Dose-Dependent Alterations to In Vitro Human Microbiota Composition and Butyrate Inhibition by a Supercritical Carbon Dioxide Hops Extract

Simulated gastrointestinal digestion of beer using the simgi® model. Investigation of colonic phenolic metabolism and impact on human gut microbiota

Beer is a source of bioactive compounds, mainly polyphenols, which can reach the large intestine and interact with colonic microbiota. However, the effects of beer consumption in the gastrointestinal function have scarcely been studied. This paper reports, for the first time, the in vitro digestion of beer and its impact on intestinal microbiota metabolism. Three commercial beers of different styles were subjected to gastrointestinal digestion using the simgi® model, and the digested fluids were further fermented in triplicate with faecal microbiota from a healthy volunteer. The effect of digested beer on human gut microbiota was evaluated in terms of microbial metabolism (short-chain fatty acids (SCFAs) and ammonium ion), microbial diversity and bacterial populations (plate counting and 16S rRNA gene sequencing). Monitoring beer polyphenols through the different digestion phases showed their extensive metabolism, mainly at the colonic stage. In addition, a higher abundance of taxa related to gut health, especially Bacteroides, Bifidobacterium, Mitsuokella and Succinilasticum at the genus level, and the Ruminococcaceae and Prevotellaceae families were found in the presence of beers. Regarding microbial metabolism, beer feeding significantly increased microbial SCFA production (mainly butyric acid) and decreased ammonium content. Overall, these results evidence the positive actions of moderate beer consumption on the metabolic activity of colonic microbiota, suggesting that the raw materials and brewing methods used may affect the beer gut effects.

Effects of Hops Treatment on Nitrogen Retention, Volatile Fatty Acid Accumulations, and Select Microbial Populations of Composting Poultry Litter Intended for Use as a Ruminant Feedstuff

Poultry litter is a valuable crude protein feedstuff for ruminants, but it must be treated to kill pathogens before feeding. Composting effectively kills pathogens, but it risks losing ammonia to volatilization or leaching during degradation of uric acid and urea. Hops bitter acids also exert antimicrobial activity against certain pathogenic and nitrogen-degrading microbes. Consequently, the present studies were conducted to test if adding bitter acid-rich hop preparations to simulated poultry litter composts may improve nitrogen retention while simultaneously improving pathogen killing. Results from an initial study, testing doses of Chinook or Galena hops preparations designed to each deliver 79 ppm hops β-acid, revealed that, after nine days simulated composting of wood chip litter, ammonia concentrations were 14% lower (p < 0.05) in Chinook-treated composts than untreated composts (13.4 ± 1.06 µmol/g). Conversely, urea concentrations were 55% lower (p < 0.05) in Galena-treated than untreated composts (6.2 ± 1.72 µmol/g). Uric acid accumulations were unaffected by hops treatments in this study but were higher (p < 0.05) after three days than after zero, six, or nine days of composting. In follow-up studies, Chinook or Galena hops treatments (delivering 2042 or 6126 ppm of β-acid, respectively) for simulated composts (14 days) of wood chip litter alone or mixed 3:1 with ground Bluestem hay (Andropogon gerardii) revealed that these higher dosages had little effect on ammonia, urea, or uric acid accumulations when compared to untreated composts. Volatile fatty acid accumulations measured in these later studies were affected by the hops treatments, with butyrate accumulations being lower after 14 days in hops-treated composts than in untreated compost. In all studies, beneficial effects of Galena or Chinook hops treatments were not observed on the antimicrobial activity of the simulated composts, with composting by itself decreasing (p < 0.05) counts of select microbial populations by more than 2.5 log10 colony forming units/g compost dry matter. Thus, while hops treatments had little effect on pathogen control or nitrogen retention within the composted litter, they did lessen accumulations of butyrate, which may prevent adverse effects of this fatty acid on palatability of litter fed to ruminants.

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.

Beer Safety: New Challenges and Future Trends within Craft and Large-Scale Production

The presence of physical, chemical, or microbiological contaminants in beer represents a broad and worthy problem with potential implications for human health. The expansion of beer types makes it more and more appreciated for the sensorial properties and health benefits of fermentation and functional ingredients, leading to significant consumed quantities. Contaminant sources are the raw materials, risks that may occur in the production processes (poor sanitation, incorrect pasteurisation), the factory environment (air pollution), or inadequate (ethanol) consumption. We evaluated the presence of these contaminants in different beer types. This review covers publications that discuss the presence of bacteria (Lactobacillus, Pediococcus), yeasts (Saccharomyces, Candida), moulds (Fusarium, Aspergillus), mycotoxins, heavy metals, biogenic amines, and micro- and nano-plastic in beer products, ending with a discussion regarding the identified gaps in current risk reduction or elimination strategies.

Medicinal Plants and Their Impact on the Gut Microbiome in Mental Health: A Systematic Review

Background: Various neurocognitive and mental health-related conditions have been associated with the gut microbiome, implicating a microbiome–gut–brain axis (MGBA). The aim of this systematic review was to identify, categorize, and review clinical evidence supporting medicinal plants for the treatment of mental disorders and studies on their interactions with the gut microbiota. Methods: This review included medicinal plants for which clinical studies on depression, sleeping disorders, anxiety, or cognitive dysfunction as well as scientific evidence of interaction with the gut microbiome were available. The studies were reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Results: Eighty-five studies met the inclusion criteria and covered thirty mental health-related medicinal plants with data on interaction with the gut microbiome. Conclusion: Only a few studies have been specifically designed to assess how herbal preparations affect MGBA-related targets or pathways. However, many studies provide hints of a possible interaction with the MGBA, such as an increased abundance of health-beneficial microorganisms, anti-inflammatory effects, or MGBA-related pathway effects by gut microbial metabolites. Data for Panax ginseng, Schisandra chinensis, and Salvia rosmarinus indicate that the interaction of their constituents with the gut microbiota could mediate mental health benefits. Studies specifically assessing the effects on MGBA-related pathways are still required for most medicinal plants.

The Promising Ability of Humulus lupulus L. Iso-α-acids vs. Diabetes, Inflammation, and Metabolic Syndrome: A Systematic Review

For centuries, natural medicines have represented the only option for treating human diseases and, nowadays, plant phytochemicals are considered as promising compounds to treat or prevent chronic conditions. Among them, hop flowers (Humulus lupulus L.), typically used in brewing industries to give the typical aroma and flavor to beer, have attracted particular attention for their health promoting properties. Several in vivo/vitro studies and human interventional trials have demonstrated the beneficial effects of these molecules on weight gain, lipid metabolism, glucose homeostasis, insulin sensitivities, and inflammation by acting on different targets. All these activities suggest a possible role of bitter hop acid in preventing metabolic syndrome and its related diseases. A systematic quest on PubMed and Scopus databases was performed to identify pre-clinical and clinical studies focusing on this topic. This systematic review summarizes the results obtained by different cell lines, animal models, and human interventional trials to propose iso-α-acids as medical nutrition therapy to treat or prevent metabolic syndrome and its related disorders as diabetes, dislipidemia inflammation, etc.

Hop bioactive compounds in prevention of nutrition-related noncommunicable diseases

Nutrition-related noncommunicable diseases (NR-NCDs) such as cardiovascular disease and type 2 diabetes both negatively impact the quality of life of many individuals and generate a substantial burden on society, demonstrating a need for intervention. Phytochemicals are investigated as a potential approach for combating NR-NCDs, and those found in hops have gained increased attention in recent decades. Hops, the strobile of the plant Humulus lupulus, are grown primarily for the brewing industry as they confer taste and increased shelf-life. The bitter acids represent the main compounds of interest for improving beer quality. Additionally, bitter acids as well as the prenylated chalcone xanthohumol, exhibit a wide range of health beneficial properties. This review summarizes those beneficial effects of bitter acids and xanthohumol on NR-NCDs, including inflammatory and immune diseases, obesity and metabolic disorders, as well as cancer prevention.

A New Perspective on the Health Benefits of Moderate Beer Consumption: Involvement of the Gut Microbiota

Beer is the most widely consumed fermented beverage in the world. A moderate consumption of beer has been related to important healthy outcomes, although the mechanisms have not been fully understood. Beer contains only a few raw ingredients but transformations that occur during the brewing process turn beer into a beverage that is enriched in micronutrients. Beer also contains an important number of phenolic compounds and it could be considered to be a source of dietary polyphenols. On the other hand, gut microbiota is now attracting special attention due to its metabolic effects and as because polyphenols are known to interact with gut microbiota. Among others, ferulic acid, xanthohumol, catechins, epicatechins, proanthocyanidins, quercetin, and rutin are some of the beer polyphenols that have been related to microbiota. However, scarce literature exists about the effects of moderate beer consumption on gut microbiota. In this review, we focus on the relationship between beer polyphenols and gut microbiota, with special emphasis on the health outcomes.