The Oral Bioavailability of 8-Prenylnaringenin from Hops (Humulus Lupulus L.) in Healthy Women and Men is Significantly Higher than that of its Positional Isomer 6-Prenylnaringenin in a Randomized Crossover Trial

Chemistry, bioactivities, structure-activity relationship, biosynthesis and metabolism of prenylated flavonoids in Moraceae plants

Plants from Moraceae are globally popular as they represent a valuable resource with wide applications in food, health-care products, and other fields. Prenylated flavonoids are important active components in Moraceae. These compounds share a flavonoid skeleton with prenylated side chain, mostly in the form of single or multiple isoprenyl substituents and benzodimethylfuran structures. So far, nearly 400 prenylated flavonoids have been found in Moraceae, especially a large number of Diels-Alder adducts, which are characteristic components of this family. Due to their distinctive structures, diverse pharmacological properties and interesting synthesis processes, these compounds have attracted considerable attention from scientists. Herein, we review the advances in the structural characteristics, bioactivities, structure-activity relationships, biosynthesis strategies and in vivo metabolism of prenylated flavonoids in Moraceae plants, aiming at strengthening research efforts and utilization toward the great untapped potential of these unique constituents in human health.

(Poly)phenol-related gut metabotypes and human health: an update

Dietary (poly)phenols have received great interest due to their potential role in the prevention and management of non-communicable diseases. In recent years, a high inter-individual variability in the biological response to (poly)phenols has been demonstrated, which could be related to the high variability in (poly)phenol gut microbial metabolism existing within individuals. An interplay between (poly)phenols and the gut microbiota exists, with (poly)phenols being metabolised by the gut microbiota and their metabolites modulating gut microbiota diversity and composition. A number of (poly)phenol metabolising phenotypes or metabotypes have been proposed, however, potential metabotypes for most (poly)phenols have not been investigated, and the relationship between metabotypes and human health remains ambiguous. This review presents updated knowledge on the reciprocal interaction between (poly)phenols and the gut microbiome, associated gut metabotypes, and subsequent impact on human health.

Compounds derived from Humulus lupulus inhibit SARS-CoV-2 papain-like protease and virus replication

BACKGROUND

Selected natural compounds exhibit very good antiviral properties. Especially, the medicinal plant Humulus lupulus (hop) contains several secondary plant metabolites some of which have previously shown antiviral activities. Among them, the prenylated chalcone xanthohumol (XN) demonstrated to be a potent inhibitor of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (Mpro).

HYPOTHESIS/PURPOSE

Following the finding that xanthohumol (XN) is a potent inhibitor of SARS-CoV-2 Mpro, the effect of XN and its major derivatives isoxanthohumol (IXN), 6-prenylnaringenin (6-PN), and 8-prenylnaringenin (8-PN) from hops on SARS-CoV-2 papain-like protease (PLpro) were investigated.

STUDY DESIGN

The modulatory effect of the hop compounds on PLpro were studied first in silico and then in vitro. In addition, the actual effect of hop compounds on the replication of SARS-CoV-2 in host cells was investigated.

METHODS

In silico docking analysis was used to predict the binding affinity of hop compounds to the active site of PLpro. A recombinant PLpro was cloned, purified, characterized, and analyzed by small-angle X-ray scattering (SAXS), deISGylation assays, and kinetic analyses. Antiviral activity of hop compounds was assessed using the fluorescently labeled wildtype SARS-CoV-2 (icSARS-CoV-2-mNG) in Caco-2 host cells.

RESULTS

Our in silico docking suggests that the purified hop compounds bind to the active site of SARS-CoV-2 PLpro blocking the access of its natural substrates. The hop-derived compounds inhibit SARS-CoV-2 PLpro with half maximal inhibitory concentration (IC50) values in the range of 59-162 µM. Furthermore, we demonstrate that XN and 6-PN, in particular, impede viral replication with IC50 values of 3.3 µM and 7.3 µM, respectively.

CONCLUSION

In addition to the already known inhibition of Mpro by XN, our results show, for the first time, that hop-derived compounds target also SARS-CoV-2 PLpro which is a promising therapeutic target as it contributes to both viral replication and modulation of the immune system. These findings support the possibility to develop new hop-derived antiviral drugs targeting human coronaviruses.

Modulation of the replication of positive-sense RNA viruses by the natural plant metabolite xanthohumol and its derivatives

The COVID-19 pandemic has highlighted the importance of identifying new potent antiviral agents. Nutrients as well as plant-derived substances are promising candidates because they are usually well tolerated by the human body and readily available in nature, and consequently mostly cheap to produce. A variety of antiviral effects have recently been described for the hop chalcone xanthohumol (XN), and to a lesser extent for its derivatives, making these hop compounds particularly attractive for further investigation. Noteworthy, mounting evidence indicated that XN can suppress a wide range of viruses belonging to several virus families, all of which share a common reproductive cycle. As a result, the purpose of this review is to summarize the most recent research on the antiviral properties of XN and its derivatives, with a particular emphasis on the positive-sense RNA viruses human hepatitis C virus (HCV), porcine reproductive and respiratory syndrome virus (PRRSV), and severe acute respiratory syndrome corona virus (SARS-CoV-2).

Current strategies for the management of valuable compounds from hops waste for a circular economy

World beer production generates large volumes of waste discharged with every brew. Recently, new methods of reducing and reusing hops waste: hot trub (HT), and brewer-spent hops (BSH) are being exploited to improve the circular economy processes. This review outlines the current achievements in the management of hops waste. Following an in-depth review of various scientific publications, current strategies are discussed as a sustainable alternative to food waste exploitation and an inexpensive source of valuable compounds. Moreover, key aspects concerning the nutritional value of hops waste and the potential to enhance the functional properties of food and beverages are highlighted. Due to their nutritional composition, hops residues may be used as prospective sources of added-value co-products or additives for food enrichment, especially for products rich in fat, or as a new source of vegetable protein.

Phytotherapy of mood disorders in the light of microbiota-gut-brain axis

BACKGROUND

Clinical research in natural product-based psychopharmacology has revealed a variety of promising herbal medicines that may provide benefit in the treatment of mild mood disorders, however failed to unambiguously indicate pharmacologically active constituents. The emerging role of the microbiota-gut-brain axis opens new possibilities in the search for effective methods of treatment and prevention of mood disorders.

PURPOSE

Considering the clinically proven effectiveness juxtaposed with inconsistencies regarding the indication of active principles for many medicinal plants applied in the treatment of anxiety and depression, the aim of the review is to look at their therapeutic properties from the perspective of the microbiota-gut-brain axis.

METHOD

A literature-based survey was performed using Scopus, Pubmed, and Google Scholar databases. The current state of knowledge regarding Hypericum perforatum, Valeriana officinalis, Piper methysticum, Passiflora incarnata, Humulus lupulus, Melissa officinalis, Lavandula officinalis, and Rhodiola rosea in terms of their antimicrobial activity, bioavailability, clinical effectiveness in depression/anxiety and gut microbiota - natural products interaction was summarized and analyzed.

RESULTS

Recent studies have provided direct and indirect evidence that herbal extracts and isolated compounds are potent modulators of gut microbiota structure. Additionally, some of the formed postbiotic metabolites exert positive effects and ameliorate depression-related behaviors in animal models of mood disorders. The review underlines the gap in research on natural products - gut microbiota interaction in the context of mood disorders.

CONCLUSION

Modification of microbiota-gut-brain axis by natural products is a plausible explanation of their therapeutic properties. Future studies evaluating the effectiveness of herbal medicine and isolated compounds in treating mild mood disorders should consider the bidirectional interplay between phytoconstituents and the gut microbiota community.

Phytoestrogens and Health Effects

Phytoestrogens are literally estrogenic substances of plant origin. Although these substances are useful for plants in many aspects, their estrogenic properties are essentially relevant to their predators. As such, phytoestrogens can be considered to be substances potentially dedicated to plant-predator interaction. Therefore, it is not surprising to note that the word phytoestrogen comes from the early discovery of estrogenic effects in grazing animals and humans. Here, several compounds whose activities have been discovered at nutritional concentrations in animals and humans are examined. The substances analyzed belong to several chemical families, i.e., the flavanones, the coumestans, the resorcylic acid lactones, the isoflavones, and the enterolignans. Following their definition and the evocation of their role in plants, their metabolic transformations and bioavailabilities are discussed. A point is then made regarding their health effects, which can either be beneficial or adverse depending on the subject studied, the sex, the age, and the physiological status. Toxicological information is given based on official data. The effects are first presented in humans. Animal models are evoked when no data are available in humans. The effects are presented with a constant reference to doses and plausible exposure.

An Updated Review of the Genus Humulus: A Valuable Source of Bioactive Compounds for Health and Disease Prevention

The medicinal potential of hop (Humulus lupulus L.) is widely cited in ancient literature and is also allowed in several official pharmacopoeias for the treatment of a variety of ailments, mainly related to anxiety states. This is due to the plethora of phytoconstituents (e.g., bitter acids, polyphenols, prenyl flavonoids) present in the female inflorescences, commonly known as cones or strobili, endowed with anti-inflammatory, antioxidant, antimicrobial, and phytoestrogen activities. Hop has recently attracted the interest of the scientific community due to the presence of xanthohumol, whose strong anti-cancer activity against various types of cancer cells has been well documented, and for the presence of 8-prenyl naringenin, the most potent known phytoestrogen. Studies in the literature have also shown that hop compounds can hinder numerous signalling pathways, including ERK1/2 phosphorylation, regulation of AP-1 activity, PI3K-Akt, and nuclear factor NF-κB, which are the main targets of the antiproliferative action of bitter acids and prenylflavonoids. In light of these considerations, the aim of this review was to provide an up-to-date overview of the main biologically active compounds found in hops, as well as their in vitro and in vivo applications for human health and disease prevention. To this end, a quantitative literature analysis approach was used, using VOSviewer software to extract and process Scopus bibliometric data. In addition, data on the pharmacokinetics of bioactive hop compounds and clinical studies in the literature were analysed. To make the information more complete, studies on the beneficial properties of the other two species belonging to the genus Humulus, H. japonicus and H. yunnanensis, were also reviewed for the first time.

The role of key gut microbial metabolites in the development and treatment of cancer

In recent years, the role of gut microbial metabolites on the inhibition and progression of cancer has gained significant interest in anticancer research. It has been established that the gut microbiome plays a pivotal role in the development, treatment and prognosis of different cancer types which is often mediated through the gut microbial metabolites. For instance, gut microbial metabolites including bacteriocins, short-chain fatty acids and phenylpropanoid-derived metabolites have displayed direct and indirect anticancer activities through different molecular mechanisms. Despite the reported anticancer activity, some gut microbial metabolites including secondary bile acids have exhibited pro-carcinogenic properties. This review draws a critical summary and assessment of the current studies demonstrating the carcinogenic and anticancer activity of gut microbial metabolites and emphasises the need to further investigate the interactions of these metabolites with the immune system as well as the tumour microenvironment in molecular mechanistic and clinical studies.

Postbiotics as the new frontier in food and pharmaceutical research

Food is the essential need of human life and has nutrients that support growth and health. Gastrointestinal tract microbiota involves valuable microorganisms that develop therapeutic effects and are characterized as probiotics. The investigations on appropriate probiotic strains have led to the characterization of specific metabolic byproducts of probiotics named postbiotics. The probiotics must maintain their survival against inappropriate lethal conditions of the processing, storage, distribution, preparation, and digestion system so that they can exhibit their most health effects. Conversely, probiotic metabolites (postbiotics) have successfully overcome these unfavorable conditions and may be an appropriate alternative to probiotics. Due to their specific chemical structure, safe profile, long shelf-life, and the fact that they contain various signaling molecules, postbiotics may have anti-inflammatory, immunomodulatory, antihypertensive properties, inhibiting abnormal cell proliferation and antioxidative activities. Consequently, present scientific literature approves that postbiotics can mimic the fundamental and clinical role of probiotics, and due to their unique characteristics, they can be applied in an oral delivery system (pharmaceutical/functional foods), as a preharvest food safety hurdle, to promote the shelf-life of food products and develop novel functional foods or/and for developing health benefits, and therapeutic aims. This review addresses the latest postbiotic applications with regard to pharmaceutical formulations and commercial food-based products. Potential postbiotic applications in the promotion of host health status, prevention of disease, and complementary treatment are also reviewed.

The Potent Phytoestrogen 8-Prenylnaringenin: A Friend or a Foe?

8-prenylnaringenin (8-PN) is a prenylated flavonoid, occurring, in particular, in hop, but also in other plants. It has proven to be one of the most potent phytoestrogens in vitro known to date, and in the past 20 years, research has unveiled new effects triggered by it in biological systems. These findings have aroused the hopes, expectations, and enthusiasm of a “wonder-drug” for a host of human diseases. However, the majority of 8-PN effects require such high concentrations that they cannot be reached by normal dietary exposure, only pharmacologically; thus, adverse impacts may also emerge. Here, we provide a comprehensive and up-to-date review on this fascinating compound, with special reference to the range of beneficial and untoward health consequences that may ensue from exposure to it.

AHR agonistic effects of 6-PN contribute to potential beneficial effects of Hops extract

Hops (Humulus lupulus) is used as an alternative to hormone replacement therapy due to the phytoestrogen, 8-prenylnaringenin (8-PN). To examine the potential risks/benefits of hops extract and its compounds (8-PN and 6-prenylnaringenin, 6-PN), we aimed to evaluate the estrogen receptor α (ERα) and aryl hydrocarbon receptor (AHR) signaling pathways in human endometrial cancer cells. Hops extract, 8-PN and 6-PN showed estrogenic activity. Hops extract and 6-PN activated both ERα and AHR pathways. 6-PN increased the expression of the tumor suppressor gene (AHRR), and that of genes involved in the estrogen metabolism (CYP1A1, CYP1B1). Although 6-PN might activate the detoxification and genotoxic pathways of estrogen metabolism, hops extract as a whole only modulated the genotoxic pathway by an up-regulation of CYP1B1 mRNA expression. These data demonstrate the relevant role of 6-PN contained in the hops extract as potential modulator of estrogen metabolism due to its ERα and AHR agonist activity.

Current methodologies to refine bioavailability, delivery, and therapeutic efficacy of plant flavonoids in cancer treatment

Over the last two decades, several advancements have been made to improve the therapeutic efficacy of plant flavonoids, especially in cancer treatment. Factors such as low bioavailability, poor flavonoid stability and solubility, ineffective targeted delivery, and chemo-resistance hinder the application of flavonoids in anti-cancer therapy. Many anti-cancer compounds failed in the clinical trials because of unexpected altered clearance of flavonoids, poor absorption after administration, low efficacy, and/or adverse effects. Hence, the current research strategies are focused on improving the therapeutic efficacy of plant flavonoids, especially by enhancing their bioavailability through combination therapy, engineering gut microbiota, regulating flavonoids interaction with adenosine triphosphate binding cassette efflux transporters, and efficient delivery using nanocrystal and encapsulation technologies. This review aims to discuss different methodologies with examples from reported dietary flavonoids that showed an enhanced anti-cancer efficacy in both in vitro and in vivo models. Further, the review discusses the recent progress in biochemical modifications of flavonoids to improve bioavailability, solubility, and therapeutic efficacy.

6-Prenylnaringenin from Hops Disrupts ERα-Mediated Downregulation of CYP1A1 to Facilitate Estrogen Detoxification

Botanical dietary supplements (BDS) containing hops are sold as women's health supplements due to the potent hop phytoestrogen, 8-prenylnaringenin (8-PN), and the cytoprotective chalcone, xanthohumol. Previous studies have shown a standardized hop extract to beneficially influence chemical estrogen carcinogenesis in vitro by fostering detoxified 2-hydroxylation over genotoxic 4-hydroxylation estrogen metabolism. In this study, hop extract and its bioactive compounds were investigated for its mechanism of action within the chemical estrogen carcinogenesis pathway, which is mainly mediated through the 4-hydroxylation pathway catalyzed by CYP1B1 that can form gentoxic quinones. Aryl hydrocarbon receptor (AhR) agonists induce CYP1A1 and CYP1B1, while estrogen receptor alpha (ERα) inhibits transcription of CYP1A1, the enzyme responsible for 2-hydroxylated estrogens and the estrogen detoxification pathway. An In-Cell Western MCF-7 cell assay revealed hop extract and 6-prenylnaringenin (6-PN) degraded ERα via an AhR-dependent mechanism. Reverse transcription PCR and xenobiotic response element luciferase assays showed hop extract and 6-PN-mediated activation of AhR and induction of CYP1A1. A reduction in estrogen-mediated DNA (cytosine-5)-methyltransferase 1 (DNMT1) downregulation of CYP1A1 accompanied this activity in a chromatin immunoprecipitation assay. Ultimately, hop extract and 6-PN induced preferential metabolism of estrogens to their detoxified form in vitro. These results suggest that the standardized hop extract and 6-PN activate AhR to attenuate epigenetic inhibition of CYP1A1 through degradation of ERα, ultimately increasing 2-hydroxylated estrogens. A new mechanism of action rationalizes the positive influence of hop BDS and 6-PN on oxidative estrogen metabolism in vitro and, thus, potentially on chemical estrogen carcinogenesis. The findings underscore the importance of elucidating various biological mechanisms of action and standardizing BDS to multiple phytoconstituents for optimal resilience promoting properties.

Flavonoids as Phytoestrogenic Components of Hops and Beer

The value of hops (Humulus lupulus L.) in beer production has been undisputed for centuries. Hops is rich in humulones and lupulones which gives the characteristic aroma and bitter taste, and preserves this golden drink against growing bacteria and molds. Besides α- and β-acids, the lupulin glands of hop cones excrete prenylated flavonoids, which exhibit a broad spectrum of biological activities and therefore has therapeutic potential in humans. Recently, interest in hops was raised due to hop prenylated flavanones which show extraordinary estrogen activities. The strongest known phytoestrogen so far is 8-prenylnaringenin (8-PN), which along with 6-prenylanaringenin (6-PN), 6,8-diprenylnaringenin (6,8-DPN) and 8-geranylnaringenin (8-GN) are fundamental for the potent estrogen activity of hops. This review provides insight into the unusual hop phytoestrogens and shows numerous health benefits associated with their wide spectrum of biological activities including estrogenic, anticancer, neuropreventive, antinflamatory, and antimicrobial properties, which were intensively studied, and potential applications of these compounds such as, as an alternative to hormone replacement therapy (HRT).

Semi-Synthetic Approach Leading to 8-Prenylnaringenin and 6-Prenylnaringenin: Optimization of the Microwave-Assisted Demethylation of Xanthohumol Using Design of Experiments

The isomers 8-prenylnaringenin and 6-prenylnaringenin, both secondary metabolites occurring in hops, show interesting biological effects, like estrogen-like, cytotoxic, or neuro regenerative activities. Accordingly, abundant sources for this special flavonoids are needed. Extraction is not recommended due to the very low amounts present in plants and different synthesis approaches are characterized by modest yields, multiple steps, the use of expensive chemicals, or an elaborate synthesis. An easy synthesis strategy is the demethylation of xanthohumol, which is available due to hop extraction industry, using lithium chloride and dimethylformamide, but byproducts and low yield did not make this feasible until now. In this study, the demethylation of xanthohumol to 8-prenylnaringenin and 6-prenylnaringenin is described the first time and this reaction was optimized using Design of Experiment and microwave irradiation. With the optimized conditions—temperature 198 °C, 55 eq. lithium chloride, and a reaction time of 9 min, a final yield of 76% of both prenylated flavonoids is reached.

Where to Look into the Puzzle of Polyphenols and Health? The Postbiotics and Gut Microbiota Associated with Human Metabotypes

The full consensus on the role of dietary polyphenols as human-health-promoting compounds remains elusive. The two-way interaction between polyphenols and gut microbiota (GM) (i.e., modulation of GM by polyphenols and their catabolism by the GM) is determinant in polyphenols' effects. The identification of human metabotypes associated with a differential gut microbial metabolism of polyphenols has opened new research scenarios to explain the inter-individual variability upon polyphenols consumption. The metabotypes unequivocally identified so far are those involved in the metabolism of isoflavones (equol and(or) O-desmethylangolesin producers versus non-producers) and ellagic acid (urolithin metabotypes, including producers of only urolithin-A (UM-A), producers of urolithin-A, isourolithin-A, and urolithin-B (UM-B), and non-producers (UM-0)). In addition, the microbial metabolites (phenolic-derived postbiotics) such as equol, urolithins, valerolactones, enterolactone, and enterodiol, and 8-prenylnaringenin, among others, can exert differential health effects. The knowledge is updated and position is taken here on i) the two-way interaction between GM and polyphenols, ii) the evidence between phenolic-derived postbiotics and health, iii) the role of metabotypes as biomarkers of GM and the clustering of individuals depending on their metabotypes (metabotyping) to explain polyphenols' effects, and iv) the gut microbial metabolism of catecholamines to illustrate the intersection between personalized nutrition and precision medicine.

Dietary natural flavonoids treating cancer by targeting aryl hydrocarbon receptor

The role of aryl hydrocarbon receptor (AhR) as a ligand-activated transcription factor in the field of cancer has gradually been unveiled. A strong body of evidence indicated that AhR is implicated in cell proliferation and apoptosis, immune metabolism and other processes, which further affected tumor growth, survival, migration, and invasion. Therefore, AhR targeted therapy may become a new method for cancer treatment and provide a new direction for clinical tumor treatment. Astonishingly, the largest source of exposure of animals and humans to AhR ligands (synthetic and natural) comes from the diet. Myriad studies have described that various natural dietary chemicals can directly activate and/or inhibit the AhR signaling pathway. Of note, numerous natural products contribute to AhR active, of which dietary flavonoids are the largest class of natural AhR ligands. As interest in AhR and its ligands increases, it seems sensible to summarize current research on these ligands. In this review, we highlight the role of AhR in tumorigenesis and focus on the double effect of AhR in cancer therapy. We explored the molecular mechanism of AhR ligands on cancer through a few AhR agonists/antagonists currently in clinical practice. Ultimately, we summarize and highlight the latest progression of dietary flavonoids as AhR ligands in cancer inhibition, including the limitations and deficiencies of it in clinical research. This review will offer a comprehensive understanding of AhR and its dietary ligands which may dramatically pave the way for targeted cancer treatment.

The Multiple Biological Targets of Hops and Bioactive Compounds

Botanical dietary supplements for women's health are increasingly popular. Older women tend to take botanical supplements such as hops as natural alternatives to traditional hormone therapy to relieve menopausal symptoms. Especially extracts from spent hops, the plant material remaining after beer brewing, are enriched in bioactive prenylated flavonoids that correlate with the health benefits of the plant. The chalcone xanthohumol (XH) is the major prenylated flavonoid in spent hops. Other less abundant but important bioactive prenylated flavonoids are isoxanthohumol (IX), 8-prenylnaringenin (8-PN), and 6-prenylnaringenin (6-PN). Pharmacokinetic studies revealed that these flavonoids are conjugated rapidly with glucuronic acid. XH also undergoes phase I metabolism in vivo to form IX, 8-PN, and 6-PN. Several hop constituents are responsible for distinct effects linked to multiple biological targets, including hormonal, metabolic, inflammatory, and epigenetic pathways. 8-PN is one of the most potent phytoestrogens and is responsible for hops' estrogenic activities. Hops also inhibit aromatase activity, which is linked to 8-PN. The weak electrophile, XH, can activate the Keap1-Nrf2 pathway and turn on the synthesis of detoxification enzymes such as NAD(P)H-quinone oxidoreductase 1 and glutathione S-transferase. XH also alkylates IKK and NF-κB, resulting in anti-inflammatory activity. Antiobesity activities have been described for XH and XH-rich hop extracts likely through activation of AMP-activated protein kinase signaling pathways. Hop extracts modulate the estrogen chemical carcinogenesis pathway by enhancing P450 1A1 detoxification. The mechanism appears to involve activation of the aryl hydrocarbon receptor (AhR) by the AhR agonist, 6-PN, leading to degradation of the estrogen receptor. Finally, prenylated phenols from hops are known inhibitors of P450 1A1/2; P450 1B1; and P450 2C8, 2C9, and 2C19. Understanding the biological targets of hop dietary supplements and their phytoconstituents will ultimately lead to standardized botanical products with higher efficacy, safety, and chemopreventive properties.

Hop Compounds: Extraction Techniques, Chemical Analyses, Antioxidative, Antimicrobial, and Anticarcinogenic Effects

Hop plants comprise a variety of natural compounds greatly differing in their structure and properties. A wide range of methods have been developed for their isolation and chemical analysis, as well as for determining their antioxidative, antimicrobial, and antigenotoxic potentials. This contribution provides an overview of extraction and fractionation techniques of the most important hop compounds known for their health-promoting features. Although hops remain the principal ingredient for providing the taste, stability, and antimicrobial protection of beer, they have found applications in the pharmaceutical and other food industries as well. This review focuses on numerous health-promoting effects of hops raging from antioxidative, sedative, and anti-inflammatory potentials, over anticarcinogenic features to estrogenic activity. Therefore, hops should be exploited for the prevention and even healing of several prevalent diseases like cardiovascular disorders and various cancer types. New ideas for future studies on hops are finally presented: computational investigations of chemical reactivities of hop compounds, nanoencapsulation, and synergistic effects leading to a higher bioavailability of biologically active substances as well as the application of waste hop biomass from breweries for the production of high-added-value products in accordance with the biorefinery concept.

Therapeutic Perspectives of 8-Prenylnaringenin, a Potent Phytoestrogen from Hops

Hop (Humulus lupulus L.), as a key ingredient for beer brewing, is also a source of many biologically active molecules. A notable compound, 8-prenylnaringenin (8-PN), structurally belonging to the group of prenylated flavonoids, was shown to be a potent phytoestrogen, and thus, became the topic of active research. Here, we overview the pharmacological properties of 8-PN and its therapeutic opportunities. Due to its estrogenic effects, administration of 8-PN represents a novel therapeutic approach to the treatment of menopausal and post-menopausal symptoms that occur as a consequence of a progressive decline in hormone levels in women. Application of 8-PN in the treatment of menopause has been clinically examined with promising results. Other activities that have already been assessed include the potential to prevent bone-resorption or inhibition of tumor growth. On the other hand, the use of phytoestrogens is frequently questioned regarding possible adverse effects associated with long-term consumption. In conclusion, we emphasize the implications of using 8-PN in future treatments of menopausal and post-menopausal symptoms, including the need for precise evidence and further investigations to define the safety risks related to its therapeutic use.