Affinity For Estrogen Receptor Research Articles

Adolescent exposure to tris(1,3-dichloro-2-propyl) phosphate (TCPP) induces reproductive toxicity in zebrafish through hypothalamic-pituitary-gonadal axis disruption

Tris(1,3-dichloro-2-propyl) phosphate (TCPP), a prevalent organophosphorus flame retardant in aquatic environments, has raised significant concerns regarding its ecological risks. This study aims to explore the impacts of TCPP on the reproductive functions of zebrafish and delineate its gender-related toxic mechanisms. By assessing the effects on zebrafish of 10 mg/L TCPP exposure from 30 to 120 days post-fertilization (dpf), we thoroughly evaluated the reproductive capability and endocrine system alterations. Our findings indicated that TCPP exposure disrupted gender differentiation in zebrafish and markedly impaired their reproductive capacity, resulting in decreased egg laying and offspring development quality. Histological analyses of gonadal tissues showed an abnormal increase in immature oocytes in females and a reduction in mature sperm count and spermatogonial structure integrity in males, collectively leading to compromised embryo quality. Additionally, molecular docking results indicated that TCPP showed a strong affinity for estrogen receptors, and TCPP-treated zebrafish exhibited imbalanced sex hormones and increased estrogen receptor expression. Alterations in genes associated with the hypothalamic-pituitary-gonadal (HPG) axis and activation of the steroidogenesis pathway suggested that TCPP targets the HPG axis to regulate sex hormone homeostasis. Tamoxifen (TAM), as a competitive inhibitor of estrogen, exhibited a biphasic effect, as evidenced by the counteraction of TCPP-induced effects in both male and female zebrafish after TAM addition. Overall, our study underscored the gender-dependent reproductive toxicity of TCPP exposure in zebrafish, characterized by diminished reproductive capacity and hormonal disturbances, likely due to interference in the HPG axis and steroidogenesis pathways. These findings emphasize the critical need to consider gender differences in chemical risk assessments for ecosystems and highlight the importance of understanding the mechanisms underlying the effects of chemical pollutants on the reproductive health of aquatic species.

Receptor mediated biological activities of phytoestrogens

Phytoestrogens are plant-derived compounds that have chemical structures and functions similar to estrogen. Phytoestrogens act as ligand-inducible transcription factors involved in cellular growth by binding to estrogen receptors (ERs), specifically ER alpha (ERα) and beta (ERβ). Through this mechanism, phytoestrogens have a physiological function similar to that of the female hormone 17β-estradiol (E2), which can be useful in treating osteoporosis, cardiovascular disease, and cancer. Furthermore, phytoestrogens have been found to elicit various cellular responses depending on their affinity for ERs; in particular, they show a greater affinity with for ERβ. This study aimed to comprehensively analyze the mode of action of eight phytoestrogens, namely kaempferol, coumestrol, glycitein, apigenin, daidzein, genistein, equol, and resveratrol, by evaluating their estrogenic activity as ER ligands. Based on the bioluminescence resonance energy transfer (BRET)-based ER dimerization and transactivation assay results, all the phytoestrogens tested were identified as estrogen agonists by mediating ERα and ERβ dimerization. The specific binding and functions of ERα and ERβ were distinguished by differentiating between their dimerization activity. In addition, this study contributes to advancing our understanding of the overall mechanism of action involving both ERs.

Affinity for Estrogen Receptor α (ERα) in a <i>trans</i>-Stilbene Derivative Containing a Pyridoxine Fragment

Molecular targets for a promising antitumor agent based on trans-stilbene containing a pyridoxine fragment were identified. The lead compound, (E)-6-(3,4-dimethoxystyryl)-2,2,5,8-tetramethyl-4H-[1,3] dioxino[4,5-c]pyridine, was found to selectively induce apoptosis in MCF-7 breast adenocarcinoma cells overexpressing estrogen receptor, but not in MDA-MB-231 cells negative for estrogen receptor. The mechanism by which the novel trans-stilbene derivative acts as a selective estrogen receptor modulator was analyzed, and the affinity for human estrogen receptor α (ERα) was assessed by fluorescence polarization. Unlike its structural analogs—tamoxifen and raloxifene, the lead compound showed no affinity for ERα and did not form complexes with it. Therefore, it was concluded that the selective action of the pyridoxine-containing derivative of trans-stilbene on estrogen-positive breast cancer cells occurs through an alternative mechanism. The EC 50 values for the displacement of the fluorescent ligand from the ERα active site were 22, 120, and 595 nM for estradiol, raloxifene, and tamoxifen, respectively.

Estrogen receptor signaling and targets: Bones, breasts and brain (Review).

Estrogens are involved in a number of physiological functions, including in the development of the brain, growth, reproduction and metabolism. The biological actions of estrogens are achieved by binding to estrogen receptors (ERs) in numerous types of tissues. ERα and ERβ belong to the nuclear receptor superfamily and the G‑protein coupled ER1 (GPER1) is a membrane receptor. The primary biologically active estrogen, 17β‑estradiol demonstrates a high affinity for ERs. Mechanistically, estrogens bind to the ERs in the nucleus, and the complex then dimerize and bind to estrogen response elements (EREs) located in the promoter regions of the target genes. This is referred to as the genomic mechanism of ERs' function. Furthermore, ERs can also act through kinases and other molecular interactions leading to specific gene expression and functions, referred to as the non‑genomic mechanism. While ERα and ERβ exert their functions via both genomic and non‑genomic pathways, GPER1 exerts its function primarily via the non‑genomic pathways. Any aberrations in ER signaling can lead to one of a number of diseases such as disorders of growth and puberty, fertility and reproduction abnormalities, cancer, metabolic diseases or osteoporosis. In the present review, a focus is placed on three target tissues of estrogens, namely the bones, the breasts and the brain, as paradigms of the multiple facets of the ERs. The increasing prevalence of breast cancer, particularly hormone receptor‑positive breast cancer, is a challenge for the development of novel antihormonal therapies other than tamoxifen and aromatase inhibitors, to minimize toxicity from the long treatment regimens in patients with breast cancer. A complete understanding of the mechanism of action of ERs in bones may highlight options for novel targeted treatments for osteoporosis. Likewise, the aging of the brain and related diseases, such as dementia and depression, are associated with a lack of estrogen, particularly in women following menopause. Furthermore, gender dysphoria, a discordance between experienced gender and biological sex, is commonly hypothesized to emerge due to discrepancies in cerebral and genital sexual differentiation. The exact role of ERs in gender dysphoria requires further research.

Lomitapide as a Potential Estrogen Receptor Inhibitor: A Computational Drug Repurposing Study

Objective: Estrogen receptor (ER) inhibitors have significant therapeutic potential for hormone-dependent cancers and related disorders. Tamoxifen, a well-known selective estrogen receptor modulator, has been widely used as adjuvant therapy for estrogen receptor-positive breast cancer. However, tamoxifen may exhibit a tendency to develop resistance with prolonged usage and particularly elevate the risk of uterine cancer. Therefore, there is a need for the discovery and development of new ER modulators or inhibitors. In this study, we identified potential estrogen receptor inhibitors through computational drug repositioning.
 
 Methods: A set of 2048 compounds, encompassing FDA-approved drugs and active metabolites, were subjected to molecular docking, molecular dynamics simulations, and free energy calculations to evaluate their interaction with estrogen receptor α (ERα).
 
 Results: Among the compounds evaluated, conivaptan, atogepant, and lomitapide exhibited the highest affinities for ERα. Lomitapide displayed a superior docking score (-12 kcal/mol) compared to the established ER inhibitor, tamoxifen (-10 kcal/mol). Further investigation using molecular dynamics simulations and free energy calculations disclosed lomitapide's heightened binding affinity of -380.727 kJ/mol, surpassing tamoxifen's binding affinity of -352.029 kJ/mol.
 
 Conclusion: This comprehensive computational exploration underscores lomitapide's potential as a compelling candidate with an envisaged stronger estrogen receptor affinity than the acknowledged standard, tamoxifen. To validate lomitapide's promise as a novel ER inhibitor, essential in vitro and in vivo studies are suggested. These investigations will provide essential insights into lomitapide's reposition in addressing the challenges tied to hormone-dependent cancers and associated maladies.

Synthesis and biological evaluation of novel D-ring fused steroidal N(2)-substituted-1,2,3-triazoles.

In this study, a series of 13 new D-ring fused steroidal N(2)-substituted-1,2,3-triazoles were synthesized, characterized and evaluated for their biological activities. The relative binding affinities of the synthesized compounds for the ligand-binding domains of estrogen receptors α and β, androgen receptor and glucocorticoid receptor demonstrated that androstane derivatives 3a and 3h and estratriene derivative 4e showed highly specific and strong binding affinity for estrogen receptor β, while 3b, 3e, 4a and 4b displayed high binding affinity for the glucocorticoid receptor. The synthesized compounds were tested for their ability to inhibit aldo-keto reductases 1C3 and 1C4 in vitro by monitoring NADPH consumption using fluorescence spectroscopy. The most potent aldo-keto reductase 1C3 inhibitors were compounds 3h (71.17%) and 3f (69.9%). Moreover, a molecular docking study was carried out for compounds 3f and 3h against aldo-keto reductase 1C3 and results showed that compounds 3h and 3f could bind in the same site and orientation as EM1404. However, polar atoms in the triazole group enable additional hydrogen bonding deeper in SP1 with Tyr319, Tyr216 and the NADP+ cofactor, which are not visible in the AKR1C3-EM1404 crystal structure. The synthesized compounds were screened for their anticancer activity against four cancer cell lines. Compound 3f demonstrated moderate toxic effects across various cancer types, while displaying lower toxicity towards the healthy cell line. In summary, our findings indicate that N(2)-substituted-1,2,3-triazoles are high-affinity ligands for estrogen receptor β and glucocorticoid receptor, inhibitors of aldo-keto reductase 1C3 enzyme, and exhibit antiproliferative effects against cancer cells, suggesting that they could serve as scaffolds for anticancer drug development.

The obesogenic side of Genistein.

Genistein (GN) has been highly recommended for its medicinal properties like anticancer, antidiabetic, antihyperlipidemic, antiviral, and antioxidant activities among others. Recently, scientists realized that Genistein is an endocrine disruptor. It is an obesogen that interferes with the endocrine system causing obesity through many mechanisms like inducing adipocyte differentiation, lipid accumulation, and transformation of some stem cells into adipocytes (bone marrow mesenchymal stem cells for example) in vitro. Animal studies show that GN upregulates genes associated with adipogenesis like CCAAT/enhancer binding protein alpha (Cebpα), CCAAT/enhancer binding protein beta (Cebpβ), and PPARγ. In silico studies reveal a strong binding affinity for estrogen receptors. All these findings were contingent on concentration and tissues. It is beyond dispute that obesity is one of the most frustrating medical conditions under the sun. The pathophysiology of this disease was first attributed to a high-calorie diet and lack of physical activity. However, studies proved that these two factors are not enough to account for obesity in both children and adults. This mini review highlights how Genistein interaction with the peroxisome proliferator-activated receptor gamma protein can cause obesity.

Exploring aryl hydrocarbon receptor (AhR) as a target for Bisphenol-A (BPA)-induced pancreatic islet toxicity and impaired glucose homeostasis: Protective efficacy of ethanol extract of Centella asiatica

The estrogenic impact of Bisphenol-A (BPA), a widely recognized endocrine disruptor, causes disruption of pancreatic β-cell function through estrogen receptors (ERs). While BPA's binding affinity for ERs is significantly lower than that of its natural counterpart, estrogen, recent observations of BPA's affinity for aryl hydrocarbon receptor (AhR) in specific cellular contexts have sparked a specific question: does AhR play a role in BPA's toxicological effects within the endocrine pancreas? To explore this question, we investigated BPA's (10 and 100 μg/ kg body weight/day for 21 days) potential to activate AhR within pancreatic islets and assessed the protective role of ethanol extract of Centella asiatica (CA) (200 and 400 mg/kg body weight/day for 21 days) against BPA-mediated toxicity in mouse model. Our results indicate that BPA effectively triggers the activation of AhR and modulates its target genes within pancreatic islets. In contrast, CA activates AhR but directs downstream pathways differentially and activates Nrf2. Additionally, CA was observed to counteract the disruption caused by BPA in glucose homeostasis and insulin sensitivity. Furthermore, BPA-induced oxidative stress and exaggerated production of proinflammatory cytokines were effectively counteracted by CA supplementation. In summary, our study suggests that CA influenced AhR signaling to mitigate the disrupted pancreatic endocrine function in BPA exposed mice. By shedding light on how BPA interacts with AhR, our research provides valuable insights into the mechanisms involved in the diabetogenic actions of BPA.

Effects of novel raloxifene analogs alone or in combination with mechanical loading in the Col1a2G610c/+ murine model of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a hereditary bone disease in which gene mutations affect collagen formation, leading to a weak, brittle bone phenotype that can cause severe skeletal deformity and increased fracture risk. OI interventions typically repurpose osteoporosis medications to increase bone mass, but this approach does not address compromised tissue-level material properties. Raloxifene (RAL) is a mild anti-resorptive used to treat osteoporosis that has also been shown to increase bone strength by a-cellularly increasing bone bound water content, but RAL cannot be administered to children due to its hormonal activity. The goal of this study was to test a RAL analog with no estrogen receptor (ER) signaling but maintained ability to reduce fracture risk. The best performing analog from a previous analog characterization project, named RAL-ADM, was tested in an in vivo study. Female wildtype (WT) and Col1a2G610C/+ (G610C) mice were randomly assigned to treated or untreated groups, for a total of 4 groups (n = 15). Starting at 10 weeks of age, all mice underwent compressive tibial loading 3×/week to induce an anabolic bone formation response in conjunction with RAL-ADM treatment (0.5 mg/kg; 5×/week) for 6 weeks. Tibiae were scanned via microcomputed tomography then tested to failure in four-point bending. RAL-ADM had reduced ER affinity, and increased post-yield properties, but did not improve bone strength in OI animals, suggesting some properties can be improved by RAL analogs but further development is needed to create an analog with decidedly positive impacts to OI bone.

Genistein exerts anti-colorectal cancer actions: clinical reports, computational and validated findings.

Colorectal cancer (CRC) is presently a health challenge in China. Although clinical chemotherapy is prescribed availably, the negative effects and poor prognoses still occur. Genistein has antitumor properties in our previous studies. However, the molecular mechanisms underlying the anti-CRC effects of genistein remain unclear. Increasing evidences have indicated that the induction of autophagy, one of cell death models, is closely associated with the formation and development of human cancer. In the current study, a systematic bioinformatics approach using network pharmacology and molecular docking imitation was aimed at identifying the pharmacological targets and anti-CRC mechanisms of genistein, characterized by autophagy-related processes and pathways. Moreover, experimental validation was conducted by using clinical and cell culture samples. All 48 potential targets of genistein-anti-CRC-associated autophagy were screened accordingly. Further bioinformatics analyses identified 10 core genistein-anti-CRC targets related to autophagy, and enrichment-assayed results revealed that the biological processes of these core targets might regulate multiple molecular pathways, including the estrogen signaling pathway. Additionally, molecular docking data demonstrated that genistein has a high affinity for epidermal growth factor receptor (EGFR) and estrogen receptor 1 (ESR1). Both EGFR and ESR1 proteins were highly expressed in clinical CRC samples. Preliminary in vitro data showed that genistein effectively reduced cellular proliferation, activated apoptosis, and suppressed EGFR and ESR1 protein expressions in CRC cells. Our research findings uncovered the molecular mechanisms of genistein against CRC, and the potential drug targets associated with autophagy in genistein treatment of CRC were identified and validated experimentally, including EGFR and ESR1.

Estrogen receptor targeting with genistein radiolabeled Technetium-99m as radiotracer of breast cancer: Its optimization, characterization, and predicting stability constants by DFT calculation

ObjectiveGenistein is an isoflavone molecule with a high affinity for estrogen receptors (ER), which could lead to the mechanism of selective estrogen receptor modulators (SERMs) in breast cancer. Genistein labeling with technetium-99m can be a new promising strategy for diagnostic breast cancer. In this research, we evaluate the physicochemical characteristics of the [99mTc]Tc-genistein complex and describe the optimal labeling method parameters. We also calculated density functional theory to study the stability constants to support complex formation analysis (DFT). MethodsThe genistein was directly labeled with 99mTc, and its stability as well as its potential for usage as a radiotracer were all investigated. DFT calculations with thermodynamic cycles to determine chemical coordination models and calculate thermodynamic constants of complex more accurately. ResultsThe radiochemical purity of [99mTc]Tc-genistein showed a high yield of 93.25% ± 0.30% and had good physicochemical properties. The stability of the Tc(IV)-genistein complex was confirmed by DFT calculations at a value of 99.0822. ConclusionsAs a result, [99mTc]Tc-genistein could be a potential radiotracer kit for SPECT imaging of breast cancer.

Synthesis and evaluation of radioiodinated estrogens for diagnosis and therapy of male urogenital tumours.

The preparation of 24 estrogens, their estrogen receptor (ER) affinity and studies of radioiodinated estrogen binding to ER-positive male bladder tumor cells (HTB9) are described. The estrogens with the highest affinity were selected using fluorescence anisotropy assays. A 2,2,2-trifluoroethyl group at the 11β-position caused particularly promising affinity. (Radio)iodination was performed on the 17α-vinyl group. Binding studies on HTB9 cells revealed picomolar affinities of radioconjugates 19 and 31, indicating promising ability for targeting of urogenital tumors.

17β-Hydroxysteroid dehydrogenases types 1 and 2: Enzymatic assays based on radiometric and mass-spectrometric detection.

The 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) has a key role in estrogen biosynthesis as it catalyzes the reduction of estrone to the most potent estrogen, estradiol. Estradiol has a high affinity for estrogen receptors and thus stimulates their transactivation, which leads to cell proliferation and numerous other effects. HSD17B2 catalyzes the oxidation of estradiol to the less potent estrone, thereby decreasing estrogen receptor activation, which results in reduction of estrogen-associated effects. HSD17B1 and HSD17B2 overexpressing E.coli homogenates or recombinant enzymes can be used for screening and development of drugs against various pathologies such as cancer, endometriosis or osteoporosis. Here we describe the preparation of HSD17B1 and HSD17B2 bacterial homogenates and purified recombinant HSD17B1 protein as enzyme sources as well as enzymatic assays based on radiometric and mass-spectrometric detection for enzyme characterization.

Isoflavone consumption reduces inflammation through modulation of phenylalanine and lipid metabolism.

Phytoestrogens found in soy, fruits, peanuts, and other legumes, have been identified as metabolites capable of providing beneficial effects in multiple pathological conditions due to their ability to mimic endogenous estrogen. Interestingly, the health-promoting effects of some phytoestrogens, such as isoflavones, are dependent on the presence of specific gut bacteria. Specifically, gut bacteria can metabolize isoflavones into equol, which has a higher affinity for endogenous estrogen receptors compared to dietary isoflavones. We have previously shown that patients with multiple sclerosis (MS), a neuroinflammatory disease, lack gut bacteria that are able to metabolize phytoestrogen. Further, we have validated the importance of both isoflavones and phytoestrogen-metabolizing gut bacteria in disease protection utilizing an animal model of MS. Specifically, we have shown that an isoflavone-rich diet can protect from neuroinflammatory diseases, and that protection was dependent on the ability of gut bacteria to metabolize isoflavones into equol. Additionally, mice on a diet with isoflavones showed an anti-inflammatory response compared to the mice on a diet lacking isoflavones. However, it is unknown how isoflavones and/or equol mediates their protective effects, especially their effects on host metabolite levels. In this study, we utilized untargeted metabolomics to identify metabolites found in plasma that were modulated by the presence of dietary isoflavones. We found that the consumption of isoflavones increased anti-inflammatory monounsaturated fatty acids and beneficial polyunsaturated fatty acids while reducing pro-inflammatory glycerophospholipids, sphingolipids, phenylalanine metabolism, and arachidonic acid derivatives. Isoflavone consumption alters the systemic metabolic landscape through concurrent increases in monounsaturated fatty acids and beneficial polyunsaturated fatty acids plus reduction in pro-inflammatory metabolites and pathways. This highlights a potential mechanism by which an isoflavone diet may modulate immune-mediated disease.

Wenshenyang recipe treats infertility through hormonal regulation and inflammatory responses revealed by transcriptome analysis and network pharmacology.

The Wenshenyang recipe (WSYR) has the effect of treating infertility, but the mechanisms underlying this activity have not been fully elucidated. In this study, network pharmacology and RNA sequencing were combined, with database-based “dry” experiments and transcriptome analysis-based “wet” experiments used conjointly to analyse the mechanism of WSYR in the treatment of infertility. In the dry analysis, 43 active compounds in WSYR and 44 therapeutic targets were obtained through a database search, 15 infertility pathways were significantly enriched, and key targets, such as ESR1, TP53, AKT1, IL-6, and IL-10 were identified. Then the wet experiments were performed to detect the expression changes of the 412 genes from 15 infertility pathways identified by dry analysis. HK-2 cells were treated with the three herbs of WSYR and subjected to targeted RNA sequencing. Based on the results, 92 of the 412 genes in 15 infertility pathways were identified as DEGs. Additionally, key targets, such as ESR2, STAT1, STAT3, and IL6, were also identified in the wet experiments. RT-qPCR experiments further verified that WSYR played an anti-inflammatory role by upregulating IL-4 and IL-10 and Epimedium brevicornu Maxim (Yinyanghuo) showed broader effect than Drynaria fortunei (Kunze) J. Sm (Gusuibu) and Cistanche deserticola Y.C.Ma (Roucongrong). By screening compounds of WSYR using molecular docking models of ESR1 and ESR2, it was further found that xanthogalenol in Gusuibu, arachidonate in Roucongrong, and anhydroicaritin in Yinyanghuo had good affinity for estrogen receptors. These findings provide evidence for an estrogen-regulating role of the three herbs in WSYR.

BPS and BPF are as Carcinogenic as BPA and are Not Viable Alternatives for its Replacement.

Plastic polymers are omnipresent, and life without them is virtually impossible. Despite the advantages provided by the material, conventional plastic also has harmful effects on the environment and human health. Plastics release microplastics and compounds, such as BPA, which is a xenoestrogen and once absorbed by the body, have an affinity for estrogen receptors α and β, acting as an agonist on human cells, being an endocrine disrupter able to cause various diseases and acting as a potential neoplastic inducer. BPS and BPF are BPA's analogs, a proposed solution to solve its harmful effects. The analogs can be found in daily use products and are used in several industrial applications. In the present work, the researchers aimed to conduct a revisional study on BPA's harmful effects on human health, focusing on its carcinogenic potential, discussing its mechanisms of action, as well as its analogs effects, and identifying if BPS and BPF are viable alternatives to BPA's substitution in plastic polymers' production. In this review, articles published in the last 15 years related to the different aspects of conventional plastics and BPA were analyzed and revised with precision. The subjects ranged from conventional plastics and the problems related to their large-scale production, BPA, its negative aspects, and the feasibility of using its analogs (BPS and BPF) to replace the compound. The articles were extensively reviewed and concisely discussed. This study demonstrated that BPA has a high carcinogenic potential, with known mechanisms to trigger breast, ovarian, prostate, cervical, and lung cancers, thus elucidating that its analogs are also xenoestrogens, and they can exert similar effects to BPA and, therefore, cannot be considered viable alternatives for its replacement. .This study suggests that new research should be carried out to develop such alternatives, allowing the substitution of plastic materials containing BPA in their composition, such as developing economically viable and sustainable biodegradable bioplastics for socioenvironmental well-being.

A New Chemotype of Chemically Tractable Nonsteroidal Estrogens Based on a Thieno[2,3-d]pyrimidine Core.

Despite continued interest in the development of nonsteroidal estrogens and antiestrogens, there are only a few chemotypes of estrogen receptor ligands. Using targeted screening in a ligand sensing assay, we identified a phenolic thieno[2,3-d]pyrimidine with affinity for estrogen receptor α. An efficient three-step synthesis of the heterocyclic core and structure-guided optimization of the substituents resulted in a series of potent nonsteroidal estrogens. The chemical tractability of the thieno[2,3-d]pyrimidine chemotype will support the design of new estrogen receptor ligands as therapeutic hormones and antihormones.

Challenging Approach to the Development of Novel Estrogen Receptor Modulators Based on the Chemical Properties of Guaiazulene.

Tamoxifen, a therapeutic agent for breast cancer, has been associated with genetic polymorphisms in the metabolism of N,N-dialkylaminoethyl substituent, which plays an important role in the expression of selective estrogen receptor modulator (SERM) activity. To solve this problem, we developed a novel estrogen receptor (ER) modulator, Az-01, on the basis of the aromaticity, dipole moment, and isopropyl group of guaiazulene. Az-01 showed four-fold lower binding affinity for ER than E2 but had similar ER-binding affinity to that of 4-hydroxytamoxifen (4-HOtam). Unlike tamoxifen, Az-01 acted as a partial agonist with very weak estrogenic activity at high concentrations when used alone, and it showed potent anti-estrogenic activity in the presence of E2. The cell proliferation and inhibition activities of Az-01 were specific to ER-expressing MCF-7 cells, and no effect of Az-01 on other cell proliferation signals was observed. These findings are important for the development of new types of SERMs without the N,N-dialkylaminoethyl substituent as a privileged functional group for SERMs.

Adverse effects of phytoestrogens on mammalian reproductive health

Phytoestrogen Phytoestrogens are a diverse class of nonsteroidal, diphenolic, estrogenic plant compounds, including prenylated flavonoids, isoflavones, coumestans, and lignans [1,2]. They are plantderived nonsteroidal compounds structurally or functionally similar to mammalian estrogen (E2), especially 17β-estradiol [3,4]. Phytoestrogens have an affinity for estrogen receptor -α (ER α) and -β (ER β) [3,5,6],

Dietary syringic acid reduces fat mass in an ovariectomy-induced mouse model of obesity

Postmenopausal women are at increased risk of metabolic diseases such as obesity and diabetes. Therefore, the chemoprevention of postmenopausal changes in health via dietary supplements is important. Syringic acid (SA) is a phenolic compound present in the fruit of the assai palm, Euterpe oleracea, and in the mycelium of the shiitake mushroom, Lentinula edodes. This compound shows no affinity for estrogen receptors and may exert disease-preventive effects. Reportedly, dietary SA ameliorates high-fat diet-induced obesity in mice; however, its effects on estrogen deficiency-induced obesity are still unclear. Therefore, in this study, we investigated whether and how dietary SA affects these factors in ovariectomized (OVX) mice. Ten-week-old OVX mice were fed SA-containing diets (100 mg/kg body weight/d) for 12 weeks. Their body weights, food intake, and uterus weights as well as other parameters were measured and comparisons were made with mice in the control group. Dietary SA did not affect the body weight, food intake, or uterus weight of OVX mice over the study period; however, the SA-fed group showed lower fat mass (ie, visceral, subcutaneous, and total fat) than the OVX-control group (11.1 ± 3.3 vs. 8.3 ± 2.4, P < 0.05; 7.9 ± 1.1 vs. 5.9 ± 1.6, P < 0.05; 19.0 ± 4.2 vs. 14.1 ± 3.8, P < 0.05, respectively). Furthermore, blood analysis revealed that SA-treatment resulted in a dose-dependent decrease and increase in serum triglyceride (59.2 ± 8.3 vs. 43.9 ± 12.2 mg/dL P < 0.05) and adiponectin (7.7 ± 0.3 vs. 9.5 ± 0.6 μg/mL, P < 0.05) levels, respectively. These results suggest that the SA diet improves lipid metabolism without affecting the uterus in OVX mice. Therefore, dietary SA has potential applicability for the prevention of postmenopausal obesity and type 2 diabetes.