Ethanolic extract of Persea americana Mill. (Lauraceae) seeds induced antiestrogenic effects in young female Wistar rats.

OBJECTIVES: The ethanol extract of Persea americana seeds was found to inhibit the development of estrogen-dependent conditions in female Wistar rats, suggesting the ability of its secondary metabolites to interact with estrogen receptors (ERs), either as partial agonists or as antagonists. To test this hypothesis, the abovementioned extract was assessed for its ability to mimic and/or antagonize estradiol effects. METHODS: Two experiments were conducted in ovariectomized (OVX) rats: (1) animals were treated with estradiol valerate (E2V; 1 mg/kg) or P. americana at doses of 25 and 50 mg/kg; (2) animals were treated with E2V alone (0.75 mg/kg) or in combination with P. americana at the abovementioned doses. Treatments were given orally for 3 days and animals were sacrificed for biochemical and histological analyses of the uterus and vagina. RESULTS: When administered alone, P. americana did not change the histomorphology of both organs (uterus and vagina). In combination with E2V, P. americana decreased uterine weight [30 % decrease (p<0.001) at 25 mg/kg and 24 % (p<0.01) at 50 mg/kg] and epithelium height (37 % decrease). This was associated with decreased estradiol levels (at least 86 % decrease, p<0.001) in the uterus. Similarly, vagina epithelium height decreased by at least 34 % (p<0.05) when E2V was co-administered with P. americana. CONCLUSIONS: The seed extract of P. americana contains ER antagonist secondary metabolites accounting for its ability to inhibit the development of estrogen-dependent conditions in female rats.

Naringenin: A Promising Therapeutic Agent against Organ Fibrosis.

Fibrosis is the final common pathology of most chronic diseases as seen in the heart, liver, lung, kidney, and skin and contributes to nearly half of death in the developed countries. Fibrosis, or scarring, is mainly characterized by the transdifferentiation of fibroblasts into myofibroblasts and the excessive accumulation of extracellular matrix (ECM) secreted by myofibroblasts. Despite immense efforts made in the field of organ fibrosis over the past decades and considerable understanding of the occurrence and development of fibrosis gained, there is still lack of an effective treatment for fibrotic diseases. Therefore, identifying a new therapeutic strategy against organ fibrosis is an unmet clinical need. Naringenin, a flavonoid that occurs naturally in citrus fruits, has been found to confer a wide range of pharmacological effects including antioxidant, anti-inflammatory, and anticancer benefits and thus potentially exerting preventive and curative effects on numerous diseases. In addition, emerging evidence has revealed that naringenin can prevent the pathogenesis of fibrosis in vivo and in vitro via the regulation of various pathways that involved signaling molecules such as transforming growth factor-ß1/small mother against decapentaplegic protein 3 (TGF-ß1/Smad3), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt), sirtuin1 (SIRT1), nuclear factor-kappa B (NF-κB), or reactive oxygen species (ROS). Targeting these profibrotic pathways by naringenin could potentially become a novel therapeutic approach for the management of fibrotic disorders. In this review, we present a comprehensive summary of the antifibrotic roles of naringenin in vivo and in vitro and their underlying mechanisms of action. As a food derived compound, naringenin may serve as a promising drug candidate for the treatment of fibrotic disorders.

Natural-derived compounds and their mechanisms in potential autosomal dominant polycystic kidney disease (ADPKD) treatment.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a monogenic kidney disorder that impairs renal functions progressively leading to kidney failure. The disease affects between 1:400 and 1:1000 ratio of the people worldwide. It is caused by the mutated PKD1 and PKD2 genes which encode for the defective polycystins. Polycystins mimic the receptor protein or protein channel and mediate aberrant cell signaling that causes cystic development in the renal parenchyma. The cystic development is driven by the increased cyclic AMP stimulating fluid secretion and infinite cell growth. In recent years, natural product-derived small molecules or drugs targeting specific signaling pathways have caught attention in the drug discovery discipline. The advantages of natural products over synthetic drugs enthusiast researchers to utilize the medicinal benefits in various diseases including ADPKD. CONCLUSION: Overall, this review discusses some of the previously studied and reported natural products and their mechanisms of action which may potentially be redirected into ADPKD.

Structure-based investigation of MARK4 inhibitory potential of Naringenin for therapeutic management of cancer and neurodegenerative diseases.

MAP/microtubule affinity-regulating kinase 4 (MARK4) is a member of serine/threonine kinase family and considered an attractive drug target for many diseases. Screening of Indian Medicinal Plants, Phytochemistry, and Therapeutics (IMPPAT) using virtual high-throughput screening coupled with enzyme assay suggested that Naringenin (NAG) could be a potent inhibitor of MARK4. Structure-based molecular docking analysis showed that NAG binds to the critical residues found in the active site pocket of MARK4. Furthermore, molecular dynamics (MD) simulation studies for 100 ns have delineated the binding mechanism of NAG to MARK4. Results of MD simulation suggested that binding of NAG further stabilizes the structure of MARK4 by forming a stable complex. In addition, no significant conformational change in the MARK4 structure was observed. Fluorescence binding and isothermal titration calorimetric measurements revealed an excellent binding affinity of NAG to MARK4 with a binding constant (K) = 0.13 × 106 M-1 obtained from fluorescence binding studies. Further, enzyme inhibition studies showed that NAG has an admirable IC50 value of 4.11 µM for MARK4. Together, these findings suggest that NAG could be an effective MARK4 inhibitor that can potentially be used to treat cancer and neurodegenerative diseases.

Inhibition of Antiestrogen-Promoted Pro-Survival Autophagy and Tamoxifen Resistance in Breast Cancer through Vitamin D Receptor.

We determined how vitamin D receptor (VDR) is linked to disease outcome in estrogen receptor-positive (ER+) breast cancer patients treated with tamoxifen (TAM). Breast cancer patients (n = 581) in four different datasets were divided into those expressing higher (above median) and lower levels of VDR in pretreatment ER+ tumors. Across all datasets, TAM-treated patients with higher pretreatment tumor VDR expression exhibited significantly longer recurrence-free survival. Ingenuity pathway analysis identified autophagy and unfolded protein response (UPR) as top differentially expressed pathways between high and low VDR-expressing ER+ cancers. Activation of VDR with vitamin D (VitD), either calcitriol or its synthetic analog EB1089, sensitized MCF-7-derived, antiestrogen-resistant LCC9 human breast cancer cells to TAM, and attenuated increased UPR and pro-survival autophagy. Silencing of VDR blocked these effects through the IRE1α-JNK pathway. Further, silencing of VDR impaired sensitivity to TAM in antiestrogen-responsive LCC1 cells, and prevented the effects of calcitriol and EB1089 on UPR and autophagy. In a preclinical mouse model, dietary VitD supplementation induced VDR activation and reduced carcinogen-induced ER+ mammary tumor incidence. In addition, IRE1α-JNK signaling was downregulated and survival autophagy was inhibited in mammary tumors of VitD-supplemented mice. Thus, activation of VDR is predictive of reduced risk of breast cancer recurrence in ER+ patients, possibly by inhibiting antiestrogen-promoted pro-survival autophagy.

The nephroprotective effects and mechanisms of rehmapicrogenin include ROS inhibition via an oestrogen-like pathway both in vivo and in vitro.

BACKGROUND: The root of Rehmannia glutinosa (R. glutinosa) is commonly used in various traditional Chinese herbal formulae to ameliorate nephropathy; however, little is known about its active component(s) and mechanisms. AIM: In the present study, we examined the protective effect and potential mechanism of rehmapicrogenin, a monomeric compound extracted from R. glutinosa, against Adriamycin (ADR)-induced nephropathy (AN) in vivo and in vitro. METHODS: In this study, an ADR-induced kidney injury model was employed to investigate the nephroprotective effects of rehmapicrogenin in mice. In vivo, ELISA kits, flow cytometry, haematoxylin-eosin staining, immunofluorescence techniques, and western blotting were used to evaluate the effect of rehmapicrogenin on kidney injury in mice. In vitro, the effects of rehmapicrogenin on NRK-52E cellular damage induced by ADR were determined using the 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The mechanism was investigated using ELISA kits, flow cytometry and In-Cell Western™ blotting. RESULTS: In vivo, rehmapicrogenin treatment significantly attenuated the pathological changes in the kidney induced by ADR; rescued weight, serum creatinine (Scr), blood urea nitrogen (BUN) and urine albumin (U-ALB) levels; reduced reactive oxygen species (ROS) accumulation; and decreased oxidative stress, the apoptosis rate, and cell survival in ADR-treated mice. Importantly, both in vivo and in vitro experimental results demonstrated that rehmapicrogenin regulates the Nrf2/ARE signalling pathway, the most important pathway for oxidative stress. Rehmapicrogenin attenuated ADR-induced kidney damage by reducing oxidative stress through the oestrogen receptor pathway. Moreover, after treatment with ICI 182780 (the oestrogen receptor-nonspecific antagonist Faslodex), the improvement induced by rehmapicrogenin was significantly reversed. CONCLUSIONS: In conclusion, rehmapicrogenin attenuates kidney damage by reducing inflammatory factor release through the oestrogen signalling pathway.

Induced Fit Docking and Automated QSAR Studies Reveal the ER-α Inhibitory Activity of Cannabis sativa in Breast Cancer.

BACKGROUND: Breast Cancer (BC), a common fatal disease and the deadliest cancer next to lung cancer, is characterized by an abnormal growth of cells in the tissues of the breast. BC chemotherapy is marked by targeting the activities of some receptors such as Estrogen Receptor alpha (ER-α). At present, one of the most commonly used and approved marketed therapeutic drugs for BC is tamoxifen. Despite the short-term success of tamoxifen usage, its long time treatment has been associated with significant side effects. Therefore, there is a pressing need for the development of novel anti-estrogens for the prevention and treatment of BC. OBJECTIVE: In this study, we evaluate the inhibitory effect of Cannabis sativa phytoconstituents on ER-α. METHODS: Glide and induced fit docking followed by ADME, automated QSAR and binding free energy (Δ>Gbind) studies were used to evaluate anti-breast cancer and ER-α inhibitory activity of Cannabis sativa, which has been reported to be effective in inhibiting breast cancer cell proliferation. RESULTS: Phyto-constituents of Cannabis sativa possess lower docking scores and good ΔGbind when compared to that of tamoxifen. ADME and AutoQSAR studies revealed that our lead compounds demonstrated the properties required to make them promising therapeutic agents. CONCLUSION: The results of this study suggest that naringenin, dihydroresveratrol, baicalein, apigenin and cannabitriol could have relatively better inhibitory activity than tamoxifen and could be a better and patent therapeutic candidate in the treatment of BC. Further research such as in vivo and/or in vitro assays could be conducted to verify the ability of these compounds.

Targeting ERα degradation by L-Tetrahydropalmatine provides a novel strategy for breast cancer treatment.

The incidence and mortality of breast cancer (BCa) are the highest among female cancers. There are approximate 70% BCa that are classified as estrogen receptor alpha (ERα) positive. Therefore, targeting ERα is the most significantly therapeutic schedule. However, patients with breast cancer develop resistance to ERα or estrogen (E2) antagonists such as fulvestrant and tamoxifen. In the present study, we found that L-Tetrahydropalmatine (L-THP) significantly suppressed cell proliferation in ERα+ BCa cells via inducing cell cycle arrest rather than apoptosis. Additionally, L-THP enhanced the sensitivity of ERα+ BCa cells to tamoxifen and fulvestrant. Mechanically, the application of L-THP promotes ERα degradation through accumulating ubiquitin chains on ERα. Overexpressing ERα abrogates L-THP induced-antiproliferation in ERα+ BCa cells. Collectively, our work indicates that L-THP may represent a potentially novel therapeutic medicine for ERα+ breast cancer patient.

Anti-Estrogenic Activity of Guajadial Fraction, from Guava Leaves (Psidium guajava L.).

The research of natural products has allowed for the discovery of biologically relevant compounds inspired by plant secondary metabolites, which contributes to the development of many chemotherapeutic drugs used in cancer treatment. Psidium guajava leaves present a diverse phytochemical composition including flavonoids, phenolics, meroterpenoids, and triterpenes as the major bioactive constituents. Guajadial, a caryophyllene-based meroterpenoid, has been studied for potential anticancer effects tested in tumor cells and animal experimental models. Moreover, guajadial has been reported to have a mechanism of action similar to tamoxifen, suggesting this compound as a promisor phytoestrogen-based therapeutic agent. Herein, the anti-estrogenic action and anti-proliferative activity of guajadial is reported. The enriched guajadial fraction was obtained by sequential chromatographic techniques from the crude P. guajava dichloromethane extract showing promising anti-proliferative activity in vitro with selectivity for human breast cancer cell lines MCF-7 and MCF-7 BUS (Total Growth Inhibition = 5.59 and 2.27 µg·mL-1, respectively). Furthermore, evaluation of anti-estrogenic activity in vivo was performed demonstrating that guajadial enriched fraction inhibited the proliferative effect of estradiol on the uterus of pre-pubescent rats. These results suggest a relationship between anti-proliferative and anti-estrogenic activity of guajadial, which possibly acts in tumor inhibition through estrogen receptors due to the compounds structural similarity to tamoxifen.

Assessing the cytotoxic/genotoxic activity and estrogenic/antiestrogenic potential of essential oils from seven aromatic plants.

Alternative therapies with new drugs are needed because the clinical efficacy of conventional chemotherapy is often reduced due to collateral effects. Many natural products of plant origin, including essential oils (EOs) have proved to be effective in prevention and therapy of several diseases such as bacterial infections, chronic diseases and cancer. In the present study, we investigated some biological activities of EOs extracted from seven plants: Rosmarinus officinalis, Salvia somalensis, Thymus vulgaris, Achillea millefolium, Helichrysum italicum, Pistacia lentiscus, Myrtus communis. In particular, we evaluated the cytotoxic and genotoxic activity using the cytochalasin B-blocked micronucleus assay (CBMN) in human peripheral lymphocytes, cytotoxicity in a human ovarian carcinoma cell line (A2780), and the estrogenic/antiestrogenic activity using a yeast strain expressing the human estrogen receptor alpha (ERα). Our results show that most EOs can have a strong cytotoxic and a slight/moderate genotoxic effect on human peripheral lymphocytes, and also a pronounced cytotoxic effect in A2780 cells. In addition, some EOs seem to have a marked antiestrogenic activity that could potentially perturb the estrogen-dependent tissues.

Recent advances in the anti-aging effects of phytoestrogens on collagen, water content, and oxidative stress.

Skin undergoes degenerative changes as it ages, which include the loss of elasticity, reductions in the epidermal thickness and collagen content, elastic fiber degeneration, and increased wrinkling and dryness. Skin aging can be significantly delayed by the administration of estrogen. Estrogen deficiency following menopause results in atrophic skin changes and the acceleration of skin aging. Estrogen administration has positive effects on human skin by delaying or preventing skin aging manifestations, but the use of estrogen replacement is a risk factor for breast and uterine cancer. Phytoestrogens are a large family of plant-derived molecules possessing various degrees of estrogen-like activity; they exhibit agonist or antagonist estrogenic properties depending on the tissue. These molecules could be ideal candidates to combat skin aging and other detrimental effects of hypoestrogenism. In this paper, we review the effects of phytoestrogens on human skin and the mechanisms by which phytoestrogens can alleviate the changes due to aging.

Estrogenic, Antiestrogenic and Antiproliferative Activities of Euphorbia bicolor (Euphorbiaceae) Latex Extracts and Its Phytochemicals.

Estrogen receptor antagonists are effective in breast cancer treatment. However, the side effects of these treatments have led to a rise in searching for alternative therapies. The present study evaluated the estrogenic, antiestrogenic, and antiproliferative activities of Euphorbia bicolor (Euphorbiaceae), a plant native to south-central USA. Estrogenic and antiestrogenic activities of latex extract and its phytochemicals were evaluated with a steroid-regulated yeast system expressing the human estrogen receptor α and antiproliferative properties were assessed in the ER-positive MCF-7 and T47-D and triple-negative MDA-MB-231 and MDA-MB-469 breast carcinomas. Genistein and coumestrol identified in the latex extract induced higher estrogenic and antiestrogenic activities compared to diterpenes and flavonoids. The latex extract, resiniferatoxin (RTX) and rutin induced antiproliferative activities in all cell lines in a dose-dependent manner, but not in human normal primary dermal fibroblast cultures. A biphasic effect was observed with MDA-MB-468 breast carcinoma in which the latex extract at low concentrations increased and at high concentrations decreased cell proliferation. Treatments with latex extract in combination with RTX or rutin reduced even more the proliferation of MCF-7 breast carcinoma compared to the individual latex, RTX, and rutin treatments. E. bicolor latex phytochemicals could contribute to developing commercial therapeutic agents for breast cancer treatment.

Anthonotha macrophylla P. Beauv (Caesalpiniaceae) aqueous extract exhibits antiestrogenic effects in vitro and in vivo.

Background Phytoestrogens are natural compounds known as natural selective estrogen receptor modulators used as alternatives against estrogen-dependent cancers. This study aims to evaluate the antiestrogenic effects of Anthonotha macrophylla, a plant used to treat cancer in Cameroon. Methods The estrogenic/antiestrogenic activities of A. macrophylla aqueous extract were evaluated in vitro using MCF-7 cell proliferation assay. Moreover, a classical uterotrophic test was carried out to evaluate the antiestrogenic effects of A. macrophylla in rats. Changes in the uterus, vagina, and mammary glands were used as endpoints of estrogenicity. Results Anthonotha macrophylla induced antiestrogenic effects in vitro at all the tested concentrations by inhibiting estradiol-induced MCF-7 cell proliferation (p < 0.001). In vivo, a coadministration of estradiol with A. macrophylla extract led to the decrease of uterine [150 (p < 0.05) and 300 (p < 0.01) mg/kg body weight (BW)] and vaginal [75 (p < 0.01) and 300 (p < 0.05) mg/kg BW] epithelial thickness. In addition, a reduction in the mammary gland acini lumen's diameter was also observed at 75 and 150 mg/kg. Gas chromatography-time-of-flight-mass spectrometry analysis showed that phenolic acid derivatives are present in A. macrophylla extract, which are well known to be endowed with estrogenic/antiestrogenic properties. The LD50 of A. macrophylla was estimated to be less than 2000 mg/kg. Conclusions Anthonotha macrophylla aqueous extract has antiestrogenic properties. This could promote more studies to explore its ability to prevent estrogen-dependent cancers.

Dry olive leaf extract attenuates DNA damage induced by estradiol and diethylstilbestrol in human peripheral blood cells in vitro.

Phenolic groups of steroidal or nonsteroidal estrogens can redox cycle, leading to oxidative stress, where creation of reactive oxygen species are recognized as the main mechanism of their DNA damage properties. Dry olive (Olea europaea L.) leaf extract is known to contain bioactive and antioxidative components and to have an ability to modulate the effects of various oxidants in cells. The main goal of this study was to investigate antigenotoxic potential of a standardized dry olive leaf extract on DNA damage induced by 17ß-estradiol and diethylstilbestrol in human whole blood cells in vitro, using comet assay. Our results indicated that both hormones showed a genotoxic effect at a concentration of 100 µM (P < 0.05, n = 6). Dry olive leaf extract was efficient in reducing number of cells with estrogen-induced DNA damage at tested concentrations (0.125, 0.5 and 1 mg/mL) (P < 0.05, n = 6) and under two experimental protocols, pre-treatment and post-treatment, exhibiting antigenotoxic properties. Analysis of antioxidant properties of the extract revealed moderate ABTS radical scavenging properties and reducing power. Overall, our results suggested that the protective potential of dry olive leaf extract could arise from the synergistic effect of its scavenging activity and enhancement of the cells' antioxidant capacity.

Discovery of novel natural compound inhibitors targeting estrogen receptor α by an integrated virtual screening strategy.

Estrogen receptor (ER) is a nuclear hormone receptor and plays an important role in mediating the cellular effects of estrogen. ER can be classified into two receptors: estrogen receptor alpha (ERα) and beta (ERß), and the former is expressed in 50~80% of breast tumors and has been extensively investigated in breast cancer for decades. Excessive exposure to estrogen can obviously stimulate the growth of breast cancers primarily mediated by ERα, and thus anti-estrogen therapies by small molecules are of concern to clinicians and pharmaceutical industry in the treatment of ERα-positive breast cancers. Although a series of estrogen receptor modulators have been developed, these drugs can lead to resistance and side effects. Therefore, the development of small molecule inhibitors with high target specificity has been intensified. In this pursuit, an integrated computer-aided virtual screening technique, including molecular docking and pharmacophore model screening, was used to screen traditional Chinese medicine (TCM) databases. The compounds with high docking scores and fit values were subjected to ADME (adsorption, distribution, metabolism, excretion) and toxicity prediction, and ten hits were identified as potential inhibitors targeting ERα. Molecular docking was used to investigate the binding modes between ERα and three most potent hits, and molecular dynamic simulations were chosen to explore the stability of these complexes. The rank of the predicted binding free energies evaluated by MM/GBSA is consistent with the docking score. These novel scaffolds discovered in the present study can be used as critical starting point in the drug discovery process for treating ERα-positive breast cancer. Graphical abstract .

Determination and analysis of agonist and antagonist potential of naturally occurring flavonoids for estrogen receptor (ERα) by various parameters and molecular modelling approach.

Most estrogen receptor α (ERα) ligands target the ligand binding domain (LBD). Agonist 17ß-estradiol (E2) and tamoxifen (TM, known SERM), bind to the same site within the LBD. However, structures of ligand-bound complexes show that E2 and TM induce different conformations of helix 12 (H12). During the molecular modelling studies of some naturally occurring flavonoids such as quercetin, luteolin, myricetin, kaempferol, naringin, hesperidin, galangin, baicalein and epicatechin with human ERα (3ERT and 1GWR), we observed that most of the ligands bound to the active site pocket of both 3ERT and 1GWR. The docking scores, interaction analyses, and conformation of H12 provided the data to support for the estrogenic or antiestrogenic potential of these flavonoids to a limited degree. Explicit molecular dynamics for 50 ns was performed to identify the stability and compatibility pattern of protein-ligand complex and RMSD were obtained. Baicalein, epicatechin, and kaempferol with 1GWR complex showed similar RMSD trend with minor deviations in the protein backbone RMSD against 1GWR-E2 complex that provided clear indications that ligands were stable throughout the explicit molecular simulations in the protein and outcome of naringin-3ERT complex had an upward trend but stable throughout the simulations and all molecular dynamics showed stability with less than overall 1 Å deviation throughout the simulations. To examine their estrogenic or antiestrogenic potential, we studied the effect of the flavonoids on viability, progesterone receptor expression and 3xERE/3XERRE-driven reporter gene expression in ERα positive and estrogen responsive MCF-7 breast cancer cells. Epicatechin, myricetin, and kaempferol showed estrogenic potential at 5 µM concentration.

Naringenin Attenuates Myocardial Ischemia-Reperfusion Injury via cGMP-PKGIα Signaling and In Vivo and In Vitro Studies.

Endoplasmic reticulum (ER) stress and oxidative stress contribute greatly to myocardial ischemia-reperfusion (MI/R) injury. Naringenin, a flavonoid derived from the citrus genus, exerts cardioprotective effects. However, the effects of naringenin on ER stress as well as oxidative stress under MI/R condition and the detailed mechanisms remain poorly defined. This study investigated the protective effect of naringenin on MI/R-injured heart with a focus on cyclic guanosine monophosphate- (cGMP-) dependent protein kinase (PKG) signaling. Sprague-Dawley rats were treated with naringenin (50 mg/kg/d) and subjected to MI/R surgery with or without KT5823 (2 mg/kg, a selective inhibitor of PKG) cotreatment. Cellular experiment was conducted on H9c2 cardiomyoblasts subjected to simulated ischemia-reperfusion treatment. Before the treatment, the cells were incubated with naringenin (80 µmol/L). PKGIα siRNA was employed to inhibit PKG signaling. Our in vivo and in vitro data showed that naringenin effectively improved heart function while it attenuated myocardial apoptosis and infarction. Furthermore, pretreatment with naringenin suppressed MI/R-induced oxidative stress as well as ER stress as evidenced by decreased superoxide generation, myocardial MDA level, gp91 phox expression, and phosphorylation of PERK, IRE1α, and EIF2α as well as reduced ATF6 and CHOP. Importantly, naringenin significantly activated myocardial cGMP-PKGIα signaling while inhibition of PKG signaling with KT5823 (in vivo) or siRNA (in vitro) not only abolished these actions but also blunted naringenin's inhibitory effects against oxidative stress and ER stress. In summary, our study demonstrates that naringenin treatment protects against MI/R injury by reducing oxidative stress and ER stress via cGMP-PKGIα signaling. Its cardioprotective effect deserves further clinical study.

Naringenin promotes microglial M2 polarization and Aß degradation enzyme expression.

Two kinds of microglia are known, classical M1 and alternative M2 phenotypes. Amyloid ß (Aß), a critical cause of Alzheimer's disease (AD), promotes M1 microglial polarization, leading to neuroinflammation and neuronal death. M2 microglia play important roles in anti-inflammatory effects, Aß clearance, and memory recovery in AD. Therefore, increasing of M2 microglia is expected to recover from AD. We previously found that naringenin, a blood-brain barrier penetrating compound, decreased Aß deposits and recovers memory function in transgenic AD model mice. Naringenin reportedly showed anti-inflammatory properties. Here, we aim to investigate potential effects of naringenin on microglial polarization and to reveal the underlying mechanisms of Aß reduction. Primary cultured cortical microglia were treated with Aß1-42 , following administration of naringenin. Naringenin remarkably promoted M2 microglia polarization and inhibited Aß1-42 -induced M1 microglia activation. Because microglia reportedly played a critical role in cerebral Aß clearance through Aß degradation enzymes after phagocytosis, we investigated the expression of Aß degradation enzymes, such as neprilysin and insulin degradation enzyme. After naringenin treatment, these Aß degradation enzymes were downregulated in M1 microglia and upregulated in M2 microglia. Taken together, our results showed that naringenin increased Aß degradation enzymes in M2 microglia, probably leading to Aß plaque reduction.

Sesquiterpenes from Cyperus rotundus and 4α,5α-oxidoeudesm-11-en-3-one as a potential selective estrogen receptor modulator.

Estrogenic activity-oriented fractionation and purification of methanol extract from the rhizome of Cyperus rotundus, a well-known traditional herbal medicine, led to the isolation of six sesquiterpenes. 4α,5α-Oxidoeudesm-11-en-3-one (2) and cyper-11-ene-3,4-dione (3) together with four known sesquiterpenes, cyperotundone (1), caryophyllene α-oxide (4), α-cyperone (5), and isocyperol (6) were obtained from the hexane and dichloromethane fractions. Compounds 2 and 3 were newly isolated from natural resources in particular. To identify the possible use of isolated compounds as an alternative to hormone replacement therapy (HRT), estrogenic activity was evaluated by E-screen assay on MCF-7 BUS cells. Among the all isolated compounds from the rhizome of Cyperus rotundus, newly isolated from natural resource, 2 exhibited the most potent estrogenic activity. In an estrogen sensitive reporter gene assay, 2 significantly increased transcriptional activities. As a phytoestrogen, 2 was assessed by investigating dual action on ER-α and ER-ß in competitive binding assay. It was found that 2 exerted higher binding affinity to ER-ß than ER-α and it also showed both estrogenic and antiestrogenic effects depending on the E2 concentration. Our results indicate that newly isolated from Cyperus rotundus, 2 has biphasic activities on estrogen receptors which could be useful as an alternative HRT.

Aqueous Extract of Pomegranate Alone or in Combination with Citalopram Produces Antidepressant-Like Effects in an Animal Model of Menopause: Participation of Estrogen Receptors.

It has been reported that the aqueous extract of pomegranate (AE-PG) has polyphenols with estrogenic-like activities. The present work determines if AE-PG alone or in combination with the selective serotonin reuptake inhibitor, citalopram, has antidepressant-like effects. It was also analyzed the participation of estrogen receptors (ER). AE-PG (0.1, 1.0, 10, or 100 mg/kg) was evaluated in ovariectomized female Wistar rats subjected to the forced swimming test. The effects induced by AE-PG were compared with those of citalopram (2.5, 5.0, 10, and 20.0 mg/kg) and 17ß-estradiol (E2; 2.5 5.0, and 10 µg/rat). Likewise, the combination of suboptimal doses of AE-PG (0.1 mg/kg) plus citalopram (2.5 mg/kg) was evaluated. To determine if ER participates in the antidepressant-like action of pomegranate, the estrogen antagonist tamoxifen (15 mg/kg) was administered with AE-PG (1 mg/kg). AE-PG produced antidepressant-like actions with a similar behavioral profile induced by citalopram and E2. Suboptimal doses of citalopram plus AE-PG produced antidepressant-like effects. Tamoxifen was able to block AE-PG's antidepressant-like actions. These results confirm the participation of ER in AE-PG's antidepressant-like effects. Furthermore, the additive effects observed with the combined treatment of AE-PG plus citalopram could be advantageous in the treatment of depressive disorders, such as menopause.