Effect of tea phenolics and their aromatic fecal bacterial metabolites on intestinal microbiota

The Impact of Diet on the Colonization of Beneficial Microbes from an Ecological Perspective

With growing recognition of the pivotal role of gut microbiota in human health, probiotics have gained widespread attention for their potential to restore microbial homeostasis. However, a critical challenge persists: limited colonization efficiency among most probiotic strains compromises their therapeutic efficacy. This overview synthesizes ecological principles with cutting-edge microbiome research to elucidate the dynamic interplay between dietary components and probiotic colonization within the intestinal niche. This overview systematically analyzes: (1) stage-specific colonization mechanisms spanning microbial introduction, establishment, and proliferation; (2) nutrient-driven modulation of gut microbiota composition and function; and (3) the dual role of common dietary patterns as both facilitators and disruptors of probiotic persistence. Notably, this overview identifies key dietary strategies, including precision delivery of prebiotic fibers and polyphenol-microbiota crosstalk, that enhance niche adaptation through pH optimization, adhesion potentiation, and competitive exclusion of pathogens. Furthermore, this overview critically evaluates current limitations in probiotic research, particularly strain-specific variability and methodological constraints in simulating host-microbe-diet tripartite interactions. To bridge these gaps, this overview proposes an interdisciplinary framework integrating omics-driven strain selection, engineered delivery systems, and personalized nutrition models. Collectively, this work advances a mechanistic understanding of diet-microbiota interactions while providing actionable insights for developing targeted probiotic therapies and evidence-based dietary interventions to optimize gut ecosystem resilience.

Natural Products in the Management of Gastroesophageal Reflux Disease: Mechanisms, Efficacy, and Future Directions

Gastroesophageal reflux disease (GERD) is a common gastrointestinal disorder that is defined by the reflux of gastric contents into the esophagus, and it results in symptoms such as esophageal inflammation, regurgitation, and indigestion. Although proton pump inhibitors (PPIs) and histamine-2 receptor antagonists are frequently employed to treat GERD, their prolonged administration is associated with adverse effects, necessitating the development of alternative therapeutic strategies. Natural products are now recognized as promising candidates for the management of GERD due to their bioactive compounds, which possess antioxidant, anti-inflammatory, and mucosal-protective properties. The potential of natural products in the treatment of GERD is comprehensively examined in this review, with a focus on their mechanisms of action, which include acid suppression, esophageal mucosal regeneration, anti-inflammatory activity, and gut microbiota modulation. Also, the efficacy and safety of key natural products, including flavonoids, polyphenols, plant-derived oils, herbal extracts, probiotics, and dietary components, in preclinical and clinical studies, are assessed. Additionally, this review addresses the barriers confronting the translation of natural therapies into clinical practice, such as regulatory obstacles, variability in bioavailability, and the need for dosage standardization. The integration of natural products into the management of GERD has the potential to enhance conventional therapies, providing a more comprehensive and secure approach for patients.

Health-Improving Effects of Polyphenols on the Human Intestinal Microbiota: A Review

Dietary polyphenols are garnering attention in the scientific community due to their potential health-beneficial properties and preventative effects against chronic diseases, viz. cardiovascular diseases, diabetes, obesity, and neurodegenerative diseases. Polyphenols are antioxidants that change microbial composition by suppressing pathogenic bacteria and stimulating beneficial bacteria. The interaction of polyphenols with dietary fibers affects their bioaccessibility in the upper and lower parts of the digestive tract. Dietary fibers, polyphenols, their conjugates, and their metabolites modulate microbiome population and diversity. Consuming polyphenol-rich dietary fibers such as pomegranate, cranberry, berries, and tea improves gut health. A complex relationship exists between polyphenol-rich diets and gut microbiota for functioning in human health. In this review, we provide an overview of the interactions of dietary polyphenols, fibers, and gut microbiota, improving the understanding of the functional properties of dietary polyphenols.

Polyphenols synergistic drugs to ameliorate non-alcoholic fatty liver disease via signal pathway and gut microbiota: A review

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease with an increasing incidence worldwide. Single drug therapy may have toxic side effects and disrupt gut microbiota balance. Polyphenols are widely used in disease intervention due to their distinctive nutritional properties and medicinal value, which a potential gut microbiota modulator. However, there is a lack of comprehensive review to explore the efficacy and mechanism of combined therapy with drugs and polyphenols for NAFLD.

AIM OF REVIEW

Based on this, this review firstly discusses the link between NAFLD and gut microbiota, and outlines the effects of polyphenols and drugs on gut microbiota. Secondly, it examined recent advances in the treatment and intervention of NAFLD with drugs and polyphenols and the therapeutic effect of the combination of the two. Finally, we highlight the underlying mechanisms of polyphenol combined drug therapy in NAFLD. This is mainly in terms of signaling pathways (NF-κB, AMPK, Nrf2, JAK/STAT, PPAR, SREBP-1c, PI3K/Akt and TLR) and gut microbiota. Furthermore, some emerging mechanisms such as microRNA potential biomarker therapies may provide therapeutic avenues for NAFLD.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Drawing inspiration from combination drug strategies, the use of active substances in combination with drugs for NAFLD intervention holds transformative and prospective potential, both improve NAFLD and restore gut microbiota balance while reducing the required drug dosage. This review systematically discusses the bidirectional interactions between gut microbiota and NAFLD, and summarizes the potential mechanisms of polyphenol synergistic drugs in the treatment of NAFLD by modulating signaling pathways and gut microbiota. Future researches should develop multi-omics technology to identify patients who benefit from polyphenols combination drugs and devising individualized treatment plans to enhance its therapeutic effect.

Effects of tannic acid on growth performance, intestinal health, and tolerance in broiler chickens

This study investigated the optimal tannic acid dosage and assessed tolerance levels in broiler chickens. In experiment 1, 525 broilers were randomly divided into 5 treatment groups, the control group (CON group) and groups TA1 to TA4, corresponding to treatments of 0.025, 0.05, 0.075, and 0.1 % tannic acid, respectively, to determine the effect of tannic acid on broiler growth performance and gut health. Experiment 2 was performed to evaluate the tolerance of tannic acid; 416 broilers were randomly divided into control (CTR), 0.075 % tannic acid (TA), 0.375 % tannic acid (5TA), and 0.75 % tannic acid (10TA) groups. In the first experiment, compared with that in the CON group, the growth performance and the ileal intestinal villi height to crypt depth ratio showed a quadratic curve increase with tannic acid supplementation (P < 0.05). Adding 0.05 % to 0.075 % tannic acid significantly improved the growth performance, intestinal morphology, and intestinal barrier function (P < 0.05). Tannic acid concentrations of 0.075 % significantly increased the abundance of Firmicutes and Lactobacillaceae in the ileum and decreased the abundance of Vibrionaceae and Yersiniaceae (P < 0.05). In experiment 2, the growth performance of the TA group significantly improved compared with that of the CTR group (P < 0.05). The F/G was significantly higher in the 5TA and 10TA groups than in the CTR group (P < 0.05), and the 10TA group had significantly reduced body weight on d 21 (P < 0.05). The addition of tannic acid resulted in significant glomerular and glandular hyperplasia, as well as muscularis thickening of the gizzard mucosa. However, broilers could not tolerate tannic acid doses of 0.375 % and above. Tannic acid supplementation may protect the proventriculus mucosal layer, reduce villi atrophy, and enhance growth performance by positively influencing the intestinal microbiota, villus morphology, and intestinal barrier function.

Biological Mechanisms of Polyphenols against Clostridium Difficile: A Systematic Review

BACKGROUND

Clostridium difficile is an opportunistic infection that can lead to antibiotic- associated diarrhea and toxic megacolon.

OBJECTIVE

This systematic review study aimed to investigate polyphenols' antibacterial and antitoxin properties and their effects on reducing complications related to C. difficile Infections (CDI).

METHODS

This systematic review was conducted following the PRISMA guideline 2020. Multiple databases, including Web of Science, PubMed, Cochrane Library, EMBASE, and Scopus, were searched thoroughly for existing literature. After considering the inclusion and exclusion criteria for the review, 18 articles were included. Data were collected and registered into an Excel file for further investigations and conclusions.

RESULTS

Polyphenols by reducing Reactive Oxygen Species (ROS) levels, increasing inflammatory factor Interleukin 10 (IL-10), reducing Nuclear Factor kappa B (NF-κB) and Tumour Necrosis Factor- α (TNF-α), IL-6, IL-1α, IL-1β, Granulocyte Colony-stimulating Factor (G-CSF), and Monocyte Chemoattractant Protein-1 (MCP-1) and Macrophage Inflammatory Protein-1 alpha (MIP-1α) levels, and regulating the expression of Bcl-2 and Bax, make the growth and replication conditions of C. difficile more difficult and prevent it from producing toxins. Furthermore, polyphenols can exhibit prebiotic properties, promoting the growth of beneficial Bifidobacterium and Lactobacillus species and consequently regulating gut microbiota, exerting antimicrobial activities against C. difficile. They also induce their beneficial effects by inhibiting the production of C. difficile TcdA and TcdB.

CONCLUSION

Polyphenols have been reported to inhibit C. difficile growth and toxin production by several mechanisms in preclinical studies. However, more clinical studies are needed to investigate their safety in humans.

The Gut Microbiota-Brain Axis: A New Frontier in Alzheimer's Disease Pathology

Dr. Aloysius Alzheimer, a German neuropathologist and psychiatrist, recognized the primary instance of Alzheimer's disease (AD) for a millennium, and this ailment, along with its related dementias, remains a severe overall community issue related to health. Nearly fifty million individuals worldwide suffer from dementia, with Alzheimer's illness contributing to between 60 and 70% of the instances, estimated through the World Health Organization. In addition, 82 million individuals are anticipated to be affected by the global dementia epidemic by 2030 and 152 million by 2050. Furthermore, age, environmental circumstances, and inherited variables all increase the likelihood of acquiring neurodegenerative illnesses. Most recent pharmacological treatments are found in original hypotheses of disease, which include cholinergic (drugs that show affective cholinergic system availability) as well as amyloid-accumulation (a single drug is an antagonist receptor of Nmethyl D-aspartate). In 2020, the FDA provided approval on anti-amyloid drugs. According to mounting scientific data, this gut microbiota affects healthy physiological homeostasis and has a role in the etiology of conditions that range between obesity and neurodegenerative disorders like Alzheimer's. The microbiota-gut-brain axis might facilitate interconnection among gut microbes as well as the central nervous system (CNS). Interaction among the microbiota-gut system as well as the brain occurs through the "two-way" microbiota-gut-brain axis. Along this axis, the stomach as well as the brain develop physiologically and take on their final forms. This contact is constant and is mediated by numerous microbiota-derived products. The gut microbiota, for instance, can act as non-genetic markers to set a threshold for maintaining homeostasis or getting ill. The scientific community has conducted research and found that bowel dysbiosis and gastrointestinal tract dysregulation frequently occur in Alzheimer's disease (AD) patients. In this review, the effects of the microbiota- gut-brain axis on AD pathogenesis will be discussed.

Natural anti-adhesive components against pathogenic bacterial adhesion and infection in gastrointestinal tract: case studies of Helicobacter pylori, Salmonella enterica, Clostridium difficile, and diarrheagenic Escherichia coli

Antimicrobial resistance (AMR) poses a global public health concern. Recognizing the critical role of bacterial adhesion in pathogenesis of infection, anti-adhesive therapy emerges as a promising approach to impede initial bacterial attachment, thus preventing pathogenic colonization and infection. Natural anti-adhesive agents derived from food sources are generally safe and have the potential to inhibit the emergence of resistant bacteria. This comprehensive review explored diverse natural dietary components exhibiting anti-adhesive activities against several model enteric pathogens, including Helicobacter pylori, Salmonella enterica, Clostridium difficile, and three key diarrheagenic Escherichia coli (i.e., enterotoxigenic E. coli, enteropathogenic E. coli, and enterohemorrhagic E. coli). Investigating various anti-adhesive products will advance our understanding of current research of the field and inspire further development of these agents as potential nutraceuticals or adjuvants to improve the efficacy of conventional antibiotics.

From tyrosine to hydroxytyrosol: a pathway involving biologically active compounds and their determination in wines by ultra performance liquid chromatography with mass spectrometry

BACKGROUND

Hydroxytyrosol (HT) is a bioactive compound present in a limited number of foods such as wines, olives, and olive oils. During alcoholic fermentation, yeast converts aromatic amino acids into higher alcohols such as tyrosol, which can undergo hydroxylation into HT. The aim of this study was to validate an analytical method using ultra performance liquid chromatography coupled with mass spectrometry (UPLC/MS-MS) to quantify HT and its precursors (tyrosine, hydroxyphenylpyruvic acid, hydroxyphenylacetaldehyde, 4-hydroxyphenylacetic acid, and tyrosol) in wines. Their occurrence was evaluated in a total of 108 commercial Spanish wine samples.

RESULTS

The validated method simultaneously determined both HT and its precursors, with adequate limits of detection between 0.065 and 21.86 ng mL-1 and quantification limits between 0.199 and 66.27 ng mL-1 in a 5 min run. The concentration of HT in red wines was significantly higher (0.12-2.24 mg L-1) than in white wines (0.01-1.27 mg L-1). The higher the alcoholic degree, the higher was the content of HT. The bioactive 4-hydroxyphenylacetic acid was identified in Spanish wines for the first time at 3.90-127.47 mg L-1, being present in all the samples.

CONCLUSION

The highest HT concentrations were found in red wines and in wines with higher ethanol content. These data are useful for a further estimation of the intake of these bioactive compounds and to enlarge knowledge on chemical composition of wines. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Plant-derived polyphenolic compounds: nanodelivery through polysaccharide-based systems to improve the biological properties

Plant-derived polyphenols are naturally occurring compounds widely distributed in plants. They have received greater attention in the food and pharmaceutical industries due to their potential health benefits, reducing the risk of some chronic diseases due to their antioxidant, anti-inflammatory, anticancer, cardioprotective, and neuro-action properties. Polyphenolic compounds orally administered can be used as adjuvants in several treatments but with restricted uses due to chemical instability. The review discusses the different structural compositions of polyphenols and their influence on chemical stability. Despite the potential and wide applications, there is a need to improve the delivery of polyphenolics to target the human intestine without massive chemical modifications. Oral administration of polyphenols is unfeasible due to instability, low bioaccessibility, and limited bioavailability. Nano-delivery systems based on polysaccharides (starch, pectin, chitosan, and cellulose) have been identified as a viable option for oral ingestion, potentiate biological effects, and direct-controlled delivery in specific tissues. The time and dose can be individualized for specific diseases, such as intestinal cancer. This review will address the mechanisms by which polysaccharides-based nanostructured systems can protect against degradation and enhance intestinal permeation, oral bioavailability, and the potential application of polysaccharides as nanocarriers for the controlled and targeted delivery of polyphenolic compounds.

Perspective on the Coevolutionary Role of Host and Gut Microbiota in Polyphenol Health Effects: Metabotypes and Precision Health

"Personalized nutrition" aims to establish nutritional strategies to improve health outcomes for non-responders. However, it is utopian since most people share similar nutritional requirements. "Precision health," encompassing lifestyles, may be more fitting. Dietary (poly)phenols are "healthy" but non-nutritional molecules (thus, we can live without them). The gut microbiota influences (poly)phenol effects, producing metabolites with different activity than their precursors. Furthermore, producing distinctive metabolites, like urolithins, lunularin, and equol, leads to the term "polyphenol-related gut microbiota metabotypes," grouping individuals based on a genuine microbial metabolism of ellagic acid, resveratrol, and isoflavones, respectively. Additionally, (poly)phenols exert prebiotic-like effects through their antimicrobial activities, typically reducing microbial diversity and modulating microbiota functionality by impacting its composition and transcriptomics. Since the gut microbiota perceives (poly)phenols as a threat, (poly)phenol effects are mostly a consequence of microbiota adaptation through differential (poly)phenol metabolism (e.g., distinctive reductions, dehydroxylations, etc.). This viewpoint is less prosaic than considering (poly)phenols as essential nutritional players in human health, yet underscores their health significance in a coevolutionary partnership with the gut microbiota. In the perspective on the gut microbiota and (poly)phenols interplay, microbiota metabotypes could arbiter health effects. An innovative aspect is also emphasized: modulating the interacting microbial networks without altering the composition.

Microbial transformation of dietary xenobiotics shapes gut microbiome composition

Diet is a major determinant of gut microbiome composition, and variation in diet-microbiome interactions may contribute to variation in their health consequences. To mechanistically understand these relationships, here we map interactions between ∼150 small-molecule dietary xenobiotics and the gut microbiome, including the impacts of these compounds on community composition, the metabolic activities of human gut microbes on dietary xenobiotics, and interindividual variation in these traits. Microbial metabolism can toxify and detoxify these compounds, producing emergent interactions that explain community-specific remodeling by dietary xenobiotics. We identify the gene and enzyme responsible for detoxification of one such dietary xenobiotic, resveratrol, and demonstrate that this enzyme contributes to interindividual variation in community remodeling by resveratrol. Together, these results systematically map interactions between dietary xenobiotics and the gut microbiome and connect toxification and detoxification to interpersonal differences in microbiome response to diet.

Effects of Different Levels of Green Tea Powder on Performance, Antioxidant Activity, Egg Mass, Quality, and Cecal Microflora of Chickens

This study was conducted to investigate the effects of different levels of Green Tea Powder on the performance, egg quality, serum immune and antioxidant indices, and cecal microflora of 300-day-old Chishui black-bone chickens during the peak laying period. A total of 360 Chishui black-bone chickens were selected as the experimental animals. They were randomly allocated into four groups: the control group (CON), trial group I (T1), trial group II (T2), and trial group III (T3), each group with six replicates and 15 hens in each replicate. The control group was fed a basal diet, and the experimental groups were fed a basal diet supplemented with 0.8%, 1.6%, and 2.4% Green Tea Powder, respectively. The accommodation period was 14 d, and the experimental period was 60 d. The statistical software SPSS was used to perform a one-way analysis of variance (ANOVA) on the experimental data, and Duncan's method was used to perform multiple comparisons among groups. The results showed the following: compared with those of the control group, the average daily gain of the laying hens significantly decreased in the 1.6% Green Tea Powder group (p < 0.05); adding Green Tea Powder significantly reduced the content of malondialdehyde in the serum (p < 0.05), and the addition of 0.8% tea leaves significantly increased the immunoglobulin M and immunoglobulin A contents (p < 0.05); the egg yolk weight, eggshell thickness, eggshell strength, and yolk color of the laying hens significantly decreased in the 1.6% Green Tea Powder group (p < 0.05), and the addition of Green Tea Powder at the level of 2.4% significantly increased the percentage of umami, essential, and total amino acids (p < 0.05); and the structure of intestinal microorganisms was improved, and the abundance of Bacteroidetes and Bacteroidaceae significantly increased, while the abundance of Firmicutes and Lachnospiraceae significantly decreased (p < 0.05).

The Influence of Flavonoids with -Br, -Cl Atoms and -NO2, -CH3 Groups on the Growth Kinetics and the Number of Pathogenic and Probiotic Microorganisms

The pursuit of novel or modified substances based on a natural origin, like flavonoids, is essential in addressing the increasing number of diseases and bacterial resistance to antibiotics, as well as in maintaining intestinal balance and enhancing overall gut health. The primary goal of this research was to evaluate the impact of specific flavonoid compounds-chalcones, flavanones, and flavones-substituted with -Br, -Cl, -CH3, and -NO2 on both pathogenic and probiotic microorganisms. Additionally, this study aimed to understand these compounds' influence on standardized normal and pathologically altered intestinal microbiomes. 8-Bromo-6-chloroflavone 4'-O-β-D-(4″-O-methyl)-glucopyranoside and 8-bromo-6-chloroflavanone showed the most promising results as bactericidal agents. They significantly limited or inhibited the growth of pathogenic bacteria without adversely affecting the probiotic's growth. Digestion in vitro studies indicated that 6-methyl-8-nitroflavone and 8-bromo-6-chloroflavone positively modulated the gut microbiome by increasing beneficial bacteria and reducing potentially pathogenic microbes. This effect was most notable in microbiomes characteristic of older individuals and those recovering from chemotherapy or antibiotic treatments. This study underscores the therapeutic potential of flavonoid compounds, particularly those with specific halogen and nitro substitutions, in enhancing gut health.

Effects of Differently Processed Tea on the Gut Microbiota

Tea is a highly popular beverage, primarily due to its unique flavor and aroma as well as its perceived health benefits. The impact of tea on the gut microbiome could be an important means by which tea exerts its health benefits since the link between the gut microbiome and health is strong. This review provided a discussion of the bioactive compounds in tea and the human gut microbiome and how the gut microbiome interacts with tea polyphenols. Importantly, studies were compiled on the impact of differently processed tea, which contains different polyphenol profiles, on the gut microbiota from in vivo animal feeding trials, in vitro human fecal fermentation experiments, and in vivo human feeding trials from 2004-2024. The results were discussed in terms of different tea types and how their impacts are related to or different from each other in these three study groups.

The Postbiotic Properties of Butyrate in the Modulation of the Gut Microbiota: The Potential of Its Combination with Polyphenols and Dietary Fibers

The gut microbiota is a diverse bacterial community consisting of approximately 2000 species, predominantly from five phyla: Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Verrucomicrobia. The microbiota's bacterial species create distinct compounds that impact the host's health, including well-known short-chain fatty acids. These are produced through the breakdown of dietary fibers and fermentation of undigested carbohydrates by the intestinal microbiota. The main short-chain fatty acids consist of acetate, propionate, and butyrate. The concentration of butyrate in mammalian intestines varies depending on the diet. Its main functions are use as an energy source, cell differentiation, reduction in the inflammatory process in the intestine, and defense against oxidative stress. It also plays an epigenetic role in histone deacetylases, thus helping to reduce the risk of colon cancer. Finally, butyrate affects the gut-brain axis by crossing the brain-blood barrier, making it crucial to determine the right concentrations for both local and peripheral effects. In recent years, there has been a significant amount of attention given to the role of dietary polyphenols and fibers in promoting human health. Polyphenols and dietary fibers both play crucial roles in protecting human health and can produce butyrate through gut microbiota fermentation. This paper aims to summarize information on the key summits related to the negative correlation between intestinal microbiota diversity and chronic diseases to guide future research on determining the specific activity of butyrate from polyphenols and dietary fibers that can carry out these vital functions.

Unravelling the effect of extraction on anthocyanin functionality and prebiotic potential

Anthocyanins, considered as prebiotic ingredients for functional foods, were extracted from black soybean (BS), black grape (BG), black carrot (BCPm), and black rice (BR) using conventional solvent extraction (CSE) and microwave-assisted extraction (MAE). The study employed a split-plot design with CSE and MAE as main plot factors and anthocyanin extracts (AEs) as subplot factors. Anthocyanins were evaluated for stability (polymeric color, degradation index) and functionality (antioxidant capacity). Prebiotic potential on Lactobacillus rhamnosus, Lactobacillus acidophilus, Weissella confusa was assessed in fermented soymilk. MAE showed higher extraction yield than CSE in BG (3-fold), BS (2-fold), BCPm (1.2-fold), and BR (1.6-fold). Black grape (1255.76 mg/L) and black soybean (976.5 mg/L) had highest anthocyanin with better stability, functionality, and prebiotic potential. The SCFA concentration (propionic acid and butyric acid) increased significantly in BG fortified-fermented soymilk. Overall, anthocyanin-enriched soymilk exhibited higher prebiotic potential, with MAE as the superior extraction method for anthocyanin functionality and stability.

Cascade Microbial Metabolism of Ferulic Acid In Vitro Fermented by the Human Fecal Inoculum

Ferulic acid (FA), predominantly existing in most cereals, can modulate the gut microbiome, but the influences of its metabolites on the microbial population and FA-transforming microorganisms are still unclear. In this study, FA and its potential phenolic metabolites were fermented in vitro for 24 h with the human fecal inoculum. A comparable short chain fatty acid (SCFA) production trend was observed in the presence and absence of substrates, suggesting limited contribution of FA mechanism to SCFA formation. Dihydroferulic acid, 3-(3,4-dihydroxyphenyl)propionic acid, and 3-(3-hydroxyphenyl)propionic acid were ascertained to be successive metabolites of FA, by tracking the intermediate variation. FA remarkably promoted the absolute abundances of total bacteria, while different metabolites affected bacterial growth of selective genera. Specific genera were identified as quantitatively correlating to the content of FA and its metabolites. Ultimately, FA-mediated gut microbiota modulation involves both the action of metabolizing microbes and the regulation effects of metabolites on bacterial growth.

Pharmacological effects of ginseng and ginsenosides on intestinal inflammation and the immune system

Intestinal inflammatory imbalance and immune dysfunction may lead to a spectrum of intestinal diseases, such as inflammatory bowel disease (IBD) and gastrointestinal tumors. As the king of herbs, ginseng has exerted a wide range of pharmacological effects in various diseases. Especially, it has been shown that ginseng and ginsenosides have strong immunomodulatory and anti-inflammatory abilities in intestinal system. In this review, we summarized how ginseng and various extracts influence intestinal inflammation and immune function, including regulating the immune balance, modulating the expression of inflammatory mediators and cytokines, promoting intestinal mucosal wound healing, preventing colitis-associated colorectal cancer, recovering gut microbiota and metabolism imbalance, alleviating antibiotic-induced diarrhea, and relieving the symptoms of irritable bowel syndrome. In addition, the specific experimental methods and key control mechanisms are also briefly described.

Evaluation of dietary lignin on broiler performance, nutrient digestibility, cholesterol and triglycerides concentrations, gut morphometry, and lipid oxidation

Two trials were performed in order to evaluate the effects of dietary Kraft lignin inclusion on broiler performance, ileal nutrient digestibility, blood lipid profile, intestinal morphometry, and lipid oxidation of meat. Trial 1 was conducted in order to evaluate performance and ileal digestibility for the period of 1 to 21 d of age, randomly distributing 490 day-old broiler chicks across 5 dietary treatments with 14 replicates containing 7 birds each in metabolic cages, while trial 2 was executed in order to evaluate performance, blood parameters, intestinal morphometry, carcass yield and abdominal fat, and lipid oxidation for the period of 1 to 42 d of age, randomly distributing 900 day-old broiler chicks across 5 dietary treatments with 15 replicates of 12 birds each in floor pens, being each bird in trial 2 challenged with coccidiosis vaccine at 10 d of age. The treatments used in both trials were: positive control (PC): basal diet + antimicrobial; negative control (NC): Basal diet; NC1: NC + 1% lignin; NC2: NC + 2% lignin; NC3: NC + 3% lignin. For trial 1, it was observed that birds fed diets containing 1% lignin had a significant positive effect for BW, feed intake (FI), average daily weight gain (BWG) and feed conversion rate (FCR), similar to the PC, but also showing better EE, CP and AAs ileal digestibility percentages when compared to other treatments. For trial 2, it was observed that during the period of 21 to 35 d, the inclusion of lignin in the diet provided better results in animal performance, similar to the PC group, but at 42 d, animals fed with dietary lignin showed results lower than animals fed the PC diet (P < 0.05). Animals fed with increasing lignin concentrations showed decreasing levels of HDL (P < 0.05). As of intestinal morphometry, animals fed with 1% and 3% lignin showed longer intestinal length (P < 0.05). At 14 d of age, it was observed that animals fed with lignin showed oxidation levels similar to the control treatments. The inclusion of up to 1% lignin in the diet provides beneficial effects on productive performance and nutrient digestibility, while the inclusion of 2% lignin provided lower cholesterol levels, lower villus/crypt ratio, and better internal organ development, therefore, it can be considered an alternative to performance-enhancing antimicrobials in broiler chicken diets.

Effect of pine bark extract and its phenolic compounds on selected pathogenic and probiotic bacterial strains

Introduction

Inflammatory bowel disease (IBD) comprises a heterogeneous group of chronic diseases as ulcerative colitis (UC) and Crohn's disease (CD). IBD is the result of a dysregulation of intestinal homeostasis with a host's loss of tolerance toward normal enteric microflora. Plant-based extracts as phenolic compounds can play a role by modulating the intestinal inflammation response.

Methods

The in vitro antimicrobial activity of French maritime pine bark extract (PBE) and its phenolic constituents has been investigated in this study. Furthermore, the ability of PBE and phenolic compounds (caffeic acid, chlorogenic acid, ferulic acid, gallic acid and taxifolin) to modulate the microbiota has been assessed.

Results

Phenolic compounds and PBE showed a great inhibitory effect on the pathogens growth at the highest concentration assessed (1.25 mg/mL). The growth of E. sakazakii and E. faecalis were affected by the effect of caffeic acid and ferulic acid. Taxifolin showed a very strong activity against Listeria sp. (with a reduction ~98%). Gallic acid revealed antibacterial effect on S. aureus at different concentrations. The inhibitory effect of PBE was highly significant on the growth of E. coli O157:H7. PBE, caffeic acid and chlorogenic acid seem to provide the greatest beneficial effect on the probiotic bacteria. However, the highest concentrations of taxifolin may have impaired the growth of beneficial microbiota.

Conclusion

Present findings could be of interest for considering PBE and/or its phenolic constituents as protectors against gastrointestinal disturbances which lead to ulcerative colitis and Crohn's disease.

(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.

The effect of aqueous extract of Arctium lappa root on the survival of Lactobacillus acidophilus La-5 and Bifidobacterium bifidum Bb-12 and sensorial and physicochemical properties of synbiotic yogurt

The effect of aqueous extract of Arctium lappa root (ALE) on the survival of Lactobacillus acidophilus La-5 and Bifidobacterium bifidum Bb-12 probiotic bacteria and sensory and physicochemical properties of synbiotic yogurt was evaluated during 4 weeks storage at 4°C. According to this study, using 0.5% and 1% ALE significantly affected the survival of La-5 and Bb-12 during storage. The results showed that 1% of ALE counting of La-5 and Bb-12 has been reached from 6.96 and 8.14 Log CFU/g to 7.3 and 7.30 Log CFU/g after 28 days of storage. Moreover, adding 1% ALE to yogurt enhanced antioxidant activity and phenolic content to 1299.8 mg gallic acid/kg and 392.8 mg BHT eq./kg compared with the control (without extract) after storage, respectively. In general, in yogurt containing ALE, a decrease in Syneresis, undesirable changes in taste, texture, and appearance, and reduced overall acceptances were observed compared to the control. In conclusion, using this prebiotic compound (ALE) can improve nutritional properties and probiotic protection in yogurt during long time storage; thus, it is a good choice for application in the dairy industry.

Polyphenols: Role in Modulating Immune Function and Obesity

Polyphenols, long-used components of medicinal plants, have drawn great interest in recent years as potential therapeutic agents because of their safety, efficacy, and wide range of biological effects. Approximately 75% of the world's population still use plant-based medicinal compounds, indicating the ongoing significance of phytochemicals for human health. This study emphasizes the growing body of research investigating the anti-adipogenic and anti-obesity functions of polyphenols. The functions of polyphenols, including phenylpropanoids, flavonoids, terpenoids, alkaloids, glycosides, and phenolic acids, are distinct due to changes in chemical diversity and structural characteristics. This review methodically investigates the mechanisms by which naturally occurring polyphenols mediate obesity and metabolic function in immunomodulation. To this end, hormonal control of hunger has the potential to inhibit pro-obesity enzymes such as pancreatic lipase, the promotion of energy expenditure, and the modulation of adipocytokine production. Specifically, polyphenols affect insulin, a hormone that is essential for regulating blood sugar, and they also play a role, in part, in a complex web of factors that affect the progression of obesity. This review also explores the immunomodulatory properties of polyphenols, providing insight into their ability to improve immune function and the effects of polyphenols on gut health, improving the number of commensal bacteria, cytokine production suppression, and immune cell mediation, including natural killer cells and macrophages. Taken together, continuous studies are required to understand the prudent and precise mechanisms underlying polyphenols' therapeutic potential in obesity and immunomodulation. In the interim, this review emphasizes a holistic approach to health and promotes the consumption of a wide range of foods and drinks high in polyphenols. This review lays the groundwork for future developments, indicating that the components of polyphenols and their derivatives may provide the answer to urgent worldwide health issues. This compilation of the body of knowledge paves the way for future discoveries in the global treatment of pressing health concerns in obesity and metabolic diseases.

Effects of cashew nut shell extract and monensin on in vitro ruminal fermentation, methane production, and ruminal bacterial community

The objective of this study was to evaluate the effects of cashew nut shell extract (CNSE) and monensin on ruminal in vitro fermentation, CH4 production, and ruminal bacterial community structure. Treatments were as follows: control (CON, basal diet without additives); 2.5 μM monensin (MON); 0.1 mg CNSE granule/g DM (CNSE100); and 0.2 mg CNSE granule/g DM (CNSE200). Each treatment was incubated with 52 mL of buffered ruminal content and 500 mg of total mixed ration for 24 h using serum vials. The experiment was performed as a complete randomized block design with 3 runs. Run was used as a blocking factor. Each treatment had 5 replicates, in which 2 were used to determine nutrient degradability, and 3 were used to determine pH, NH3-N, volatile fatty acids, lactate, total gas, CH4 production, and bacterial community composition. Treatment responses for all data, excluding bacterial abundance, were analyzed with the GLIMMIX procedure of SAS v9.4. Treatment responses for bacterial community structure were analyzed with a PERMANOVA test run with the R package vegan. Orthogonal contrasts were used to test the effects of (1) additive inclusion (ADD: CON vs. MON, CNSE100, and CNSE200); (2) additive type (MCN: MON vs. CNSE100 and CNSE200); and (3) CNSE dose (DOS: CNSE100 vs. CNSE200). We observed that pH, acetate, and acetate:propionate ratio in the CNSE100 treatment were lower compared with CNSE200, and propionate in the CNSE100 treatment was greater compared with CNSE200. Compared with MON, CNSE treatments tended to decrease total lactate concentration. Total gas production of CON was greater by 2.63% compared with all treatments, and total CH4 production was reduced by 10.64% in both CNSE treatments compared with MON. Also, compared with MON, in vitro dry matter degradabilities in CNSE treatments were lower. No effects were observed for NH3-N or in vitro neutral detergent fiber degradability. Finally, the relative abundances of Prevotella, Treponema, and Schwartzia were lower, whereas the relative abundances of Butyrivibrio and Succinivibrio were greater in all treatments compared with CON. Overall, the inclusion of CNSE decreased CH4 production compared with MON, making CNSE a possible CH4 mitigation additive in dairy cattle diets.

Polyphenol intake and gastric cancer: A case-control study in the Brazilian Amazon region

BACKGROUND

Polyphenol intake has been associated with a decreased risk of some types of cancer, including gastric cancer (GC). However, few studies address this topic in the Latin American population. In the present study, we evaluated the association between polyphenol intake and the risk of GC in the Brazilian Amazon region.

METHODS

A case-control study was conducted in Belém (Amazon region) from July 2017 to February 2021. A total of 193 GC cases and 194 controls of both sexes, between 18 and 75 years old, were included in the study. Dietary data were collected using a validated food-frequency questionnaire and polyphenol intake identified using the Phenol-Explorer database. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI), with adjustement for potential confounders.

RESULTS

Cases and controls had similar total polyphenol intake (356.4 mg/1000 kcal/d and 331.1 mg/1000 kcal/d, respectively; p = 0.086). After adjusting for potential confounders, high consumption of flavan-3-ols (highest vs. lowest tertile: OR 0.41, 95% CI 0.18-0.94) and hydroxybenzoic acids (highest vs. lowest tertile: OR 0.24, 95% CI 0.10-0.56) was associated with a decreased risk of GC. The opposite was true regarding the intake of flavones (OR 2.46, 95% IC 1.17-5.18) and other polyphenols (OR 2.54, 95% IC 1.16-5.54). When stratifying according to anatomical topography, we observed that the intake of total flavonoids, flavan-3-ols, and flavanones reduced the risk of cardia GC while that of hydroxybenzoic acids reduced the risk of non-cardia GC. In addition, the intake of flavones and other polyphenols was associated with an increased risk of non-cardia GC. According to histologic subtypes, hydroxybenzoic acid intake was associated with a reduced risk of intestinal-type GC (OR 0.21, 95% IC 0.07-0.64), while flavone consumption was associated with an increased risk of diffuse-type GC (OR 2.59, 95% IC 1.05-6.42).

CONCLUSIONS

Our findings suggest that in the Brazilian Amazon region the high intake of flavan-3-ols and hydroxybenzoic acids is associated with a reduced risk of GC, suggesting a potential beneficial role of these compounds against GC.

The Role of Diet and Gut Microbiota in Alzheimer's Disease

Alzheimer's disease (AD), the most prevalent form of dementia, is characterized by the accumulation of amyloid-beta (Aβ) plaques and hyperphosphorylated tau tangles. Currently, Alzheimer's disease (AD) impacts 50 million individuals, with projections anticipating an increase to 152 million by the year 2050. Despite the increasing global prevalence of AD, its underlying pathology remains poorly understood, posing challenges for early diagnosis and treatment. Recent research suggests a link between gut dysbiosis and the aggregation of Aβ, the development of tau proteins, and the occurrence of neuroinflammation and oxidative stress are associated with AD. However, investigations into the gut-brain axis (GBA) in the context of AD progression and pathology have yielded inconsistent findings. This review aims to enhance our understanding of microbial diversity at the species level and the role of these species in AD pathology. Additionally, this review addresses the influence of confounding elements, including diet, probiotics, and prebiotics, on AD throughout different stages (preclinical, mild cognitive impairment (MCI), and AD) of its progression.

The intestinal-level metabolic benefits of green tea catechins: Mechanistic insights from pre-clinical and clinical studies

BACKGROUND

The intestinal-level host-microbiota interaction has been implicated in the pathogenesis of chronic diseases. The current review is intended to provide a comprehensive insight into deciphering whether intestinal-level bioactivities mediate the overall metabolic health benefits of green tea catechins.

PURPOSE

We have comprehensively discussed pre-clinical and clinical evidences of intestinal-level changes in metabolism, microbiota, and metabolome due to catechin-rich green tea treatments, ultimately limiting metabolic diseases. Exclusive emphasis has been given to purified catechins and green tea, and discussions on extraintestinal mechanisms of metabolic health benefits were avoided.

METHODS

A literature search for relevant pre-clinical and clinical studies was performed in various online databases (e.g., PubMed) using specific keywords (e.g., catechin, intestine, microbiota). Out of all the referred literature, ∼15% belonged to 2021-2023, ∼51% were from 2011-2020, and ∼32% from 2000-2010.

RESULT

The metabolic health benefits of green tea catechins are indeed influenced by the intestinal-level bioactivities, including reduction of mucosal inflammation and oxidative stress, attenuation of gut barrier dysfunction, decrease in intestinal lipid absorption and metabolism, favorable modulation of mucosal nuclear receptor signaling, alterations of the luminal global metabolome, and mitigation of the gut dysbiosis. The results from the recent clinical studies support the pre-clinical evidences. The challenges and pitfalls of the currently available knowledge on catechin bioactivities have been discussed, and constructive directions to harness the translational benefits of green tea through future interventions have been provided.

CONCLUSION

The metabolism, metabolome, and microbiota at the intestinal epithelia play critical roles in catechin metabolism, pharmacokinetics, bioavailability, and bioactivities. Especially the reciprocal interaction between the catechins and the gut microbiota dictates the metabolic benefits of catechins.

Food Polyphenols as Preventive Medicine

Reactive oxygen species (ROS) are the initiators in foods and in the stomach of oxidized dietary lipids, proteins, and lipid-oxidation end-products (ALEs), inducing in humans the development of several chronic diseases and cancer. Epidemiological, human clinical and animal studies supported the role of dietary polyphenols and derivatives in prevention of development of such chronic diseases. There is much evidence that polyphenols/derivatives at the right timing and concentration, which is critical, acts mostly in the aerobic stomach and generally in the gastrointestinal tract as reducing agents, scavengers of free radicals, trappers of reactive carbonyls, modulators of enzyme activity, generators of beneficial gut microbiota and effectors of cellular signaling. In the blood system, at low concentration, they act as generators of electrophiles and low concentration of H2O2, acting mostly as cellular signaling, activating the PI3K/Akt-mediated Nrf2/eNOS pathways and inhibiting the inflammatory transcription factor NF-κB, inducing the cells, organs and organism for eustress, adaptation and surviving.

Green tea extracts alleviate acetic acid-induced oral inflammation and reconstruct oral microbial balance in mice

Oral cavity contains the second largest microbial community in the human body. Due to the highly vascularized feature of mouth, oral microbes could directly access the bloodstream and affect the host healthy systemically. The imbalance of oral microbiota is closely related to various oral and systemic diseases. Green tea extracts (GTE) mainly contain tea polyphenols, alkaloids, amino acid, flavones, and so on, which equipped with excellent anti-inflammatory activities. Previous studies have demonstrated the beneficial effects of GTE on oral health. However, most researches used in vitro models or focused on limited microorganisms. In this study, the regulatory effect of GTE on oral microbiome and the alleviative effect on oral inflammation in vivo were evaluated. The results showed that GTE could efficiently alleviate the inflammations of the tongue, cheek pouch, as well as throat. GTE effectively inhibited the activation of NF-κB through the upregulation of the anti-inflammatory cytokine interleukin (IL)-10, consequently leading to reduced expression of pro-inflammatory cytokines IL-6 and tumor necrosis factor-α. The indexes of spleen and thymus were also elevated by GTE in stomatitis mice. Moreover, GTE promoted the growth of probiotics Lactobacillus and Bacillus, inhibited the reproduction of pathogens Achromobacter, reversing the microbiota disorders in oral cavity. This study not only presents a novel approach for enhancing oral microecology but also facilitates the wider adoption of tea consumption.

Gut microbial metabolites of dietary polyphenols and their potential role in human health and diseases

Polyphenols contribute as one of the largest groups of compounds among all the phytochemicals. Common sources of dietary polyphenols are vegetables, fruits, berries, cereals, whole grains, etc. Owing to their original form, they are difficult to get absorbed. Dietary polyphenols after undergoing gut microbial metabolism form bioaccessible and effective metabolites. Polyphenols and derived metabolites are all together a diversified group of compounds exhibiting pharmacological activities against cardiovascular, cancer, oxidative stress, inflammatory, and bacterial diseases. The formed metabolites are sometimes even more bioavailable and efficacious than the parent polyphenols. Studies on gut microbial metabolism of dietary polyphenols have introduced new approach for the use of polyphenol-rich food in the form of supplementary diet. This review provides insights on various aspects including classification of polyphenols, gut microbiota-mediated metabolism of polyphenols, chemistry of polyphenol metabolism, and pharmacological actions of gut microbial metabolites of polyphenols. It also suggests the use of polyphenols from marine source for the microbial metabolism studies. Till date, gut microbial metabolism of polyphenols from terrestrial sources is extensively studied as compared to marine polyphenols. Marine ecosystem is a profound but partially explored source of phytoconstituents. Among them, edible seaweeds contain high concentration of polyphenols, especially phlorotannins. Hence, microbial metabolism studies of seaweeds can unravel the pharmacological potential of marine polyphenol-derived metabolites.

Extraction Methods, Properties, Functions, and Interactions with Other Nutrients of Lotus Procyanidins: A Review

Lotus procyanidins, natural polyphenolic compounds isolated from the lotus plant family, are widely recognized as potent antioxidants that scavenge free radicals in the human body and exhibit various pharmacological effects, such as anti-inflammatory, anticancer, antiobesity, and hypoglycemic. With promising applications in food and healthcare, lotus procyanidins have attracted extensive attention in recent years. This review provides a comprehensive summary of current research on lotus procyanidins, including extraction methods, properties, functions, and interactions with other nutrient components. Furthermore, this review offers an outlook on future research directions, providing ideas and references for the exploitation and utilization of lotus.

Chia Phenolic Extract Appear to Improve Small Intestinal Functionality, Morphology, Bacterial Populations, and Inflammation Biomarkers In Vivo (Gallus gallus)

Phenolic compounds can act as a substrate for colonic resident microbiota. Once the metabolites are absorbed and distributed throughout the body, they can have diverse effects on the gut. The objective of this study was to evaluate the effects of the intra-amniotic administration of a chia phenolic extract on intestinal inflammation, intestinal barrier, brush border membrane functionality, intestinal microbiota, and morphology in vivo (Gallus gallus model). Cornish-cross fertile broiler eggs, at 17 days of embryonic incubation, were separated into groups as follows: non-injected (NI; this group did not receive an injection); 18 MΩ H2O (H2O; injected with ultrapure water), and 10 mg/mL (1%) chia phenolic extract (CPE; injected with phenolic extract diluted in ultrapure water). Immediately after hatch (21 days), chickens were euthanized and their small intestine, cecum, and cecum content were collected and analyzed. The chia phenolic extract reduced the tumor necrosis factor-alpha (TNF-α) and increased the sucrose isomaltase (SI) gene expression, reduced the Bifidobacterium and E. coli populations, reduced the Paneth cell diameter, increased depth crypt, and maintained villus height compared to the non-injected control group. Chia phenolic extract may be a promising beneficial compound for improving intestinal health, demonstrating positive changes in intestinal inflammation, functionality, microbiota, and morphology.

The Role of Green Tea on the Regulation of Gut Microbes and Prevention of High-Fat Diet-Induced Metabolic Syndrome in Mice

Green tea is a popular non-alcoholic beverage consumed worldwide and has been shown to be beneficial for human health. However, further exploration is needed to fully understand its function in reducing obesity and regulating gut microbes. Here, we investigated the modulatory effects of green tea and its functional components on high-fat diet (HF)-induced metabolic alterations and gut microbiota in obese mice. Our results showed that 1%, 2%, and 4% of green tea promotes weight loss, with the 2% and 4% groups exhibiting distinct gut microflora clusters compared to the HF group. These results were comparable to those observed in the tea polyphenols (TPP)-treated group, suggesting the TPP in green tea plays a crucial role in body weight control and gut microbiota regulation. Additionally, 32 bacteria were identified as potential obesity markers via 16S rRNA gene sequencing. The 16SrDNA gene is a chromosomal gene present in all bacterial species, highly conserved in structure and function, that can reflect the differences between different taxa. The 16S rRNA-based analysis revealed that Akkermansia, a gut-beneficial bacteria, significantly increased in the TPP group.

Unraveling Obesity: Transgenerational Inheritance, Treatment Side Effects, Flavonoids, Mechanisms, Microbiota, Redox Balance, and Bioavailability-A Narrative Review

Obesity is known as a transgenerational vicious cycle and has become a global burden due to its unavoidable complications. Modern approaches to obesity management often involve the use of pharmaceutical drugs and surgeries that have been associated with negative side effects. In contrast, natural antioxidants, such as flavonoids, have emerged as a promising alternative due to their potential health benefits and minimal side effects. Thus, this narrative review explores the potential protective role of flavonoids as a natural antioxidant in managing obesity. To identify recent in vivo studies on the efficiency of flavonoids in managing obesity, a comprehensive search was conducted on Wiley Online Library, Scopus, Nature, and ScienceDirect. The search was limited to the past 10 years; from the search, we identified 31 articles to be further reviewed. Based on the reviewed articles, we concluded that flavonoids offer novel therapeutic strategies for preventing obesity and its associated co-morbidities. This is because the appropriate dosage of flavonoid compounds is able to reduce adipose tissue mass, the formation of intracellular free radicals, enhance endogenous antioxidant defences, modulate the redox balance, and reduce inflammatory signalling pathways. Thus, this review provides an insight into the domain of a natural product therapeutic approach for managing obesity and recapitulates the transgenerational inheritance of obesity, the current available treatments to manage obesity and its side effects, flavonoids and their sources, the molecular mechanism involved, the modulation of gut microbiota in obesity, redox balance, and the bioavailability of flavonoids. In toto, although flavonoids show promising positive outcome in managing obesity, a more comprehensive understanding of the molecular mechanisms responsible for the advantageous impacts of flavonoids-achieved through translation to clinical trials-would provide a novel approach to inculcating flavonoids in managing obesity in the future as this review is limited to animal studies.

Beer-gut microbiome alliance: a discussion of beer-mediated immunomodulation via the gut microbiome

As a long-established fermented beverage, beer is rich in many essential amino acids, vitamins, trace elements, and bioactive substances that are involved in the regulation of many human physiological functions. The polyphenols in the malt and hops of beer are also important active compounds that interact in both directions with the gut microbiome. This review summarizes the mechanisms by which polyphenols, fiber, and other beneficial components of beer are fermentatively broken down by the intestinal microbiome to initiate the mucosal immune barrier and thus participate in immune regulation. Beer degradation products have anti-inflammatory, anticoagulant, antioxidant, and glucolipid metabolism-modulating potential. We have categorized and summarized reported data on changes in disease indicators and in vivo gut microbiota abundance following alcoholic and non-alcoholic beer consumption. The positive effects of bioactive substances in beer in cancer prevention, reduction of cardiovascular events, and modulation of metabolic syndrome make it one of the candidates for microecological modulators.

Liposomal Epigallocatechin-3-Gallate for the Treatment of Intestinal Dysbiosis in Children with Autism Spectrum Disorder: A Comprehensive Review

Autism Spectrum Disorder (ASD) is characterized by varying degrees of difficulty in social interaction and communication. These deficits are often associated with gastrointestinal symptoms, indicating alterations in both intestinal microbiota composition and metabolic activities. The intestinal microbiota influences the function and development of the nervous system. In individuals with ASD, there is an increase in bacterial genera such as Clostridium, as well as species involved in the synthesis of branched-chain amino acids (BCAA) like Prevotella copri. Conversely, decreased amounts of Akkermansia muciniphila and Bifidobacterium spp. are observed. Epigallocatechin-3-gallate (EGCG) is one of the polyphenols with the greatest beneficial activity on microbial growth, and its consumption is associated with reduced psychological distress. Therefore, the objective of this review is to analyze how EGCG and its metabolites can improve the microbial dysbiosis present in ASD and its impact on the pathology. The analysis reveals that EGCG inhibits the growth of pathogenic bacteria like Clostridium perfringens and Clostridium difficile. Moreover, it increases the abundance of Bifidobacterium spp. and Akkermansia spp. As a result, EGCG demonstrates efficacy in increasing the production of metabolites involved in maintaining epithelial integrity and improving brain function. This identifies EGCG as highly promising for complementary treatment in ASD.

Background and Perspectives on the Utilization of Canes' and Bunch Stems' Residues from Wine Industry as Sources of Bioactive Phenolic Compounds

Viticulture activity produces a significant amount of grapevine woody byproducts, such as bunch stems and canes, which constitute potential sources of a wide range of phenolic compounds (PCs) with purported applications. Recently, the study of these byproducts has been increased as a source of health-promoting phytochemicals. Antioxidant, antimicrobial, antifungal, and antiaging properties have been reported, with most of these effects being linked to the high content of PCs with antioxidant properties. This Review summarizes the data related to the qualitative and quantitative composition of PCs recovered from canes and bunch stems side streams of the wine industry, the influence that the different environmental and storage conditions have on the final concentration of PCs, and the current reported applications in specific technological fields. The objective is to give a complete valuation of the key factors to consider, starting from the field to the final extracts, to attain the most suitable and stable characterized product.

A comparative study of tea polyphenols and its palmitic acid-modified derivatives: their effects on the microbial ecosystem and biogenic amines in Chinese sausage

Control of biogenic amines (BAs) is important to guarantee the safety of sausage-like fermented meat products. This study investigated the influences of tea polyphenols (TP) and its lipophilic palmitic acid-modified derivatives, palmitoyl-TP (pTP) and palmitoyl-epigallocatechin gallate (pEGCG), on BAs and microbial ecosystem in Chinese sausages. TP, epigallocatechin gallate (EGCG), pTP, and pEGCG all reduced the formation of BAs and N-nitrosodimethylamine at 0.05% (g/g); yet, compared with TP and EGCG, the modified derivatives exhibited stronger action on BAs decreasing (P < 0.05), and pEGCG showed the highest effect (a reduction of total BAs from 376.22 to 168.98 mg/kg compared to control). The improved inhibitory effect of pTP and pEGCG should be attributed to their stronger dual-directional regulation of the bacterial and fungal communities during the natural fermentation of sausage. The modified pTP and pEGCG highly suppressed the growth of Staphylococcus, Candida, and Kurtzmaniella, all of which were positively correlated with BAs formation (all P < 0.05). However, pTP and pEGCG worked more effectively than the unmodified ones to promote Lactobacillus, Lactococcus, and Debaryomyces (all P < 0.05). The results above are significant for the application of palmitoyl-TP and similar TP derivatives in meat products in consideration of food safety.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05717-z.

Dietary Polyphenols as a Protection against Cognitive Decline: Evidence from Animal Experiments; Mechanisms and Limitations

Emerging evidence suggests that cognitive impairments may result from various factors, such as neuroinflammation, oxidative stress, mitochondrial damage, impaired neurogenesis, synaptic plasticity, blood-brain barrier (BBB) disruption, amyloid β protein (Aβ) deposition, and gut dysbiosis. Meanwhile, dietary polyphenol intake in a recommended dosage has been suggested to reverse cognitive dysfunction via various pathways. However, excessive intake of polyphenols could trigger unwanted adverse effects. Thus, this review aims to outline possible causes of cognitive impairments and how polyphenols alleviate memory loss via various pathways based on in vivo experimental studies. Thus, to identify potentially relevant articles, the keywords (1) nutritional polyphenol intervention NOT medicine AND neuron growth OR (2) dietary polyphenol AND neurogenesis AND memory impairment OR (3) polyphenol AND neuron regeneration AND memory deterioration (Boolean operators) were used in the Nature, PubMed, Scopus, and Wiley online libraries. Based on the inclusion and exclusion criteria, 36 research papers were selected to be further reviewed. The outcome of all the studies included supports the statement of appropriate dosage by taking into consideration gender differences, underlying conditions, lifestyle, and causative factors for cognitive decline, which will significantly boost memory power. Therefore, this review recapitulates the possible causes of cognitive decline, the mechanism of polyphenols involving various signaling pathways in modulating the memory, gut dysbiosis, endogenous antioxidants, bioavailability, dosage, and safety efficacy of polyphenols. Hence, this review is expected to provide a basic understanding of therapeutic development for cognitive impairments in the future.

Dietary Phenolic Compounds: Their Health Benefits and Association with the Gut Microbiota

Oxidative stress causes various diseases, such as type II diabetes and dyslipidemia, while antioxidants in foods may prevent a number of diseases and delay aging by exerting their effects in vivo. Phenolic compounds are phytochemicals such as flavonoids which consist of flavonols, flavones, flavanonols, flavanones, anthocyanidins, isoflavones, lignans, stilbenoids, curcuminoids, phenolic acids, and tannins. They have phenolic hydroxyl groups in their molecular structures. These compounds are present in most plants, are abundant in nature, and contribute to the bitterness and color of various foods. Dietary phenolic compounds, such as quercetin in onions and sesamin in sesame, exhibit antioxidant activity and help prevent cell aging and diseases. In addition, other kinds of compounds, such as tannins, have larger molecular weights, and many unexplained aspects still exist. The antioxidant activities of phenolic compounds may be beneficial for human health. On the other hand, metabolism by intestinal bacteria changes the structures of these compounds with antioxidant properties, and the resulting metabolites exert their effects in vivo. In recent years, it has become possible to analyze the composition of the intestinal microbiota. The augmentation of the intestinal microbiota by the intake of phenolic compounds has been implicated in disease prevention and symptom recovery. Furthermore, the “brain–gut axis”, which is a communication system between the gut microbiome and brain, is attracting increasing attention, and research has revealed that the gut microbiota and dietary phenolic compounds affect brain homeostasis. In this review, we discuss the usefulness of dietary phenolic compounds with antioxidant activities against some diseases, their biotransformation by the gut microbiota, the augmentation of the intestinal microflora, and their effects on the brain–gut axis.

Red osier dogwood extract vs. trimethoprim-sulfadiazine (Part 2). Pharmacodynamic effects on ileal and cecal microbiota of broiler chickens challenged orally with Salmonella Enteritidis

With the subsisting restrictions on the use of antibiotics in poultry production, the use of plant extracts has shown some promising antimicrobial capacity similar to antibiotics; however, such capacity is largely dependent on their total polyphenol concentration and profile. Given the emerging antimicrobial potential of red osier dogwood (ROD) extract, the study aimed to investigate the pharmacodynamic effect of ROD extract on the ileal and cecal microbiota of broiler chickens challenged orally with Salmonella Enteritidis (SE). A 21 d 4 × 2 factorial experiment was conducted based on 2 main factors, including diets and SE challenge. A total of 384 one-day-old mixed-sex Cobb-500 broiler chicks were randomly allotted to 4 dietary treatments; Negative control (NC), NC + 0.075 mg trimethoprim-sulfadiazine (TMP/SDZ)/kg of diet, and NC containing either 0.3 or 0.5% ROD extract. On d 1, half of the birds were orally challenged with 0.5 mL of phosphate-buffered saline (Noninfected group) and the remaining half with 0.5 mL of 3.1 × 105 CFU/mL SE (Infected group). Dietary treatments were randomly assigned to 8 replicate cages at 6 birds/cage. On d 21, 10 birds/treatment were euthanized and eviscerated to collect ileal and cecal digesta for gut microbiota analysis. The ileal and cecal microbiota was dominated by phyla Firmicutes, Proteobacteria, and Actinobacteriota. The SE infection decreased (P < 0.05) the relative abundance of Proteobacteria and Actinobacteriota in the ileum and ceca, respectively, however, it increased (P < 0.05) Proteobacteria in the ceca. Both 0.3 and 0.5% ROD extracts (P < 0.05) depressed the relative abundance of Actinobacteriota in the ileum but marginally improved (P < 0.05) it in the ceca compared to the TMP/SDZ treatment. Dietary TMP/SDZ increased (P < 0.05) genus Bifidobacterium at the ileal and cecal segments compared to other treatments. Dietary 0.3 and 0.5% marginally improved (P < 0.05) Bifidobacterium in the ceca and depressed (P < 0.05) Weissella and was comparably similar to TMP/SDZ in the ileum. Regardless of the dietary treatments and SE infection, alpha diversity differed (P < 0.05) between ileal and cecal microbiota. Beta diversity was distinct (P < 0.05) in both ileal and cecal digesta along the SE infection model. Conclusively, both ROD extract levels yielded a pharmacodynamic effect similar to antibiotics on ileal and cecal microbiota.

The content and distribution of 18 phenolic compounds in 462 batches of edible flowers from 73 species commercially available in China

Phenolic compounds are widely distributed in plant flowers. The present study systematically analyzed 18 phenolic compounds, represented by 4 monocaffeoylquinic acids, 4 dicaffeoylquinic acids, 5 flavones and 5 other phenolic acids, in 73 species (462 batches of samples) of edible flowers by a new established and validated HPLC-UV (high-performance liquid chromatography ultraviolet) (327/217 nm) method. Among all the species analyzed, 59 species were demonstrated to contain at least one or more quantifiable phenolic compounds, especially in families of Composite, Rosaceae and Caprifoliaceae. 3-Caffeoylquinic acid was found to be the most ubiquitous phenolic compound (in 193 batches of 73 species with the content between 0.061 and 65.10 mg/g), followed by rutin and isoquercitrin. While sinapic acid, 1-Caffeoylquinic acid and 1,3-dicaffeoylquinic acid (only in 5 batches of 1 specie with the content between 0.069 and 0.12 mg/g) were the least ones both in ubiquity and concentration. Additionally, the distribution and abundances of phenolic compounds were compared between these flowers, which would be valuable for auxiliary authentication or other usages. This research covered almost all edible and medicinal flowers in the Chinese market with 18 phenolic compounds therein quantified, which delivered a bird view of phenolic compounds in a broad perspective of edible flowers.

Possible Side Effects of Polyphenols and Their Interactions with Medicines

Polyphenols are an important component of plant-derived food with a wide spectrum of beneficial effects on human health. For many years, they have aroused great interest, especially due to their antioxidant properties, which are used in the prevention and treatment of many diseases. Unfortunately, as with any chemical substance, depending on the conditions, dose, and interactions with the environment, it is possible for polyphenols to also exert harmful effects. This review presents a comprehensive current state of the knowledge on the negative impact of polyphenols on human health, describing the possible side effects of polyphenol intake, especially in the form of supplements. The review begins with a brief overview of the physiological role of polyphenols and their potential use in disease prevention, followed by the harmful effects of polyphenols which are exerted in particular situations. The individual chapters discuss the consequences of polyphenols’ ability to block iron uptake, which in some subpopulations can be harmful, as well as the possible inhibition of digestive enzymes, inhibition of intestinal microbiota, interactions of polyphenolic compounds with drugs, and impact on hormonal balance. Finally, the prooxidative activity of polyphenols as well as their mutagenic, carcinogenic, and genotoxic effects are presented. According to the authors, there is a need to raise public awareness about the possible side effects of polyphenols supplementation, especially in the case of vulnerable subpopulations.

Modulation of the gut microbiota: opportunities and regulatory aspects

The human gut is an intensively colonized organ containing microorganisms that can be health-promoting or pathogenic. This feature led to the development of functional foods aiming to fortify the former category at the expense of the latter. Since long, cultured products, including probiotics fortification, have been used for humans as live microbial feed additions. This review presents some of the microbes used as probiotics and discusses how supplementation with probiotics may help initiate and/or restore eubiotic composition of gut microbiota. Additionally, it considers safety and regulatory aspects of probiotics.

Gut microbiota-mediated metabolism of green tea catechins and the biological consequences: An updated review

Multiple beneficial effects have been attributed to green tea catechins (GTCs). However, the bioavailability of GTCs is generally low, with only a small portion directly absorbed in the small intestine. The majority of ingested GTCs reaches the large intestinal lumen, and are extensively degraded via biotransformation by gut microbiota, forming many low-molecular-weight metabolites such as phenyl-γ-valerolactones, phenolic acids, butyrate, and acetate. This process not only improves the overall bioavailability of GTC-derived metabolites but also enriches the biological activities of GTCs. Therefore, the intra- and inter-individual differences in human gut microbiota as well as the resulting biological contribution of microbial metabolites are crucial for the ultimate health benefits. In this review, the microbial degradation of major GTCs was characterized and an overview of the in vitro models used for GTC metabolism was summarized. The intra- and inter-individual differences of human gut microbiota composition and the resulting divergence in the metabolic patterns of GTCs were highlighted. Moreover, the potential beneficial effects of GTCs and their gut microbial metabolites were also discussed. Overall, the microbial metabolites of GTCs with higher bioavailability and bioactive potency are key factors for the observed beneficial effects of GTCs and green tea consumption.

Bioaccessibility and Bioavailability of Diet Polyphenols and Their Modulation of Gut Microbiota

It is generally accepted that diet-derived polyphenols are bioactive compounds with several potentially beneficial effects on human health. In general, polyphenols have several chemical structures, and the most representative are flavonoids, phenolic acids, and stilbenes. It should be noted that the beneficial effects of polyphenols are closely related to their bioavailability and bioaccessibility, as many of them are rapidly metabolized after administration. Polyphenols-with a protective effect on the gastrointestinal tract-promote the maintenance of the eubiosis of the intestinal microbiota with protective effects against gastric and colon cancers. Thus, the benefits obtained from dietary supplementation of polyphenols would seem to be mediated by the gut microbiota. Taken at certain concentrations, polyphenols have been shown to positively modulate the bacterial component, increasing Lactiplantibacillus spp. and Bifidobacterium spp. involved in the protection of the intestinal barrier and decreasing Clostridium and Fusobacterium, which are negatively associated with human well-being. Based on the diet-microbiota-health axis, this review aims to describe the latest knowledge on the action of dietary polyphenols on human health through the activity of the gut microbiota and discusses micro-encapsulation of polyphenols as a strategy to improve the microbiota.

Improvement of Caciotta-like cheese nutritional value by means of enrichment with blackcurrant (Ribes nigrum) and Cornelian cherry (Cornus mas)

Introduction

In this study, we supplemented models of Caciotta-like cheese with blackcurrant (Ribes nigrum) and Cornelian cherry (Cornus mas), as they have a high content of polyphenols, known as phytochemicals associated with health benefits. We evaluated the microbial composition, organoleptic aspects, total phenolic content, and chemical composition of model cheeses enriched with blackcurrant and Cornelian cherry.

Methods

Two different suppliers have been tested: a conventional and an organic one. Two different conditions of preparation (freeze-dried and not freeze-dried) were tested in two different amounts (0.3 and 0.6% dry weight w/v milk volume). Polyphenols were determined using Folin-Ciocalteu reaction and spectrometry; microbial community was determined with selective 24 media and plate counts; composition was determined using nuclear magnetic resonance spectrometry. Organoleptic tests with an untrained panel have been performed.

Results

The enrichments with blackcurrant and Cornelian cherry increased the total polyphenol content in model cheeses, in particular, when blackcurrant and Cornelian cherry were from conventional farming. Blackcurrant-enriched cheeses showed higher counts of lactic acid bacteria, higher levels of organic acids, amino acids, gamma-aminobutyric acid, histamine, and lower amount of monosaccharides deriving from bacterial lactose fermentation in cheese, suggesting a positive effect of blackcurrant compounds on the growth and activity of lactic acid bacteria. The enrichments did not affect the acceptance of the cheese, neither by blackcurrant nor by Cornelian cherry incorporation, with the exception of the appearance.

Discussion

Overall, we showed that cheeses enriched with blackcurrant or Cornelian cherry from conventional farming increased the bioactive potential of the dairy product without having an adverse effect on the microbial community, physiochemical properties, or organoleptic properties.