized geometry, total energy, potential energy surface and vibrational wavenumbers of daidzein have been determined using density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set and a good correlation was found between observed and calculated values. The double well potential energy curve of the molecule about three bonds, has been plotted, as obtained from DFT/6-31G basis. The HOMO-LUMO energy gap of possible conformers has been calculated for comparing their chemical activity. Global reactivity descriptors have been calculated for predicting the chemical reactivity and the stability of chemical systems. Electrostatic potential surface has been plotted for predicting the structure activity relationship. NBO analysis has also been performed to study the stability of the molecule. NLO study reveals the nonlinear properties of the molecule. 1H and 13C NMR spectra have also been studied. Finally, the calculated results were used to simulate infrared and Raman spectra of the title compound which showed a good agreement with the observed spectra.

Effects of soybean isoflavones on reproductive parameters in Chinese mini-pig boars

BACKGROUND

Soybean isoflavones are structurally similar to mammalian estrogens and therefore may act as estrogen agonists or antagonists. However, it has not been determined if they have any negative effects on reproductive parameters in male livestock. Therefore, the objective of this study was to evaluate the effects of soybean isoflavones on male reproduction using Chinese mini-pig boars as a model. Fifty Xiang boars were randomly divided into five groups and fed diets containing 0, 125, 250, or 500 ppm soybean isoflavones or 0.5 ppm diethylstilbestrol for 60 days.

RESULTS

Dietary supplementation with 250 ppm of soy isoflavones markedly increased the testis index (P < 0.05), fructose content (P < 0.05), and α-glycosidase content in testicular tissue (P < 0.01), as well as increased the number of viable germ cells (P < 0.01) and the level of Bcl-2 protein (P < 0.01). However, 500 ppm of soybean isoflavones significantly reduced both testis and epididymis indexes (P < 0.05) and lactate dehydrogenase levels (P < 0.01), as well as reduced serum LH and testosterone levels (P < 0.05). High levels of soybean isoflavones also increased malondialdehyde levels (P < 0.05), as well as increased the numbers of early and late apoptotic germ cells (P < 0.01) and the level of Bax proteins (P < 0.05) in the testis.

CONCLUSIONS

The results of this study indicate that consumption of soy isoflavones at dietary levels up to 250 ppm did not adversely affect reproductive parameters in Chinese mini-pig boars whereas higher levels of soy isoflavones may adversely affect male reproduction.

Effects of non-fermented and fermented soybean milk intake on faecal microbiota and faecal metabolites in humans

The effects of non-fermented soybean milk (NFSM) and fermented soybean milk (FSM) intake on the faecal microbiota and metabolic activities in 10 healthy volunteers were investigated. Soybean oligosaccharides, raffinose and stachyose were utilized by bifidobacteria except for Bifidobacterium bifidum, but most strains of Escherichia coli and Clostridium perfringens could not use them. During the dietary administration of FSM, the number of bifidobacteria and lactobacilli in the faeces increased (p < 0.05), and clostridia decreased (p < 0.05). Moreover, the concentrations of faecal sulphide were decreased (p < 0.01) in the intake of FSM. During the dietary administration of NFSM, the number of bifidobacteria tended to increase. These results indicate that the consumption of soybean milk, especially FSM, is related to improvement of the intestinal environment.

Dietary, endocrine, and metabolic factors in the development of colorectal cancer

INTRODUCTION

Colorectal cancer is the third cause of death in industrialized countries. Genetic susceptibility and diet are determinant of cancer risk and tumor behavior. Variation in cancer incidence among and within populations with similar dietary patterns suggests that an individual response may reflect interactions with genetic factors, which may modify gene, protein, and metabolite expression patterns. Nutrigenomics, defined as the interaction between nutrition and an individual genome, will likely provide important clues about responders and non-responders to nutritional intervention.

DISCUSSION

Epidemiological and experimental studies suggest a protective role of some normal components of daily diet (fish oil, milk, and vegetables), estrogens, and phytoestrogens in colorectal cancer. The effect of estrogen seems to be mediated by their binding to estrogen receptor beta (ER-β), one of the two estrogen receptors with high affinity for these hormones. Very recently, the demonstration of an involvement of ER-β in the development of adenomatous polyps of the colon has also been documented, suggesting the use of selective ER-β agonists in primary colorectal cancer prevention. Phytoestrogens are plant-derived compounds that structurally and functionally act as estrogen agonists in mammals. They are characterized by a higher binding affinity to ER-β as compared to estrogen receptor alpha (ER-α), the other estrogen receptor subtype. These biological characteristics explain why the administration of phytoestrogens does not produce the classical side effects associated to estrogen administration (cerebro- and cardiovascular accidents, higher incidence of endometrial and breast cancer) and makes these substances potential candidates for colorectal cancer prevention.

TAK-778 induces osteogenesis in ovariectomized rats via an estrogen receptor-dependent pathway

TAK-778, a derivative of ipriflavone, has been shown to induce bone growth both in vitro and in vivo. Recently, it has been shown that TAK-778 can enhance osteoblast differentiation of human bone marrow cells via an estrogen receptor (ER)-dependent pathway. However, the mechanism by which TAK-778 exerts its effect in vivo has not been determined. Considering the evidence that TAK-778 acts via ER-mediated signaling in vitro, in the present study we tested if TAK-778 induced osteogenesis via an ER-dependent pathway using an ovariectomized (OVX) rat model. Two weeks after test animals underwent ovariectomy, TAK-778 and/or tamoxifen was administered orally over 3 months. Vehicle-treated and sham-operated rats served as controls. The bone mineral density (BMD) of the lumbar vertebrae and sagittal two-dimensional images of the L3 vertebral body were measured. In addition, bone formation rates (BFR) and serum calcium and osteocalcin levels were measured. The results indicated that TAK-778 significantly increased BMD, serum calcium and osteocalcin levels, and BFR when compared to that of the vehicle-treated group. However, tamoxifen, a well-known ER antagonist, clearly inhibited the increase in these parameters induced by TAK-778. In addition, micro-computed tomography scans showed that treatment with TAK-778 increased the structure model index, bone volume/tissue volume, and trabecular thickness parameters and decreased the trabecular separation/spacing in OVX rats. Tamoxifen suppressed these effects when administered in combination with TAK-778. Taken together, the present study showed that TAK-778 enhanced bone formation in OVX rats and that this effect was dependent on an ER-mediated pathway.

Profiles of phytoestrogens in human urine from several Asian countries

Intake of a diet rich in phytoestrogens has been associated with a decreased risk for hormone-dependent cancers in humans. Biomonitoring of phytoestrogens in human urine has been used to assess the intake of phytoestrogens. Although studies have reported phytoestrogen levels in urine specimens from the United States and Japan, little is known of human intake of phytoestrogens in other Asian countries. In this study we determined the concentrations of seven phytoestrogens, namely, enterolactone, enterodiol, daidzein, equol, O-desmethylangolensin (O-DMA), genistein, and coumestrol, in 199 human urine samples from three Asian countries, Vietnam (Hanoi and Ho Chi Minh), Cambodia (Phnom Penh), and India (Chennai and Kolkata), using a simple, sensitive, and reliable liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method. The residue levels of phytoestrogens in urine samples from the three Asian countries were compared with the concentrations in 26 urine samples from Japan (Ehime) and 16 urine samples from the United States (Albany), analyzed in this study. Among the phytoestrogens analyzed, isoflavones such as daidzein and genistein were predominant in urine samples from Vietnam; samples from Cambodia and India contained higher concentrations of enterolactone than isoflavones. Urinary concentrations of isoflavones in samples from Hanoi, Vietnam, were notably higher than the concentrations in samples from Cambodia, India, and the United States and similar to the concentrations in samples from Japan. The lowest concentrations of daidzein and the highest concentrations of enterolactone were found in urine samples from India. Concentrations of equol and O-DMA, which are microbial transformation products of daidzein (produced by gut microflora), were notably high in urine samples from Hanoi, Vietnam. The ratios of the concentration of equol or O-DMA to that of daidzein were significantly higher in samples from Hanoi than from Japan, indicating high biotransformation efficiency of daidzein by the population in Hanoi. High concentrations of equol, in addition to isoflavones, in urine have been linked to reduced breast cancer risk in previous studies, and, thus, the Vietnamese population may have potential protective effect against breast cancer. This study suggests that the dietary intake and profiles of phytoestrogens vary considerably, even among Asian countries.

Daidzein administration positively affects thyroid C cells and bone structure in orchidectomized middle-aged rats

SUMMARY

Thyroid C cells hormone, calcitonine, inhibits bone resorption. We have demonstrated that daidzein treatment of orchidectomized rats (model for osteoporosis) stimulated C cells and increased trabecular bone mass. These results suggest that, besides direct action, daidzein may also affect bone structure indirectly through enhancement of thyroid C cell activity.

INTRODUCTION

Thyroid C cells produce calcitonin (CT) which acts as an inhibitor of bone resorption. In this study, the influence of daidzein treatment on thyroid C cells, bone structure, and bone function in orchidectomized (Orx) middle-aged rats was investigated.

METHODS

Sixteen-month-old Wistar rats were divided into Orx and sham-operated (SO) groups. Half the Orx rats were given subcutaneous injections of daidzein (30 mg/kg b.w./day) for 3 weeks. CT-immunopositive thyroid C cells were morphometrically analyzed. The metaphyseal region of the proximal tibia was measured histomorphometrically, and cancellous bone area (B.Ar), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) were calculated. Serum samples were analyzed for CT and osteocalcin (OC), calcium (Ca) and phosphorus concentrations, and urine samples for Ca levels.

RESULTS

Treatment of Orx animals with daidzein significantly increased volume of C cells compared to the Orx rats. Daidzein also enhanced B.Ar, Tb.Th, and Tb.N and reduced Tb.Sp. The serum OC and urinary Ca concentrations decreased significantly in comparison with the Orx group.

CONCLUSIONS

These findings indicate that daidzein treatment stimulates thyroid C cells, increase trabecular bone mass, and decrease bone turnover in Orx middle-aged rats, which is the model of male osteoporosis.

Breast, colorectal, and prostate cancer risk in the European Prospective Investigation into Cancer and Nutrition-Norfolk in relation to phytoestrogen intake derived from an improved database

BACKGROUND

The characterization of phytoestrogen intake and cancer risk has been hindered by the absence of accurate dietary phytoestrogen values.

OBJECTIVE

We examined the risk of breast, colorectal, and prostate cancers relative to phytoestrogen intake on the basis of a comprehensive database.

DESIGN

Demographic and anthropometric characteristics, a medical history, and 7-d records of diet were collected prospectively from participants (aged 40-79 y) in the European Prospective Investigation into Cancer and Nutrition-Norfolk (EPIC-Norfolk). Five hundred nine food items were analyzed by liquid chromatography-mass spectrometry/mass spectrometry, and (13)C(3)-labeled internal standards were analyzed for isoflavones (genistein, daidzein, glycitein, biochanin A, and formononetin), lignans (secoisolariciresinol and matairesinol), and enterolignans from gut microbial metabolism in animal food sources (equol and enterolactone). From the direct analysis, values for 10,708 foods were calculated. Odds ratios (ORs) for breast (244 cases, 941 controls), colorectal (221 cases, 886 controls), and prostate (204 cases, 812 controls) cancers were calculated relative to phytoestrogen intake.

RESULTS

Phytoestrogen intake was not associated with breast cancer among women or colorectal cancer among men. Among women, colorectal cancer risk was inversely associated with enterolactone (OR: 0.33; 95% CI: 0.14, 0.74) and total enterolignans (OR: 0.32; 95% CI: 0.13, 0.79), with a positive trend detected for secoisolariciresinol (OR: 1.60; 95% CI: 0.96, 2.69). A positive trend between enterolignan intake and prostate cancer risk (OR: 1.27; 95% CI: 0.97, 1.66) was attenuated after adjustment for dairy intake (OR: 1.19; 95% CI: 0.77, 1.82).

CONCLUSION

Dietary phytoestrogens may contribute to the risk of colorectal cancer among women and prostate cancer among men.

Hormones in international meat production: biological, sociological and consumer issues

Beef and its products are an important source of nutrition in many human societies. Methods of production vary and include the use of hormonal compounds ('hormones') to increase growth and lean tissue with reduced fat deposition in cattle. The hormonal compounds are naturally occurring in animals or are synthetically produced xenobiotics and have oestrogenic (oestradiol-17beta and its esters; zeranol), androgenic (testosterone and esters; trenbolone acetate) or progestogenic (progesterone; melengestrol acetate) activity. The use of hormones as production aids is permitted in North American countries but is no longer allowed in the European Union (EU), which also prohibits the importation of beef and its products derived from hormone-treated cattle. These actions have resulted in a trade dispute between the two trading blocs. The major concern for EU authorities is the possibility of adverse effects on human consumers of residues of hormones and metabolites. Methods used to assess possible adverse effects are typical of those used by international agencies to assess acceptability of chemicals in human food. These include analysis of quantities present in the context of known biological activity and digestive, absorptive, post-absorptive and excretory processes. Particular considerations include the low quantities of hormonal compounds consumed in meat products and their relationships to endogenous production particularly in prepubertal children, enterohepatic inactivation, cellular receptor- and non-receptor-mediated effects and potential for interference with growth, development and physiological function in consumers. There is particular concern about the role of oestradiol-17beta as a carcinogen in certain tissues. Now subject to a 'permanent' EU ban, current evidence suggests that certain catechol metabolites may induce free-radical damage of DNA in cell and laboratory animal test systems. Classical oestrogen-receptor mediation is considered to stimulate proliferation in cells maintaining receptivity. Mathematical models describing quantitative relationships between consumption of small amounts of oestrogens in meat in addition to greater concentrations from endogenous production, chemical stoichiometry at cellular level and human pathology have not been developed. Such an approach will be necessary to establish 'molecular materiality' of the additional hormone intake as a component of relative risk assessment. The other hormones, although generally less well researched, are similarly subject to a range of tests to determine potentially adverse effects. The resulting limited international consensus relates to the application of the 'precautionary principle' and non-acceptance by the European Commission of the recommendations of the Codex Alimentarius Commission, which determined that meat from cattle, hormone-treated according to good practice, was safe for human consumers. The present review considers the hormone issue in the context of current international social methodology and regulation, recent advances in knowledge of biological activity of hormones and current status of science-based evaluation of food safety and risk for human consumers.

Effects of 25-hydroxycholecalciferol and soy isoflavones supplementation on bone mineralisation of quail

1. The effects of 25-hydroxycholecalciferol (25-OH-D(3)) and soy isoflavones supplementation on performance, carcase recovery, bone mineral density, and tibia ash, Ca, P, and serum vitamin D concentrations and alkaline phosphatase activity in the Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature were evaluated. 2. A total of 270 ten-d-old Japanese quail were randomly assigned to 9 treatment groups, 6 replicates of 5 birds each in a 2 x 3 x 3 factorial arrangement of treatments. Birds were kept in a temperature-controlled room at either 22 degrees C (thermo-neutral) or 34 degrees C (heat stress) for 8 h/d (09:00-17:00 h) and given a basal (control) diet or the basal diet supplemented with one of three levels of 25-OH-D(3) (0, 250 and 500 IU/kg of diet) combined with one of three levels of soy isoflavones (0, 400 and 800 mg/kg of diet). 3. Birds kept at 34 degrees C consumed less feed and gained less weight than control birds. An increase in body weight, feed intake (and improvement in feed efficiency and carcase recovery were found in soy isoflavones and 25-OH-D(3)-supplemented quail reared under heat stress conditions. Bone mineral density, tibia ash, Ca, and P were linearly improved by 25-OH-D(3) and soy isoflavones supplementation in both thermoneutral and heat stress groups. Serum vitamin D levels and alkaline phosphatase activity were improved by 25-OH-D(3) and soy isoflavones supplementation in both thermoneutral and heat stress groups in quail. 4. In conclusion, a combination of 25-OH-D(3) and soy isoflavones supplementation to basal diet significantly improved bone mineralisation in quail.

Regulation of the colonic vitamin D system for prevention of tumor progression: an update

A compromised vitamin D status and nutritional calcium deficit are linked with sporadic colorectal cancer incidence. 25(OH)D3 serum concentration is a major determinant of 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) synthesis in colonic mucosa, which expresses the vitamin D receptor and both the synthesizing (CYP27B1) and catabolic (CYP24A1) hydroxylases. Receptor-bound, 1,25(OH)2D3 regulates proliferation, differentiation and apoptosis in an autocrine/paracrine manner. During early malignancy 1,25(OH)2D3 synthesis is often enhanced to counteract hyperproliferation. In many advanced tumors, vitamin D catabolism surpasses synthesis. In vivo, expression and activity of CYP27B1 and vitamin D receptor are stimulated by (phyto)estrogens. Conversely, low nutritional calcium and folate enhance vitamin D catabolism. These insights could explain the lower colorectal cancer incidence in females, the chemopreventive potency of vitamin D and calcium against colorectal cancer, and the benefit of nutritional folate as a methyl donor for epigenetic regulation of the vitamin D system.

Lack of prospective associations between plasma and urinary phytoestrogens and risk of prostate or colorectal cancer in the European Prospective into Cancer-Norfolk study

Dietary phytoestrogens are suggested to reduce the risk of prostate and colorectal cancer, but the results of epidemiologic studies have not yielded consistent support for this proposed effect, possibly due to inadequate databases of phytoestrogen levels in foods. Biomarkers of phytoestrogen intakes may provide a clearer insight into the relationship between phytoestrogen exposure and the risk of prostate or colorectal cancer risks. From the European Prospective into Cancer-Norfolk cohort (ages 45-75), serum and urine samples were analyzed for seven phytoestrogens [daidzein, enterodiol, enterolactone, genistein, glycitein, O-desmethylangolensin (O-DMA), and equol] among 193 cases of prostate cancer and 828 controls, and 221 cases of colorectal cancer with 889 controls. Summary variables of total lignans (enterodiol and enterolactone) and total isoflavones (daidzein, genistein, O-DMA, equol, and glycitein) were created and analyzed in conjunction with individual phytoestrogens. Logistic regression analyses revealed that there was no significant association between prostate cancer risk and total serum isoflavones [odds ratio (OR), 1.01; 95% confidence interval (CI), 0.93-1.10] or total serum lignans (OR, 0.94; 95% CI, 0.86-1.04) or between colorectal cancer risk and total serum isoflavones (OR, 1.01; 95% CI, 0.94-1.08) or total serum lignans (OR, 1.03; 95% CI, 0.94-1.12). Similarly, null associations were observed for individual serum phytoestrogens and for all urinary phytoestrogen biomarkers. In conclusion, we have found no evidence to support an inverse association between phytoestrogen exposure and prostate or colorectal cancer risk.

The key importance of soy isoflavone bioavailability to understanding health benefits

Research over the past two decades has provided significant epidemiological and other evidence for the health benefits of the consumption of soy-based foods. A large number of dietary intervention studies have examined the effects of soy isoflavones on risk factors for cardiovascular disease and hormone-dependent cancers. However, these report large variability in outcome measures, very limited reproducibility between studies, and in some cases, controversy between the results of clinical trials using dietary soy or soy protein and isoflavone supplementation. This highlights a major gap in our understanding of soy isoflavone uptake, metabolism, distribution, and overall bioavailability. There are many potential factors that may influence bioavailability and a better knowledge is necessary to rationalize the inconsistencies in the intervention and clinical studies. This review focuses attention on our current state of knowledge in this area and highlights the importance of metabolism of the parent soy isoflavones and the critical role of gut microbiota on the bioavailability of these compounds and their metabolites.

Haemostatic effects of phytoestrogen genistein in postmenopausal women

INTRODUCTION

Genistein is an isoflavone phytoestrogen derived from the soybean which acts as natural selective estrogen receptor modulator. Various studies have pointed out its cardioprotective role. The aim of the study was to evaluate the haemostatic effects of genistein in postmenopausal women.

MATERIAL AND METHODS

In this double-blind placebo-controlled trial we enrolled 104 healthy postmenopausal women with osteopenia. 53 patients (mean age 54.9+/-4.2 yr; BMI 23.4+/-3.2 Kg/m(2)) received genistein (54 mg/day) and 51 patients (mean age 55.4+/-4.3 yr; BMI 23.6+/-3.6 Kg/m(2)) received an identical placebo-tablet. Both groups received a calcium and vitamin D supplement. Plasma levels of D-dimer (DD), plasminogen activator inhibitor-1 (PAI-1) and prothrombin fragment 1+2 (F1+2) were measured at baseline and after 6 and 12 months of treatment.

RESULTS

Baseline characteristics of the two groups were similar. Compared with placebo, genistein decreased significantly DD (p<0.001), but did not affect PAI-1 and F 1+2 plasma levels.

CONCLUSION

The results of our study do not confirm effects of genistein on activation of the haemostatic system, but on the contrary the significant decrease of DD could indicate a possible cardioprotective role of genistein in postmenopausal women.

Estrogens, phytoestrogens and colorectal neoproliferative lesions

Epidemiological and experimental studies suggest a protective role of estrogens against colorectal cancer. This effect seems to be mediated by their binding to estrogen receptor beta (ER-beta), one of the two estrogen receptors with high affinity for these hormones. Very recently, the demonstration of an involvement of ER-beta in the development of adenomatous polyps of the colon has also been documented, suggesting the use of selective ER-beta agonists in primary colorectal cancer prevention. Phytoestrogens are plant-derived compounds that structurally and functionally act as estrogen-agonists in mammals. They are characterized by a higher binding affinity to ER-beta as compared to estrogen receptor alpha (ER-alpha), the other estrogen receptor subtype. These biological characteristics explain why the administration of phytoestrogens does not produce the classical side effects associated to estrogen administration (cerebro- and cardio-vascular accidents, higher incidence of endometrial and breast cancer) and makes these substances ideal candidates for the prevention of colorectal cancer.

Effects of aqueous hop (Humulus Lupulus L.) extract on vascular reactivity in rats: mechanisms and influence of gender and hormonal status

Phytoestrogens, naturally occurring plant compounds having oestrogenic and/or anti-oestrogenic activity, are present in many human foodstuffs including hop. Moderate intakes of isoflavonoid phytoestrogens have been associated with a reduction in cardiovascular diseases incidence. So, it is possible that hop (Humulus Lupulus L.) might similarly contribute to the reported health-beneficial effects of moderate beer consumption. Thus, the purpose of this study was to investigate in vitro effects of aqueous hop extract on thoracic vascular reactivity in Sprague Dawley male and female rats. Endothelium-intact thoracic arterial rings from male rats (MALE, n=8), sham-ovariectomized (Sham OVX) female (n=8) and ovariectomized (OVX) female rats (n=8) were used. We assessed the relaxation induced by aqueous hop extract (10(-9), 10(-2)g/l) in aortic rings precontracted with norepinephrine (10(-7)M), in the absence or in the presence of l-NAME (10(-4)M), indomethacin (10(-5)M), thapsigargin (10(-4)M), iberiotoxin (3.10(-8)M), apamin (3.10(-8)M) and TEA (3.10(-4)M). Aqueous hop extract induced relaxation of endothelium-intact thoracic arterial rings in MALE and Sham OVX rats, whereas a weak effect was observed in OVX rats. This vasorelaxation was strongly inhibited in presence of l-NAME, indomethacin and thapsigargin. These data indicated that aqueous hop extract-induced vasodilation, in male and intact female rats, is mediated by NOS activation, cyclooxygenase products and Ca(2+) pathways. Moreover, our results suggested that effect of hop in enhancing vascular reactivity was independent of gender but strongly related to hormonal status.

Consumption of soy foods and the risk of breast cancer: findings from the Japan Collaborative Cohort (JACC) Study

OBJECTIVE

The association between a lower incidence of breast cancer within the Asian population and the consumption of a diet high in soy has recently been the subject of much attention. To examine whether soy foods really have protective effects against breast cancer and how their influence on breast cancer is modified according to menopausal status, we conducted a population-based, prospective cohort study in Japan.

METHODS

We analyzed the data from the Japan Collaborative Cohort (JACC) Study. From 1988 to 1990, 30,454 women aged 40-79 years, completed a questionnaire on diet and other lifestyle features. Hazard ratios (HRs) were computed to examine the association between soy intake and the risk of breast cancer.

RESULTS

During the mean follow-up of 7.6 years, 145 cases of breast cancer were documented. We found no significant association between the risk of breast cancer and consumption of tofu, boiled beans, and miso soup; the multivariate HRs (95% CI) in the highest category of consumption were 1.14 (0.74-1.77), 0.77 (0.47-1.27) and 1.01 (0.65-1.56), respectively. Only among postmenopausal women, we found no significant associations between soy foods and the risk of breast cancer.

CONCLUSIONS

This prospective study suggests that consumption of soy food has no protective effects against breast cancer. Further large-scale investigations eliciting genetic factors may clarify different roles of various soybean-ingredient foods on the risk of breast cancer.

The effect of soy isoflavones on egg quality and bone mineralisation during the late laying period of quail

1. Soy isoflavones play a role in calcium and bone metabolism. Poor egg quality, skeletal abnormalities and architectural deterioration of bone tissue are common problems under hot climate conditions and with increased age in poultry. 2. In this study, we investigated the effects of soy isoflavone supplementation on egg production, egg quality, bone mineral density (BMD), levels of osteocalcin (OC), vitamin D, calcium (Ca), phosphorus (P) and alkaline phosphatase (ALP) activity in quail (Coturnix coturnix japonica) during the late laying period. 3. The birds (n = 180; 28 weeks old) were randomly assigned to 6 treatment groups consisting of 6 replicates of 5 birds each in a 2 x 3 factorial arrangement of treatments (temperatures, soy isoflavone concentration). Birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (thermo-neutral, TN) or 34 degrees C (heat stress, HS) for 8 h/d (09:00 to 17:00 h; until the end of the study) and fed either on a basal (control) diet or on the basal diet supplemented with either 400 or 800 mg of soy isoflavones/kg of diet. 4. Heat exposure reduced feed intake, egg production, egg quality, BMD, OC, vitamin D, Ca, P and ALP when the basal diet was given. Feed intake, egg production and egg weight were not affected, while eggshell thickness and eggshell weight increased in soy isoflavone-supplemented quails reared under TN conditions. However, feed intake, egg production, egg weight, eggshell thickness, eggshell weight and Haugh units were positively influenced by soy isoflavone supplementation in HS groups for quail during the late laying period. Bone mineral density, serum OC, vitamin D, Ca, P levels and ALP activity were significantly improved by soy isoflavone supplementation in both the TN and HS groups in quail during the late laying period. 5. Soy isoflavone supplementation of basal diet significantly improved egg quality and bone mineralisation in quail during the late laying period.

Genistein and resveratrol: mammary cancer chemoprevention and mechanisms of action in the rat

The environment, including diet, plays a critical role in a woman's subsequent risk of breast cancer. Two dietary polyphenols that have received attention from the health and research communities for their ability to protect against breast cancer are: genistein, a component of soy; and resveratrol, a phytoalexin found in red grapes and red wine. We and others have shown that both genistein and resveratrol can protect against mammary cancer in rodents. The timing of exposure to genistein appears critical for its mammary protective effects. It has been reported that genistein early in life causes enhanced mammary gland differentiation, alterations in cell proliferation and apoptosis, and upregulation of tumor-suppressor genes. With resveratrol in the diet, changes in cell proliferation and apoptosis in terminal ductal structures of the mammary gland might help to explain its protective effects. We conclude that genistein and resveratrol can protect against breast cancer by regulating important mammary growth and differentiation pathways.

Dietary phytoestrogen intake is associated with reduced colorectal cancer risk

Evidence suggests dietary phytoestrogens may reduce the risk of certain hormonal cancers (e.g. breast and prostate). There is a paucity of data regarding phytoestrogens and colorectal cancer risk. Phytoestrogens are plant compounds with estrogen-like activities. Main classes include isoflavones (found in legumes such as soy) and lignans (found in grains, seeds, nuts, fruits, and vegetables). Although isoflavones have dominated phytoestrogen cancer research, lignans may be more relevant to North American diets. Food questionnaires and analytic databases have recently been modified to incorporate some lignan information. We conducted a case-control study to evaluate the association between phytoestrogen intake and colorectal cancer risk. Colorectal cancer cases were diagnosed in 1997-2000, aged 20-74 y, identified through the population-based Ontario Cancer Registry, and recruited by the Ontario Familial Colorectal Cancer Registry. Controls were a sex and age-group matched random sample of the population of Ontario. Epidemiologic and food frequency questionnaires were completed by 1095 cases and 1890 control subjects. Multivariate logistic regression analysis was used to obtain adjusted odds ratio (OR) estimates. Dietary lignan intake was associated with a significant reduction in colorectal cancer risk [OR (T3 vs. T1) = 0.73; 95% CI: 0.56, 0.94], as was isoflavone intake [OR (T3 vs. T1) = 0.71; 95% CI: 0.58, 0.86]. We evaluated interactions between polymorphic genes that encode enzymes possibly involved in metabolism of phytoestrogens (CYPs, catechol O-methyl transferase, GSTs, and UGTs) and found no significant effect modification with respect to phytoestrogen intake. This finding that phytoestrogen intake may reduce colorectal cancer risk is important, because dietary intake is potentially modifiable.

Soy isoflavones attenuate bone loss in early postmenopausal Chinese women : a single-blind randomized, placebo-controlled trial

BACKGROUND

Previous studies show that daily doses of 40-99 mg soy isoflavones produce inconsistent effects on preventing estrogen-related bone loss in postmenopausal women.

AIM OF THE STUDY

To examined the bone-sparing effect of isoflavones at a higher dose in early Chinese postmenopausal women.

METHODS

A total of 90 eligible women aged 45-60 years were randomly assigned to three treatment groups (30 subjects/group) with daily dosages of 0 (placebo), 84 and 126 mg isoflavones for 6 months. Further inclusion criteria included body mass index <30 kg/m(2) and Kuppermann Climacteric Scale >15. Bone mineral density (BMD) of the spine and hip were measured using dual- energy X-ray absorptiometry at 0 and 6 months. Serum osteocalcin, bone-specific alkaline phosphatase (BAP) and urinary deoxypyridinoline were examined at 0, 3 and 6 months.

RESULTS

Mean percent changes in BMD at the lumbar spine (p = 0.114) and femoral neck (p = 0.053) increased with the supplementations of soy isoflavones after adjusting for age, years since menopause, body weight and height, dietary intakes of isoflavones, calcium and protein, physical activities and baseline BMD at the relevant sites. We observed significantly dose-dependent linear relationship between the supplemental isoflavones and percent changes of BMD at the spine (p = 0.042) and femoral neck (p = 0.016) post-treatment, and urinary total deoxypyridinoline (p = 0.014) at 12 weeks but not at 24 weeks after adjusting for the above factors. No significant difference in percent changes in serum osteocalcin (p > 0.05) and BAP (p > 0.05) was found among the three treatment groups at 12-week and 24-week post-treatment.

CONCLUSION

There is a significantly dose-dependent effect of soy isoflavones on attenuating bone loss at the spine and femoral neck possibly via the inhibition of bone resorption in non-obese postmenopausal Chinese women with high Kuppermann Scale.

A spectroscopic study of the interaction of isoflavones with human serum albumin

Genistein and daidzein, the major isoflavones present in soybeans, possess a wide spectrum of physiological and pharmacological functions. The binding of genistein to human serum albumin (HSA) has been investigated by equilibrium dialysis, fluorescence measurements, CD and molecular visualization. One mole of genistein is bound per mole of HSA with a binding constant of 1.5 +/- 0.2 x 10(5) m(-1). Binding of genistein to HSA precludes the attachment of daidzein. The ability of HSA to bind genistein is found to be lost when the tryptophan residue of albumin is modified with N-bromosuccinimide. At 27 degrees C (pH 7.4), van't Hoff's enthalpy, entropy and free energy changes that accompany the binding are found to be -13.16 kcal x mol(-1), -21 cal x mol(-1) K(-1) and -6.86 kcal x mol(-1), respectively. Temperature and ionic strength dependence and competitive binding measurements of genistein with HSA in the presence of fatty acids and 8-anilino-1-naphthalene sulfonic acid have suggested the involvement of both hydrophobic and ionic interactions in the genistein-HSA binding. Binding measurements of genistein with BSA and HSA, and those in the presence of warfarin and 2,3,5-tri-iodobenzoic acid and Förster energy transfer measurements have been used for deducing the binding pocket on HSA. Fluorescence anisotropy measurements of daidzein bound and then displaced with warfarin, 2,3,5-tri-iodobenzoic acid or diazepam confirm the binding of daidzein and genistein to subdomain IIA of HSA. The ability of HSA to form ternery complexes with other neutral molecules such as warfarin, which also binds within the subdomain IIA pocket, increases our understanding of the binding dynamics of exogenous drugs to HSA.

The stimulation of cell proliferation by quercetin is mediated by the estrogen receptor

Quercetin causes biphasic modulation of the proliferation of specific colon and mammary cancer cells. In this study, the possible involvement of the estrogen receptor (ER) in the stimulation of cell proliferation by quercetin was investigated. For this purpose, the effect of quercetin on cell proliferation was tested in ER-positive MCF-7 and T47D cells, and in ER-negative HCC-38 and MDA-MB231 cells. Quercetin stimulated proliferation of ER-positive cells only, suggesting this effect to be ER-dependent. In support of these results, quercetin induced ER-ERE-mediated gene expression in a reporter gene assay using U2-OS cells transfected with either ERalpha or ERbeta, with 10(5)-10(6) times lower affinity than 17beta-estradiol (E2) and 10(2)-10(3 )times lower affinity than genistein. Quercetin activated the ERbeta to a 4.5-fold higher level than E2, whereas the maximum induction level of ERalpha by quercetin was only 1.7 fold that of E2. These results point at the relatively high capacity of quercetin to stimulate supposed 'beneficial' ERbeta responses as compared to the stimulation of ERalpha, the receptor possibly involved in adverse cell proliferative effects. Altogether, the results of this study reveal that physiologically relevant concentrations of quercetin can exert phytoestrogen-like activity similar to that observed for the isoflavonoid genistein.