Isoxanthohumol

Exploring two types of prenylated bitter compounds from hop plant (Humulus lupulus L.) against alpha-glucosidase in vitro and in silico.[Pubmed:34543921]

Food Chem. 2021 Aug 30;370:130979.

Hops are abundant in natural bioactive compounds. In this work, nine prenylated bitter compounds from hop were evaluated for their inhibitory activity against alpha-glucosidase. As a result, four flavonoids and one phloroglucinol (lupulone, LP) outperformed acarbose in inhibiting alpha-glucosidase. Isoxanthohumol (IX) and LP with two types of structures were selected for inhibition mechanism studies by spectroscopic methods and molecular dynamics simulation (MD). Results showed that IX acted as noncompetitive inhibitor and bound to alpha-glucosidase in allosteric sites via hydrogen bonds, hydrophobic, van der Waals (vdW), and electrostatic force, whereas LP was uncompetitive inhibitor and bound to catalytic sites via hydrophobic and vdW interactions. Notably, the conformation around binding site of alpha-glucosidase formed stable alpha-helix and tightened after binding IX and LP, respectively, which helped to elucidate noncompetitive and uncompetitive inhibitory mechanisms. This work demonstrated that two types of prenylated bitter compounds are discrepant in their mechanisms of interaction with alpha-glucosidase.

Differences in the Levels of the Selected Phytoestrogens and Stable Isotopes in Organic vs. Conventional Hops and Beer.[Pubmed:34441615]

Foods. 2021 Aug 9;10(8). pii: foods10081839.

Xanthohumol (XN), Isoxanthohumol (IX) and 8-prenylnaringenin (8-PN) are important prenylflavonoids present in hops with potential beneficial properties. In this study, we examined differences in the content of XN, IX and 8-PN in hops and beer produced under organic and conventional production regimes. A An ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method for analysing XN, IX and 8-PN in hops and beer was developed and validated, with LOQ ranging from 0.5 to 10 ng/mL. Finally, we examined (15)N/(14)N and (12)C/(13)C isotope ratios in the hops and beer using isotope ratio mass spectrometry (IRMS). The results show no statistically significant difference in the content of the selected prenylflavonoids between organic and conventionally produced hops and beer-in the whole sample group, as well as between the matched pairs. Stable isotope analysis indicated that only delta(15)N values are statistically higher in organically produced hops and beer. However, the differentiation according to the type of production could not be made solely based on the delta(15)N signature, but it could be used to provide supporting evidence.

Moderate Consumption of Beer (with and without Ethanol) and Menopausal Symptoms: Results from a Parallel Clinical Trial in Postmenopausal Women.[Pubmed:34209273]

Nutrients. 2021 Jun 30;13(7). pii: nu13072278.

The menopausal transition can be a challenging period for women's health and a trigger of uncomfortable symptoms. Beer is the main food source of Isoxanthohumol, a precursor of 8-prenylnaringenin, the strongest phytoestrogen identified to date. As phytoestrogens are reported to reduce perimenopausal symptoms, we evaluated if a daily moderate consumption of beer with (AB) and without alcohol (NAB) could improve menopausal symptoms and modify cardiovascular risk factors. A total of 37 postmenopausal women were enrolled in a parallel controlled intervention trial and assigned to three study groups: 16 were administered AB (330 mL/day), 7 NAB (660 mL/day), and 14 were in the control group. After a 6-month follow-up of the 34 participants who finished the trial, both interventions (AB and NAB) significantly reduced the severity of the menopause-related symptoms (p-value AB vs. Control: 0.009; p-value NAB vs. Control: 0.033). Moreover, AB had a beneficial net effect on psychological menopausal discomforts compared to the control group. As the sex hormone profile did not differ significantly between the study groups, the effects of both types of beers (AB and NAB) are attributed to the non-alcoholic fraction of beer. Furthermore, moderate NAB consumption improved the lipid profile and decreased blood pressure in postmenopausal women.

Chemoprotective Effects of Xanthohumol against the Carcinogenic Mycotoxin Aflatoxin B1.[Pubmed:34207931]

Foods. 2021 Jun 9;10(6). pii: foods10061331.

The present study addresses the chemoprotective effects of xanthohumol (XN), a prenylated flavonoid found in the female inflorescences (hops) of the plant Humulus lupulus L., against the carcinogenic food contaminant aflatoxin B1 (AFB1). The chemical reactions of XN and its derivatives (Isoxanthohumol (IXN), 8-prenylnaringenin (8-PN), and 6-prenylnaringenin (6-PN)) with the AFB1 metabolite, aflatoxin B1 exo-8,9-epoxide (AFBO), were investigated in silico, by calculating activation free energies (DeltaG(double dagger)) at the Hartree-Fock level of theory in combination with the 6-311++G(d,p) basis set and two implicit solvation models. The chemoprotective effects of XN were investigated in vitro in the metabolically competent HepG2 cell line, analyzing its influence on AFB1-induced cytotoxicity using the MTS assay, genotoxicity using the comet and gammaH2AX assays, and cell cycle modulation using flow cytometry. Our results show that the DeltaG(double dagger) required for the reactions of XN and its derivatives with AFBO are comparable to the DeltaG(double dagger) required for the reaction of AFBO with guanine, indicating that XN, IXN, 8-PN, and 6-PN could act as scavengers of AFBO, preventing DNA adduct formation and DNA damage induction. This was also reflected in the results from the in vitro experiments, where a reduction in AFB1-induced cytotoxicity and DNA single-strand and double-strand breaks was observed in cells exposed to combinations of AFB1 and XN, highlighting the chemoprotective effects of this phytochemical.

Properties of Dry Hopped Dark Beers with High Xanthohumol Content.[Pubmed:34064972]

Antioxidants (Basel). 2021 May 11;10(5). pii: antiox10050763.

The antioxidant activity of beers comes mainly from phenolic compounds and melanoidins. The aim of this research was to evaluate the effect of technological operations, especially the ethanol fermentation process using top fermentation brewer's yeast Saccharomyces cerevisiae, on the antioxidant activity of dark dry hopped beers with a high xanthohumol content. Four beers were produced using different varieties of hops. The polyphenol content during beer processing increased at the stage of hopping and fermentation, while it decreased during aging. The ability to reduce iron ions increased for all beers compared to hopped wort. The opposite tendency was noted for the antioxidant capacity expressed as the ability to reduce the radical cation ABTS(*+) generated from 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid). Fermentation and aging caused a decrease in beer color intensity. The content of 5-hydroxymethylfurfural (5-HMF) increased with the color intensity of wort, therefore in beers no presence of 5-HMF was observed. The beers were characterized by a distinctly high content of xanthohumol in the range of 1.77-3.83 mg/L and 0.85-1.19 mg/L of Isoxanthohumol. The content of prenylflavonoids and bitterness of beer depended on the variety of hops used.

Molecular Evidence of Compound Kushen Injection Against Lung Cancer: A Network Pharmacology-Based Investigation from Western Medicine to Traditional Medicine.[Pubmed:33573576]

Anticancer Agents Med Chem. 2021;21(15):2012-2022.

BACKGROUND: Compound Kushen Injection (CKI) is used clinically for relieving cancer pain and treating various solid tumors, particularly lung cancer. However, the underlying mechanisms of CKI in lung cancer remain to be further elucidated. OBJECTIVE: This study aimed to obtain evidence regarding the potential efficacy of the active compounds and therapeutic targets of CKI at a molecular level by using Network Pharmacology (NP), which is an emerging technique for dealing with complex systems, such as those of herbal medicine. METHODS: The chemical and predicted target information of CKI was obtained from databases and computational prediction, respectively; lung-cancer drugs and their corresponding targets were retrieved from Drugbank and Drugcentral. The online tool, STRING, was used to gather target-pathway interactions for establishing a target-(pathway)-target network to identify the target group that was most relevant to cancer. Based on this module, a protein-protein interaction network was established for identifying the potential therapeutic targets and the potential active ingredients. RESULTS: CKI might affect lung cancer drug targets or their neighbor nodes to trigger anti-cancer effects. The compounds that were predicted to bind to the potential therapeutic targets were recommended as potential active ingredients of CKI, which included naringenin from Baituling, and kurarinone and Isoxanthohumol from Kushen. CONCLUSION: This NP-based study might provide insights into understanding CKI from the perspective of modern science with reference to approved Western medicine for lung cancer. Moreover, network-based methods could also be further used with distinct advantages in dealing with complex information and systems of medicine.

Stable Isotope Dilution Analysis of the Major Prenylated Flavonoids Found in Beer, Hop Tea, and Hops.[Pubmed:33385009]

Front Nutr. 2020 Dec 15;7:619921.

Prenylated flavonoids from hops (Humulus lupulus) have become of interest in recent years due to a range of bioactivities. The potential health benefits of prenylated flavonoids include anti-cancerous activities and treatment of the metabolic syndrome among others. Since prenylated flavonoids from hops have shown pharmaceutical potential in clinical trials, robust analytical methods to determine their concentrations in food, supplements, and beverages are required. One such, the gold standard of analytical methods, is stable isotope dilution analysis due to its ability to compensate matrix effects and losses during sample work-up. As no commercial standards were available, the synthesis of seven different prenylated flavonoid isotopes utilizing various strategies (microwave assistance, acid base catalyst in the presence of deuterated substance and lastly, the use of Strykers catalyst) is described. The produced prenylated flavonoid isotopes were then applied in the first stable isotope dilution analysis method that quantified six natural prenylated flavonoids (Isoxanthohumol, Isoxanthohumol-C, 8-Prenylnaringenin, 6- Prenylnaringenin, Xanthohumol, and Xanthohumol-C) in beer, hop tea and hops to prove its applicability. The SIDA-LC-MS/MS method was validated resulting in LODs and LOQs for all analytes between 0.04 and 3.2 mug/L. Moreover, due to the simple clean-up the developed method allows the prospect for measuring clinical samples in the future.

Alcoholic and Non-Alcoholic Beer Modulate Plasma and Macrophage microRNAs Differently in a Pilot Intervention in Humans with Cardiovascular Risk.[Pubmed:33379359]

Nutrients. 2020 Dec 28;13(1). pii: nu13010069.

Beer is a popular beverage and some beneficial effects have been attributed to its moderate consumption. We carried out a pilot study to test if beer and non-alcoholic beer consumption modify the levels of a panel of 53 cardiometabolic microRNAs in plasma and macrophages. Seven non-smoker men aged 30-65 with high cardiovascular risk were recruited for a non-randomised cross-over intervention consisting of the ingestion of 500 mL/day of beer or non-alcoholic beer for 14 days with a 7-day washout period between interventions. Plasma and urine Isoxanthohumol were measured to assess compliance with interventions. Monocytes were isolated and differentiated into macrophages, and plasma and macrophage microRNAs were analysed by quantitative real-time PCR. Anthropometric, biochemistry and dietary parameters were also measured. We found an increase in plasma miR-155-5p, miR-328-3p, and miR-92a-3p after beer and a decrease after non-alcoholic beer consumption. Plasma miR-320a-3p levels decreased with both beers. Circulating miR-320a-3p levels correlated with LDL-cholesterol. We found that miR-17-5p, miR-20a-5p, miR-145-5p, miR-26b-5p, and miR-223-3p macrophage levels increased after beer and decreased after non-alcoholic beer consumption. Functional analyses suggested that modulated microRNAs were involved in catabolism, nutrient sensing, Toll-like receptors signalling and inflammation. We concluded that beer and non-alcoholic beer intake modulated differentially plasma and macrophage microRNAs. Specifically, microRNAs related to inflammation increased after beer consumption and decreased after non-alcoholic beer consumption.

Prevention of Fine Dust-Induced Vascular Senescence by Humulus lupulus Extract and Its Major Bioactive Compounds.[Pubmed:33297587]

Antioxidants (Basel). 2020 Dec 7;9(12). pii: antiox9121243.

Both short- and long-term exposure to fine dust (FD) from air pollution has been linked to various cardiovascular diseases (CVDs). Endothelial cell (EC) senescence is an important risk factor for CVDs, and recent evidence suggests that FD-induced premature EC senescence increases oxidative stress levels. Hop plant (Humulus lupulus) is a very rich source of polyphenols known to have nutritional and therapeutic properties, including antioxidant behavior. The aims of this study were to evaluate whether Humulus lupulus extract prevents FD-induced vascular senescence and dysfunction and, if so, to characterize the underlying mechanisms and active components. Porcine coronary arteries and endothelial cells were treated with FD in the presence or absence of hop extract (HOP), and the senescence-associated-beta galactosidase (SA-beta-gal) activity, cell-cycle progression, expression of senescence markers, oxidative stress level, and vascular function were evaluated. Results indicated that HOP inhibited FD-induced SA-beta-gal activity, cell-cycle arrest, and oxidative stress, suggesting that HOP prevents premature induction of senescence by FD. HOP also ameliorated FD-induced vascular dysfunction. Additionally, xanthohumol (XN) and Isoxanthohumol (IX) were found to produce the protective effects of HOP. Treatment with HOP and its primary active components XN and IX downregulated the expression of p22(ph)(o)(x), p53, and angiotensin type 1 receptor, which all are known FD-induced redox-sensitive EC senescence inducers. Taken together, HOP and its active components protect against FD-induced endothelial senescence most likely via antioxidant activity and may be a potential therapeutic agent for preventing and/or treating air-pollution-associated CVDs.

Humulone Modulation of GABAA Receptors and Its Role in Hops Sleep-Promoting Activity.[Pubmed:33177986]

Front Neurosci. 2020 Oct 14;14:594708.

Humulus lupulus L. (hops) is a major constituent of beer. It exhibits neuroactive properties that make it useful as a sleeping aid. These effects are hypothesized to be mediated by an increase in GABAA receptor function. In the quest to uncover the constituents responsible for the sedative and hypnotic properties of hops, recent evidence revealed that humulone, a prenylated phloroglucinol derivative comprising 35-70% of hops alpha acids, may act as a positive modulator of GABAA receptors at low micromolar concentrations. This raises the question whether humulone plays a key role in hops pharmacological activity and potentially interacts with other modulators such as ethanol, bringing further enhancement in GABAA receptor-mediated effects of beer. Here we assessed electrophysiologically the positive modulatory activity of humulone on recombinant GABAA receptors expressed in HEK293 cells. We then examined humulone interactions with other active hops compounds and ethanol on GABA-induced displacement of [(3)H]EBOB binding to native GABAA receptors in rat brain membranes. Using BALB/c mice, we assessed humulone's hypnotic behavior with pentobarbital- and ethanol-induced sleep as well as sedation in spontaneous locomotion with open field test. We demonstrated for the first time that humulone potentiates GABA-induced currents in alpha1beta3gamma2 receptors. In radioligand binding to native GABAA receptors, the inclusion of ethanol enhanced humulone modulation of GABA-induced displacement of [(3)H]EBOB binding in rat forebrain and cerebellum as it produced a leftward shift in [(3)H]EBOB displacement curves. Moreover, the additive modulatory effects between humulone, Isoxanthohumol and 6-prenylnaringenin were evident and corresponded to the sum of [(3)H]EBOB displacement by each compound individually. In behavioral tests, humulone shortened sleep onset and increased the duration of sleep induced by pentobarbital and decreased the spontaneous locomotion in open field at 20 mg/kg (i.p.). Despite the absence of humulone effects on ethanol-induced sleep onset, sleep duration was increased dose-dependently down to 10 mg/kg (i.p.). Our findings confirmed humulone's positive allosteric modulation of GABAA receptor function and displayed its sedative and hypnotic behavior. Humulone modulation can be potentially enhanced by ethanol and hops modulators suggesting a probable enhancement in the intoxicating effects of ethanol in hops-enriched beer.

Anti-obesity effect of a hop-derived prenylflavonoid isoxanthohumol in a high-fat diet-induced obese mouse model.[Pubmed:32775137]

Biosci Microbiota Food Health. 2020;39(3):175-182.

We examined whether oral administration of a hop-derived prenylflavonoid Isoxanthohumol (IX) would show anti-obesity activity and the underlying mechanism of the potential activity using a high-fat diet (HFD)-induced obese mouse model. Oral administration of 180 mg/kg IX for 8 weeks suppressed HFD-induced accumulation of visceral fat and body weight gain in mice. Simultaneously, IX changed the composition of the microbiome, as determined by a significant increase in the relative abundances of Akkermansia muciniphila, Blautia, and Escherichia coli. A. muciniphila accounted for 23% and 24% of the total microbiome in the HFD+60 mg/kg and 180 mg/kg IX groups, respectively, while it was undetectable in the normal diet (ND) and HFD groups. Similarly, Blautia accounted for 8% and 10% of the total microbiome in the HFD+60 mg/kg and 180 mg/kg IX groups, respectively, while it accounted for less than 1% in the ND and HFD groups. In contrast, a significant decrease in the relative abundance of Oscillospira was observed in the HFD+60 mg/kg and 180 mg/kg IX groups compared with the HFD group. We further examined the anti-obesity effect of IX using a germ-free (GF) mouse model to clarify the relationship between the microbiome and the effect of IX. IX showed no significant anti-obesity effect on fat accumulation and weight gain in GF mice. These results suggest that the anti-obesity effect of IX may involve microbial changes.

Isoxanthohumol, a hop-derived flavonoid, alters the metabolomics profile of mouse feces.[Pubmed:32775127]

Biosci Microbiota Food Health. 2020;39(3):100-108.

The aim of this study was to verify the effect of treatment with Isoxanthohumol (IX) on the metabolomics profile of mouse feces to explore the host-intestinal bacterial interactions at the molecular level. The fecal contents of several amino acids in the high-fat diet (HFD) + 0.1% IX group (treated with IX mixed in diets for 12 weeks) were significantly lower than in the HFD group. The fecal contents of the secondary bile acid deoxycholic acid (DCA) in the HFD + 180 mg/kg IX group (orally treated with IX for 8 weeks) were significantly lower than in the HFD group; the values in the HFD group were higher than those in the normal diet (ND) group. Administration of IX changed the fecal metabolomics profile. For some metabolites, IX normalized HFD-induced fluctuations.

Metabolism of different dietary phenolic compounds by the urolithin-producing human-gut bacteria Gordonibacter urolithinfaciens and Ellagibacter isourolithinifaciens.[Pubmed:32716447]

Food Funct. 2020 Aug 1;11(8):7012-7022.

Gordonibacter urolithinfaciens and Ellagibacter isourolithinifaciens are two human gut bacterial species that convert ellagic acid into urolithins. Urolithins are bioactive postbiotics produced by dehydroxylation reactions catalyzed by different catechol-dehydroxylases. The metabolic ability of these anaerobic bacteria on other dietary-phenolic compounds is unknown. In the present study, we evaluated the metabolism of flavonoids (quercetin, hesperetin, hesperidin, nobiletin, catechin, Isoxanthohumol), isoflavonoids (daidzein), coumarins (esculetin, umbelliferone, scoparone), phenylpropanoids [caffeic acid; 3-(3',4'-dihydroxyphenyl)propanoic acid (dihydrocaffeic acid); rosmarinic acid, and chlorogenic acid], benzoic acid derivatives (gallic acid, ellagic acid), lignans (secoisolariciresinol diglucoside), stilbenes (resveratrol), and secoiridoids (oleuropein) by G. urolithinfaciens DSM 27213(T) and E. isourolithinifaciens DSM 104140(T). Both strains metabolized ellagic acid leading to the characteristic urolithins. They also metabolized caffeic, dihydrocaffeic, rosmarinic, and chlorogenic acids. The rest of the phenolic compounds were not transformed. Catechol dehydroxylation and double bond reduction were prominent transformations observed during the incubations. The enzymatic activities seem to have a narrow substrate scope as many catechol- (quercetin, catechin, esculetin, gallic acid) and double bond-containing (resveratrol, esculetin, scoparone, umbelliferone) phenolics were not metabolized. The catechol-dehydroxylase activity was more efficient in E. isourolithinifaciens, while the reductase activity was more relevant in G. urolithinfaciens.

Beer Phenolic Composition of Simple Phenols, Prenylated Flavonoids and Alkylresorcinols.[Pubmed:32498371]

Molecules. 2020 Jun 2;25(11). pii: molecules25112582.

Beer is a fermented beverage with beneficial phenolic compounds and is widely consumed worldwide. The current study aimed to describe the content of three families of phenolic compounds with relevant biological activities: prenylated flavonoids (from hops), simple phenolic alcohols (from fermentation) and alkylresorcinols (from cereals) in a large sample of beers (n = 45). The prenylated flavonoids analyzed were xanthohumol, Isoxanthohumol, 6- and 8-prenylnaringenin. The total prenylated flavonoids present in beer ranged from 0.0 to 9.5 mg/L. The simple phenolic alcohols analyzed were tyrosol and hydroxytyrosol, ranging from 0.2 to 44.4 and 0.0 to 0.1 mg/L, respectively. Our study describes, for the first time, the presence of low amounts of alkylresorcinols in beer, in concentrations ranging from 0.02 to 11.0 microg/L. The results in non-alcoholic beer and the differences observed in the phenolic composition among different beer types and styles highlight the importance of the starting materials and the brewing process (especially fermentation) on the final phenolic composition of beer. In conclusion, beer represents a source of phenolic compounds in the diet that could act synergistically, triggering beneficial health effects in the context of its moderate consumption.

Exploration of isoxanthohumol bioconversion from spent hops into 8-prenylnaringenin using resting cells of Eubacterium limosum.[Pubmed:32333233]

AMB Express. 2020 Apr 24;10(1):79.

Hops is an almost unique source of the potent phytoestrogen 8-prenylnaringenin (8-PN). As hops contain only low levels of 8-PN, synthesis may be more attractive than extraction. A strain of the Gram-positive Eubacterium limosum was isolated previously for 8-PN production from more abundant precursor Isoxanthohumol (IX) from hops. In this study, spent hops, an industrial side stream from the beer industry, was identified as interesting source of IX. Yet, hop-derived compounds are well-known antibacterial agents and the traces of a large variety of different compounds in spent hops interfered with growth and IX conversion. Critical factors to finally enable bacterial 8-PN production from spent hops, using a food and feed grade medium, were evaluated in this research. The use of bacterial resting cells and complex medium at a pH of 7.8-8 best fulfilled the requirements for 8-PN production and generated a solid basis for development of an economic process.