xanthohumol and lupulon

Beer is one of the earliest human inventions and globally the most consumed alcoholic beverage in terms of volume. In addition to water, the 'German Beer Purity Law', based on the Bavarian Beer Purity Law from 1516, allows only barley, hops, yeasts and water for beer brewing. The extracts of these ingredients, especially the hops, contain an abundance of polyphenols such as kaempferol, quercetin, tyrosol, ferulic acid, xanthohumol/isoxanthohumol/8-prenylnaringenin, α-bitter acids like humulone and β-bitter acids like lupulone. 8-prenylnaringenin is the most potent phytoestrogen known to date. These compounds have been shown to possess various anti-bacterial, anti-inflammatory, anti-oxidative, anti-angiogenic, anti-melanogenic, anti-osteoporotic and anti-carcinogenic effects. Epidemiological studies on the association between beer drinking and skin disease are limited while direct evidence of beer compounds in clinical application is lacking. Potential uses of these substances in dermatology may include treatment of atopic eczema, contact dermatitis, pigmentary disorders, skin infections, skin ageing, skin cancers and photoprotections, which require an optimization of the biostability and topical delivery of these compounds. Further studies are needed to determine the bioavailability of these compounds and their possible beneficial health effects when taken by moderate beer consumption.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Beer; Coumaric Acids; Cyclohexenes; Flavanones; Flavonoids; Humans; Kaempferols; Phenylethyl Alcohol; Phytoestrogens; Propiophenones; Quercetin; Skin; Skin Diseases; Terpenes; Xanthones

Bacterial biofilms pose a serious medical problem due to their significant resistance to antimicrobials, and staphylococci are recognized as the most frequent cause of biofilm-associated infections. The hop plant (Humulus lupulus L.) contains substances that have been determined to act as anti-infective agents against bacteria, mainly in planktonic form. Therefore, we decided to investigate the antibiofilm properties of H. lupulus L.-derived compounds (humulone, lupulone and xanthohumol) against a selected group of Staphylococcus spp., including methicillin-susceptible and resistant strains. All tested hop compounds were shown to possess antimicrobial properties against all tested staphylococci, both planktonic and biofilm-dwelling, with no significant difference between resistant and susceptible strains. All compounds lowered the number of bacterial cells released from the biofilm, with the strongest effect seen for lupulone, followed by xanthohumol. Moreover, lupulone and xanthohumol were not only able to penetrate the biofilm and reduce the number of bacteria within it, but their higher concentrations (∼60 μg/mL for xanthohumol and ∼125 μg/mL for lupulone) reduced the number of surviving bacterial cells to zero.

Topics: Anti-Bacterial Agents; Biofilms; Cell Line; Cell Survival; Cyclohexenes; Flavonoids; Humans; Humulus; Microbial Sensitivity Tests; Plant Extracts; Propiophenones; Staphylococcus; Terpenes

Hops and the components extracted from them are well known antibacterial agents used in beers and as food preservatives, in formulations for topical applications on their own or together with other antimicrobial agents, in hormone replacement therapy, as antioxidants, tumor development antagonists, and angiogenesis inhibitors. Their shortcomings: very low bioavailability, bitter taste, and susceptibility to oxidative decomposition have limited their applications. We propose nanosized chitosan, an inexpensive, readily available biopolymer with a broad spectrum of antibacterial activity, as carrier for lupulone (L) and xanthohumol (X), two components of hops. Chitosan nanoparticles (CNP) and chitosan-based nanocomposites encapsulating lupulone (CNL) and xanthohumol (CNX) were prepared by ionotropic gelation using sodium tripolyphosphate (TPP) as crosslinker. Different preparative ratios and conditions were investigated and the nanoparticles obtained were characterized by FTIR, colloidal titration, size, zeta potential, and antimicrobial activity. The kinetics of the release of L/X from composites was studied in vitro. All the nanoparticles were active against several Gram-positive, Gram-negative, and Candida strains. Synergistic interactions were observed in all cases, although hops are known mainly for their activity against Gram-positive bacteria. All nanoparticles showed good stability over several months.

Topics: Anti-Bacterial Agents; Antioxidants; Beer; Chitosan; Flavonoids; Food Preservatives; Humans; Humulus; Nanoparticles; Polyphosphates; Propiophenones; Spectroscopy, Fourier Transform Infrared; Terpenes

Anaerobic bacteria, such as Bacteroides fragilis or Clostridium perfringens, are part of indigenous human flora. However, Clostridium difficile represents also an important causative agent of nosocomial infectious antibiotic-associated diarrhoea. Treatment of C. difficile infection is problematic, making it imperative to search for new compounds with antimicrobial properties. Hops (Humulus lupulus L.) contain substances with antibacterial properties. We tested antimicrobial activity of purified hop constituents humulone, lupulone and xanthohumol against anaerobic bacteria. The antimicrobial activity was established against B. fragilis, C. perfringens and C. difficile strains according to standard testing protocols (CLSI, EUCAST), and the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were calculated. All C. difficile strains were toxigenic and clinically relevant, as they were isolated from patients with diarrhoea. Strongest antimicrobial effects were observed with xanthohumol showing MIC and MBC values of 15-107 μg/mL, which are close to those of conventional antibiotics in the strains of bacteria with increased resistance. Slightly higher MIC and MBC values were obtained with lupulone followed by higher values of humulone. Our study, thus, shows a potential of purified hop compounds, especially xanthohumol, as alternatives for treatment of infections caused by select anaerobic bacteria, namely nosocomial diarrhoea caused by resistant strains.

Topics: Anaerobiosis; Anti-Bacterial Agents; Bacteroides fragilis; Clostridioides difficile; Clostridium perfringens; Cross Infection; Cyclohexenes; Diarrhea; Enterocolitis, Pseudomembranous; Flavonoids; Humans; Humulus; Microbial Sensitivity Tests; Plant Extracts; Propiophenones; Symbiosis; Terpenes

Seven naturally derived components from hop plant (Humulus lupulus L.) extracts were tested for evaluation of biological activities affecting acne vulgaris. Five strains, Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus, Kocuria rhizophila and, Staphylococcus pyogenes, were selected as the main acne-causing bacteria. Hop extracts xanthohumol and the lupulones showed strong inhibitory activities against all of the strains. Although hydrogenated derivatives did not show the same level of activity, naturally occurring xanthohumol, humulones, and lupulones all showed moderate to strong anticollagenase inhibitory activities. Antioxidant capacity was also evaluated with seven different methods based on different reactive oxygen species. Xanthohumol showed the highest activity in total oxygen radical absorbance capacity as well as singlet oxygen absorbance capacity.

Topics: Acne Vulgaris; Actinobacteria; Anti-Bacterial Agents; Antioxidants; Bacteria; Biphenyl Compounds; Cyclohexenes; Flavonoids; Humans; Humulus; Matrix Metalloproteinase 1; Matrix Metalloproteinase 8; Matrix Metalloproteinase Inhibitors; Microbial Sensitivity Tests; Phytotherapy; Picrates; Plant Extracts; Propionibacterium acnes; Propiophenones; Staphylococcus; Terpenes

The research reported here deals with co-action of the hop (Humulus lupulus)-derived anti-bacterial compounds, lupulone and xanthohumol, with several antibiotics. Among the antibiotics investigated for their co-action, polymyxin B sulfate, tobramycin and ciprofloxacin had a positive co-action in inhibiting selected test bacteria. The disc/well-diffusion assay and the minimum inhibitory concentration test (MIC) were employed to determine co-action. Both Gram-positive and Gram-negative bacteria were used in the evaluation. There was some co-action against all Gram-positive bacteria tested. Surprisingly, there was some positive co-action even against certain Gram-negative bacteria but not against others. Particularly, there was no co-action against E.coli. An antibacterial cream with lupulone, neomycin and polymyxin B sulfate was prepared and showed co-action. Ideas for other practical applications of this effect are put forth. The mechanism of the synergistic effect is briefly discussed but no attempt was made to prove it experimentally.

Topics: Anti-Infective Agents; Bacteria; Ciprofloxacin; Cyclohexenes; Drug Combinations; Drug Synergism; Flavonoids; Humulus; Microbial Sensitivity Tests; Plant Extracts; Polymyxin B; Propiophenones; Terpenes; Tobramycin

The ethyl acetate soluble fraction of hops (Humulus lupulus) showed potent inhibitory activity on the production of nitric oxide (NO) induced by a combination of LPS and IFN-gamma. Four known prenylflavonoids (1-4) and a new prenylflavonoid (5), hulupinic acid (6), lupulone (7), and its six new derivatives (8-13) were isolated from the active fraction. The structures were determined on the basis of physiochemical properties and spectroscopic analysis. Their inhibitory activities on the production of NO in macrophage RAW 264.7 cells were examined.

Topics: Animals; Cells, Cultured; Enzyme Inhibitors; Flavonoids; Humulus; Interferon-gamma; Lipopolysaccharides; Macrophages; Mice; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nuclear Magnetic Resonance, Biomolecular; Phloroglucinol; Plants, Medicinal; Terpenes

Important secondary metabolites, present in hops (Humulus lupulus L.), include alpha-acids and beta-acids, which are essential for the brewing of beer, as well as the prenylated chalcones, desmethylxanthohumol, and xanthohumol, which exhibit interesting bioactive properties. Their formation and accumulation in five selected hop varieties, Wye Challenger, Wye Target, Golding, Admiral, and Whitbread Golding Variety, were quantitatively monitored by high-performance liquid chromatography using UV detection. All target compounds were present from the onset of flowering, not only in female hop cones but also in male inflorescences, albeit in low concentrations. During development from female inflorescences to cones, levels of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol gradually increased, while each hop variety exhibited individual accumulation rates. Furthermore, these compounds were present in leaves of fully grown hops as well. The study demonstrated that key compounds for flavor and potential beneficial health effects associated with beer not only reside in the glandular lupulin structures but also are distributed over various parts of the hop plant.

Topics: Beer; Chromatography, High Pressure Liquid; Cyclohexenes; Flavonoids; Humulus; Plant Extracts; Propiophenones; Terpenes