Phyto-oestrogens and bone health

Dietary recommendations in the prevention and treatment of osteoporosis

INTRODUCTION

This article presents the initial recommendations of the French Rheumatology Society (Société Française de Rhumatologie - SFR) and the Osteoporosis Research and Information Group (Groupe de Recherche et d'Informations sur les Ostéoporoses - GRIO) on the role of diet in the prevention and treatment of osteoporosis.

METHODS

The recommendations were produced by a working group composed of rheumatologists, physician nutrition specialists and a geriatrician. Fifteen (15) questions pertaining to "daily practices" were preselected by the working group. For the literature review, the working group focussed mainly on the effects of diet on bone mineral density (BMD) and fractures, and primarily on meta-analyses of longitudinal studies and dietary intervention studies.

RESULTS

A Mediterranean-type diet and the daily consumption of 2 to 3 dairy products are recommended. Together, these provide the calcium and "high quality" protein required to maintain a normal calcium-phosphorus balance and bone metabolism, and are associated with lower fracture risk. Conversely, unbalanced Western diets, vegan diets, weight-loss diets in non-overweight individuals, alcohol consumption and daily consumption of sodas are advised against. In terms of the beneficial effects on bone mineral density and fracture risk, current scientific data are either insufficient or too divergent to recommend increasing or restricting the consumption of tea or coffee, vitamins other than vitamin D, vitamin D-enriched or phytoestrogen-rich foods, calcium-enriched plant-based beverages, oral nutritional supplements, or dietary sources of prebiotics and probiotics.

CONCLUSIONS

These are the first set of recommendations addressing the role of diet in the prevention and treatment of osteoporosis. More research is necessary to direct and support guidelines.

Higher modified dietary inflammatory index is associated with increased risk of osteoporosis in US adults: Data from NHANES

Objective

The aim of this study was to study the relationship between modified dietary inflammatory index (MDII) score with osteoporosis (OP) in adult Americans.

Methods

Data were extracted from the United States National Health and Nutrition Examination Survey (NHANES) (2007–2008, 2009–2010, 2013–2014, and 2017–2018). In this cross-sectional study, 5,446 participants were included and analyzed. Potential dietary inflammatory was assessed by MDII score (24-h recall), a composite method computed according to the relationship between nutrients and systemic pro-inflammatory cytokine level, and was further classified into tertiles. Weighted multivariable logistic regression analysis was employed to examine the associations between OP and MDII scores.

Results

In weighted multivariable-adjusted logistic regression models, the highest tertile of MDII score was associated with an increased risk of OP [odds ratio (OR): 1.73, 95% confidence interval (95 CI%): 1.14–2.63]. In participants aged above 59 years, a higher MDII score showed a higher risk of OP (OR: 1.92; 95 CI%: 1.16–3.15). In the sex-stratified models, the results remained significant only among women (OR: 1.80; 95% CI: 1.02–3.17). In the menopausal status stratified model, after adjusting potential confounding variables, the association between the MDII score, either as a categorical (OR: 1.88; 95% CI: 1.07–3.13) or continuous variables (OR: 1.19; 95%CI: 1.02–1.38), and OP risk was significant among postmenopausal women.

Conclusion

Our study indicates that a higher MDII score (pro-inflammatory effect) is significantly associated with an increased risk of OP in US adults, especially among those postmenopausal women more than 60 years. This study further supports that those dietary changes have the potential to prevent OP.

Lifelong soya consumption in males does not increase lifespan but increases health span under a metabolic stress such as type 2 diabetes mellitus

Soya consumption can decrease oxidative stress in animal models. Moreover, phytoestrogens such as genistein, present in soya, can mimic some of the beneficial effects of estrogens and are devoid of significant side effects, such as cancer. In this study, we have performed a controlled lifelong study with male OF1 mice that consumed either a soya-free diet or a soya-rich diet. We show that, although we found an increase in the expression and activity of antioxidant enzymes in soya-consuming mice, it did not increase lifespan. We reasoned that the soya diet could not increase lifespan in a very healthy population, but perhaps it could extend health span in stressed animals such as type 2 diabetic Goto Kakizaki (GK) rats. Indeed, this was the case: we found that male GK rats consuming a soya-rich diet developed the disease at a lower rate and, therefore, lived longer than soya-free diet-consuming rats.

The Beneficial Role of Natural Endocrine Disruptors: Phytoestrogens in Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of dementia with a growing incidence rate primarily among the elderly. It is a neurodegenerative, progressive disorder leading to significant cognitive loss. Despite numerous pieces of research, no cure for halting the disease has been discovered yet. Phytoestrogens are nonestradiol compounds classified as one of the endocrine-disrupting chemicals (EDCs), meaning that they can potentially disrupt hormonal balance and result in developmental and reproductive abnormalities. Importantly, phytoestrogens are structurally, chemically, and functionally akin to estrogens, which undoubtedly has the potential to be detrimental to the organism. What is intriguing, although classified as EDCs, phytoestrogens seem to have a beneficial influence on Alzheimer's disease symptoms and neuropathologies. They have been observed to act as antioxidants, improve visual-spatial memory, lower amyloid-beta production, and increase the growth, survival, and plasticity of brain cells. This review article is aimed at contributing to the collective understanding of the role of phytoestrogens in the prevention and treatment of Alzheimer's disease. Importantly, it underlines the fact that despite being EDCs, phytoestrogens and their use can be beneficial in the prevention of Alzheimer's disease.

Dietary interventions for better management of osteoporosis: An overview

Osteoporosis is a public health concern and a cause of bone loss, increased risk of skeletal fracture, and a heavy economic burden. It is common in postmenopausal women and the elderly and is impacted by dietary factors, lifestyle and some secondary factors. Although many drugs are available for the treatment of osteoporosis, these therapies are accompanied by subsequent side effects. Hence, dietary interventions are highly important to prevent osteoporosis. This review was aimed to provide a comprehensive understanding of the roles of dietary nutrients derived from natural foods and of common dietary patterns in the regulation of osteoporosis. Nutrients from daily diets, such as unsaturated fatty acids, proteins, minerals, peptides, phytoestrogens, and prebiotics, can regulate bone metabolism and reverse bone loss. Meanwhile, these nutrients generally existed in food groups and certain dietary patterns also play critical roles in skeletal health. Appropriate dietary interventions (nutrients and dietary patterns) could be primary and effective strategies to prevent and treat osteoporosis across the lifespan for the consumers and food enterprises.

Quercetin-Based Nanocomposites as a Tool to Improve Dental Disease Management

The restoration and prosthetic rehabilitation of missing teeth are commonly performed using dental implants, which are extremely effective and long-lasting techniques due to their osteointegration ability with the preimplant tissues. Quercetin is a phytoestrogen-like flavonoid well known for its several positive effects on human health, mostly linked to the anti-inflammatory, antioxidant, and antibacterial activities against both Gram-positive and Gram-negative bacteria. Moreover, many studies in dentistry and the maxillofacial fields have highlighted the positive effects of quercetin on osteogenesis, acting on osteoblast activity and angiogenetic process, and promoting soft and hard tissue regeneration. This review focuses on the role of quercetin on the healing and restoration of bony defects, considering the experimental findings of its application both in vitro and in vivo as a mere compound or in association with scaffolds and dental implants having functionalized surfaces.

Effect of dihydrotestosterone, 17-β-estrogen, genistein and equol on remodeling and morphology of bone in osteoporotic male rats during bone healing

Introduction

The aim of this study was to investigate the effect of dihydrotestosterone (DHT), 17-β-estrogen (E2), genistein (GEN) and equol (EQ) on bone remodeling and bone morphology during healing of osteoporotic male rat tibiae.

Materials and methods

180 Sprague-Dawley male rats were divided in 5 groups of 36 animals. After orchidectomy (ORX) and development of osteoporosis, trepanation of the tibia was performed. Until the time of trepanation all groups received soya free food (SF), then food change occurred and treatment started. At day 95, 102 and 151, samples were taken and histomorphometry was performed to analyze changes in bone structure under treatment. At day 33 and 70 all animals received calcein respective alizarin for polychrome bone labeling.

Results

The cortical bone was particularly affected. Treatment with DHT and E2 led to a significant long-term expansion of the thickness of the diaphyseal cortical bone, while the phytoestrogens EQ and GEN only had a positive short-term effect in this area. Only E2 preserved the trabecular bone for a limited time. In all groups, periosteal and endosteal bone areas showed the highest bone formation activity. The osteoporotic male injured bone shows a shift in mineral apposition rate (MAR) from periosteal to endosteal bone in the SF, DHT and E2 groups but not in the GEN and EQ phytohormones groups. An MAR decrease in trabecular bone formation was observed at day 70 in all groups except the E2 group.

Conclusion

We conclude from our results that healing of cortical bone defects in a rat model of male osteoporosis are mainly influenced by the estrogen pathway. Nevertheless, effects via purely androgenic mechanisms can also be demonstrated. The role of a phytohormone therapy is only marginal and if only useful for a short-term supportive approach. The role of the periosteal to endosteal shift during male osteoporotic bone healing needs to be further examined.

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The estrogen pathway is leading in the healing osteoporotic male rat bone.

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Osteoporotic rat bone has the highest apposition rate in the periosteal area.

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Healing increases periosteal, endosteal and decreases trabecular bone formation.

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The highest apposition rate shifts from periosteal to endosteal bone during healing.

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Testosterone as a drug could harness positive estrogenic and androgenic effects.

The effects of Elaeagnus angustifolia L. whole fruit on the sex hormone profile in menopausal women: A double-blind, randomized, placebo-controlled study

ETHNOPHARMACOLOGICAL RELEVANCE

Menopause is a product of interrupted ovarian activity and decrease in its estradiol production. Herbal medicines as an alternative to hormone therapy are increasingly used by menopausal women. Elaeagnus angustifolia L. (Senjed in Persian) is a well-known herbal remedy with various therapeutic effects according to Iranian traditional medicine which is recommended to relieve the menopausal side effects. The aim of present study was to evaluate the effects of oral intake of whole fruit powder of E. angustifolia on the sex hormones profile in menopausal women.

MATERIALS AND METHODS

In present double-blind randomized placebo-controlled trial, 58 eligible women who were referred to Kamali Women Hospital (Karaj, Iran, 2017) were randomly assigned into herbal medicine (15 g E. angustifolia) and placebo (7.5 g cornstarch +7.5 g isomalt) groups. Initially and after 10 weeks of the treatment, serum levels of estradiol, progesterone, testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) hormones were measured.

RESULTS

According to between-group analyses, the changes in the studied parameters were not significant between herbal medicine and placebo groups, except for joint pain that improved significantly in herbal medicine group. However, by within-group analysis the levels of FSH and FSH to testosterone showed a significant increase, whereas the level of progesterone decreased significantly after 10 weeks of E. angustifolia consumption.

CONCLUSIONS

The improvement of the sex hormone profile was not in a full accordance with Iranian folklore after E. angustifolia consumption in the present menopausal participants. However, considering a strong belief on the beneficial effects of E. angustifolia in Iranian folklore, a long-term studies of larger group participants are needed to evaluate the efficacy.

Effect of puerarin on osteogenic differentiation of human periodontal ligament stem cells

Objective

To investigate the effects of the flavonoid, puerarin, on osteogenic differentiation of human periodontal ligament stem cells (PDLSCs).

Methods

Human PDLSCs were isolated from patients undergoing orthodontic treatment, and the cell surface markers CD146, CD34, CD45, and STRO-1 were identified by immunofluorescence. Cell proliferation was detected by MTT assay; alkaline phosphatase (ALP) activity was measured, and calcium deposition was detected by alizarin red staining. PCR was then used to detect the distributions of COL-I, OPN, Runx2, and OCN, genes related to osteogenic differentiation.

Results

Staining was positive for cytokines CD146, CD34, CD45, and STRO-1 in the experimental group; staining was also positive for silk protein, but negative for keratin. After 7 days of culture, exposure to puerarin significantly promoted the level of intracellular ALP; increased puerarin concentration led to increased intracellular ALP. Red mineralized nodules appeared upon exposure to puerarin and the number of nodules was concentration-dependent. PCR analysis revealed that COL-I, OPN, Runx2, and OCN expression levels increased as puerarin concentration increased.

Conclusions

Exposure to puerarin can promote proliferation and ALP activity in human PDLSCs, thus promoting both molecular and osteogenic differentiation; these findings may provide a theoretical basis for the clinical treatment of periodontal disease with puerarin.

Randomized double-blind placebo-controlled trial of the effect of Morus nigra L. (black mulberry) leaf powder on symptoms and quality of life among climacteric women

OBJECTIVE

To test the efficacy of Morus nigra L. (MN) leaf powder for treating climacteric symptoms by comparison with hormone therapy (HT) and placebo.

METHODS

A randomized controlled trial among 62 climacteric women attending Hospital of the Federal University of Maranhão, Brazil. Women were divided into MN, HT, and placebo groups, and received 250 mg of MN leaf powder, 1 mg of estradiol, or placebo for 60 days. Primary outcomes were the Blatt-Kupperman index (BKI) for climacteric symptoms and SF-36 health questionnaire scores.

RESULTS

Baseline sociodemographic variables, BKI scores, symptoms, and SF-36 domains did not differ among the groups. There was a reduction in mean BKI in the MN (17.5 vs 9.7, P<0.001), HT (15.4 vs 8.6, P=0.001), and placebo (16.1 vs 12.4, P=0.040) groups. Analysis of quality of life (QoL) showed that functional capacity (P=0.006), vitality (P=0.031), mental health (P=0.017), and social aspect (P<0.01) improved after treatment in the MN group. The HT group showed improvement in emotional limitation (P=0.040), and the placebo group showed better functional capacity (P=0.030) after treatment.

CONCLUSIONS

Climacteric symptoms and QoL improved after administration of 250 mg of MN leaf powder for 60 days, similar to the effects of HT. The trial is registered in the Brazilian Registry of Clinical Trials (REBEC) under registration number RBR-9t4xxk.

The Impact of Long-and Short-Term Strontium Treatment on Metabolites and Minerals in Glycine max

The impact of long-term exposure to Sr2+ (LTE, four doses, 43.5 mg Sr2+ per pot, with a total of 174 mg Sr2+ per pot during the entire period of cultivation) and short-term exposure to Sr2+ (STE, one dose, 870 mg Sr2+ per pot four days before harvest) on the content of phytoestrogens and allantoin in soybeans were compared. Sr2+ accumulation, the effect on the concentration of macroelements, and basic physiology were also analyzed. LTE reduced the content of malonyldaidzin and malonylgenistin in the roots (58% and 50% compared to the control, respectively). STE increased the amount of all isoflavones in the stem and genistein in the leaves and decreased the content of malonyldaidzin and malonylgenistin in the leaves (55% and 48% compared to the control, respectively) and roots (69% and 62% of the control, respectively) as well as genistein and coumestrol in the roots (both 50% compared to the control). Sr2+ presence stimulated the accumulation of allantoin in the roots (three-fold higher than in the control), but only STE had similar effects on the shoots. In contrast to LTE, Sr2+ was transported extensively from the roots to the leaves under STE. In comparison to the control, LTE resulted in an increase in the Ca content in the stem by 36%, whereas Ca2+ accumulation in the leaves, stems, and roots increased by 60%, 80%, and 36%, respectively, under STE. Additionally, a significant accumulation of K was found only in the roots of the LTE group. The chlorophyll content did not differ between the treatments. Overall, the production of phytoestrogens and Sr accumulation were affected by both the applied dose and the duration of exposure to Sr.

Scientific Papers and Patents on Substances with Unproven Effects. Part 2

Several examples are discussed in this review, where substances without proven effects were proposed for practical use within the scope of evidence-based medicines. The following is discussed here: generalizations of the hormesis concept and its use in support of homeopathy; phytoestrogens and soy products potentially having feminizing effects; glycosaminoglycans for the treatment of osteoarthritis and possibilities of their replacement by diet modifications; flavonoids recommended for the treatment of chronic venous insufficiency and varicose veins; acetylcysteine as a mucolytic agent and its questionable efficiency especially by an oral intake; stem cells and cell therapies. In conclusion, placebo therapies can be beneficial and ethically justifiable but it is not a sufficient reason to publish biased information. Importantly, placebo must be devoid of adverse effects, otherwise, it is named pseudo-placebo. Therapeutic methods with unproven effects should be tested in high-quality research shielded from the funding bias. Some issues discussed in this review are not entirely clear, and the arguments provided here can initiate a constructive discussion.

8-Prenylgenistein, a prenylated genistein derivative, exerted tissue selective osteoprotective effects in ovariectomized mice

Our previous study reported that the in vitro osteogenic effects of 8-prenylgenistein (8PG) were more potent than its parent compound genistein. This study aimed to evaluate the osteoprotective effects of 8PG in ovariectomized (OVX) mice as well as to characterize its estrogenic effects in uterus. Mature OVX mice were treated with phytoestrogen-free diet containing 8PG or genistein. Trabecular bone mass and most of the micro-structural parameters were ameliorated at the distal femoral metaphysis in OVX mice upon treatment with genistein and both doses of 8PG. The beneficial effects of 8PG on trabecular bone were confirmed by safranin O and ABHO staining. 8PG markedly inhibited the ovariectomy-induced mRNA expressions of RANKL/OPG, ALP, COL, OCN, cathepsin K and ER-α in bone. In contrast, genistein further increased the ovariectomy-induced ER-α expression in bone. The uterus index was increased in genistein-treated group. Genistein up-regulated the expression of ER-α and PR, while 8PG significantly down-regulated the ER-α and C3 expression in uterus of OVX mice. Moreover, genistein, but not 8PG, increased expressions of ER-α, PCNA and C3 in Ishikawa cell. This study suggested that 8PG improved trabecular bone properties in OVX mice without exerting uterotrophic effects and its estrogenic actions were distinct from those of genistein.

Effect of age and estrogen on biochemical markers of bone turnover in postmenopausal women: a population-based study from Nepal

BACKGROUND

Osteoporosis, a common disease worldwide, is characterized by low bone mass and architectural deterioration of bone tissue, leading to enhanced bone fragility and increase in fracture risks. Both menopause and aging are related factors leading to greater risk of bone disease, particularly among postmenopausal women. Hence, the main purpose of this study was to investigate the differences in biochemical markers of bone turnover and to evaluate the association of hormones and age-related factors with biochemical markers between pre- and postmenopausal women.

METHODS

A descriptive cross-sectional study was conducted over a period of 6 months among the female population of Dholahity community, Lalitpur, Nepal. A total of 496 healthy women were selected based on the questionnaire strategy. Among them, 244 were premenopausal and 252 were postmenopausal women. Different bone markers were evaluated as per the guideline provided by the reagent manufacturer, and hormonal assay, particularly estradiol level assessment, was performed by chemiluminescence immunoassay-based technique.

RESULTS

A significant decrease in serum calcium level and estradiol level was observed in postmenopausal women as compared to premenopausal women, whereas a significant increase in serum phosphorus and alkaline phosphatase (ALP) levels was seen among postmenopausal (p<0.001). Age was significantly correlated with bone markers (ALP and calcium) in postmenopausal group (p<0.005), while there was no significant correlation in premenopausal group. In addition, there was significant positive correlation between calcium and estradiol in postmenopausal women, while ALP was negatively correlated with estradiol in that group. Further, no significant correlation was demonstrated between estradiol and bone markers in postmenopausal women in body mass index and age-adjusted partial correlation analysis.

CONCLUSION

Timely diagnosis of osteoporosis in women would be of significant benefit for effective care for required populations and help to minimize mortality rate and financial burden of our country.

A systematic review and meta-analysis of the effects of isoflavone formulations against estrogen-deficient bone resorption in peri- and postmenopausal women

Background: Age-related estrogen deficiency leads to accelerated bone resorption. There is evidence that, through selective estrogen receptor modulation, isoflavones may exert beneficial effects against estrogen-deficient bone loss. Isoflavone aglycones show higher bioavailability than their glycosidic counterparts and thus may have greater potency.Objective: To summarize evidence, we executed a systematic review and meta-analysis examining isoflavone therapies and bone mineral density (BMD) loss in peri- and postmenopausal women.Design: We systematically searched EMBASE and PubMed for randomized controlled trials (RCTs) evaluating isoflavone therapies for treating BMD loss at the lumbar spine and femoral neck in estrogen-deficient women. Separate meta-analyses were carried out with the use of random-effects models for the lumbar spine and femoral neck for all studies providing isoflavones as aglycones.Results: Twenty-six RCTs (n = 2652) were included in the meta-analysis. At the lumbar spine, isoflavone treatment was associated with a significantly (P < 0.00001) higher weighted mean difference (WMD) of BMD change of 0.01 (95% CI: 0.01, 0.02) than the control. For the femoral neck (18 RCTs, n = 1604), isoflavone treatment showed a significantly (P < 0.01) higher WMD of BMD change of 0.01 (95% CI: 0.00, 0.02) compared with the control. When isolating studies that provide isoflavone aglycones in their treatment arm, the average effect was further significantly increased at the spine (5 RCTs, n = 682) to 0.04 (P < 0.00001; 95% CI: 0.02, 0.05) and femoral neck (4 RCTs, n = 524) to 0.03 (P < 0.05; 95% CI: 0.00, 0.06) compared with the control. This protective effect against bone loss disappeared when only studies with formulations comprising predominantly isoflavone glycosides were included.Conclusions: Isoflavone treatments exert a moderately beneficial effect against estrogen-deficient bone loss in women. The effect appears dependent on whether isoflavone treatments are in aglycone form; we conclude that beneficial effects against bone loss may be enhanced for isoflavone aglycones.

Combined bioavailable isoflavones and probiotics improve bone status and estrogen metabolism in postmenopausal osteopenic women: a randomized controlled trial

Background: Female age-related estrogen deficiency increases the risk of osteoporosis, which can be effectively treated with the use of hormone replacement therapy. However, hormone replacement therapy is demonstrated to increase cancer risk. Bioavailable isoflavones with selective estrogen receptor affinity show potential to prevent and treat osteoporosis while minimizing or eliminating carcinogenic side effects.Objective: In this study, we sought to determine the beneficial effects of a bioavailable isoflavone and probiotic treatment against postmenopausal osteopenia.Design: We used a novel red clover extract (RCE) rich in isoflavone aglycones and probiotics to concomitantly promote uptake and a favorable intestinal bacterial profile to enhance isoflavone bioavailability. This was a 12-mo, double-blind, parallel design, placebo-controlled, randomized controlled trial of 78 postmenopausal osteopenic women supplemented with calcium (1200 mg/d), magnesium (550 mg/d), and calcitriol (25 μg/d) given either RCE (60 mg isoflavone aglycones/d and probiotics) or a masked placebo [control (CON)].Results: RCE significantly attenuated bone mineral density (BMD) loss at the L2-L4 lumbar spine vertebra (P < 0.05), femoral neck (P < 0.01), and trochanter (P < 0.01) compared with CON (-0.99% and -2.2%; -1.04% and -3.05%; and -0.67% and -2.79, respectively). Plasma concentrations of collagen type 1 cross-linked C-telopeptide was significantly decreased in the RCE group (P < 0.05) compared with CON (-9.40% and -6.76%, respectively). RCE significantly elevated the plasma isoflavone concentration (P < 0.05), the urinary 2-hydroxyestrone (2-OH) to 16α-hydroxyestrone (16α-OH) ratio (P < 0.05), and equol-producer status (P < 0.05) compared with CON. RCE had no significant effect on other bone turnover biomarkers. Self-reported diet and physical activity were consistent and differences were nonsignificant between groups throughout the study. RCE was well tolerated with no adverse events.Conclusions: Twice daily RCE intake over 1 y potently attenuated BMD loss caused by estrogen deficiency, improved bone turnover, promoted a favorable estrogen metabolite profile (2-OH:16α-OH), and stimulated equol production in postmenopausal women with osteopenia. RCE intake combined with supplementation (calcium, magnesium, and calcitriol) was more effective than supplementation alone. This trial was registered at clinicaltrials.gov as NCT02174666.

Long-term kinetics of daidzein and its main metabolites in human equol-producers after soymilk intake: identification of equol-conjugates by UPLC-orbitrap-MS and influence of the number of transforming bacteria on plasma kinetics

The main aim of the study was to establish in vivo a correlation between equol (EQU) production and a number of intestinal bacteria able to perform the transformation. Thus, healthy female volunteers were selected for their ability to convert slowly (n = 6, 10⁵-10⁹ cells/g wet feces) or quickly (n = 6, 10¹⁰-10¹² cells/g wet feces) daidzein (DAI) in EQU. After oral administration of 100 mg DAI in soymilk, plasma (0-99 h) and urine (0-96 h) samples were collected. DAI and its metabolites were determined by LC-MS/MS and EQU -conjugates by UPLC-High Resolution-MS. Only for EQU a direct correlation was found between the number of transforming microorganisms and parameters such as t_max and t_1/2 (p = 0.027). Peak serum concentration time, C_max, AUC_0-72 h and t_1/2 for total EQU (n = 12) were 36 ± 10 h, 89 ± 78 nM, 2.4 ± 1.7 (μmol × h/L) and 15.6 ± 3.3 h, respectively. In plasma and urine EQU was found mainly as 7-O-glucuronide.

Quercetin-loaded solid lipid nanoparticles improve osteoprotective activity in an ovariectomized rat model: a preventive strategy for post-menopausal osteoporosis

A formulation of quercetin-based solid lipid nanoparticles (QSLNs) was developed to increase the bioavailability of quercetin, with an aim to evaluate its effects on bone health in comparison to free quercetin (Q).

9-Demethoxy-medicarpin promotes peak bone mass achievement and has bone conserving effect in ovariectomized mice: Positively regulates osteoblast functions and suppresses osteoclastogenesis

We report a new bone anabolic and anti-catabolic pterocarpan 9-demethoxy-medicarpin (DMM) for the management of postmenopausal osteoporosis. DMM promoted osteoblast functions via activation of P38MAPK/BMP-2 pathway and suppressed osteoclastogenesis in bone marrow cells (BMCs). In calvarial osteoblasts, DMM blocked nuclear factor kappaB (NFκB) signaling and inhibited the mRNA levels of pro-inflammatory cytokines. DMM treatment led to increased OPG (osteoprotegrin) and decreased transcript levels of TRAP (tartarate resistant acid phosphatase), RANK (receptor activator of NFκB) and RANKL (RANK ligand) in osteoblast-osteoclast co-cultures. Immature female SD rats administered with DMM exhibited increased bone mineral density, bone biomechanical strength, new bone formation and cortical bone parameters. Ovx mice administered with DMM led to significant restoration of trabecular microarchitecture and had reduced formation of osteoclasts and increased formation of osteoprogenitor cells in BMCs. DMM exhibited no uterine estrogenicity. Overall, these results demonstrate the therapeutic potential of DMM for the management of postmenopausal osteoporosis.

The proliferation, differentiation, and mineralization effects of puerarin on osteoblasts in vitro

AIM

Osteoblasts are key functional cells in the process of bone metabolic balance. Phytoestrogens have an important influence on the proliferation and differentiation of osteoblasts. Puerarin, a plant estrogen, has a wide range concentration in vitro on the function of osteoblasts. The current study investigates the effect of the phytoestrogen puerarin on the proliferation, differentiation, and mineralization of osteoblasts in vitro.

METHODS

The calvaria bone of eight-ten Wistar rats which were born within 24 h were obtained in aseptic condition. After enzyme digestion, isolation, purified osteoblasts of rats were cultured for further study. The cells of the first to third generation were divided into a control group and a puerarin-treated group with 10(-3)-10(-10) mol·L(-1) puerarin. The cells were exposed to the medium containing a low level of carbohydrates, 10% (V/V) FBS for 24 h. After 1 to 4 days of culture, the OD values on the proliferation of osteoblasts in each group were determined by microplate reader. The cells were cultured in the medium containing 50 μg·mL(-1) vitamin C, 10(-2) mol·L(-1) sodium glycerophosphate, 10% FBS and the medium was changed every 3 to 4 days. After 2 to 8 days of culture, expression of alkaline phosphatase were tested and compared by microplate reader. The mineral nodes of osteoblasts were dyed using alizarin red or improved Von Kossa way after four weeks.

RESULTS

Compared with those in the 10(-5)-10(-9) mol·L(-1) puerarin, the proliferation of osteoblasts, the expression of alkaline phosphatase, and the number of mineral nodes of osteoblasts were significantly decreased in the control group. The increase was the fastest in the third day, while on the fourth day it was decreased, and arrived at statistical significance compared with the alkaline phosphatase activities and control group. The 10(-6) mol·L(-1) group was the most distinct, and formed the most mineralized nodule. Compared with the 10(-3) mol·L(-1) puerarin group, those changes were markedly increased in the control group.

CONCLUSIONS

Puerarin has proliferation, differentiation, and mineralization effects on osteoblasts in a dose-dependent manner, and has a double-way effect on the osteoblasts in vitro. A low-dose showed positive effects on the development of osteoblasts, and high-dose puerarin could inhibit the formation of bone.

Soy and phytoestrogens: possible side effects

Phytoestrogens are present in certain edible plants being most abundant in soy; they are structurally and functionally analogous to the estrogens. Phytoestrogens have been applied for compensation of hormone deficiency in the menopause. At the same time, soy products are used in infant food and other foodstuffs. Furthermore, soy is applied as animal fodder, so that residual phytoestrogens and their active metabolites such as equol can remain in meat and influence the hormonal balance of the consumers. There have been only singular reports on modified gender-related behavior or feminization in humans in consequence of soy consumption. In animals, the intake of phytoestrogens was reported to impact fertility, sexual development and behavior. Feminizing effects in humans can be subtle and identifiable only statistically in large populations.

Formononetin attenuates osteoclastogenesis via suppressing the RANKL-induced activation of NF-κB, c-Fos, and nuclear factor of activated T-cells cytoplasmic 1 signaling pathway

Formononetin (1), a plant-derived phytoestrogen, possesses bone protective properties. To address the potential therapeutic efficacy and mechanism of action of 1, we investigated its antiosteoclastogenic activity and its effect on nuclear factor-kappaB ligand (RANKL)-induced bone-marrow-derived macrophages (BMMs). Compound 1 markedly inhibited RANKL-induced osteoclast differentiation in the absence of cytotoxicity, by regulating the expression of osteoprotegerin (OPG) and RANKL in BMMs and in cocultured osteoblasts. Compound 1 significantly inhibited RANKL-induced tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T cell expressed and secreted (RANTES), and macrophage inflammatory protein-1α (MIP-1α) in a concentration-dependent manner. These effects were accompanied by a decrease in RANKL-induced activation of the NF-κB p65 subunit, degradation of inhibitor κBα (IκBα), induction of NF-κB, and phosphorylation of AKT, extracellular-signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK). NF-κB siRNA suppressed AKT, ERK, JNK, and p38 MAPK phosphorylation. Furthermore, 1 significantly suppressed c-Fos and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), key transcription factors during osteoclastogenesis. SP600125, a specific inhibitor of JNK, reduced RANKL-induced expression of phospho-c-Jun, c-Fos, and NFATc1 and inhibited osteoclast formation. These results suggested that 1 acted as an antiresorption agent by blocking osteoclast activation.

Phytoestrogens as alternative hormone replacement therapy in menopause: What is real, what is unknown

Menopause is characterized by an altered hormonal status and by a decrease in life quality due to the appearance of uncomfortable symptoms. Nowadays, with increasing life span, women spend one-third of their lifetime under menopause. Understanding menopause-associated pathophysiology and developing new strategies to improve the treatment of menopausal-associated symptoms is an important topic in the clinic. This review describes physiological and hormone alterations observed during menopause and therapeutic strategies used during this period. We critically address the benefits and doubts associated with estrogen/progesterone-based hormone replacement therapy (HRT) and discuss the use of phytoestrogens (PEs) as a possible alternative. These relevant plant-derived compounds have structural similarities to estradiol, interacting with cell proteins and organelles, presenting several advantages and disadvantages versus traditional HRT in the context of menopause. However, a better assessment of PEs safety/efficacy would warrant a possible widespread clinical use.

Pantoea agglomerans lipopolysaccharide maintains bone density in premenopausal women: a randomized, double-blind, placebo-controlled trial

Lipopolysaccharide fromPantoea agglomerans (LPSp) facilitates Ca and P turnover in chicken calvaria and femurs. This study investigated osteoporosis prevention by the oral administration of LPSp in mice and in double-blind clinical tests. Using ovariectomized (OVX) osteoporosis mice model, we investigated the effects of LPSp on the bone density and Ca concentration after ingesting LPSp-containing water for 4 weeks. Oral administration of LPSp tended to suppress the decline in the bone density and the cortical bone thickness in the OVX mice. Moreover, the Ca concentrations were maintained in the OVX-LPSp mice. The effects of LPSp on bone turnover were tested in randomized and double-blind clinical test subjects, who were healthy women aged 40-79 years. The subjects ingested either soy milk without LPSp (control group) or with LPSp (LPSp group) for 3 months. The results showed that the LPSp group on premenopause maintained their bone density compared with the control group pre- and postmenopause. Moreover, these effects were maintained for 2 months postobservation. LPSp maintains bone volume and density in vivo. Thus, a combination of soy milk and LPSp may be useful for osteoporosis prevention.

Genistein production in rice seed via transformation with soybean IFS genes

To produce genistein in rice, the isoflavone synthase (IFS) genes, SpdIFS1 and SpdIFS2 were cloned from the Korean soybean cultivar, Sinpaldalkong II as it has a higher genistein content than other soybean varieties. SpdIFS1 and SpdIFS2 show a 99.6% and 98.2% identity at the nucleotide level and 99.4% and 97.9% identity at the amino acid level, respectively, with IFS1 and IFS2 from soybean (GenBank accession Nos. AF195798 and AF195819). Plant expression vectors were constructed harboring SpdIFS1 or SpdIFS2 under the control of a rice globulin promoter that directs seed specific expression, and used to transform two rice varieties, Heugnam, a black rice, and Nakdong, a normal rice cultivar without anthocyanin pigment. Because naringenin, the substrate of SpdIFS1 and SpdIFS2, is on the anthocyanin biosynthesis pathway, the relative production rate of genistein was compared between SpdIFS-expressing transgenic Heugnam and Nakdong. Southern blot analysis of eight of the resulting transgenic rice plants revealed that the T0 plants had one to three copies of the SpdIFS1 or SpdIFS2 gene. The highest level of genistein content found in rice seeds was 103 μg/g. These levels were about 30-fold higher in our transgenic rice lines than the genistein aglycon content of a non-leguminous IFS-expressing transgenic tobacco petal, equaling about 12% of total genistein content of Sinpaldalkong II. There were no significant differences found between the genistein content in Heugnam and Nakdong transgenic rice plants.

R(-)-O-desmethylangolensin is the main enantiomeric form of daidzein metabolite produced by human in vitro and in vivo

After ingestion, human intestinal bacteria transform daidzein into dihydrodaidzein, which can be further metabolised to O-desmethylangolensin. This metabolite, unlike daidzein, has a chiral centre and can therefore occur as two distinct enantiomers; however, it is unclear which enantiomer is present in humans. The aim of this study was to define in vitro and in vivo the structure of O-desmethylangolensin and then to evaluate its pharmacokinetic parameters. Daidzein metabolism was preliminarily investigated in anaerobic batch cultures inoculated with mixed faecal bacteria from O-desmethylangolensin producer volunteers. The transformation was monitored by liquid chromatography-mass spectrometry and a chiral column was used to distinguish dihydrodaidzein and O-desmethylangolensin enantiomers. These were purified, analysed by circular dichroism and the results established R(-)-O-desmethylangolensin as the main product (enantiomer excess 91%). However, both dihydrodaidzein enantiomers were detected. Similar results were obtained by in vivo trials. The in vitro formation of O-desmethylangolensin seems to be directly correlated with the number of transforming microorganisms. This correlation was found in vivo for tmax but not for other pharmacokinetic indexes. The pharmacokinetics of daidzein, dihydrodaidzein and O-desmethylangolensin were then evaluated in 11 healthy adult O-desmethylangolensin producers after the single administration of soy milk containing 100mg daidzein. The conjugated forms of daidzein, dihydrodaidzein and O-desmethylangolensin represent more than 90 and 95% of the plasmatic and urinary forms, respectively. The Cmax, tmax and half-life of O-desmethylangolensin in plasma were 62±53nM, 28±11 and 15±6h, respectively. Relevant inter-individual variations were observed as indicated by the high standard deviations.

Black tea may be a prospective adjunct for calcium supplementation to prevent early menopausal bone loss in a rat model of osteoporosis

The present study was undertaken to find out the ability of black tea extract (BTE) as a suitable alternative of adjunct for calcium supplementation in treating an ovariectomized rat model of early osteoporosis. Female Wistar rats weighing 140-150 g were divided into four groups consisting of six animals in each group: (A) sham-operated control; (B) bilaterally ovariectomized; (C) bilaterally ovariectomized + BTE; (D) bilaterally ovariectomized + 17 β -estradiol. Results suggest that BTE could promote intestinal absorption of calcium significantly (P < 0.01 for duodenum and ileum; and P < 0.05 for jejunum). This was found associated with enhanced activities of two relevant intestinal mucosal enzymes alkaline phosphatase (P < 0.01 for duodenum, jejunum, and ileum) and Ca(2+) activated ATPase (P < 0.01 for duodenum, jejunum, and ileum). Such BTE-mediated promotion of calcium absorption was coupled with increase in serum estrogen titer (P < 0.01) and recovery of all urinary, bone, and serum osteoporotic marker parameters, including bone histological features. Serum parathyroid hormone level, however, was not altered in these animals (P > 0.05). A comparative study with 17 β -estradiol, a well-known adjunct for calcium supplementation, indicated that efficacy of BTE in maintaining skeletal health is close to that of 17 β -estradiol. This study suggests that simultaneous use of BTE is promising as a prospective candidate for adjunctive therapies for calcium supplementation in the early stage of menopausal bone changes.

A naturally occurring naringenin derivative exerts potent bone anabolic effects by mimicking oestrogen action on osteoblasts

BACKGROUND AND PURPOSE

Naringenin and its derivatives have been assessed in bone health for their oestrogen-'like' effects but low bioavailability impedes clinical potential. This study was aimed at finding a potent form of naringenin with osteogenic action.

EXPERIMENTAL APPROACH

Osteoblast cultures were harvested from mouse calvaria to study differentiation by naringenin, isosakuranetin, poncirin, phloretin and naringenin-6-C-glucoside (NCG). Balb/cByJ ovariectomized (OVx) mice without or with osteopenia were given naringenin, NCG, 17β-oestradiol (E2) or parathyroid hormone (PTH). Efficacy was evaluated by bone microarchitecture using microcomputed tomography and determination of new bone formation by fluorescent labelling of bone. Plasma levels of NCG and naringenin were determined by HPLC.

KEY RESULTS

NCG stimulated osteoblast differentiation more potently than naringenin, while isosakuranetin, poncirin or phloretin had no effect. NCG had better oral bioavailability than naringenin. NCG increased the mRNA levels of oestrogen receptors (ERs) and bone morphogenetic protein (an ER responsive gene) in vivo, more than naringenin. In OVx mice, NCG treatment in a preventive protocol increased bone formation rate (BFR) and improved trabecular microarchitecture more than naringenin or E2. In osteopenic mice, NCG but not naringenin, in a therapeutic protocol, increased BFR and improved trabecular microarchitecture, comparable with effects of PTH treatment. Stimulatory effects of NCG on osteoblasts were abolished by an ER antagonist. NCG transactivated ERβ but not ERα. NCG exhibited no uterine oestrogenicity unlike naringenin.

CONCLUSIONS AND IMPLICATIONS

NCG is a potent derivative of naringenin that has bone anabolic action through the activation of osteoblast ERs and exhibited substantial oral bioavailability.

Habitual flavonoid intakes are positively associated with bone mineral density in women

Dietary flavonoids exert bone-protective effects in animal models, but there is limited information on the effect of different flavonoid subclasses on bone health in humans. The aim of this observational study was to examine the association between habitual intake of flavonoid subclasses with bone mineral density (BMD) in a cohort of female twins. A total of 3160 women from the TwinsUK adult twin registry participated in the study. Habitual intakes of flavonoids and subclasses (flavanones, anthocyanins, flavan-3-ols, polymers, flavonols, and flavones) were calculated from semiquantitative food frequency questionnaires using an updated and extended U.S. Department of Agriculture (USDA) database. Bone density was measured using dual-energy X-ray absorptiometry. In multivariate analyses, total flavonoid intake was positively associated with higher BMD at the spine but not at the hip. For the subclasses, the magnitude of effect was greatest for anthocyanins, with a 0.034 g/cm(2) (3.4%) and 0.029 g/cm(2) (3.1%) higher BMD at the spine and hip, respectively, for women in the highest intake quintile compared to those in the lowest. Participants in the top quintile of flavone intake had a higher BMD at both sites; 0.021 g/cm(2) (spine) and 0.026 g/cm(2) (hip). At the spine, a greater intake of flavonols and polymers was associated with a higher BMD (0.021 and 0.024 g/cm(2) , respectively), whereas a higher flavanone intake was positively associated with hip BMD (0.008 g/cm(2) ). In conclusion, total flavonoid intake was positively associated with BMD, with effects observed for anthocyanins and flavones at both the hip and spine, supporting a role for flavonoids present in plant-based foods on bone health. .

Synergistic effect of isoflavone glycosides and fructooligosaccharides on postgastrectomy osteopenia in rats

Fructooligosaccharides stimulate the growth of Bifidobacteria, which cleave isoflavone glycosides to yield corresponding aglycones, and convert metabolites by enhancing enterohepatic recirculation of isoflavones in rats. In the present study, we determined the synergistic effect of dietary isoflavone glycosides and fructooligosaccharides on postgastrectomy osteopenia in rats. Nine-week-old male Sprague-Dawley rats were gastrectomized (n = 20) or sham operated, (control, n = 5) and then randomly assigned to 5 diet groups: sham-a purified diet control, gastrectomized-control, gastrectomized-isoflavone (0.2% isoflavone glycosides), gastrectomized-fructooligosaccharides (7.5% fructooligosaccharides), and isoflavone and fructooligosaccharides (0.2% isoflavone glycosides + 7.5% fructooligosaccharides). After 6 weeks, the rats were killed and biological samples were collected. In gastrectomized rats, fructooligosaccharides prevented femoral bone fragility, but isoflavone without fructooligosaccharides did not inhibit postgastrectomy osteopenia. Isoflavone and fructooligosaccharides exhibited a synergistic in the distal metaphyseal trabecular bone, indicated by peripheral quantitative computed tomography. Moreover, fructooligosaccharides increased calcium absorption and equol production from daidzein in gastrectomized rats. These results indicate that isoflavone alone did not inhibit postgastrectomy osteopenia, but the combination of isoflavone and fructooligosaccharides improved the inhibition of trabecular bone loss by increasing calcium absorption and equol production through fructooligosaccharides supplementation.

Kaempferol as a flavonoid induces osteoblastic differentiation via estrogen receptor signaling

Background

Flavonoids, a group of compounds mainly derived from vegetables and herbal medicines, chemically resemble estrogen and some have been used as estrogen substitutes. Kaempferol, a flavonol derived from the rhizome of Kaempferia galanga L., is a well-known phytoestrogen possessing osteogenic effects that is also found in a large number of plant foods.

The herb K. galanga is a popular traditional aromatic medicinal plant that is widely used as food spice and in medicinal industries. In the present study, both the estrogenic and osteogenic properties of kaempferol are evaluated.

Methods

Kaempferol was first evaluated for its estrogenic properties, including its effects on estrogen receptors. The osteogenic properties of kaempferol were further determined its induction effects on specific osteogenic enzymes and genes as well as the mineralization process in cultured rat osteoblasts.

Results

Kaempferol activated the transcriptional activity of pERE-Luc (3.98 ± 0.31 folds at 50 μM) and induced estrogen receptor α (ERα) phosphorylation in cultured rat osteoblasts, and this ER activation was correlated with induction and associated with osteoblast differentiation biomarkers, including alkaline phosphatase activity and transcription of osteoblastic genes, e.g., type I collagen, osteonectin, osteocalcin, Runx2 and osterix. Kaempferol also promoted the mineralization process of osteoblasts (4.02 ± 0.41 folds at 50 μM). ER mediation of the kaempferol-induced effects was confirmed by pretreatment of the osteoblasts with an ER antagonist, ICI 182,780, which fully blocked the induction effect.

Conclusion

Our results showed that kaempferol stimulates osteogenic differentiation of cultured osteoblasts by acting through the estrogen receptor signaling.

Androgens and estrogens prevent rosiglitazone-induced adipogenesis in human mesenchymal stem cells

Thiazolidinediones (TZD), a class of anti-diabetic drugs, determine bone loss and increase fractures particularly in post-menopausal women, thus suggesting a protective role of sex steroids. We have previously demonstrated that the TZD rosiglitazone (RGZ) negatively affects bone mass by inhibiting osteoblastogenesis, yet inducing adipogenesis, in bone marrow-derived human mesenchymal stem cells (hMSC). The aim of this study was to determine whether estrogens and androgens are able to revert the effects of RGZ on bone. hMSC express estrogen receptor α and β and the androgen receptor. We found that 17β-estradiol (10 nM), the phytoestrogen genistein (10 nM), testosterone (10 nM) and the non-aromatizable androgens dihydrotestosterone (10 nM) and methyltrienolone (10 nM) effectively counteracted the adipogenic effect of RGZ (1 μM) in hMSC induced to differentiate into adipocytes, as determined by evaluating the expression of the adipogenic marker peroxisome proliferator-activated receptor γ and the percentage of fat cells. Furthermore, when hMSC were induced to differentiate into osteoblasts, all the above-mentioned molecules and also quercetin, another phytoestrogen, significantly reverted the inhibitory effect of RGZ on the expression of the osteogenic marker osteocalcin and decreased the number of fat cells observed after RGZ exposure. Our study represents, to our knowledge, the first demonstration in hMSC that androgens, independently of their aromatization, and estrogens are able to counteract the negative effects of RGZ on bone. Our data, yet preliminary, suggest the possibility to try to prevent the negative effects of TZD on bone, using steroid receptor modulators, such as plant-derived phytoestrogens, which lack evident adverse effects.

Protective effect of Sideritis euboea extract on bone mineral density and strength of ovariectomized rats

OBJECTIVE

The aim of this study was to investigate the potential protective effect of Sideritis euboea extract (SID), commonly consumed as "mountain tea," on bone mineral density (BMD) and the strength of the ovariectomized (OVX) rat model of osteoporosis.

METHODS

Thirty-two 10-month-old Wistar rats were separated into controls (sham operated), OVX, and OVX plus SID in their drinking water (dose, 330 mg/kg body weight per day), starting immediately after OVX for 6 months. Tibial BMD at baseline and at 3 and 6 months post-OVX, three-point-bending of the femur, and body and uterine weight at the study end were examined.

RESULTS

BMD percentage change from baseline of the whole tibia was similar in control and OVX + SID rats at 3 months (-3.02% vs -4.67%, P = not significant), revealing a strong osteoprotective effect. At 6 months, the corresponding changes were -6.02% versus -14.37%, P < 0.05, indicating a greater bone loss in treated rats, albeit significantly less than the OVX change (-20.46%; OVX vs OVX + SID, P < 0.05). The proximal (metaphyseal) tibial BMD percentage change from baseline to 3 and 6 months between the OVX and OVX + SID groups (-26.47% vs -15.57% and -31.22% vs -16.57%, respectively) was statistically significant, demonstrating that SID preserved the proximal tibial BMD of the OVX + SID group significantly. Three-point-bending showed a significant increase in the treated compared with the OVX groups. Body and uterine weights were similar in the OVX and treated groups.

CONCLUSIONS

SID significantly protected tibial bone loss and improved femoral biomechanical strength in OVX + SID rats compared with OVX rats.

Double directional adjusting estrogenic effect of naringin from Rhizoma drynariae (Gusuibu)

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese traditional medicine Rhizoma drynariae (Gusuibu) is widely used for clinically treating osteoporosis and bone non-union. Naringin and its active metabolite naringenin are the main active ingredients of Rhizoma drynariae total flavonoids.

AIM OF THE STUDY

The purpose of this paper is to confirm estrogenic and anti-estrogenic activity of naringin and naringenin, and provide the basic data to further study for the dose-effect relationship and the mechanism for Rhizoma drynariae in treatment of osteoporosis and other estrogen deficiency-related diseases.

MATERIALS AND METHODS

Naringin was extracted from Rhizoma drynariae. Naringin and its metabolin naringenin were tested estrogenic and anti-estrogenic activities through the experiment of cell proliferation and uterus weight gain in mice. Their estrogen-receptor binding abilities were tested by yeast two-hybrid experiment and nuclear receptor cofactor assays (RCAS) experiment, and their possible binding sites for ERβ were performed by computer aided molecular docking technology.

RESULTS

Naringin and naringenin showed significant effects on the proliferation of estrogen-sensitive ER(+) MCF-7 cells in the absence of estrogen. Induction increased proliferation as the drug concentration, and the strongest proliferation appeared at a concentration of 8.6×10(-5)M. When estradiol (10(-10)M) and the different concentrations of naringin or naringenin were treated at the same time, naringin and naringenin could result in antagonistic effects on estradiol-induced MCF-7 cell proliferation, but they did not significantly affect proliferation of estrogen-insensitive ER(-) MDA-MB-231 cells. Naringin and naringenin exhibited higher binding capacity to estrogen receptor β (ERβ) than estrogen receptor α (ERα) in yeast two-hybrid experiments and nuclear receptor cofactor assays (RCAS) experiment. Docking simulation between naringin/naringenin and ERβ were performed, and the corresponding binding free energies of naringin-receptor and naringenin-receptor docked complexes were -7.95 and -10.45kcal/mol. Hydrogen bonds were found between naringin and the amino acid residues Lys304 and His308. The oxygen atom (O11) of naringenin formed hydrogen bond to Arg346, and there may be hydrophobic space interactions between phenyl group (C13-C18) of naringenin and the amino acid residues Leu298, Met336, Met340, Phe356, Ile376 and Leu380.

CONCLUSIONS

Naringin and naringenin revealed a double directional adjusting function of estrogenic and anti-estrogenic activities. Both of them showed estrogenic agonist activity at low concentration or lack of endogenous estrogen. On the other hand, they also acted as estrogenic antagonists at high concentrations or too much endogenous estrogen. They produced estrogenic and anti-estrogenic effects primarily through selectively binding with ERβ, which could prevent and treat osteoporosis with the mechanism of estrogenic receptor agitation. This paper confirmed the estrogenic and anti-estrogenic activity of naringin and naringenin, and further studies were still essential to study their dose-effect relationship and the anti-osteoporosis mechanism for Rhizoma drynariae in the treatment of osteoporosis and other estrogen deficiency-related diseases.

Quercetin-6-C-β-D-glucopyranoside isolated from Ulmus wallichiana planchon is more potent than quercetin in inhibiting osteoclastogenesis and mitigating ovariectomy-induced bone loss in rats

OBJECTIVE

The aim of this study was to determine the skeletal effect of quercetin-6-C-β-D-glucopyranoside (QCG) isolated from the extract of Ulmus wallichiana and compare this effect with quercetin (Q) in a rat model of postmenopausal bone loss.

METHODS

Murine bone marrow cells were used to study the effect of QCG or Q on osteoclast differentiation. QCG or Q (1.0 and 5.0 mg kg(-1) d(-1) doses) was administered orally to ovarietomized (OVx) rats for 12 weeks. Sham-operated + vehicle and OVx + vehicle groups served as positive and negative controls, respectively. Bone mineral density, bone microarchitecture, biomechanical strength, bone turnover markers, and uterotrophic effect were studied. One-way analysis of variance was used to test significance of effects.

RESULTS

QCG at 1.0 nM significantly inhibited differentiation of multinucleated osteoclasts and expression of osteoclastogenic genes from bone marrow cells, whereas Q at 10.0 μM had comparable results. OVx rats treated with QCG exhibited significantly higher bone mass and better microarchitecture in trabecular and cortical bones compared with OVx + vehicle. QCG treatment of OVx rats had better functional impact than did Q-treated OVx rats, evident from increased bone biomechanical strength. Serum osteocalcin and urinary fragments of type 1 collagen were significantly lower in QCG-treated OVx rats compared with OVx + vehicle group. The protective effect of QCG under ovariectomy-induced bone loss setting was found to be significantly better than Q. Uterine histomorphometry parameters of OVx rats did not change with QCG treatment.

CONCLUSIONS

QCG improves bone biomechanical quality more effectively than Q through positive modifications of bone mineral density and bone microarchitecture without a hyperplastic effect on the uterus.

Association between dietary phyto-oestrogens and bone density in men and postmenopausal women

Phyto-oestrogens have been associated with a decreased risk for osteoporosis, but results from intervention and observational studies in Western countries have been inconsistent. In the present study, we investigated the association between habitual phyto-oestrogen intake and broadband ultrasound attenuation (BUA) of the calcanaeum as a marker of bone density. We collected 7 d records of diet, medical history and demographic and anthropometric data from participants (aged 45-75 years) in the European Prospective Investigation into Cancer-Norfolk study. Phyto-oestrogen (biochanin A, daidzein, formononetin; genistein, glycitein; matairesinol; secoisolariciresinol; enterolactone; equol) intake was determined using a newly developed food composition database. Bone density was assessed using BUA of the calcanaeum. Associations between bone density and phyto-oestrogen intake were investigated in 2580 postmenopausal women who were not on hormone replacement therapy and 4973 men. Median intake of total phyto-oestrogens was 876 (interquartile range 412) μg/d in postmenopausal women and 1212 (interquartile range 604) μg/d in men. The non-soya isoflavones formononetin and biochanin A were marginally significant or significantly associated with BUA in postmenopausal women (β = 1·2; P < 0·1) and men (β = 1·2; P < 0·05), respectively; enterolignans and equol were positively associated with bone density in postmenopausal women, but this association became non-significant when dietary Ca was added to the model. In the lowest quintile of Ca intake, soya isoflavones were positively associated with bone density in postmenopausal women (β = 1·4; P < 0·1). The present results therefore suggest that non-soya isoflavones are associated with bone density independent of Ca, whereas the association with soya or soya isoflavones is affected by dietary Ca.

Medicarpin, a legume phytoalexin, stimulates osteoblast differentiation and promotes peak bone mass achievement in rats: evidence for estrogen receptor β-mediated osteogenic action of medicarpin

Dietary isoflavones including genistein and daidzein have been shown to have favorable bone conserving effects during estrogen deficiency in experimental animals and humans. We have evaluated osteogenic effect of medicarpin (Med); a phytoalexin that is structurally related to isoflavones and is found in dietary legumes. Med stimulated osteoblast differentiation and mineralization at as low as 10⁻¹⁰ M. Studies with signal transduction inhibitors demonstrated involvement of a p38 mitogen activated protein kinase-ER-bone morphogenic protein-2 pathway in mediating Med action in osteoblasts. Co-activator interaction studies demonstrated that Med acted as an estrogen receptor (ER) agonist; however, in contrast to 17β-estradiol, Med had no uterine estrogenicity and blocked proliferation of MCF-7 cells. Med increased protein levels of ERβ in osteoblasts. Selective knockdown of ERα and ERβ in osteoblasts established that osteogenic action of Med is ERβ-dependent. Female Sprague-Dawley (weaning) rats were administered Med at 1.0- and 10.0 mg.kg⁻¹ doses by gavage for 30 days along with vehicle control. Med treatment resulted in increased formation of osteoporgenitor cells in the bone marrow and osteoid formation (mineralization surface, mineral apposition/bone formation rates) compared with vehicle group. In addition, Med increased cortical thickness and bone biomechanical strength. In pharmacokinetic studies, Med exhibited oral bioavailability of 22.34% and did not produce equol. Together, our results demonstrate Med stimulates osteoblast differentiation likely via ERβ, promotes achievement of peak bone mass, and is devoid of uterine estrogenicity. In addition, given its excellent oral bioavailability, Med can be potential osteogenic agent.

Biotic elicitation of isoflavone metabolism with plant growth promoting rhizobacteria in early stages of development in Glycine max var. Osumi

Nine plant growth-promoting rhizobacteria from different backgrounds were assayed on Glycine max var. Osumi to evaluate their potential as biotic elicitors to increase isoflavone (IF) levels. Strains were inoculated on 2 day old pregerminated seeds. Six days after inoculation, the seedlings were harvested. Biometric parameters were registered, and IFs were determined. Although only one strain (N21.4) increased total IF contents and only one (M84) caused significant decreases in total IF, five different behaviors were detected when the daidzein and genistein families were analyzed separately. All strains triggered IF metabolism so further studies have to be developed since the different beneficial effects of IF through the diet may be due to the different IF profiles. These are encouraging results from two points of view: (1) N21.4 increases IF in seedlings, and (2) all other beneficial strains trigger IF metabolism differentially; hence, both facts could be used to prepare food supplements or as enriched standardized foods after full development of the biotechnological procedure.