Bone resorption inhibitors from hop extract

In vitro effects and mechanisms of Humulus lupulus extract on bone marrow progenitor cells and endothelial cells

Osteoporosis is the most common metabolic bone disorder and is associated with a high incidence of fractures. Angiogenesis and adequate blood flow are important during bone repair and maintenance. Estrogens play a key role in bone formation, in the prevention of bone resorption and vasculature maintenance. Hormone replacement therapy (HRT) has been used with great benefits for bone fracture prevention but has been linked to the development of serious important side effects, including cancer and stroke. Phytoestrogens are an attractive alternative to HRT because their chemical structure is similar to estradiol but, they could behave as selective modulators: acting as antagonists of estrogen receptors in the breast and endometrium and as agonists in the vascular endothelium and bone. Hops contain a wide variety of phytoestrogens that have individually been shown to possess estrogenic activity by either blocking or mimicking. In this study we have to evaluate the in vitro effects and mechanisms of action of hops extracts on the osteogenic and adipogenic capacity of bone marrow progenitor cells (BMPCs), and the angiogenic potential of EA.hy926 endothelial cells. We show that hops extracts increase the proliferative capacity of BMPCs and promote their osteogenic differentiation while decreasing their pro-osteoclastogenic capacity; and that these effects are mediated by the MAPK pathway. Additionally, hops extracts prevent the adipogenic differentiation of BMPCs and promote endothelial cell activity, by mechanisms also partially mediated by MAPK.

The causal association between smoking, alcohol consumption and risk of upper urinary calculi: insights from a Mendelian randomization study

Background: The causal link between smoking, alcohol consumption, and upper urinary calculi remains uncertain in observational studies due to confounding factors. To uncover potential causal associations, we utilized two-sample univariable and multivariable Mendelian randomization (MR) methods. Methods: Five risk factors related to lifestyles (cigarettes per day, lifetime smoking index, smoking initiation, drinks per week and alcohol intake frequency) were chosen from the Genome-Wide Association Study (GWAS). Upper urinary calculi were obtained from the FinnGen and United Kingdom Biobank consortium. Inverse-variance-weighted (IVW) was mainly used to compute odds ratios (OR) and 95% confidence intervals (Cl). While diligently scrutinizing potential sources of heterogeneity and horizontal pleiotropy via the rigorous utilization of Cochran's Q test, the MR-PRESSO method, and MR-Egger. Results: The summary OR for upper urinary calculi was 0.6 (IVW 95% CI: 0.49-0.74; p = 1.31 × 10-06) per standard deviation decrease in drinks per week. Interestingly, the genetically predicted alcohol intake frequency was associated with a significantly increased risk upper urinary calculi (OR = 1.27; 95% CI: 1.11-1.45; p = 0.0005). Our study found no association between smoking initiation, the number of cigarettes per day, and the lifetime smoking index and the risk of upper urinary calculi. By adjusting for body mass index and education, estimates of drinks per week remained consistent in multivariate MR analyses, while alcohol intake frequency became non-significant. Conclusion: MR analysis showed that drinks per week was negatively associated with upper urinary calculi, whereas the effect of tobacco on upper urinary calculi was not significant and the detrimental effect of alcohol intake frequency on upper urinary calculi became non-significant after adjusting for BMI and education.

An Overview of Bioactive Phenolic Molecules and Antioxidant Properties of Beer: Emerging Trends

Beer is one of the oldest and most common beverages worldwide. The phenolic contents and antioxidant properties of beer are crucial factors in evaluating its nutritional quality. Special beers brewed with the addition of adjuncts are gaining in consumer preference, in response to demands for healthy food and new gustatory and olfactory stimuli. Many studies recently dealt with functional beers brewed with the addition of adjuncts. This review focuses on bioactive molecules, particularly the composition of phenolic compounds, and the antioxidant activity of beer. The current knowledge concerning the effect of the addition of adjuncts in the form of fruit, vegetables, herbs, and natural foods on the polyphenol content, antioxidant properties, and phenolic profile of beer is reviewed, with an outline of the emerging trends in brewing processes. Future studies need to complete the identification and characterization of the bioactive molecules in beer, as well as studying their absorption and metabolic fate in humans.

Preparation of Hop Estrogen-Active Material for Production of Food Supplements

In recent years, the interest in the health-promoting effects of hop prenylflavonoids, especially its estrogenic effects, has grown. Unfortunately, one of the most potent phytoestrogens identified so far, 8-prenylnaringenin, is only a minor component of hops, so its isolation from hop materials for the production of estrogenically active food supplements has proved to be problematic. The aim of this study was to optimize the conditions (e.g., temperature, the length of the process and the amount of the catalyst) to produce 8-prenylnaringenin-rich material by the magnesium oxide-catalyzed thermal isomerization of desmethylxanthohumol. Under these optimized conditions, the yield of 8-prenylnaringenin was 29 mg per 100 gDW of product, corresponding to a >70% increase in its content relative to the starting material. This process may be applied in the production of functional foods or food supplements rich in 8-prenylnaringenin, which may then be utilized in therapeutic agents to help alleviate the symptoms of menopausal disorders.

Pharmacological Properties of Allium cepa, Preclinical and Clinical Evidences; A Review

Onion or Allium cepa (A. cepa) is one of the most important condiment plants grown and consumed all over the world. This plant has various therapeutic effects attributed to its constituents, such as quercetin, thiosulphinates and phenolic acids. In the present article, various pharmacological and therapeutic effects of A. cepa were reviewed. Different online databases using keywords such as onion, A. cepa, therapeutic effects, and pharmacological effects until the end of December 2019 were searched for this purpose. Onion has been suggested to be effective in treating a broad range of disorders, including asthma, inflammatory disorders, dysentery, wounds, scars, keloids and pain. In addition, different studies have demonstrated that onion possesses numerous pharmacological properties, including anti-cancer, anti-diabetic and anti-platelet properties as well as the effect on bone, cardiovascular, gastrointestinal, nervous, respiratory, and urogenital systems effects such as anti-osteoporosis, anti-hypertensive, antispasmodic, anti-diarrheal, neuro-protective, anti-asthmatic and diuretic effects. The present review provides detailed the various pharmacological properties of onion and its constituents and possible underlying mechanisms. The results of multiple studies suggested the therapeutic effect of onion on a wide range of disorders.

Effects of the Non-Alcoholic Fraction of Beer on Abdominal Fat, Osteoporosis, and Body Hydration in Women

Several studies have shown that binge drinking of alcoholic beverages leads to non-desirable outcomes, which have become a serious threat to public health. However, the bioactive compounds in some alcohol-containing beverages might mitigate the negative effects of alcohol. In beer, the variety and concentration of bioactive compounds in the non-alcoholic fraction suggests that its consumption at moderate levels may not only be harmless but could also positively contribute to an improvement of certain physiological states and be also useful in the prevention of different chronic diseases. The present review focuses on the effects of non-alcoholic components of beer on abdominal fat, osteoporosis, and body hydration in women, conditions selected for their relevance to health and aging. Although beer drinking is commonly believed to cause abdominal fat deposition, the available literature indicates this outcome is inconsistent in women. Additionally, the non-alcoholic beer fraction might improve bone health in postmenopausal women, and the effects of beer on body hydration, although still unconfirmed seem promising. Most of the health benefits of beer are due to its bioactive compounds, mainly polyphenols, which are the most studied. As alcohol-free beer also contains these compounds, it may well offer a healthy alternative to beer consumers.

Beer and its non-alcoholic compounds in health and disease

Moderate alcohol consumption has been associated with beneficial effects on human health. Specifically, consumption of red wine and beer has shown a J-shape relation with many important diseases. While a role of ethanol cannot be excluded, the high content of polyphenols in both beverages has been proposed to contribute to these effects, with beer having the advantage over wine that it is lower in alcohol. In addition to ethanol, beer contains a wide variety of compounds with known medicinal potential such as kaempferol, quercetin, tyrosol and phenolic acids, and it is the main dietary source for the flavones xanthohumol and 8-prenylnaringenin, and bitter acids such as humulones and lupulones. Clinical and pre-clinical evidence for the protective effects of moderate beer consumption against cardiovascular disease and other diseases has been accumulating since the 1990s, and the non-alcoholic compounds of beer likely exert most of the observed beneficial effects. In this review, we summarize and discuss the effects of beer consumption in health and disease as well as the clinical potential of its non-alcoholic compounds which may be promising candidates for new therapies against common chronic diseases.

Xanthohumol prevents dextran sulfate sodium-induced colitis via inhibition of IKKβ/NF-κB signaling in mice

Xanthohumol (XN), a prenylated chalcone isolated from the hop plant, has been reported to exhibit multiple biological functions including anti-inflammation. However, the pharmacological function of XN on colitis remains unknown. In this study, we investigated the anti-inflammatory effect of synthesized XN and molecular mechanism on dextran sulfate sodium (DSS)-induced experimental colitis. XN attenuated the colitis symptoms along with the prevention of colonic lesions after DSS challenge. XN inhibited the production of pro-inflammatory cytokines, oxidative stress and cyclooxygenase-2 expression in DSS-treated mice. Moreover, XN inhibited the phosphorylation of IκBα, the nuclear translocation of NF-κB subunits and the transcriptional activity of NF-κB in vivo and in vitro. In contrast to XN, isoXN showed much less effects on the kinase activity of IKKβ and IκBα phosphorylation induced by XN in this study, suggesting that an electrophilic carbon center present in XN is critical for the anti-inflammation in colitis, especially inhibition of IKKβ/NF-κB signaling pathway. Consistently, our docking analysis revealed that XN could bind to the active site, presumably at the Cys99 of IKKβ. Taken together, these findings demonstrate a new function of XN to inhibit IKKβ/NF-κB signaling, suggesting XN could be the potential therapeutic agent for the prevention of colitis.

A standardized Humulus lupulus (L.) ethanol extract partially prevents ovariectomy-induced bone loss in the rat without induction of adverse effects in the uterus

BACKGROUND

Hops (Humulus lupulus (L.)) dietary supplements are of interest as herbal remedies to alleviate menopausal symptoms, such as hot flushes, depression and anxiety. So far, the evidence regarding estrogenic and related properties of hops preparations has been considered insufficient for a market authorization for menopausal indications.

PURPOSE

The study aims to investigate a chemically standardized hops extract regarding its safety in the uterus, as wells as its efficacy to prevent bone loss in the ovariectomized rat model.

STUDY DESIGN/METHODS

Female Wistar rats were ovariectomized and divided into a control group receiving phytoestrogen-free diet, a group treated with E₂benzoate (0.93 mg/kg body weight/d) and a group treated with the standardized hops extract (60 mg/kg body weight/d) for 8 weeks. Micro-computed tomography of the tibiae and vertebrae, as wells as histological changes in the uterus and tibia were analyzed.

RESULTS

Neither uterotrophic nor proliferative effects were observed in the endometrium in response to the oral 8-week administration of the hops extract. However, site-dependent skeletal effects were observed. The hops extract significantly decreased the number of osteoclasts in the tibial metaphysis and prevented reduction of the trabecular thickness that resulted from estradiol depletion. In contrast, the hops extract did not prevent the ovariectomy-induced micro-architectural changes in the lumbar vertebra. Certain parameters (e.g. thickness and number of trabeculae) were even found to be below the values determined in the ovariectomized control group.

CONCLUSION

Taken together, the results provide evidence for the safety of the standardized hops extract and point to a weak bone type-specific, protective effect on bone loss following estradiol depletion.

Phytoestrogens in Botanical Dietary Supplements: Implications for Cancer

Phytoestrogens are plant constituents that possess either estrogenic or antiestrogenic activity. Although their activities are weak as compared with human endogenous estrogens, the consumption of phytoestrogens may have clinically significant consequences. A number of botanicals, or the compounds contained therein, have been identified as putative estrogenic agents, but consensus in the biomedical community has been hampered by conflicting data from various in vitro and in vivo models of estrogenic activity. Phytoestrogens may serve as chemopreventive agents while at the same time being capable of promoting growth in estrogen receptor positive cancer cell lines. Furthermore, they may exert their estrogenic influence through receptor-dependent and/or receptor-independent mechanisms. These findings have led to speculation that phytoestrogen intake might be ill advised for patients at an increased risk for hormone-dependent cancers, cancer patients, or cancer survivors. This article will attempt to sort out discrepancies between various experimental models and establish whether certain herbs possess estrogenic activity. The review will focus on 5 popular botanical dietary supplements: Trifolium pratense (red clover), Cimicifuga racemosa (black cohosh), Humulus lupulus (hops), Angelica sinensis (dong quai), and Glycyrrhiza glabra (licorice). It will address their mechanisms of action, clinical evidence bases, and implications for use in cancer.

Biologically Active Compounds from Hops and Prospects for Their Use

Although female cones of the hop plant (Humulus lupulus) are known primarily as raw material supplying characteristic bitterness and aroma to beer, their equally significant health-promoting effects have been known to mankind for several thousand years and hop is a plant traditionally utilized in folk medicine. This paper summarizes the scientific knowledge on the effects of all 3 major groups of secondary metabolites of hops; polyphenols, essential oils, and resins. Because of their chemical diversity, it is no coincidence that these compounds exhibit a wide range of pharmacologically important properties. In addition to antioxidant, anti-inflammatory, and anticancer-related properties, particular attention is being paid to prenylflavonoids that occur almost exclusively in hops and are considered to be some of the most active phytoestrogens known. Hop oils and resins are well known for their sedative and other neuropharmacological properties, but in addition, these compounds exhibit antibacterial and antifungal effects. Recently, alpha bitter acids have been shown to block the development of a number of complex lifestyle diseases that are referred to by the collective name "metabolic syndrome." Information presented in this review confirms the significant potential for the use of hops in the pharmaceutical industry and provides an understanding of beer as a natural drink that, although moderately consumed, may become a source of many health-promoting compounds.

Pharmacological profile of xanthohumol, a prenylated flavonoid from hops (Humulus lupulus)

The female inflorescences of hops (Humulus lupulus L.), a well-known bittering agent used in the brewing industry, have long been used in traditional medicines. Xanthohumol (XN) is one of the bioactive substances contributing to its medical applications. Among foodstuffs XN is found primarily in beer and its natural occurrence is surveyed. In recent years, XN has received much attention for its biological effects. The present review describes the pharmacological aspects of XN and summarizes the most interesting findings obtained in the preclinical research related to this compound, including the pharmacological activity, the pharmacokinetics, and the safety of XN. Furthermore, the potential use of XN as a food additive considering its many positive biological effects is discussed.

Systematic review and meta-analysis of the effect of alcohol intake on the risk of urolithiasis including dose-response relationship

OBJECTIVE

We conducted a meta-analysis to quantitatively evaluate the correlation between alcohol consumption and the risk of urolithiasis by summarizing the results of published case-control and cohort studies and the potential dose-response association.

METHODS

A systematic literature search of articles up to February 2014 was conducted via PubMed, Web of Science, Cochrane Library, Scopus, EMBASE, the Chinese National Knowledge Infrastructure databases, and the references of the retrieved articles. Fixed- or random-effect models were used to summarize the estimates of odds ratio (OR) with 95% confidence interval (95% CI) for the highest versus the lowest consumption of alcohol. A dose-response meta-analysis was also conducted.

RESULTS

The pooled OR estimates indicated that alcohol consumption was associated with a decreased risk of urolithiasis (OR=0.683, 95% CI 0.577-0.808). In addition, the dose-response meta-analysis indicated that the rate of urolithiasis decreased by 10% for a 10 g/day increase in alcohol intake (OR=0.898, 95% CI 0.851-0.948). No evidence of publication bias was found by Begg's or Egger's test (p=0.130, p=0.130, respectively).

CONCLUSION

Our meta-analysis indicated that alcohol intake is associated with a decreased risk of urolithiasis.

Hop water extract inhibits double-stranded RNA-induced thymic stromal lymphopoietin release from human nasal epithelial cells

BACKGROUND

Thymic stromal lymphopoietin (TSLP) acts as a master switch for allergic inflammation and plays a key role in allergic diseases, including allergic rhinitis. Double-stranded RNA (dsRNA) recognized by Toll-like receptor 3 (TLR3) strongly activates TSLP release from human nasal epithelial cells (HNECs). Hop (Humulus lupulus L.) extracts have been shown to have potent pharmacologic effects on inflammation.

METHODS

To investigate whether a hop water extract (HWE) prevents TSLP release from HNECs, human telomerase reverse transcriptase (hTERT)-transfected HNECs, used as a model of normal HNECs, were pretreated with HWE before treatment with the TLR3 ligand Polyinosine-polycytidylic acid (poly[I:C]).

RESULTS

In the hTERT-transfected HNECs, treatment with HWE significantly reduced poly(I:C)-induced production and release of TSLP in a dose-dependent manner, as well as dexamethasone. Treatment with the protein kinase C (PKC) inhibitor GF109203X and NF-κB inhibitor IMD-0354 also reduced poly(I:C)-induced TSLP release from hTERT-transfected HNECs. Treatment with HWE efficiently prevented up-regulation of PKC activity by 12-O-tetradecanoyl phorbol-13-acetate but not NF-κB activity induced by IL-1β in hTERT-transfected HNECs.

CONCLUSION

Our results clearly indicated that HWE inhibited dsRNA-induced production and release of TSLP via a PKC signal pathway in HNECs and it may have potent preventive effects against allergic rhinitis.

Wine, beer, alcohol and polyphenols on cardiovascular disease and cancer

Since ancient times, people have attributed a variety of health benefits to moderate consumption of fermented beverages such as wine and beer, often without any scientific basis. There is evidence that excessive or binge alcohol consumption is associated with increased morbidity and mortality, as well as with work related and traffic accidents. On the contrary, at the moment, several epidemiological studies have suggested that moderate consumption of alcohol reduces overall mortality, mainly from coronary diseases. However, there are discrepancies regarding the specific effects of different types of beverages (wine, beer and spirits) on the cardiovascular system and cancer, and also whether the possible protective effects of alcoholic beverages are due to their alcoholic content (ethanol) or to their non-alcoholic components (mainly polyphenols). Epidemiological and clinical studies have pointed out that regular and moderate wine consumption (one to two glasses a day) is associated with decreased incidence of cardiovascular disease (CVD), hypertension, diabetes, and certain types of cancer, including colon, basal cell, ovarian, and prostate carcinoma. Moderate beer consumption has also been associated with these effects, but to a lesser degree, probably because of beer's lower phenolic content. These health benefits have mainly been attributed to an increase in antioxidant capacity, changes in lipid profiles, and the anti-inflammatory effects produced by these alcoholic beverages. This review summarizes the main protective effects on the cardiovascular system and cancer resulting from moderate wine and beer intake due mainly to their common components, alcohol and polyphenols.

Fruit and vegetable intake and bone mass in Chinese adolescents, young and postmenopausal women

OBJECTIVE

Previous studies showed an inconsistent association of fruit and vegetable consumption with bone health. We assessed the associations in Chinese adolescents, young and postmenopausal women.

DESIGN

A cross-sectional study conducted in China during July 2009 to May 2010.

SETTING

Bone mineral density (BMD) and content (BMC) at the whole body, lumbar spine and left hip were measured with dual-energy X-ray absorptiometry. Dietary intakes were assessed using an FFQ. All these values were separately standardized into Z-scores in each population subgroup.

SUBJECTS

One hundred and ten boys and 112 girls (11-14 years), 371 young women (20-34 years, postpartum within 2 weeks) and 333 postmenopausal women (50-70 years).

RESULTS

After adjustment for potential covariates, analysis of covariance showed a significantly positive association between fruit intake and BMD and BMC in all participants combined (P-trend: < 0.001 to 0.002). BMD Z-score increased by 0.25 (or 2.1 % of the mean), 0.22 (3.5 %), 0.23 (3.0 %) and 0.25 (3.5 %), and BMC Z-score increased by 0.33 (5.7 %), 0.25 (5.8 %), 0.34 (5.9 %) and 0.29 (4.7 %), at the total body, lumbar spine, total hip and femoral neck in participants belonging to the top tertile compared with the bottom tertile of fruit intake (all P < 0.05), respectively. There was no significant association between vegetable intake and bone mass at all bone sites studied except for total body BMD (P = 0.030). Relatively more pronounced effects were observed in boys and postmenopausal women.

CONCLUSION

Our findings add to the existing evidence that fruits and vegetables may have a bone sparing effect.

Xanthohumol induces apoptosis in human malignant glioblastoma cells by increasing reactive oxygen species and activating MAPK pathways

The effect of the biologically active prenylated chalcone and potential anticancer agent xanthohumol (1) has been investigated on apoptosis of the T98G human malignant glioblastoma cell line. Compound 1 decreased the viability of T98G cells by induction of apoptosis in a time- and concentration-dependent manner. Apoptosis induced by 1 was associated with activation of caspase-3, caspase-9, and PARP cleavage and was mediated by the mitochondrial pathway, as exemplified by mitochondrial depolarization, cytochrome c release, and downregulation of the antiapoptotic Bcl-2 protein. Xanthohumol induced intracellular reactive oxygen species (ROS), an effect that was reduced by pretreatment with the antioxidant N-acetyl-L-cysteine (NAC). Intracellular ROS production appeared essential for the activation of the mitochondrial pathway and induction of apoptosis after exposure to 1. Oxidative stress due to treatment with 1 was associated with MAPK activation, as determined by ERK1/2 and p38 phosphorylation. Phosphorylation of ERK1/2 and p38 was attenuated using NAC to inhibit ROS production. After treatment with 1, ROS provided a specific environment that resulted in MAPK-induced cell death, with this effect reduced by the ERK1/2 specific inhibitor PD98059 and partially inhibited by the p38 inhibitor SB203580. These findings suggest that xanthohumol (1) is a potential chemotherapeutic agent for the treatment of glioblastoma multiforme.

Preparative isolation and purification of xanthohumol from hops (Humulus lupulus L.) by high-speed counter-current chromatography

Xanthohumol (XN) and related prenylflavonoids are the main bioactive components of hops (Humulus lupulus L.). The current work is to investigate the use of high-speed counter-current chromatography (HSCCC) in search for high isolation of xanthohumol from hops. A solvent system consisted of n-hexane-ethyl acetate-methanol-water at a volume ratio of 5:5:4:3 was employed. The results demonstrated that the constructed method could be well applied for the isolation of xanthohumol from hops extract. After HSCCC isolation procedure, the purity of xanthohumol was over 95% assayed by HPLC and the yield of extraction was 93.60%. The chemical structure identification of xanthohumol was carried out by UV, (1)H NMR and (13)C NMR. The present results demonstrated that xanthohumol could be efficiently obtained using a single HSCCC step from H. lupulus L. extract.

The prenylflavonoid phytoestrogens 8-prenylnaringenin and isoxanthohumol diferentially suppress steroidogenesis in rat Leydig cells in ontogenesis

8-Prenylnaringenin and isoxanthohumol are prenylflavonoids found in the hop plant, Humulus lupulus (Cannabaceae), which is traditionally used to add bitterness and flavor to beer. Flavonoids have previously been reported to exert endocrine disrupting actions. Therefore, we investigated the effects of 8-prenylnaringenin and isoxanthohumol on steroidogenesis activated by human chorionic gonadotropin (hCG) in primary cultures of rat Leydig cells at different stages of their development. The present study is the first to demonstrate that the prenylflavonoids 8-prenylnaringenin and isoxanthohumol exert complex maturation-dependent effects on Leydig cell steroidogenesis. Those compounds inhibited hCG-stimulated androgen production by Leydig cells at all stages of their development, a process that was associated with the reduced ability of the cells to produce cAMP. However, these same compounds up-regulated hCG-activated StAR expression in progenitor (PLC) and immature (ILC) but not adult types of Leydig cells (ALC). Further, 8-prenylnaringenin and isoxanthohumol were not able to suppress androgen production activated by an exogenous analog of cAMP, (Bu)2 cAMP, in ALC and ILC but synergistically stimulated steroidogenesis in PLC. Our data suggest that 8-prenylnaringenin and isoxanthohumol affect cAMP-dependent cellular processes up-stream transport of cholesterol into mitochondria.

Transport of hop bitter acids across intestinal Caco-2 cell monolayers

Several health-beneficial properties of hop bitter acids have been reported (inhibition of bone resorption and anticarcinogenic and anti-inflammatory activities); however, scientific data on the bioavailability of these compounds are lacking. As a first approach to study the bioavailability, the epithelial transport of hop alpha- and beta-acids across Caco-2 monolayers was investigated. Hop acids were added either to the apical or to the basolateral chamber and, at various time points, amounts transported to the receiving compartment were determined. The monolayer integrity control was performed by using marker compounds (atenolol and propranolol), transepithelial electrical resistance (TEER) measurement, and determination of the fluorescein efflux. The TEER and fluorescein efflux confirmed the preservation of the monolayer integrity. The membrane permeability of the alpha-acids (apparent permeability coefficients for apical to basolateral transport (P(appAB)) ranged from 14 x 10(-6) to 41 x 10(-6) cm/s) was determined to be substantially higher than that of the beta-acids (P(appAB) values ranging from 0.9 x 10(-6) to 2.1 x 10(-6) cm/s). Notably, the beta-acids exhibited significantly different bidirectional P(app) values with efflux ratios around 10. The involvement of carrier-mediated transport for beta-acids (active efflux pathway by P-gp, BCRP, and/or MRP-2 type efflux pumps) could be confirmed by transport experiments with specific inhibitors (verapamil and indomethacin). It appears that alpha-acids are efficiently absorbed, whereas the permeability of beta-acids is low. Limiting factors in the absorption of beta-acids could involve P-gp and MRP-2 type efflux transporters and phase II metabolism.

Xanthohumol inhibits IL-12 production and reduces chronic allergic contact dermatitis

Xanthohumol (XN) and its related compounds were evaluated for their effects on modulating the production of interleukin (IL)-12, the most important factor driving T helper 1 immune responses. XN showed the strongest inhibitory effect on IL-12 production in macrophages stimulated by lipopolysaccharide (LPS) or LPS/interferon-gamma. Xanthohumol 4'-O-beta-D-glucopyranoside (XNG) inhibited IL-12 production less effectively than XN. Isoxanthohumol and 8-prenylnaringenin showed comparatively lower inhibitory effects on IL-12 production than XNG. (2S)-5-methoxy-8-prenylnaringenin 7-O-beta-D-glucopyranoside did not exert any effect on IL-12 production. We then tested how these compounds affected NF-kappaB binding activity to the kappaB site in the nucleus. The compounds inhibited kappaB binding in macrophages with the same potency order as IL-12 inhibition. Furthermore, we investigated whether XN, which showed the most effective reduction of IL-12 production, attenuated skin inflammation. Chronic allergic contact dermatitis, an experimental model for psoriasis, was used to determine the anti-inflammatory effects of XN in vivo. XN treatment reduced the degree of ear thickening induced by oxazolone. Taken together, XN might be effective as an anti-inflammatory agent to reduce skin inflammation by inhibiting IL-12 production.

Xanthohumol from hop (Humulus lupulus L.) is an efficient inhibitor of monocyte chemoattractant protein-1 and tumor necrosis factor-alpha release in LPS-stimulated RAW 264.7 mouse macrophages and U937 human monocytes

Activated macrophages in adipose tissue play a major role in the chronic inflammatory process that has been linked to the complications of overweight and obesity. The hop plant (Humulus lupulus L.) has been described to possess both anti-inflammatory and antidiabetic effects. In the present study, the chemical composition of a hop crude extract (HCE) was investigated by ultrahigh-performance liquid chromatography (UHPLC). Next, HCE and various fractions obtained by preparative HPLC were tested for their ability to inhibit production of two pro-inflammatory cytokines, monocyte chemoattractant protein-1 (MCP-1, CCL2) and tumor necrosis factor-alpha (TNF-alpha), which play crucial roles in the complications of obesity. The hop chalcone xanthohumol was found to be the most potent inhibitor of both cytokines in LPS-activated RAW 264.7 mouse macrophages and U937 human monocytes. Moreover, other constituents, namely, iso-alpha-acids, in combination with the beta-acid hulupone, showed a moderate but selective inhibitory activity only on MCP-1 release. These findings underscore the potential health effects of hop and support further optimization, selection, and use of this plant.

Hop (Humulus lupulus)-derived bitter acids as multipotent bioactive compounds

Hop acids, a family of bitter compounds derived from the hop plant (Humulus lupulus), have been reported to exert a wide range of effects, both in vitro and in vivo. They exhibit potential anticancer activity by inhibiting cell proliferation and angiogenesis, by inducing apoptosis, and by increasing the expression of cytochrome P450 detoxification enzymes. Furthermore, hop bitter acids are effective against inflammatory and metabolic disorders, which makes them challenging candidates for the treatment of diabetes mellitus, cardiovascular diseases, and metabolic syndrome. This review summarizes the current knowledge on hop bitter acids, including both phytochemical aspects, as well as the biological and pharmacological properties of these compounds.

Fundamentals and Health Benefits of Xanthohumol, a Natural Product Derived from Hops and Beer

In recent years, there has been a growing interest in phenolic compounds and their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. Xanthohumol, a prenylated chalcone from hops and beer, is among the phenolic compounds which have received the most attention in recent years. This compound has a range of interesting biological properties that may have therapeutic utility. Based on the health-promoting properties of xanthohumol, the production of a beer enriched in this substance would be of huge interest to the brewing industry, for the benefits this could bring to consumer's health. This paper reviews recent and important data with respect to the health benefits or biological activities of xanthohumol and beer. In addition, an overview of the chemistry and biotechnological aspects of xanthohumol is presented.

Effect of xanthohumol on melanogenesis in B16 melanoma cells

Xanthohumol (XH), the principal prenylflavonoid of the hop plant (Humulus lupulus L.), dose-dependently inhibited isobutylmethylxanthine (IBMX)-induced melanogenesis in B16 melanoma cells, with little cytotoxicity at the effective concentrations. Decreased melanin content was accompanied by reduced tyrosinase enzyme activity, protein and mRNA expression. The levels of tyrosinase-related protein 1 and 2 mRNAs were decreased by XH. XH also inhibited alpha-melanocyte stimulating hormone- or forskolin-induced increases in melanogenesis, suggesting an action on the cAMP-dependent melanogenic pathway. XH downregulated the protein and mRNA expression of microphthalmia-associated transcription factor (MITF), a master transcriptional regulator of key melanogenic enzymes. These results suggest that XH might act as a hypo-pigmenting agent through the downregulation of MITF in the cAMP-dependent melanogenic pathway.

Water solution of onion crude powder inhibits RANKL-induced osteoclastogenesis through ERK, p38 and NF-kappaB pathways

Onion powder has been reported to decrease the ovariectomy-induced bone resorption of rats. However, the molecular mechanism of onion powder on the bone cells has not been reported. Here, we report that water solution of onion crude powder decreases the osteoclastogenesis from co-cultures of bone marrow stromal cells and macrophage cells. Additionally, water solution of onion crude powder inhibits the RANKL-induced ERK, p38 and NF-kappaB activation in macrophages. In summary, our data showed that onion powder may benefit bone through an anti-resorption effect on the osteoclasts.

INTRODUCTION

A nutritional approach is important for both prevention and treatment of osteoporosis. Onion has been reported to decrease the ovariectomy-induced bone resorption. However, the functional effects of onion on the cultured osteoclasts and osteoblasts remain largely unknown. Here, we found that water solution of onion crude powder markedly inhibited the receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis through ERK, p38 and NF-kappaB pathways. Other studies were also designed to investigate the potential signaling pathways involved in onion-induced decrease in osteoclastogenesis.

METHODS

The osteoclastogenesis was examined using the TRAP staining method. The MAPKs and NF-kappaB pathways were measured using Western blot analysis. A transfection protocol was used to examine NF-kappaB activity.

RESULTS

Water solution of onion crude powder inhibited the RANKL plus M-CSF-induced osteoclastic differentiation from either bone marrow stromal cells or from RAW264.7 macrophage cells. Treatment of RAW264.7 macrophages with RANKL could induce the activation of ERK, p38 and NF-kappaB that was inhibited by water solution of onion crude powder. On the other hand, it did not affect the cell proliferation and differentiation of human cultured osteoblasts.

CONCLUSIONS

Our data suggest that water solution of onion crude powder inhibits osteoclastogenesis from co-cultures of bone marrow stromal cells and macrophage cells via attenuation of RANKL-induced ERK, p38 and NF-kappaB activation.

Modification of the cysteine residues in IkappaBalpha kinase and NF-kappaB (p65) by xanthohumol leads to suppression of NF-kappaB-regulated gene products and potentiation of apoptosis in leukemia cells

Xanthohumol (XN), a prenylated chalcone isolated from hop plant, exhibits anti-inflammatory, antiproliferative, and antiangiogenic properties through an undefined mechanism. Whether examined by intracellular esterase activity, phosphatidylserine externalization, DNA strand breaks, or caspase activation, we found that XN potentiated tumor necrosis factor-induced apoptosis in leukemia and myeloma cells. This enhancement of apoptosis correlated with down-regulation of nuclear factor-kappaB (NF-kappaB) survivin, bcl-xL, XIAP, cIAP1, cIAP2, cylin D1, and c-myc. XN down-regulated both constitutive and inducible NF-kappaB activation, inhibition of phosphorylation and degradation of IkappaBalpha, suppression of p65 nuclear translocation, and NF-kappaB-dependent reporter gene transcription. XN directly inhibited tumor necrosis factor-induced IkappaBalpha kinase (IKK) activation and a reducing agent abolished this inhibition, indicating the role of cysteine residue. XN had no effect on the IKK activity when cysteine residue 179 of IKK was mutated to alanine. XN also directly inhibited binding of p65 to DNA, a reducing agent reversed this effect, and mutation of cysteine residue 38 to serine of p65 abolished this effect. Thus, our results show that modification of cysteine residues of IKK and p65 by XN leads to inhibition of the NF-kappaB activation pathway, suppression of antiapoptotic gene products, and potentiation of apoptosis in leukemia cells.

Plant polyphenols and multidrug resistance: Effects of dietary flavonoids on drug transporters in Caco-2 and MDCKII-MDR1 cell transport models

The hypothesis tested was that specific flavonoids such as epicatechin gallate, epigallocatechin gallate, genistein, genistin, naringenin, naringin, quercetin and xanthohumol will modulate cellular uptake and permeability (P(e)) of multidrug-resistant substrates, cyclosporin A (CSA) and digoxin, across Caco-2 and MDCKII-MDR1 cell transport models. (3)H-CSA/(3)H-digoxin transport and uptake experiments were performed with and without co-exposure of the flavonoids. Aglycone flavonoids reduced the P(e) of CSA to a greater extent than glycosylated flavonoids with 30 microM xanthohumol producing the greatest effect (7.2 x 10(-6) to 6.6 x 10(-7) and 17.9 x 10(-6) to 4.02 x 10(-6) cm s(-1) in Caco-2 and MDCKII-MDR1 cells, respectively); while no measurable effects were seen with digoxin. Xanthohumol significantly demonstrated (1) saturable efflux, (2) increased uptake of (3)H-digoxin and (3) decreased uptake of (3)H-CSA in the Caco-2 cells. The transport data suggests that xanthohumol effects transport of CSA in a manner that is distinct from the digoxin efflux pathway and suggests that intestinal transport of these MDR1 substrates is more complex than previously reported.

Pharmacognostic and pharmacological profile of Humulus lupulus L

The present review describes the morphological, phytochemical and ethnopharmacological aspects of Humulus lupulus L. (Cannabinaceae) and summarizes the most interesting findings obtained in the preclinical and clinical research related to the plant. The female inflorescences of Humulus lupulus (hops), well-known as bittering agent in brewing industry, have long been used in traditional medicine mainly to treat sleep disturbances. However the sedative activity is still under investigation in order to recognize the active principles responsible for the neuropharmacological effects observed in laboratory animals, and their mechanism of action. Here we report the data from our experiments as well as those obtained from other researchers, focusing on the variability of the results. Other traditional applications of hops as stomachic, antibacterial and antifungal remedy have been supported by in vivo and/or in vitro investigations. In recent years some prenylated chalcones present in hops have received much attention for their biological effects: in particular, xanthohumol has been shown to exert cancer chemopreventive activity in in vitro experiments, while 8-prenylnaringenin has been characterized as one of the most potent phytoestrogens isolated until now. Nevertheless much additional work is needed to open up new biomedical application of these compounds.

Effects of isometric strength training followed by no exercise and Humulus lupulus L-enriched diet on bone metabolism in old female rats

We investigated in female rats the effects on bone metabolism of a prolonged no-training period, subsequent to an isometric exercise program, performed during young adulthood and those of a long-term consumption of Humulus lupulus L-enriched diet (genistein 1.92 and daidzein 1.24 mg/kg diet) combined or not with isometric training. Forty-eight rats (4 weeks old) were randomly divided into 4 groups: trained (C-Tr) or nontrained rats (C-NTr) fed with control diet and trained (H-Tr) or nontrained rats (H-NTr) fed with Humulus lupulus L-enriched diet. The diets lasted 100 weeks. Training was followed over a 25-week period. Bone parameters were measured at week 100. Our results showed that no significant difference was observed among the 4 groups in uterine relative weight, calcium (Ca) intake, fecal Ca, urinary Ca excretion, net Ca absorption, plasma Ca, and bone Ca content. Calcium balance was significantly enhanced in H-NTr rats in comparison with C-NTr and C-Tr rats. Isometric strength training led to a significant increase in total bone mineral density (BMD), diaphyseal BMD, and osteocalcin-deoxypyridinoline ratio in C-Tr rats compared with the other groups. The main findings of the present study indicate that in female rats, a 25-week isometric strength training performed during young adulthood followed by a prolonged no-training period increases BMD values and osteocalcin-deoxypyridinoline ratio, whereas long-term consumption of Humulus lupulus L-enriched diet does not improve bone parameters. It suggests that bone gains induced by exercise do not decrease immediately after cessation of training and also confirms the importance of the practice of physical activity during puberty and young adulthood to maximize the achieved peak bone density.