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Guido F Pauli - One of the best experts on this subject based on the ideXlab platform.
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DESIGNER Extracts as Tools to Balance Estrogenic and Chemopreventive Activities of Botanicals for Women’s Health
2017Co-Authors: Birgit M. Dietz, Shaonong Chen, Richard B. Van Breemen, Judy L. Bolton, Huali Dong, Dejan Nikolić, René F. Ramos Alvarenga, Martin Biendl, Guido F PauliAbstract:Botanical dietary supplements contain multiple bioactive compounds that target numerous biological pathways. The lack of uniform standardization requirements is one reason that inconsistent clinical effects are reported frequently. The multifaceted biological interactions of active principles can be disentangled by a coupled pharmacological/phytochemical approach using specialized (“knock-out”) extracts. This is demonstrated for hops, a botanical for menopausal symptom management. Employing targeted, adsorbent-free countercurrent separation, Humulus lupulus extracts were designed for pre- and postmenopausal women by containing various amounts of the phytoestrogen 8-Prenylnaringenin (8-PN) and the chemopreventive constituent xanthohumol (XH). Analysis of their estrogenic (alkaline phosphatase), chemopreventive (NAD(P)H-quinone oxidoreductase 1 [NQO1]), and cytotoxic bioactivities revealed that the estrogenicity of hops is a function of 8-PN, whereas their NQO1 induction and cytotoxic properties depend on XH levels. Antagonization of the estrogenicity of 8-PN by elevated XH concentrations provided evidence for the interdependence of the biological effects. A designed postmenopausal hop extract was prepared to balance 8-PN and XH levels for both estrogenic and chemopreventive properties. An extract designed for premenopausal women contains reduced 8-PN levels and high XH concentrations to minimize estrogenic while retaining chemopreventive properties. This study demonstrates the feasibility of modulating the concentrations of bioactive compounds in botanical extracts for potentially improved efficacy and safety
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Evaluation of Estrogenic Activity of Licorice Species in Comparison with Hops Used in Botanicals for Menopausal Symptoms
2016Co-Authors: Atieh Hajirahimkhan, Guido F Pauli, Yang Yuan, Shaonong Chen, Charlotte Simmler, Jeffrey R. Anderson, Birgit M. Dietz, Richard B. Van Breemen, Judy L. BoltonAbstract:The increased cancer risk associated with hormone therapies has encouraged many women to seek non-hormonal alternatives including botanical supplements such as hops (Humulus lupulus) and licorice (Glycyrrhiza spec.) to manage menopausal symptoms. Previous studies have shown estrogenic properties for hops, likely due to the presence of 8-prenylnarigenin, and chemopreventive effects mainly attributed to xanthohumol. Similarly, a combination of estrogenic and chemopreventive properties has been reported for various Glycyrrhiza species. The major goal of the current study was to evaluate the potential estrogenic effects of three licorice species (Glycyrrhiza glabra, G. uralensis, and G. inflata) in comparison with hops. Extracts of Glycyrrhiza species and spent hops induced estrogen responsive alkaline phosphatase activity in endometrial cancer cells, estrogen responsive element (ERE)-luciferase in MCF-7 cells, and Tff1mRNA in T47D cells
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hop humulus lupulus l extract and 6 prenylnaringenin induce p450 1a1 catalyzed estrogen 2 hydroxylation
Chemical Research in Toxicology, 2016Co-Authors: Shuai Wang, Guido F Pauli, Shaonong Chen, Birgit M. Dietz, Tareisha L Dunlap, Caitlin E Howell, Obinna Mbachu, R S Phansalkar, Judy L. BoltonAbstract:Humulus lupulus L. (hops) is a popular botanical dietary supplement used by women as a sleep aid and for postmenopausal symptom relief. In addition to its efficacy for menopausal symptoms, hops can also modulate the chemical estrogen carcinogenesis pathway and potentially protect women from breast cancer. In the present study, an enriched hop extract and the key bioactive compounds [6-prenylnarigenin (6-PN), 8-prenylnarigenin (8-PN), isoxanthohumol (IX), and xanthohumol (XH)] were tested for their effects on estrogen metabolism in breast cells (MCF-10A and MCF-7). The methoxyestrones (2-/4-MeOE1) were analyzed as biomarkers for the nontoxic P450 1A1 catalyzed 2-hydroxylation and the genotoxic P450 1B1 catalyzed 4-hydroxylation pathways, respectively. The results indicated that the hop extract and 6-PN preferentially induced the 2-hydroxylation pathway in both cell lines. 8-PN only showed slight up-regulation of metabolism in MCF-7 cells, whereas IX and XH did not have significant effects in either cell li...
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hop humulus lupulus l extract and 6 prenylnaringenin induce p450 1a1 catalyzed estrogen 2 hydroxylation
Chemical Research in Toxicology, 2016Co-Authors: Shuai Wang, Guido F Pauli, Shaonong Chen, Birgit M. Dietz, Tareisha L Dunlap, Caitlin E Howell, Obinna Mbachu, R S Phansalkar, Emily Rue, Judy L. BoltonAbstract:Humulus lupulus L. (hops) is a popular botanical dietary supplement used by women as a sleep aid and for postmenopausal symptom relief. In addition to its efficacy for menopausal symptoms, hops can also modulate the chemical estrogen carcinogenesis pathway and potentially protect women from breast cancer. In the present study, an enriched hop extract and the key bioactive compounds [6-prenylnarigenin (6-PN), 8-prenylnarigenin (8-PN), isoxanthohumol (IX), and xanthohumol (XH)] were tested for their effects on estrogen metabolism in breast cells (MCF-10A and MCF-7). The methoxyestrones (2-/4-MeOE1) were analyzed as biomarkers for the nontoxic P450 1A1 catalyzed 2-hydroxylation and the genotoxic P450 1B1 catalyzed 4-hydroxylation pathways, respectively. The results indicated that the hop extract and 6-PN preferentially induced the 2-hydroxylation pathway in both cell lines. 8-PN only showed slight up-regulation of metabolism in MCF-7 cells, whereas IX and XH did not have significant effects in either cell line. To further explore the influence of hops and its bioactive marker compounds on P450 1A1/1B1, mRNA expression and ethoxyresorufin O-dealkylase (EROD) activity were measured. The results correlated with the metabolism data and showed that hop extract and 6-PN preferentially enhanced P450 1A1 mRNA expression and increased P450 1A1/1B1 activity. The aryl hydrocarbon receptor (AhR) activation by the isolated compounds was tested using xenobiotic response element (XRE) luciferase construct transfected cells. 6-PN was found to be an AhR agonist that significantly induced XRE activation and inhibited 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced XRE activity. 6-PN mediated induction of EROD activity was also inhibited by the AhR antagonist CH223191. These data show that the hop extract and 6-PN preferentially enhance the nontoxic estrogen 2-hydroxylation pathway through AhR mediated up-regulation of P450 1A1, which further emphasizes the importance of standardization of botanical extracts to multiple chemical markers for both safety and desired bioactivity.
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K‑Targeted Metabolomic Analysis Extends Chemical Subtraction to DESIGNER Extracts: Selective Depletion of Extracts of Hops (Humulus lupulus)
2015Co-Authors: René F. Ramos Alvarenga, Guido F Pauli, Charlotte Simmler, Richard Van Breemen, Brent J. Friesen, Dejan Nikolić, José G. Napolitano, David C. Lankin, James B. Mcalpine, Shaonong ChenAbstract:This study introduces a flexible and compound targeted approach to Deplete and Enrich Select Ingredients to Generate Normalized Extract Resources, generating DESIGNER extracts, by means of chemical subtraction or augmentation of metabolites. Targeting metabolites based on their liquid–liquid partition coefficients (K values), K targeting uses countercurrent separation methodology to remove single or multiple compounds from a chemically complex mixture, according to the following equation: DESIGNER extract = total extract ± target compound(s). Expanding the scope of the recently reported depletion of extracts by immunoaffinity or solid phase liquid chromatography, the present approach allows a more flexible, single- or multi-targeted removal of constituents from complex extracts such as botanicals. Chemical subtraction enables both chemical and biological characterization, including detection of synergism/antagonism by both the subtracted targets and the remaining metabolite mixture, as well as definition of the residual complexity of all fractions. The feasibility of the DESIGNER concept is shown by K-targeted subtraction of four bioactive prenylated phenols, isoxanthohumol (1), 8-Prenylnaringenin (2), 6-prenylnaringenin (3), and xanthohumol (4), from a standardized hops (Humulus lupulus L.) extract using specific solvent systems. Conversely, adding K-targeted isolates allows enrichment of the original extract and hence provides an augmented DESIGNER material. Multiple countercurrent separation steps were used to purify each of the four compounds, and four DESIGNER extracts with varying depletions were prepared. The DESIGNER approach innovates the characterization of chemically complex extracts through integration of enabling technologies such as countercurrent separation, K-by-bioactivity, the residual complexity concepts, as well as quantitative analysis by 1H NMR, LC-MS, and HiFSA-based NMR fingerprinting
Dejan Nikolic - One of the best experts on this subject based on the ideXlab platform.
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biological and chemical standardization of a hop humulus lupulus botanical dietary supplement
Biomedical Chromatography, 2014Co-Authors: Elizabeth Krause, Guido F Pauli, Dejan Nikolic, Yang Yuan, Atieh Hajirahimkhan, Birgit M. Dietz, Judy L. Bolton, Huali Dong, Richard B Van BreemenAbstract:Concerned about the safety of conventional estrogen replacement therapy, women are using botanical dietary supplements as alternatives for the management of menopausal symptoms such as hot flashes. Before botanical dietary supplements can be evaluated clinically for safety and efficacy, botanically authenticated and standardized forms are required. To address the demand for a standardized, estrogenic botanical dietary supplement, an extract of hops (Humulus lupulus, L.) was developed. Although valued in the brewing of beer, hop extracts are used as anxiolytics and hypnotics and have well established estrogenic constituents. Starting with a hop cultivar used in the brewing industry, spent hops (the residue remaining after extraction of bitter acids) were formulated into a botanical dietary supplement that was then chemically and biologically standardized. Biological standardization utilized the estrogen dependent induction of alkaline phosphatase in the Ishikawa cell line. Chemical standardization was based on the prenylated phenols in hops that included estrogenic 8-Prenylnaringenin (8-PN), its isomer 6-prenylnaringenin (6-PN), and pro-estrogenic isoxanthohumol (IX) and its isomeric chalcone xanthohumol (XN), all of which were measured using high performance liquid chromatography-tandem mass spectrometry (LC/MS-MS). The product of this process was a reproducible botanical extract suitable for subsequent investigations of safety and efficacy.
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inhibition of human cytochrome p450 enzymes by hops humulus lupulus and hop prenylphenols
European Journal of Pharmaceutical Sciences, 2014Co-Authors: Yang Yuan, Guido F Pauli, Dejan Nikolic, Shaonong Chen, Ke Huang, Guannan Li, Richard B Van BreemenAbstract:Abstract As hops ( Humulus lupulus L.) are used in the brewing of beer and by menopausal women as estrogenic dietary supplements, the potential for hop extracts and hop constituents to cause drug–botanical interactions by inhibiting human cytochrome P450 enzymes was investigated. Inhibition of major human cytochrome P450 enzymes by a standardized hop extract and isolated hop prenylated phenols was evaluated using a fast and efficient assay based on ultrahigh pressure liquid chromatography–tandem mass spectrometry. The hop extract at 5 μg/mL inhibited CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%), and CYP1A2 (27%) with IC 50 values of 0.8, 0.9, 3.3, and 9.4 μg/mL, respectively, but time-dependent inactivation was observed only for CYP1A2. Isoxanthohumol from hops was the most potent inhibitor of CYP2C8 with an IC 50 of 0.2 μM, whereas 8-Prenylnaringenin was the most potent inhibitor of CYP1A2, CYP2C9 and CYP2C19 with IC 50 values of 1.1 μM, 1.1 μM and 0.4 μM, respectively. Extracts of hops contain prenylated compounds such as the flavanones isoxanthohumol and 8-Prenylnaringenin and the chalcone xanthohumol that can inhibit CYP450s, especially the CYP2C family, which may affect the efficacy and safety of some CYP2C substrate drugs when co-administered.
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evaluation of estrogenic activity of licorice species in comparison with hops used in botanicals for menopausal symptoms
PLOS ONE, 2013Co-Authors: Atieh Hajirahimkhan, Guido F Pauli, Dejan Nikolic, Yang Yuan, Shaonong Chen, Charlotte Simmler, Jeffrey R. Anderson, Birgit M. Dietz, Richard B. Van Breemen, Judy L. BoltonAbstract:The increased cancer risk associated with hormone therapies has encouraged many women to seek non-hormonal alternatives including botanical supplements such as hops (Humulus lupulus) and licorice (Glycyrrhiza spec.) to manage menopausal symptoms. Previous studies have shown estrogenic properties for hops, likely due to the presence of 8-prenylnarigenin, and chemopreventive effects mainly attributed to xanthohumol. Similarly, a combination of estrogenic and chemopreventive properties has been reported for various Glycyrrhiza species. The major goal of the current study was to evaluate the potential estrogenic effects of three licorice species (Glycyrrhiza glabra, G. uralensis, and G. inflata) in comparison with hops. Extracts of Glycyrrhiza species and spent hops induced estrogen responsive alkaline phosphatase activity in endometrial cancer cells, estrogen responsive element (ERE)-luciferase in MCF-7 cells, and Tff1 mRNA in T47D cells. The estrogenic activity decreased in the order H. lupulus > G. uralensis > G. inflata > G. glabra. Liquiritigenin was found to be the principle phytoestrogen of the licorice extracts; however, it exhibited lower estrogenic effects compared to 8-Prenylnaringenin in functional assays. Isoliquiritigenin, the precursor chalcone of liquiritigenin, demonstrated significant estrogenic activities while xanthohumol, a metabolic precursor of 8-Prenylnaringenin, was not estrogenic. Liquiritigenin showed ERβ selectivity in competitive binding assay and isoliquiritigenin was equipotent for ER subtypes. The estrogenic activity of isoliquiritigenin could be the result of its cyclization to liquiritigenin under physiological conditions. 8-Prenylnaringenin had nanomolar estrogenic potency without ER selectivity while xanthohumol did not bind ERs. These data demonstrated that Glycyrrhiza species with different contents of liquiritigenin have various levels of estrogenic activities, suggesting the importance of precise labeling of botanical supplements. Although hops shows strong estrogenic properties via ERα, licorice might have different estrogenic activities due to its ERβ selectivity, partial estrogen agonist activity, and non-enzymatic conversion of isoliquiritigenin to liquiritigenin.
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differential regulation of detoxification enzymes in hepatic and mammary tissue by hops humulus lupulus in vitro and in vivo
Molecular Nutrition & Food Research, 2013Co-Authors: Birgit M. Dietz, Guido F Pauli, Dejan Nikolic, Shaonong Chen, Jeffrey R. Anderson, Ghenet K Hagos, Jillian N Eskra, Gihani T Wijewickrama, Brian Wright, Richard B Van BreemenAbstract:Scope Hops contain the phytoestrogen, 8-Prenylnaringenin, and the cytoprotective compound, xanthohumol (XH). XH induces the detoxification enzyme, NAD(P)H-quinone oxidoreductase (NQO1) in vitro; however, the tissue distribution of XH and 8-Prenylnaringenin and their tissue-specific activity have not been analyzed. Methods and results An orally administered hop extract and subcutaneously injected XH were administered to Sprague–Dawley rats over 4 days. LC-MS-MS analysis of plasma, liver, and mammary gland revealed that XH accumulated in liver and mammary glands. Compared with the low level in the original extract, 8-Prenylnaringenin was enriched in the tissues. Hops and XH-induced NQO1 in the liver, while only hops reduced NQO1 activity in the mammary gland. Mechanistic studies revealed that hops modulated NQO1 through three mechanisms. In liver cells, (i) XH modified Kelch-like ECH-associated protein leading to nuclear factor (erythroid-derived 2)-like 2 (Nrf2) translocation and antioxidant response element (ARE) activation; (ii) hop-mediated ARE induction was partially mediated through phosphorylation of Nrf2 by PKC; (iii) in breast cells, 8-Prenylnaringenin reduced NQO1 likely through binding to estrogen receptorα, recruiting Nrf2, and downregulating ARE-regulated genes. Conclusion XH and 8-Prenylnaringenin in dietary hops are bioavailable to the target tissues. While hops and XH might be cytoprotective in the liver, 8-Prenylnaringenin seems responsible for hop-mediated NQO1 reduction in the mammary gland.
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identification of human hepatic cytochrome p450 enzymes involved in the metabolism of 8 prenylnaringenin and isoxanthohumol from hops humulus lupulus l
Drug Metabolism and Disposition, 2006Co-Authors: Dejan Nikolic, Lucas R Chadwick, Guido F PauliAbstract:The female flowers of hops ( Humulus lupulus L.) are used in the brewing of beer and are under investigation for use in dietary supplements for the management of menopausal symptoms in women. Hop extracts contain the weakly estrogenic compound isoxanthohumol (IX), proestrogenic xanthohumol, and the potent estrogen 8-Prenylnaringenin (8PN). Because IX can be metabolized in the human liver to form 8PN, the specific cytochrome P450 (P450) enzymes responsible for this O -demethylation reaction were identified. In addition, the enzymes that convert IX and 8PN to their most abundant metabolites were identified because these metabolic pathways might also affect the estrogenicity of hop preparations. Specifically, the P450 enzymes that catalyze the oxidation of the prenyl side chains of IX and 8PN into trans- or cis- alcohols were investigated. Human liver microsomes and monoclonal antibodies that inhibit specific P450 enzymes were used in combination with liquid chromatography/mass spectrometry to identify the enzymes responsible for these transformations. CYP2C19 was found to catalyze the formation of both cis- and trans- alcohols of the prenyl side chain of 8PN with K m values of 14.8 ± 3.2 and 16.6 ± 4.6 μM, respectively. CYP2C8 converted 8PN regioselectively to the trans -alcohol of the prenyl group with a K m of 3.7 ± 0.9 μM. Finally, CYP1A2 was found to catalyze the O -demethylation of IX to generate 8PN, with a K m value of 17.8 ± 3.7 μM. These results suggest that the estrogenicity of hop constituents in vivo will depend in part on metabolic conversion that may show individual variation.
Richard B Van Breemen - One of the best experts on this subject based on the ideXlab platform.
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biological and chemical standardization of a hop humulus lupulus botanical dietary supplement
Biomedical Chromatography, 2014Co-Authors: Elizabeth Krause, Guido F Pauli, Dejan Nikolic, Yang Yuan, Atieh Hajirahimkhan, Birgit M. Dietz, Judy L. Bolton, Huali Dong, Richard B Van BreemenAbstract:Concerned about the safety of conventional estrogen replacement therapy, women are using botanical dietary supplements as alternatives for the management of menopausal symptoms such as hot flashes. Before botanical dietary supplements can be evaluated clinically for safety and efficacy, botanically authenticated and standardized forms are required. To address the demand for a standardized, estrogenic botanical dietary supplement, an extract of hops (Humulus lupulus, L.) was developed. Although valued in the brewing of beer, hop extracts are used as anxiolytics and hypnotics and have well established estrogenic constituents. Starting with a hop cultivar used in the brewing industry, spent hops (the residue remaining after extraction of bitter acids) were formulated into a botanical dietary supplement that was then chemically and biologically standardized. Biological standardization utilized the estrogen dependent induction of alkaline phosphatase in the Ishikawa cell line. Chemical standardization was based on the prenylated phenols in hops that included estrogenic 8-Prenylnaringenin (8-PN), its isomer 6-prenylnaringenin (6-PN), and pro-estrogenic isoxanthohumol (IX) and its isomeric chalcone xanthohumol (XN), all of which were measured using high performance liquid chromatography-tandem mass spectrometry (LC/MS-MS). The product of this process was a reproducible botanical extract suitable for subsequent investigations of safety and efficacy.
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inhibition of human cytochrome p450 enzymes by hops humulus lupulus and hop prenylphenols
European Journal of Pharmaceutical Sciences, 2014Co-Authors: Yang Yuan, Guido F Pauli, Dejan Nikolic, Shaonong Chen, Ke Huang, Guannan Li, Richard B Van BreemenAbstract:Abstract As hops ( Humulus lupulus L.) are used in the brewing of beer and by menopausal women as estrogenic dietary supplements, the potential for hop extracts and hop constituents to cause drug–botanical interactions by inhibiting human cytochrome P450 enzymes was investigated. Inhibition of major human cytochrome P450 enzymes by a standardized hop extract and isolated hop prenylated phenols was evaluated using a fast and efficient assay based on ultrahigh pressure liquid chromatography–tandem mass spectrometry. The hop extract at 5 μg/mL inhibited CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%), and CYP1A2 (27%) with IC 50 values of 0.8, 0.9, 3.3, and 9.4 μg/mL, respectively, but time-dependent inactivation was observed only for CYP1A2. Isoxanthohumol from hops was the most potent inhibitor of CYP2C8 with an IC 50 of 0.2 μM, whereas 8-Prenylnaringenin was the most potent inhibitor of CYP1A2, CYP2C9 and CYP2C19 with IC 50 values of 1.1 μM, 1.1 μM and 0.4 μM, respectively. Extracts of hops contain prenylated compounds such as the flavanones isoxanthohumol and 8-Prenylnaringenin and the chalcone xanthohumol that can inhibit CYP450s, especially the CYP2C family, which may affect the efficacy and safety of some CYP2C substrate drugs when co-administered.
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differential regulation of detoxification enzymes in hepatic and mammary tissue by hops humulus lupulus in vitro and in vivo
Molecular Nutrition & Food Research, 2013Co-Authors: Birgit M. Dietz, Guido F Pauli, Dejan Nikolic, Shaonong Chen, Jeffrey R. Anderson, Ghenet K Hagos, Jillian N Eskra, Gihani T Wijewickrama, Brian Wright, Richard B Van BreemenAbstract:Scope Hops contain the phytoestrogen, 8-Prenylnaringenin, and the cytoprotective compound, xanthohumol (XH). XH induces the detoxification enzyme, NAD(P)H-quinone oxidoreductase (NQO1) in vitro; however, the tissue distribution of XH and 8-Prenylnaringenin and their tissue-specific activity have not been analyzed. Methods and results An orally administered hop extract and subcutaneously injected XH were administered to Sprague–Dawley rats over 4 days. LC-MS-MS analysis of plasma, liver, and mammary gland revealed that XH accumulated in liver and mammary glands. Compared with the low level in the original extract, 8-Prenylnaringenin was enriched in the tissues. Hops and XH-induced NQO1 in the liver, while only hops reduced NQO1 activity in the mammary gland. Mechanistic studies revealed that hops modulated NQO1 through three mechanisms. In liver cells, (i) XH modified Kelch-like ECH-associated protein leading to nuclear factor (erythroid-derived 2)-like 2 (Nrf2) translocation and antioxidant response element (ARE) activation; (ii) hop-mediated ARE induction was partially mediated through phosphorylation of Nrf2 by PKC; (iii) in breast cells, 8-Prenylnaringenin reduced NQO1 likely through binding to estrogen receptorα, recruiting Nrf2, and downregulating ARE-regulated genes. Conclusion XH and 8-Prenylnaringenin in dietary hops are bioavailable to the target tissues. While hops and XH might be cytoprotective in the liver, 8-Prenylnaringenin seems responsible for hop-mediated NQO1 reduction in the mammary gland.
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in vivo estrogenic comparisons of trifolium pratense red clover humulus lupulus hops and the pure compounds isoxanthohumol and 8 prenylnaringenin
Chemico-Biological Interactions, 2008Co-Authors: Cassia R Overk, Lucas R Chadwick, Guido F Pauli, Shaonong Chen, Norman R Farnsworth, Daniel D Lantvit, Alberto Minassi, Giovanni Appendino, David C Lankin, Richard B Van BreemenAbstract:Abstract The lack of a safe and reliable alternative to hormone therapy (HT) for treating menopausal symptoms underscores the need for alternative therapies. Objective The purpose of this study was to assess the in vivo estrogenic effects of the botanical dietary supplements Trifolium pratense (red clover) and Humulus lupulus (hops), and two compounds obtained from H. lupulus, isoxanthohumol and 8-Prenylnaringenin (8-PN) using the ovariectomized uterotrophic adult rat model. A H. lupulus extract and a 30% isoflavone extract of T. pratense were tested at three escalating doses as was one dose of isoxanthohumol for 21 d. 8-Prenylnaringenin, the major estrogen in H. lupulus, was also tested at three relevant escalating doses. In order to determine the in vivo metabolism of 8-PN, the major phases I and II metabolites were also identified. The primary outcome measure, uterus weight gain, indicated that H. lupulus and T. pratense did not have an estrogenic effect on the uterus, and none of the secondary outcome measures were positive. In contrast, there was a clear dose response when 8-PN was evaluated where the middle and high doses of 8-PN were active. 8-Prenylnaringenin in rat plasma, liver, and mammary gland was measured and the major phases I and II 8-PN metabolites were detected. Our findings suggest that while both the H. lupulus and T. pratense extracts do not have an effect on the rat uterus, 8-PN at equivalent doses to those previously used in humans did have an effect, and may therefore have a deleterious effect in women.
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metabolism of xanthohumol and isoxanthohumol prenylated flavonoids from hops humulus lupulus l by human liver microsomes
Journal of Mass Spectrometry, 2005Co-Authors: Dejan Nikolic, Lucas R Chadwick, Guido F Pauli, Yongmei Li, Richard B Van BreemenAbstract:The female flowers of hops (Humulus lupulus L.) used to flavor beer contain the prenylated flavonoids xanthohumol (XN) and isoxanthohumol (IX). IX is moderately estrogenic in vitro and XN has pharmacological properties that might make it useful as a cancer chemopreventive agent. The metabolism of these dietary flavonoids was investigated in vitro using human liver microsomes. Hydroxylation of a prenyl methyl group was the primary route of oxidative metabolism forming either cis or trans hydroxylated metabolites of IX but only the trans isomer of XN. The double bond on the prenyl group of both compounds formed an epoxide which was opened by an intramolecular reaction with the neighboring hydroxyl group. The potent phytoestrogen 8-Prenylnaringenin (8-PN) was detected as a demethylation product of IX. However, the analogous demethylation reaction was not observed for XN. Since XN can be converted to IX through acid-catalyzed cyclization in the stomach, XN might contribute to the in vivo levels of estrogenic 8-PN following consumption of hops extracts. Copyright © 2005 John Wiley & Sons, Ltd.
Denis De Keukeleire - One of the best experts on this subject based on the ideXlab platform.
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eubacterium limosum activates isoxanthohumol from hops humulus lupulus l into the potent phytoestrogen 8 prenylnaringenin in vitro and in rat intestine
Journal of Nutrition, 2008Co-Authors: Sam Possemiers, Denis De Keukeleire, Arne Heyerick, Sylvie Rabot, Juan Carlos Espin, Aurelia Bruneau, Catherine Philippe, Antonio Gonzalezsarrias, Francisco A Tomasbarberan, Willy VerstraeteAbstract:: Recently, it was shown that the exposure to the potent hop phytoestrogen 8-Prenylnaringenin (8-PN) depends on intestinal bacterial activation of isoxanthohumol (IX), but this occurs in only one-third of tested individuals. As the butyrate-producing Eubacterium limosum can produce 8-PN from IX, a probiotic strategy was applied to investigate whether 8-PN production could be increased in low 8-PN producers, thus balancing phytoestrogen exposure. Using fecal samples from high (Hop +) and low (Hop -) 8-PN-producing individuals, a Hop + and Hop - dynamic intestinal model was developed. In parallel, Hop + and Hop - human microbiota-associated rats were developed, germ-free (GF) rats acting as negative controls. IX and then IX + E. limosum were administered in the intestinal model and to the rats, and changes in 8-PN production and exposure were assessed. After dosing IX, 80% was converted into 8-PN in the Hop + model and highest 8-PN production, plasma concentrations, and urinary and fecal excretion occurred in the Hop + rats. Administration of the bacterium triggered 8-PN production in the GF rats and increased 8-PN production in the Hop - model and Hop - rats. 8-PN excretion was similar in the feces (294.1 +/- 132.2 nmol/d) and urine (8.5 +/- 1.1 nmol/d ) of all rats (n = 18). In addition, butyrate production increased in all rats. In conclusion, intestinal microbiota determined 8-PN production and exposure after IX intake. Moreover, E. limosum administration increased 8-PN production in low producers, resulting in similar 8-PN production in all rats.
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treatment of pc 3 and du145 prostate cancer cells by prenylflavonoids from hop humulus lupulus l induces a caspase independent form of cell death
Phytotherapy Research, 2008Co-Authors: L Delmulle, Denis De Keukeleire, T Vanden Berghe, Peter VandenabeeleAbstract:Xanthohumol (X), isoxanthohumol (IX), 8-Prenylnaringenin (8PN) and 6-prenylnaringenin (6PN), prenylflavonoids from hop (Humulus lupulus L.), were investigated for their cytotoxicity and the mechanism by which they exert cell death when incubated with prostate cancer cell lines PC-3 and DU145. All compounds induced cell death in the absence of caspase-3 activation and typical apoptotic morphological features. The general pan-caspase inhibitor zVAD-fmk could not protect this form of cell death. In addition, the formation of vacuoles was observed in PC-3 cells treated with IX and 6PN, and in DU145 treated with IX, 8PN and 6PN, which could suggest the induction of autophagy and consequent cell death. The results indicate that hop-derived prenylflavanones (IX, 8PN, 6PN), but not prenylchalcones (X) induce a caspase-independent form of cell death, suggested to be autophagy. Therefore, IX, 8PN and 6PN appear to be promising candidates for further investigation in prostate anticancer therapy. Copyright © 2007 John Wiley & Sons, Ltd.
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treatment of pc 3 and du145 prostate cancer cells by prenylflavonoids from hop humulus lupulus l induces a caspase independent form of cell death
Phytotherapy Research, 2008Co-Authors: L Delmulle, Denis De Keukeleire, T Vanden Berghe, Peter VandenabeeleAbstract:Xanthohumol (X), isoxanthohumol (IX), 8-Prenylnaringenin (8PN) and 6-prenylnaringenin (6PN), prenylflavonoids from hop (Humulus lupulus L.), were investigated for their cytotoxicity and the mechanism by which they exert cell death when incubated with prostate cancer cell lines PC-3 and DU145. All compounds induced cell death in the absence of caspase-3 activation and typical apoptotic morphological features. The general pan-caspase inhibitor zVAD-fmk could not protect this form of cell death. In addition, the formation of vacuoles was observed in PC-3 cells treated with IX and 6PN, and in DU145 treated with IX, 8PN and 6PN, which could suggest the induction of autophagy and consequent cell death. The results indicate that hop-derived prenylflavanones (IX, 8PN, 6PN), but not prenylchalcones (X) induce a caspase-independent form of cell death, suggested to be autophagy. Therefore, IX, 8PN and 6PN appear to be promising candidates for further investigation in prostate anticancer therapy.
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anti proliferative properties of prenylated flavonoids from hops humulus lupulus l in human prostate cancer cell lines
Phytomedicine, 2006Co-Authors: L Delmulle, Arne Heyerick, Frederik Roelens, Willem Dhooge, Frank Comhaire, Akeila Bellahcene, Kevin Huvaere, Vincenzo Castronovo, Denis De KeukeleireAbstract:: Chalcones xanthohumol (X) and desmethylxanthohumol (DMX), present in hops (Humulus lupulus L.), and the corresponding flavanones isoxanthohumol (IX, from X), 8-Prenylnaringenin (8-PN, from DMX), and 6-prenylnaringenin (6-PN, from DMX), have been examined in vitro for their anti-proliferative activity on human prostate cancer cells PC-3 and DU145. X proved to be the most active compound in inhibiting the growth of the cell lines with IC50 values of 12.3+/-1.1 microM for DU145 and 13.2+/-1.1 microM for PC-3. 6-PN was the second most active growth inhibitor, particularly in PC-3 cells (IC50 of 18.4+/-1.2 microM). 8-PN, a highly potent phytoestrogen, exhibited pronounced anti-proliferative effects on PC-3 and DU145 (IC50 of 33.5+/-1.0 and 43.1+/-1.2 microM, respectively), and IX gave comparable activities (IC50 of 45.2+/-1.1 microM for PC-3 and 47.4+/-1.1 microM for DU145). DMX was the least active compound. It was evidenced for the first time that this family of prenylated flavonoids from hops effectively inhibits proliferation of prostate cancer cells in vitro.
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subtle side chain modifications of the hop phytoestrogen 8 prenylnaringenin result in distinct agonist antagonist activity profiles for estrogen receptors α and β
Journal of Medicinal Chemistry, 2006Co-Authors: Frederik Roelens, Nina Heldring, Willem Dhooge, Martin Bengtsson, Frank Comhaire, Janake Gustafsson, Eckardt Treuter, Denis De KeukeleireAbstract:In search of therapeutic agents for estrogen-related pathologies, phytoestrogens are being extensively explored. In contrast to naringenin, 8-Prenylnaringenin is a potent hop-derived estrogenic compound, highlighting the importance of the prenyl group for hormonal activity. We investigated the effects of substituting the prenyl group at C(8) with alkyl chains of varying lengths and branching patterns on estrogen receptor (ER) subtype ERα- and ERβ-binding affinities and transcriptional activities. In addition, features of the ligand-induced receptor conformations were explored using a set of specific ER-binding peptides. The new 8-alkylnaringenins were found to span an activity spectrum ranging from full agonism to partial agonism to antagonism. Most strikingly, 8-(2,2-dimethylpropyl)naringenin exhibited full agonist character on ERα, but pronounced antagonist character on ERβ. Knowledge on how ER-subtype-selective activities can be designed provides valuable information for future drug or tool compound di...
Lucas R Chadwick - One of the best experts on this subject based on the ideXlab platform.
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in vivo estrogenic comparisons of trifolium pratense red clover humulus lupulus hops and the pure compounds isoxanthohumol and 8 prenylnaringenin
Chemico-Biological Interactions, 2008Co-Authors: Cassia R Overk, Lucas R Chadwick, Guido F Pauli, Shaonong Chen, Norman R Farnsworth, Daniel D Lantvit, Alberto Minassi, Giovanni Appendino, David C Lankin, Richard B Van BreemenAbstract:Abstract The lack of a safe and reliable alternative to hormone therapy (HT) for treating menopausal symptoms underscores the need for alternative therapies. Objective The purpose of this study was to assess the in vivo estrogenic effects of the botanical dietary supplements Trifolium pratense (red clover) and Humulus lupulus (hops), and two compounds obtained from H. lupulus, isoxanthohumol and 8-Prenylnaringenin (8-PN) using the ovariectomized uterotrophic adult rat model. A H. lupulus extract and a 30% isoflavone extract of T. pratense were tested at three escalating doses as was one dose of isoxanthohumol for 21 d. 8-Prenylnaringenin, the major estrogen in H. lupulus, was also tested at three relevant escalating doses. In order to determine the in vivo metabolism of 8-PN, the major phases I and II metabolites were also identified. The primary outcome measure, uterus weight gain, indicated that H. lupulus and T. pratense did not have an estrogenic effect on the uterus, and none of the secondary outcome measures were positive. In contrast, there was a clear dose response when 8-PN was evaluated where the middle and high doses of 8-PN were active. 8-Prenylnaringenin in rat plasma, liver, and mammary gland was measured and the major phases I and II 8-PN metabolites were detected. Our findings suggest that while both the H. lupulus and T. pratense extracts do not have an effect on the rat uterus, 8-PN at equivalent doses to those previously used in humans did have an effect, and may therefore have a deleterious effect in women.
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identification of human hepatic cytochrome p450 enzymes involved in the metabolism of 8 prenylnaringenin and isoxanthohumol from hops humulus lupulus l
Drug Metabolism and Disposition, 2006Co-Authors: Dejan Nikolic, Lucas R Chadwick, Guido F PauliAbstract:The female flowers of hops ( Humulus lupulus L.) are used in the brewing of beer and are under investigation for use in dietary supplements for the management of menopausal symptoms in women. Hop extracts contain the weakly estrogenic compound isoxanthohumol (IX), proestrogenic xanthohumol, and the potent estrogen 8-Prenylnaringenin (8PN). Because IX can be metabolized in the human liver to form 8PN, the specific cytochrome P450 (P450) enzymes responsible for this O -demethylation reaction were identified. In addition, the enzymes that convert IX and 8PN to their most abundant metabolites were identified because these metabolic pathways might also affect the estrogenicity of hop preparations. Specifically, the P450 enzymes that catalyze the oxidation of the prenyl side chains of IX and 8PN into trans- or cis- alcohols were investigated. Human liver microsomes and monoclonal antibodies that inhibit specific P450 enzymes were used in combination with liquid chromatography/mass spectrometry to identify the enzymes responsible for these transformations. CYP2C19 was found to catalyze the formation of both cis- and trans- alcohols of the prenyl side chain of 8PN with K m values of 14.8 ± 3.2 and 16.6 ± 4.6 μM, respectively. CYP2C8 converted 8PN regioselectively to the trans -alcohol of the prenyl group with a K m of 3.7 ± 0.9 μM. Finally, CYP1A2 was found to catalyze the O -demethylation of IX to generate 8PN, with a K m value of 17.8 ± 3.7 μM. These results suggest that the estrogenicity of hop constituents in vivo will depend in part on metabolic conversion that may show individual variation.
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comparison of the in vitro estrogenic activities of compounds from hops humulus lupulus and red clover trifolium pratense
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Cassia R Overk, Lucas R Chadwick, Guido F Pauli, Dejan Nikolic, Ping Yao, Yongkai Sun, Muriel Cuendet, Yunfan Deng, A S Hedayat, Norman R FarnsworthAbstract:Because the prevailing form of hormone replacement therapy is associated with the development of cancer in breast and endometrial tissues, alternatives are needed for the management of menopausal symptoms. Formulations of Trifolium pratense L. (red clover) are being used to alleviate menopause-associated hot flashes but have shown mixed results in clinical trials. The strobiles of Humulus lupulus L. (hops) have been reported to contain the prenylflavanone, 8-Prenylnaringenin (8-PN), as the most estrogenic constituent, and this was confirmed using an estrogen receptor ligand screening assay utilizing ultrafiltration mass spectrometry. Extracts of hops and red clover and their individual constituents including 8-PN, 6-prenylnaringenin (6-PN), isoxanthohumol (IX), and xanthohumol (XN) from hops and daidzein, formononetin, biochanin A, and genistein from red clover were compared using a variety of in vitro estrogenic assays. The IC50 values for the estrogen receptor α and β binding assays were 15 and 27 μg/mL...
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metabolism of xanthohumol and isoxanthohumol prenylated flavonoids from hops humulus lupulus l by human liver microsomes
Journal of Mass Spectrometry, 2005Co-Authors: Dejan Nikolic, Lucas R Chadwick, Guido F Pauli, Richard B. Van BreemenAbstract:The female flowers of hops (Humulus lupulus L.) used to flavor beer contain the prenylated flavonoids xanthohumol (XN) and isoxanthohumol (IX). IX is moderately estrogenic in vitro and XN has pharmacological properties that might make it useful as a cancer chemopreventive agent. The metabolism of these dietary flavonoids was investigated in vitro using human liver microsomes. Hydroxylation of a prenyl methyl group was the primary route of oxidative metabolism forming either cis or trans hydroxylated metabolites of IX but only the trans isomer of XN. The double bond on the prenyl group of both compounds formed an epoxide which was opened by an intramolecular reaction with the neighboring hydroxyl group. The potent phytoestrogen 8-Prenylnaringenin (8-PN) was detected as a demethylation product of IX. However, the analogous demethylation reaction was not observed for XN. Since XN can be converted to IX through acid-catalyzed cyclization in the stomach, XN might contribute to the in vivo levels of estrogenic 8-PN following consumption of hops extracts.
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metabolism of xanthohumol and isoxanthohumol prenylated flavonoids from hops humulus lupulus l by human liver microsomes
Journal of Mass Spectrometry, 2005Co-Authors: Dejan Nikolic, Lucas R Chadwick, Guido F Pauli, Yongmei Li, Richard B Van BreemenAbstract:The female flowers of hops (Humulus lupulus L.) used to flavor beer contain the prenylated flavonoids xanthohumol (XN) and isoxanthohumol (IX). IX is moderately estrogenic in vitro and XN has pharmacological properties that might make it useful as a cancer chemopreventive agent. The metabolism of these dietary flavonoids was investigated in vitro using human liver microsomes. Hydroxylation of a prenyl methyl group was the primary route of oxidative metabolism forming either cis or trans hydroxylated metabolites of IX but only the trans isomer of XN. The double bond on the prenyl group of both compounds formed an epoxide which was opened by an intramolecular reaction with the neighboring hydroxyl group. The potent phytoestrogen 8-Prenylnaringenin (8-PN) was detected as a demethylation product of IX. However, the analogous demethylation reaction was not observed for XN. Since XN can be converted to IX through acid-catalyzed cyclization in the stomach, XN might contribute to the in vivo levels of estrogenic 8-PN following consumption of hops extracts. Copyright © 2005 John Wiley & Sons, Ltd.
