Phytoestrogens induce differential estrogen receptor beta-mediated responses in transfected MG-63 cells

Roles of estrogen receptors during sexual reversal in Pelodiscus sinensis

BACKGROUND

The Chinese soft-shelled turtle, Pelodiscus sinensis, exhibits distinct sexual dimorphism, with the males growing faster and larger than the females. During breeding, all-male offspring can be obtained using 17β-estradiol (E2). However, the molecular mechanisms underlying E2-induced sexual reversal have not yet been elucidated. Previous studies have investigated the molecular sequence and expression characteristics of estrogen receptors (ERs).

METHODS AND RESULTS

In this study, primary liver cells and embryos of P. sinensis were treated with ER agonists or inhibitors. Cell incubation experiments revealed that nuclear ERs (nERs) were the main pathway for the transmission of estrogen signals. Our results showed that ERα agonist (ERα-ag) upregulated the expression of Rspo1, whereas ERα inhibitor (ERα-Inh) downregulated its expression. The expression of Dmrt1 was enhanced after ERα-Inh + G-ag treatment, indicating that the regulation of male genes may not act through a single estrogen receptor, but a combination of ERs. In embryos, only the ERα-ag remarkably promoted the expression levels of Rspo1, Wnt4, and β-catenin, whereas the ERα-Inh had a suppressive effect. Additionally, Dmrt1, Amh, and Sox9 expression levels were downregulated after ERβ inhibitor (ERβ-Inh) treatment. GPER agonist (G-ag) has a significant promotion effect on Rspo1, Wnt4, and β-catenin, while the inhibitor G-Inh does not affect male-related genes.

CONCLUSIONS

Overall, these results suggest that ERs play different roles during sexual reversal in P. sinensis and ERα may be the main carrier of estrogen-induced sexual reversal in P. sinensis. Further studies need to be performed to analyze the mechanism of ER action.

Insights into the antiosteoporotic mechanism of the soy-derived isoflavone genistein: Modulation of the Wnt/beta-catenin signaling

Bone remodeling is a process that involves osteoblasts, osteoclasts, and osteocytes, and different intracellular signaling, such as the canonical Wnt/β-catenin pathway. Dysregulations of this pathway may also occur during secondary osteoporosis, as in the case of glucocorticoid-induced osteoporosis (GIO), which accelerates osteoblast and osteocyte apoptosis by reducing bone formation, osteoblast differentiation and function, accelerates in turn osteoblast, and osteocyte apoptosis. Genistein is a soy-derived nutrient belonging to the class of isoflavones that reduces bone loss in osteopenic menopausal women, inhibiting bone resorption; however, genistein may also favor bone formation. The aim of this study was to investigate whether estrogen receptor stimulation by genistein might promote osteoblast and osteocyte function during glucocorticoid challenge. Primary osteoblasts, collected from C57BL6/J mice, and MLO-A5 osteocyte cell line were used to reproduce an in vitro model of GIO by adding dexamethasone (1 μM) for 24 h. Cells were then treated with genistein for 24 h and quantitative Polymerase Chain Reaction (qPCR) and western blot were performed to study whether genistein activated the Wnt/β-catenin pathway. Dexamethasone challenge reduced bone formation in primary osteoblasts and bone mineralization in osteocytes; moreover, canonical Wnt/β-catenin pathway was reduced following incubation with dexamethasone in both osteoblasts and osteocytes. Genistein reverted these changes and this effect was mediated by both estrogen receptors α and β. These data suggest that genistein could induce bone remodeling through Wnt/β-catenin pathway activation.

Estrogenic flavonoids and their molecular mechanisms of action

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

Genital whitening with topical Cyperus rotundus Oil enhance sexuality and quality of life

BACKGROUND

Cyperus Rotundus Essential Oil (CREO) is an anti-inflammatory and depigmenting agent that helps treat hyperpigmentation.

OBJECTIVES

The purpose of this study was to evaluate the depigmenting effect of CREO on genital hyperpigmentation to that of arbutin (ARB), as well as to evaluate the association between genital lightening, genital self-image, sexual performance, and life quality.

MATERIAL AND METHODS

Three hundred and eight healthy people were categorized into 3 groups: the CREO group, the ARB group, and the cold cream group (CC). In genital pigmentation, the tristimulus colorimeter is used to assess erythema and pigmentation. Additionally, we aided in the development of the female genital self-image scale (FGSIS-4), the female sexual function index (FSFI), and the dermatology life quality index (DLQI).

RESULT

The reduction in genital hyperpigmentation was significantly greater in the CREO and ARB groups than in the CC group; in physician global assessment and patients' self-assessment, the results in treated bikini with the CREO and ARB groups were excellent when compared to the CC. Furthermore, no adverse effects were found in the CREO group, but mild irritation was found in the ARB group; additionally, the percentage of hair growth, color and luminance reduction, and hair thickness were significantly reduced in the CREO group only. In addition, there were significantly different in FGSIS, FSFI, and DLQI between the CREO and ARB groups and the CC group.

CONCLUSION

CREO is equivalently efficacious in decreasing pigmentation, inflammation, and hair growth in the genital area. Positive changes boost female genital self-image, self-esteem, and sexual performance. Improving sexual health has a positive impact on quality of life.

The Role of Macronutrients, Micronutrients and Flavonoid Polyphenols in the Prevention and Treatment of Osteoporosis

Osteoporosis is considered an age-related disorder of the skeletal system, characterized primarily by decreased bone mineral density (BMD), microstructural quality and an elevated risk of fragility fractures. This silent disease is increasingly becoming a global epidemic due to an aging population and longer life expectancy. It is known that nutrition and physical activity play an important role in skeletal health, both in achieving the highest BMD and in maintaining bone health. In this review, the role of macronutrients (proteins, lipids, carbohydrates), micronutrients (minerals—calcium, phosphorus, magnesium, as well as vitamins—D, C, K) and flavonoid polyphenols (quercetin, rutin, luteolin, kaempferol, naringin) which appear to be essential for the prevention and treatment of osteoporosis, are characterized. Moreover, the importance of various naturally available nutrients, whether in the diet or in food supplements, is emphasized. In addition to pharmacotherapy, the basis of osteoporosis prevention is a healthy diet rich mainly in fruits, vegetables, seafood and fish oil supplements, specific dairy products, containing a sufficient amount of all aforementioned nutritional substances along with regular physical activity. The effect of diet alone in this context may depend on an individual’s genotype, gene-diet interactions or the composition and function of the gut microbiota.

Protective mechanism of kaempferol against Aβ25-35-mediated apoptosis of pheochromocytoma (PC-12) cells through the ER/ERK/MAPK signalling pathway

INTRODUCTION

Progressive accumulation of amyloid-β (Aβ) is a pathological trait of Alzheimer's disease (AD). Amyloid-β increases free radical production in neuronal cells, leading to neuronal cell death. Hormone replacement therapy can reduce the incidence of AD, and oestrogen significantly improves the clinical signs in patients with AD. However, the long-term use of oestrogen causes a variety of diseases. Phytoestrogens have been reported to bind and activate oestrogen receptors in mammals and humans to produce oestrogen-like or anti-oestrogen-like effects. Kaempferol is a flavonoid phytoestrogen that can produce a certain protective effect in neurons. However, the molecular mechanism of kaempferol in AD is unclear.

MATERIAL AND METHODS

This study used pheochromocytoma (PC-12) cells that were damaged by Aβ_25-35 as an in vitro model of AD, and oestradiol was a positive control. The cells were incubated with kaempferol alone or in combination with fulvestrant (an antagonist of ER) and U0126 (an inhibitor of ERK) in Aβ_25-35 culture. Cell activity was measured by the MTT method. Cell apoptosis was evaluated by flow cytometry. Gene and protein expression levels were tested by qRT-PCR and Western blotting.

RESULTS

This study demonstrated that kaempferol protected PC-12 cells from Aβ_25-35-induced cell death and apoptosis in a dose-dependent manner. Treatment with fulvestrant (an antagonist of ER) and U0126 (an inhibitor of ERK) significantly increased the apoptosis of PC-12 cells. Moreover, kaempferol promoted the expression of anti-apoptotic molecules and inhibited the expression of pro-apoptotic molecules, which were blocked by fulvestrant and U0126.

CONCLUSIONS

Kaempferol protected PC-12 cells against Aβ_25-35-induced cell apoptosis through the ER/ERK/MAPK signalling pathway.

Proanthocyanidin-rich grape seed extract improves bone loss, bone healing, and implant osseointegration in ovariectomized animals

The purpose of the present study was to confirm if proanthocyanidin-rich grape seed extract (GSE) had the ability to improve bone health such as bone loss, bone healing, and implant osseointegration (defined as the direct connection between bone tissue and an implant) in ovariectomized (OVX) animals. We demonstrated that daily oral administration of GSE prevented bone loss in the lumbar vertebrae and femur in OVX mice. In addition, osteoclastogenesis in the lumbar spine bone of OVX mice, as assessed by histological and histomorphometric analyses, was accelerated but GSE prevented this dynamization, suggesting that GSE could counteract OVX-induced accelerated osteoclastogenic activity. In rats, OVX clearly impaired the healing of defects created on the calvaria, and GSE overcame this OVX-impaired healing. In the same way, osseointegration of a tibial implant in rats was retarded by OVX, and GSE counteracted the OVX-induced poor osseointegration, likely promoting bone healing by preventing imbalanced bone turnover. These results suggest that orally administered GSE improved implant osseointegration by mitigating the impaired bone health induced by OVX as a model of estrogen deficiency.

Effects of Puerarin on the Ovariectomy-Induced Depressive-Like Behavior in ICR Mice and Its Possible Mechanism of Action

Daily treatment of ovariectomized (OVX) ICR mice with puerarin, a glycosyl isoflavone isolated from the root bark of Pueraria candollei var. mirifica, and 17β-estradiol attenuated ovariectomy-induced depression-like behavior, as indicated by a decrease in immobility times in the tail suspension test (TST) and the forced swimming test (FST), an increase in the uterine weight and volume, a decrease in serum corticosterone levels, and dose-dependently normalized the downregulated transcription of the brain-derived neurotrophic factor (BDNF) and estrogen receptor (Erβ and Erα) mRNAs. Like 17β-estradiol, puerarin also inhibited ovariectomy-induced suppression of neurogenesis in the dentate gyrus of the hippocampus (increased the number of doublecortin (DCX)-immunosuppressive cells). These results suggest that puerarin exerts antidepressant-like effects in OVX animals, possibly by attenuating the OVX-induced hyperactivation of the HPA axis and/or normalizing the downregulated transcription of BDNF and ER mRNA in the brain.

The Osteoprotective Effects Of Kaempferol: The Evidence From In Vivo And In Vitro Studies

Kaempferol is a dietary bioflavonoid ubiquitously found in various types of plant. It possesses a wide range of medicinal properties suggesting its potential clinical utility that requires further investigation. The present review intends to highlight the efficacy of kaempferol and its molecular mechanisms of action in regulating bone metabolism. Many reports have acknowledged the bone-protecting property of kaempferol and kaempferol-containing plants using in vitro and in vivo experimental models. Kaempferol supplementation showed bone-sparing effects in newborn rats, glucocorticoid-induced and ovariectomy-induced osteoporotic models as well as bone fracture models. It achieves the bone-protective effects by inhibiting adipogenesis, inflammation, oxidative stress, osteoclastic autophagy and osteoblastic apoptosis while activating osteoblastic autophagy. The anti-osteoporotic effects of kaempferol are mediated through regulation of estrogen receptor, bone morphogenetic protein-2 (BMP-2), nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) signaling pathways. In summary, kaempferol exhibits beneficial effects on skeleton, thus is potentially effective for the prophylaxis and treatment of osteoporosis.

Molecular signaling mechanisms behind polyphenol-induced bone anabolism

For millennia, in the different cultures all over the world, plants have been extensively used as a source of therapeutic agents with wide-ranging medicinal applications, thus becoming part of a rational clinical and pharmacological investigation over the years. As bioactive molecules, plant-derived polyphenols have been demonstrated to exert many effects on human health by acting on different biological systems, thus their therapeutic potential would represent a novel approach on which natural product-based drug discovery and development could be based in the future. Many reports have provided evidence for the benefits derived from the dietary supplementation of polyphenols in the prevention and treatment of osteoporosis. Polyphenols are able to protect the bone, thanks to their antioxidant properties, as well as their anti-inflammatory actions by involving diverse signaling pathways, thus leading to bone anabolic effects and decreased bone resorption. This review is meant to summarize the research works performed so far, by elucidating the molecular mechanisms of action of polyphenols in a bone regeneration context, aiming at a better understanding of a possible application in the development of medical devices for bone tissue regeneration.

Cyperus rotundus L.: Traditional uses, phytochemistry, and pharmacological activities

ETHNO-PHARMACOLOGICAL RELEVANCE

Cyperus rotundus L. (Cyperaceae) is a medicinal herb traditionally used to treat various clinical conditions at home such as diarrhea, diabetes, pyresis, inflammation, malaria, and stomach and bowel disorders. Currently, it is one of the most widespread, problematic, and economically damaging agronomic weeds, growing wildly in various tropical and subtropical regions of the world. The present paper summarizes the available information that will aid in future medicine preparation by identifying active ingredients and their mode of action for a specific therapeutic activity using the latest technologies.

MATERIAL AND METHOD

This review article is based on the information available on the phytochemical, toxicological, and pharmacological studies on and traditional uses of C. rotundus. The present paper covers the literature available particularly from 2000 to 2015 online (Google Scholar, PubMed, ScienceDirect, Scopus, SpringerLink, and Web of Science) and in books on phytochemistry, ethnopharmacology, and botany of this plant.

RESULTS

Phytochemical and pharmacological studies revealed the significance of C. rotundus as an antiandrogenic, antibacterial, anticancerous, anticonvulsant, antidiabetic, antidiarrheal, antigenotoxic, anti-inflammatory, antilipidemic, antimalarial, antimutagenic, antiobesity, antioxidant, anti-uropathogenic, hepatoprotective, cardioprotective, neuroprotective, and nootropic agent. This is the most investigated plant worldwide due to the higher concentration of active ingredients in the form of essential oils, phenolic acids, ascorbic acids, and flavonoids in the tuber and rhizomes. Unfortunately, this significant plant species has not been assessed under improved cultivation conditions with the aim of conservation in natural habitats and high quality.

CONCLUSION

Reports can be found on the ehtnobotanical use of C. rotundus in atherosclerosis, aging, apoptosis, cancer, cystitis, epilepsy, hirsutism, nociception, prostatitis, and genotoxicity disorders. The phytochemical and pharmacological activities of C. rotundus have supported its traditional as well as prospective uses as a valuable Ayurvedic plant. Previous researches focuses on the phytochemistry, biological properties and clinical application of rhizomes and tubers of C. rotundus. However, such studies on the other parts of this medicinally important plant are still quest to be investigate. Furthermore, future study should aim at confirming the clinical activities and safety of this plant before being used for the development of new therapeutic agent in human subjects.

Glutamic acid ameliorates estrogen deficiency-induced menopausal-like symptoms in ovariectomized mice

Some amino acids are considered alternative therapies for improving menopausal symptoms. Glutamic acid (GA), which is abundant in meats, fish, and protein-rich plant foods, is known to be a neurotransmitter or precursor of γ-aminobutyric acid. Although it is unclear if GA functions in menopausal symptoms, we hypothesized that GA would attenuate estrogen deficiency-induced menopausal symptoms. The objective to test our hypothesis was to examine an estrogenic effect of GA in ovariectomized (OVX) mice, estrogen receptor (ER)-positive human osteoblast-like MG-63 cells, and ER-positive human breast cancer MCF-7 cells. The results demonstrated that administration with GA to mice suppressed body weight gain and vaginal atrophy when compared with the OVX mice. A microcomputed tomographic analysis of the trabecular bone showed increases in bone mineral density, trabecular number, and connectivity density as well as a significant decrease in total porosity of the OVX mice treated with GA. In addition, GA increased serum levels of alkaline phosphatase and estrogen compared with the OVX mice. Furthermore, GA induced proliferation and increased ER-β messenger RNA (mRNA) expression, estrogen response element (ERE) activity, extracellular signal-regulated kinase phosphorylation, and alkaline phosphatase activity in MG-63 cells. In MCF-7 cells, GA also increased proliferation, Ki-67 mRNA expression, ER-β mRNA expression, and ERE activity. Estrogen response element activity increased by GA was inhibited by an estrogen antagonist. Taken together, our data demonstrated that GA has estrogenic and osteogenic activities in OVX mice, MG-63 cells, and MCF-7 cells.

Protective effect of porcine placenta in a menopausal ovariectomized mouse

Menopause is a significant physiological phase that occurs as women's ovaries stop producing ovum and the production of estrogen declines. Human placenta and some amino acids are known to improve menopausal symptoms. In this study, we investigated that porcine placenta extract (PPE) and arginine (Arg), a main amino acid of PPE, would have estrogenic activities in ovariectomized (OVX) mice as a menopause mouse model, human breast cancer cell line (MCF-7) cells, and human osteoblast cell line (MG-63) cells. PPE or Arg significantly inhibited the body weight and increased the vagina weight compared to the OVX mice. PPE or Arg ameliorated the vaginal atrophy in the OVX mice. The levels of 17β-estradiol and the activities of alkaline phosphatase (ALP) were significantly increased by PPE or Arg in the serum of OVX mice. Trabecular bone parameters such as bone mineral density and porosity were also improved by PPE or Arg in the OVX mice. In the MCF-7 and MG-63 cells, PPE or Arg significantly increased the cell proliferation, estrogen receptor β mRNA expression, and estrogen-response elements luciferase activity. Finally, PPE or Arg increased the activations of ALP and extracellular signal-regulated kinase 1/2 in the MG-63 cells. These results indicate that PPE or Arg would have estrogenic and osteoblastic activity. Therefore, PPE or Arg may be useful as new pharmacological tools for treating menopausal symptoms including osteoporosis. Free Korean abstract: A Korean translation of this abstract is freely available at http://www.reproduction-online.org/content/150/3/173/suppl/DC1.

A grape-enriched diet increases bone calcium retention and cortical bone properties in ovariectomized rats

BACKGROUND

Grapes and their associated phytochemicals have been investigated for beneficial effects on cardiovascular health, cancer prevention, and other chronic diseases, but the effect of grape consumption on bone health has not been fully determined. We previously found short-term benefits of grape products on reducing bone turnover in ovariectomized rats.

OBJECTIVE

The objective of this study was to determine the long-term benefits of a grape-enriched diet on bone in ovariectomized rats.

METHODS

Rats were ovariectomized at 3 mo of age and were administered a single dose of (45)Ca to prelabel bones at 4 mo of age. After a 1-mo equilibration period, baseline urinary (45)Ca excretion was determined. Rats (n = 22/group) were then randomly assigned to a modified AIN93M diet containing 25% freeze-dried grape powder or to a control diet for 8 wk. Urinary (45)Ca excretion was monitored throughout the study to determine changes in bone (45)Ca retention. Calcium balance was assessed after 1 and 8 wk of consuming the experimental diets, and a calcium kinetic study was performed at 8 wk. After 8 wk, femurs were collected for micro-computed tomographic imaging, 3-point bending, and reference point indentation.

RESULTS

Rats fed the grape-enriched diet had 44% greater net bone calcium retention than did rats fed the control diet. There were no differences in calcium balance due to diet at either week 1 or week 8, but there was a significant increase in net calcium absorption (10.6%) and retention (5.7%) from week 1 to week 8 in the grape-enriched diet group only. Grape-enriched diet-fed rats had 3% greater cortical thickness and 11% greater breaking strength. There were no differences in femur bone mineral density, trabecular microarchitecture, or reference point indentation variables due to diet.

CONCLUSION

This study of ovariectomized rats indicates that the consumption of grape products may improve calcium utilization and suppress bone turnover, resulting in improvements in bone quality.

Kaempferol, a potential cytostatic and cure for inflammatory disorders

Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g., tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries, and grapes) and in plants or botanical products commonly used in traditional medicine (e.g., Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Its anti-oxidant/anti-inflammatory effects have been demonstrated in various disease models, including those for encephalomyelitis, diabetes, asthma, and carcinogenesis. Moreover, kaempferol act as a scavenger of free radicals and superoxide radicals as well as preserve the activity of various anti-oxidant enzymes such as catalase, glutathione peroxidase, and glutathione-S-transferase. The anticancer effect of this flavonoid is mediated through different modes of action, including anti-proliferation, apoptosis induction, cell-cycle arrest, generation of reactive oxygen species (ROS), and anti-metastasis/anti-angiogenesis activities. In addition, kaempferol was found to exhibit its anticancer activity through the modulation of multiple molecular targets including p53 and STAT3, through the activation of caspases, and through the generation of ROS. The anti-tumor effects of kaempferol have also been investigated in tumor-bearing mice. The combination of kaempferol and conventional chemotherapeutic drugs produces a greater therapeutic effect than the latter, as well as reduces the toxicity of the latter. In this review, we summarize the anti-oxidant/anti-inflammatory and anticancer effects of kaempferol with a focus on its molecular targets and the possible use of this flavonoid for the treatment of inflammatory diseases and cancer.

Topical Cyperus rotundus oil: a new therapeutic modality with comparable efficacy to Alexandrite laser photo-epilation

BACKGROUND

Topical Cyperus rotundus oil is an effective and safe method to decrease hair growth. The oil's flavonoids have antiandrogenic activity on androgenic hair. To date, there have been no randomized controlled trials comparing topical C rotundus oil to the available allopathic modalities, such as laser-assisted hair removal.

OBJECTIVES

In an open-label pilot study, the author prospectively evaluated the efficacy of C rotundus essential oil, compared with the Alexandrite laser (GentleLase; Candela Laser Corp, Wayland, Massachusetts) and saline, for reducing unwanted axillary hair.

METHODS

Eligible participants (n=65) with unwanted axillary hair were assigned randomly to 1 of 3 study groups: topical C rotundus oil (group 1), saline (group 2), and Alexandrite laser (group 3). Sixty patients completed the entire study. Three methods were used to evaluate the results: hair counts, observations of independent professionals, and patient self-assessments.

RESULTS

Overall results did not differ significantly between C rotundus oil and the Alexandrite laser (P>.05). However, statistically significant differences were noted with respect to decreased growth of white hair (P<.05), favoring the oil. This finding was evident by all 3 methods of assessment. No side effects were detected.

CONCLUSIONS

Cyperus rotundus essential oil is as effective as the Alexandrite laser for decreasing the growth of axillary hair (both dark and white).

LEVEL OF EVIDENCE

3.

Puerarin: a review of pharmacological effects

Puerarin is the major bioactive ingredient isolated from the root of the Pueraria lobata (Willd.) Ohwi, which is well known as Gegen (Chinese name) in traditional Chinese medicine. As the most abundant secondary metabolite, puerarin was isolated from Gegen in the late 1950s. Since then, its pharmacological properties have been extensively investigated. It is available in common foods and is used in alternative medicine. It has been widely used in the treatment of cardiovascular and cerebrovascular diseases, diabetes and diabetic complications, osteonecrosis, Parkinson's disease, Alzheimer's disease, endometriosis, and cancer. The beneficial effects of puerarin on the various medicinal purposes may be due to its wide spectrum of pharmacological properties such as vasodilation, cardioprotection, neuroprotection, antioxidant, anticancer, antiinflammation, alleviating pain, promoting bone formation, inhibiting alcohol intake, and attenuating insulin resistance. However, the direct molecular mechanisms and targets remain unclear. This review provides a comprehensive summary of the pharmacological effects of puerarin.

Functions and action mechanisms of flavonoids genistein and icariin in regulating bone remodeling

Increasingly natural products particularly flavonoids are being explored for their therapeutic potentials in reducing bone loss and maintaining bone health. This study has reviewed previous studies on the two better known flavonoids, genistein and icariin, their structures, functions, action mechanisms, relative potency, and potential application in regulating bone remodeling and preventing bone loss. Genistein, an isoflavone abundant in soy, has dual functions on bone cells, able to inhibit bone resorption activity of osteoclasts and stimulate osteogenic differentiation and maturation of bone marrow stromal progenitor cells (BMSCs) and osteoblasts. Genistein is an estrogen receptor (ER)-selective binding phytoestrogen, with a greater affinity to ERβ. Genistein inhibits tyrosine kinases and inhibits DNA topoisomerases I and II, and may act as an antioxidant. Genistein enhances osteoblastic differentiation and maturation by activation of ER, p38MAPK-Runx2, and NO/cGMP pathways, and it inhibits osteoclast formation and bone resorption through inducing osteoclastogenic inhibitor osteoprotegerin (OPG) and blocking NF-κB signaling. Icariin, a prenylated flavonol glycoside isolated from Epimedium herb, stimulates osteogenic differentiation of BMSCs and inhibits bone resorption activity of osteoclasts. Icariin, whose metabolites include icariside I, icariside II, icaritin, and desmethylicaritin, has no estrogenic activity. However, icariin is more potent than genistein in promoting osteogenic differentiation and maturation of osteoblasts. The existence of a prenyl group on C-8 of icariin molecular structure has been suggested to be the reason why icariin is more potent than genistein in osteogenic activity. Thus, the prenylflavonoids may represent a class of flavonoids with a higher osteogenic activity.

Quercetin and epigallocatechin gallate induce in vitro a dose-dependent stiffening and hyperpolarizing effect on the cell membrane of human mononuclear blood cells

The bioactivity of polyphenols is closely linked to their ability to interact with biological membranes. The study evaluates the in vitro effect of quercetin and epigallocatechin on the membrane anisotropy and transmembrane potential of peripheral blood mononuclear cells (PBMCs) isolated from 26 type 2 diabetes mellitus patients compared to 25 age matched controls. The in vitro assays were analyzed in correlation with the biochemical and inflammatory profile of the subjects and with insulin resistance parameters (HOMA-IR, plasma resistin) as well. For type 2 diabetes patients, the increase of HOMA-IR and resistin concentration was associated with a significant decrease of the PBMCs membrane anisotropy. The two tested polyphenols induced a dose-dependent hyperpolarizing effect and stiffening of the cell membranes for all tested subjects. Physiological levels of quercetin and epigallocatechin gallate had the tendency to normalize the PBMCs membrane anisotropy of the cells isolated from diabetes patients, bringing it to the level of cells isolated from normoglycemic ones. Epigallocatechin gallate induced higher effects compared to quercetin on the membranes isolated from subjects with higher cardiovascular risk. The decrease of membrane fluidity and the hyperpolarizing effect could explain the cardiovascular protective action of the tested compounds.

TAZ is required for the osteogenic and anti-adipogenic activities of kaempferol

Kaempferol (KMP) exerts protective effects against both osteoporosis and obesity by regulating cellular activities, but the underlying molecular mechanisms have not been fully elucidated. TAZ (transcriptional coactivator with PDZ-binding motif) modulates both osteoblast and adipocyte differentiation from mesenchymal stem cells by stimulating the activities of RUNX2 (runt-related transcription factor 2) and suppressing the activities of PPARγ (peroxisome proliferator-activated receptor γ). In this study, we investigated the effects of KMP on TAZ regulated osteoblast and adipocyte differentiation. KMP increased the osteoblast differentiation of mesenchymal cells by facilitating the physical interaction between TAZ and RUNX2, thus the increasing transcriptional activities of RUNX2. KMP also enhanced the association of TAZ with PPARγ, thereby suppressing the gene transcription of PPARγ targets and resulting in diminished adipocyte differentiation. Interestingly, the regulatory effects of kaempferol on RUNX2 and PPARγ-mediated transcriptional activity were impaired in TAZ-null mouse embryonic fibroblasts but recovered by restoration of TAZ expression. Our results demonstrate that KMP fortifies TAZ activity, which enhances RUNX2-mediated osteoblast differentiation and suppresses PPARγ-stimulated adipocyte differentiation, indicating the potential of KMP as an effective therapeutic reagent for controlling bone loss and adiposity through TAZ activation.

The role of nutraceuticals in chemoprevention and chemotherapy and their clinical outcomes

The genesis of cancer is often a slow process and the risk of developing cancer increases with age. Altering a diet that includes consumption of beneficial phytochemicals can influence the balance and availability of dietary chemopreventive agents. In chemopreventive approaches, foods containing chemicals that have anticancer properties can be supplemented in diets to prevent precancerous lesions from occurring. This necessitates further understanding of how phytochemicals can potently maintain healthy cells. Fortunately there is a plethora of plant-based phytochemicals although few of them are well studied in terms of their application as cancer chemopreventive and therapeutic agents. In this analysis we will examine phytochemicals that have strong chemopreventive and therapeutic properties in vitro as well as the design and modification of these bioactive compounds for preclinical and clinical applications. The increasing potential of combinational approaches using more than one bioactive dietary compound in chemoprevention or cancer therapy will also be evaluated. Many novel approaches to cancer prevention are on the horizon, several of which are showing great promise in saving lives in a cost-effective manner.

Isoflavones suppress cyclic adenosine 3',5'-monophosphate regulatory element-mediated transcription in osteoblastic cell line

Soy isoflavones have been implicated to exert benefit on bone loss in postmenopausal women. Isoflavones can induce estrogen response element-mediated transcription in osteoblastic cells. In the present study, we investigate whether isoflavones genistein and daidzein regulate target gene transcription through cAMP regulatory element (CRE) in osteoblastic cells. It was found that 17β-estradiol (E(2)), genistein and daidzein suppressed the transcriptional activity of CRE-luciferase reporter gene in human osteoblastic cell line MG-63 cells. E(2) and genistein but not daidzein inhibited the cAMP analogue 8-Br cAMP-induced transcription of CRE reporter gene. Both genistein and E(2) inhibited basal and cAMP-induced mRNA levels of endogenous estrogen responsive genes containing CRE/CRE-like elements in their promoter regions, including interleukin (IL) 8 and serum- and glucocorticoid-inducible kinase 1 (SGK1). Daidzein inhibited basal and cAMP-induced IL-8, but not SGK1 mRNA expression. The inhibitory effects of E(2), genistein and daidzein on CRE-mediated transcription activity were enhanced by estrogen receptor (ER) α overexpression in MG-63 cells, which could be blocked by nonselective ER antagonists ICI182780, 4-OH tamoxifen and specific ERα antagonist MPP. Genistein and daidzein, but not E(2) treatment, caused a significant decrease in CRE-mediated transcription activity in ERβ-transfected MG-63 cells, which could be blocked by ICI182780, 4-OH tamoxifen and the selective ERβ antagonist (R,R)-5,11-diethyl-5.6,11,12-tetradro-2,8-chrysenediol. Our results indicate that isoflavones genistein and daidzein might modulate bone remodeling through ERs by regulating target gene expression through the CRE motifs.

Kaempferol stimulates bone sialoprotein gene transcription and new bone formation

Kaempferol is a typical flavonol-type flavonoid that is present in a variety of vegetables and fruits, and has a protective effect on postmenopausal bone loss. Bone sialoprotein (BSP) is thought to function in the initial mineralization of bone and could be crucial for osteoblast differentiation, bone matrix mineralization and tumor metastasis. In the present study we investigated the regulation of BSP transcription by kaempferol in rat osteoblast-like UMR106 cells, and the effect of kaempferol on new bone formation. Kaempferol (5 microM) increased BSP and Osterix mRNA levels at 12 h and up-regulated Runx2 mRNA expression at 6 h. Kaempferol increased luciferase activity of the construct pLUC3, which including the promoter sequence between nucleotides -116 to +60. Transcriptional stimulation by kaempferol abrogated in constructs included 2 bp mutations in the inverted CCAAT, CRE, and FRE elements. Gel shift analyses showed that kaempferol increased nuclear protein binding to CRE and FRE elements, whereas the CCAAT-protein complex did not change after kaempferol stimulation. Twelve daily injections of 5 microM kaempferol directly into the periosteum of parietal bones of newborn rats increased new bone formation. These data suggest that kaempferol increased BSP gene transcription mediated through inverted CCAAT, CRE, and FRE elements in the rat BSP gene promoter, and could induce osteoblast activities in the early stage of bone formation.