Role of dietary polyphenols on gut microbiota, their metabolites and health benefits

Biological effects and mechanisms of dietary chalcones: latest research progress, future research strategies, and challenges

Dietary plants are an indispensable part of the human diet, and the various natural active compounds they contain, especially polyphenols, polysaccharides, and amino acids, have always been a hot topic of research among nutritionists. As precursors to polyphenolic substances in dietary plants, chalcones are not only widely distributed but also possess a variety of biological activities due to their unique structure. However, there has not yet been a comprehensive article summarizing the biological activities and mechanisms of dietary chalcones. This review began by discussing the dietary sources and bioavailability of chalcones, providing a comprehensive description of their biological activities and mechanisms of action in antioxidation, anti-inflammation, anti-tumor, and resistance to pathogenic microbes. Additionally, based on the latest research findings, some future research strategies and challenges for dietary chalcones have been proposed, including computer-aided design and molecular docking, targeted biosynthesis and derivative design, interactions between the gut microbiota and chalcones, as well as clinical research. It is expected that this review will contribute to supplementing the scientific understanding of dietary chalcones and promoting their practical application and the development of new food products.

(Poly)phenol-rich grape and blueberry extract prevents LPS-induced disruption of the blood-brain barrier through the modulation of the gut microbiota-derived uremic toxins

The dynamic protective capacity of (poly)phenols, attributed to their potent antioxidant and anti-inflammatory properties, has been consistently reported. Due to their capacity to alter gut microbiome composition, further actions of (poly)phenols may be exerted through the modulation of the microbiota-gut-brain axis. However, the underlying mechanisms remain poorly defined. Here, we investigated the protective effect of a (poly)phenol-rich grape and blueberry extract (Memophenol™), on the microbiota-gut-brain axis in a model of chronic low-grade inflammation (0.5 mg/kg/wk lipopolysaccharide (LPS) for 8 weeks). Dietary supplementation of male C57BL/6 J mice with Memophenol™ prevented LPS-induced increases in the microbe-derived uremia-associated molecules, indoxyl sulfate (IS) and trimethylamine N-oxide (TMAO). These changes coincided with shifts in gut microbiome composition, notably Romboutsia and Desulfovibrio abundance, respectively. In the brain, LPS exposure disrupted the marginal localisation of the endothelial tight junction ZO-1 and downregulated ZO-1 mRNA expression to an extent closely correlated with TMAO and IS levels; a process prevented by Memophenol™ intake. Hippocampal mRNA sequencing analysis revealed significant downregulation in regulatory pathways of neurodegeneration with Memophenol™ intake. These findings may indicate a novel protective role of the (poly)phenol-rich grape and blueberry extract on the endothelial tight junction component ZO-1, acting through modulation of gut microbial metabolism.

Targeting cow's milk allergy using hypoallergenic protein-polyphenol formulas: A proof of concept

Cow's milk allergy caused by a hypersensitivity to milk proteins has increased over the last years. Hypoallergenic responses can be induced by altering the structure of such proteins with chemical modifiers; this paper is about the creation of edible matrices based on polyphenols from orange peel. Some compounds were able to significantly lower the IgE binding from β-lactoglobulin allergic serum in sensitized patients. Such effects could also be observed for casein allergic serum in patients sensitized to both proteins. A certain inter-individual variability is observed, although polyphenols do actually induce salient structural changes. This indicates that molecular modifications aimed at oral treatments against food allergy may or may not correlate with reduced allergenicity, and hence the necessity for serum monitoring through immunological assays. Overall, the results are promising enough to validate the polyphenol-fortified approach. In addition, this study highlights the upgrading of vegetable waste, consistent with a circular economy in food chemistry.

Exploring the bioaccessibility of polyphenols and glucosinolates from Brassicaceae microgreens by combining metabolomics profiling and computational chemometrics

Microgreens constitute natural-based foods with health-promoting properties mediated by the accumulation of glucosinolates (GLs) and phenolic compounds (PCs), although their bioaccessibility may limit their nutritional potential. This work subjected eight Brassicaceae microgreens to in vitro gastrointestinal digestion and large intestine fermentation before the metabolomics profiling of PCs and GLs. The application of multivariate statistics effectively discriminated among species and their interaction with in vitro digestion phases. The flavonoids associated with arugula and the aliphatic GLs related to red cabbage and cauliflower were identified as discriminant markers among microgreen species. The multi-omics integration along in vitro digestion and fermentation predicted bioaccessible markers, featuring potential candidates that may eventually be responsible for these functional foods' nutritional properties. This combined analytical and computational framework provided a promising platform to predict the nutritional metabolome-wide outcome of functional food consumption, as in the case of microgreens.

Chemical structure and prebiotic activity of a Dictyophora indusiata polysaccharide fraction

This study aimed to investigate the chemical structure and prebiotic activity of a Dictyophora indusiata polysaccharide fraction DIP0p. Our results indicated that DIP0p belongs to a heteropolysaccharide composed of glucose, galactose, mannose and xylose, accounting for 53.25 %, 24.18 %, 19.19 % and 3.37 %, respectively. Methylation and NMR results suggested that the main glycosidic bonds of DIP0p is →3)-Glcp-(1 → with →4)-Glcp-(1→, →3,4)-Glcp-(1→, →3,4)-Galp-(1 → and →6)-Manp-(1 → branches. In addition, DIP0p increased the abundance of benificial bacteria during the in vitro fecal fermentation, including Phascolarctobacterium, Parabacteroides and Bifidobacterium. It is remarkable that DIP0p improved the level of acetic acid, propionic acid, and butyric acid of the fermentation system, which were 1.31, 1.52, and 2.64 folds higher than the Controls, respectively. In summary, this study comprehensively analyzed the structure and probiotic activity of DIP0p, which providing a theoretical basis for the development of the functional foods.

The Effects of Rice Bran on Neuroinflammation and Gut Microbiota in Ovariectomized Mice Fed a Drink with Fructose

Rice bran, which is abundant in dietary fiber and phytochemicals, provides multiple health benefits. Nonetheless, its effects on neuroinflammation and gut microbiota in postmenopausal conditions are still not well understood. This study investigated the effects of rice bran and/or tea seed oil supplementation in d-galactose-injected ovariectomized (OVX) old mice fed a fructose drink. The combination of d-galactose injection, ovariectomy, and fructose drink administration creates a comprehensive model that simulates aging in females under multiple metabolic stressors, including oxidative stress, estrogen deficiency, and high-sugar diets, and allows the study of their combined impact on metabolic disorders and related diseases. Eight-week-old and 6-8-month-old female C57BL/6 mice were used. The mice were divided into six groups: a sham + young mice, a sham + old mice, an OVX + soybean oil, an OVX + soybean oil with rice bran, an OVX + tea seed oil (TO), and an OVX + TO with rice bran diet group. The OVX groups were subcutaneously injected with d-galactose (100 mg/kg/day) and received a 15% (v/v) fructose drink. The rice bran and tea seed oil supplementation formed 10% of the diet (w/w). The results showed that the rice bran with TO diet increased the number of short-chain fatty acid (SCFA)-producing Clostridia and reduced the number of endotoxin-producing Tannerellaceae, which mitigated imbalances in the gut-liver-brain axis. Rice bran supplementation reduced the relative weight of the liver, levels of hepatic triglycerides and total cholesterol; aspartate transaminase and alanine aminotransferase activity; brain levels of proinflammatory cytokines, including interleukin-1β and tumor necrosis factor-α; and plasma 8-hydroxy-2-deoxyguanosine. This study concludes that rice bran inhibits hepatic fat accumulation, which mitigates peripheral metaflammation and oxidative damage and reduces neuroinflammation in the brain.

Organic arabic coffee husk: Antioxidant and cytoprotective properties and potential impacts on selected human intestinal bacterial populations of individuals with diabetes

Coffee husks are the main by-product of the coffee industry and have been traditionally discarded in the environment or used as fertilizers. However, recent studies have shown that coffee husks have bioactive compounds, such as phenolics and fiber-bound macro antioxidants, offering a range of potential health benefits. This study evaluated the antioxidant capacity, cytoprotective/cytotoxic properties, and stimulatory effects on the relative abundance of selected intestinal bacterial populations of individuals with diabetes of organic coffee husks. Organic coffee husk had good antioxidant capacity, maintained under simulated gastric conditions, with more than 50% of antioxidant capacity remaining. Organic coffee husk exerted cytoprotective properties in Caco-2 cells, indicating that cellular functions were not disturbed, besides not inducing oxidation. Overall, organic coffee husk promoted positive effects on the abundance of distinct intestinal bacterial groups of individuals with diabetes during in vitro colonic fermentation, with a higher relative abundance of Bifidobacterium spp., indicating the availability of components able to reach the colon to be fermented by intestinal microbiota. Organic coffee husk could be a circular material to develop new safe and pesticide-free functional ingredients with antioxidant and potential beneficial effects on human intestinal microbiota.

Cereal polyphenols inhibition mechanisms on advanced glycation end products and regulation on type 2 diabetes

Advanced glycation end products (AGEs), the products of non-enzymatic browning reactions between the active carbonyl groups of reducing sugars and the free amines of amino acids, are largely considered oxidative derivatives resulting from diabetic hyperglycemia, which are further recognized as a potential risk for insulin resistance (IR) and type 2 diabetes (T2D). The accumulation of AGEs can trigger numerous negative effects such as oxidative stress, carbonyl stress, inflammation, autophagy dysfunction and imbalance of gut microbiota. Recently, studies have shown that cereal polyphenols have the ability to inhibit the formation of AGEs, thereby preventing and alleviating T2D. In the meanwhile, phenolics compounds could produce different biological effects due to the quantitative structure activity-relationship. This review highlights the effects of cereal polyphenols as a nonpharmacologic intervention in anti-AGEs and alleviating T2D based on the effects of oxidative stress, carbonyl stress, inflammation, autophagy, and gut microbiota, which also provides a new perspective on the etiology and treatment of diabetes.

Impacts of Whole-Grain Soft Red, Whole-Grain Soft White, and Refined Soft White Wheat Flour Crackers on Gastrointestinal Inflammation and the Gut Microbiota of Adult Humans

Consumption of whole-grain wheat has been associated with positive health outcomes, but it remains unclear whether different types of wheat elicit varying effects on the gut microbiome and intestinal inflammation. The objectives of this research were to investigate the effect of two whole-grain wheat flours versus refined wheat flour on the diversity of the human gut microbiota, as well as on butyrate production capacity and gastrointestinal inflammation, using one-week dietary interventions. For this study, 28 participants were recruited, with ages ranging from 18 to 55 years and a mean BMI of 26.0 kg/m2. For four weeks, participants were provided 80 g daily servings of different wheat crackers: Week A was a run-in period of crackers made from soft white wheat flour, Week B crackers were whole-grain soft white wheat flour, Week C crackers were a wash-out period identical to Week A, and Week D crackers were whole-grain soft red wheat flour. At the end of each week, participants provided fecal samples that were analyzed for markers of intestinal inflammation, including lipocalin and calprotectin, using enzyme-linked immunosorbent assays and quantitative real-time PCR. The primary outcome, gut bacterial community alpha and beta diversity, was similar across timepoints. Three taxa significantly differed in abundance following both whole-grain wheat flour interventions: Escherichia/Shigella and Acidaminococcus were significantly depleted, and Lachnospiraceae NK4A136 group was enriched. Secondary outcomes determined that protein markers of intestinal inflammation and genes related to putative butyrate production capacity were similar throughout the study period, with no significant changes. Lipocalin concentrations ranged from 14.8 to 22.6 ng/mL while calprotectin ranged from 33.2 to 62.5 ng/mL across all 4 weeks. The addition of wheat crackers to the adult human subjects' usual diet had a minimal impact on their gastrointestinal inflammation or the gut microbiota.

Research progress on the functions and biosynthesis of theaflavins

Theaflavins are beneficial to human health due to various bioactivities. Biosynthesis of theaflavins using polyphenol oxidase (PPO) is advantageous due to cost effectiveness and environmental friendliness. In this review, studies on the mechanism of theaflavins formation, the procedures to screen and prepare PPOs, optimization of reaction systems and immobilization of PPOs were described. The challenges associated with the mass biosynthesis of theaflavins, such as poor enzyme activity, undesirable subproducts and inclusion bodies of recombinant PPOs were presented. Further strategies to solve these challenges and improve theaflavins production, including enzyme engineering, immobilization enzyme technology, water-immiscible solvent-water biphasic systems and recombinant enzyme technology, were proposed.

Physiological potential of different Sorghum bicolor varieties depending on their bioactive characteristics and antioxidant potential as well as different extraction methods

A comprehensive study of sorghum bran and flour was performed to explore the secondary metabolite profiles of differently coloured genotypes and to evaluate the variability in the antioxidant properties based on differences in polarity and solubility. This research included one red variety and one white variety. Among the samples, the red variety contained significantly greater amounts of secondary metabolites than did the white variety, with total polyphenol contents of 808.04 ± 63.89 mg.100 g-1 and 81.56 ± 3.87 mg.100 g-1, respectively. High-molecular-weight condensed tannin-type flavonoid extracts with high antioxidant activity were obtained by using relatively low-polarity acetone-water solvents, which was reflected by the measured antioxidant values. Among the methods used, the electron-donating Trolox equivalent antioxidant assay provided the highest antioxidant capacity, with values ranging from 118.5 to 182.6 μmol g-1 in the case of the red variety, in accordance with the electron donor properties of condensed tannins. Key secondary metabolites were identified using MS techniques and quantified using HPLC. Catechin and procyanidin B1 were found in the red variety at concentrations of 3.20 and 96.11 mg.100 g-1, respectively, while the concentrations in the white variety were under the limit of detection. All four tocopherols were found in sorghum, with the red variety containing a higher amount than the white variety, but the vitamin B complex concentrations were higher in the white variety. Overall, the red sorghum variety proved to be a better source of secondary metabolites with potential health benefits and could be used as a nutrient-rich food source.

Enhancing pediatric attention-deficit hyperactivity disorder treatment: exploring the gut microbiota effects of French maritime pine bark extract and methylphenidate intervention

Introduction

The pathogenesis of Attention-Deficit Hyperactivity Disorder (ADHD) is thought to be multifactorial, with a potential role for the bidirectional communication between the gut microbiome and brain development and function. Since the "golden-standard" medication therapy with methylphenidate (MPH) is linked to multiple adverse effects, there is a need for alternative treatment options such as dietary polyphenols. These secondary plant metabolites exert antioxidant and anti-inflammatory effects, but much less is known about their impact on the gut microbiota. Since polyphenols are believed to modulate gut microbial composition, interventions might be advantageous in ADHD therapy. Therefore, intervention studies with polyphenols in ADHD therapy investigating the gut microbial composition are highly relevant.

Methods

Besides the primary research questions addressed previously, this study explored a potential prebiotic effect of the polyphenol-rich French Maritime Pine Bark Extract (PBE) compared to MPH and a placebo in pediatric ADHD patients by studying their impact on the gut microbiota via amplicon sequencing of the full length 16S rRNA gene ribosomal subunit (V1-V9).

Results

One interesting finding was the high relative abundance of Bifidobacteria among all patients in our study cohort. Moreover, our study has identified that treatment (placebo, MPH and PBE) explains 3.94% of the variation in distribution of microbial taxa (adjusted p-value of 0.011).

Discussion

Our small sample size (placebo: n = 10; PBE: n = 13 and MPH: n = 14) did not allow to observe clear prebiotic effects in the patients treated with PBE. Notwithstanding this limitation, subtle changes were noticeable and some limited compositional changes could be observed.

Clinical Trial Registration

doi: 10.1186/S13063-017-1879-6.

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.

In vivo absorption and excretion in rats and in vitro digestion and fermentation by the human intestinal microbiota of 2-O-β-D-glucopyranosyl-L-ascorbic acid from the fruits of Lycium barbarum L

2-O-β-D-Glucopyranosyl-L-ascorbic acid (AA-2βG) from Lycium barbarum fruits has diverse bioactivities, yet its absorption and digestion are poorly understood. Therefore, the in vivo absorption of AA-2βG in rats was investigated in the present study. After oral administration to SD rats, AA-2βG was absorbed intact, reaching a peak plasma concentration of 472.32 ± 296.64 nM at 90 min, with fecal excretion peaking at 4-8 h and decreasing rapidly by 12-24 h, indicating a prolonged intestinal presence. Furthermore, the digestibility under simulated gastrointestinal conditions and the impact on the gut flora through in vitro fermentation of AA-2βG were investigated. The results reveal that AA-2βG resisted in in vitro simulated digestion, indicating potential interactions with the gut microbiota. The results of in vitro fermentation showed that AA-2βG regulated the composition of the gut microbiota by promoting Oscillospiraceae, Faecalibacterium, Limosilactobacillus, and Fusicatenibacter, while inhibiting Enterococcus, Phocaeicola, Bacteroides, and Streptococcus. Furthermore, at the species level, AA-2βG promoted the growth of Limosilactobacillus mucosae and Faecalibacterium prausnitzii, and inhibited the growth of Enterococcus. F. prausnitzii is a major producer of n-butyric acid, and the results of short-chain fatty acids also demonstrated a significant promotion of n-butyric acid. Therefore, the study on the absorption, excretion, and regulatory effects of AA-2βG on the gut microbiota supported its potential development as a functional food additive to enhance intestinal health and prevent diseases.

Mulberry polyphenols restored both small and large intestinal microflora in db/db mice, potentially alleviating type 2 diabetes

Polyphenols in mulberry fruit have potential anti-diabetic effects by targeting the gut microbiota. This study investigated how mulberry polyphenols (MPs) influence the microbiota of the small and large intestines and their effects on type 2 diabetes symptoms. The results showed lower microbiota densities in the small intestine. MP treatments improved microbiota richness and diversity in both intestines, similar to metformin. In particular, at a 400 mg kg-1 dose, mulberry polyphenols decreased Firmicutes, Lactobacillus, and Bacilli, while increasing Bacteroidetes, leading to elevated propionate and butyrate levels. Less abundant small intestinal microbiota, like Enterobacterales, Mycoplasmatales, Enterobacteriaceae, and Ureaplasma, were involved in regulating blood glucose and insulin levels. Functional analysis suggested that mulberry polyphenols reshaped the small intestinal microbiota to influence blood glucose balance via unknown pathways, while in the large intestine, they primarily affected blood glucose through carbohydrate transport and metabolism. Based on their ability to regulate the composition of intestinal flora, MPs likely improved glucose homeostasis by enhancing glucose utilization, supporting pancreatic tissue health, and increasing serum antioxidant capacity. However, the specific mechanisms underlying this potential are yet to be fully explored. This study provides new insights into the influence of MPs on remodeling the microbiota residing in both the small and large intestines, which thereby may contribute to the improvement of the pathophysiology of type 2 diabetes.

Possibility and challenge of plant-derived ferritin cages encapsulated polyphenols in the precise nutrition field

Polyphenols have attracted extensive attention due to their rich functional activities, such as antioxidant, anti-inflammatory and anti-tumor. However, the low solubility and poor stability limit their bioavailability and functional activities. Plant-derived ferritin cages have a unique hollow cage structure that can embed polyphenols to improve their unfavorable properties. Therefore, it is essential to adequately elaborate and summarize plant-derived ferritin cages to maximize their potential benefits in nutritional interventions. This review focuses on the fundamental properties of plant-derived ferritin cages, including the preparation process, purification technology, identification methods, and structural and functional properties. The relevant research on ferritin cages in polyphenol delivery has been summarized, including the delivery of water/lipid soluble polyphenols, modification of ferritin cages, and the interaction between polyphenols and ferritin cages. The research progress, shortcomings and prospects of plant-derived ferritin cages in precise nutrition are introduced. In addition, the relevant research on ferritin in immune response and protein engineering is also discussed to provide the theoretical basis for applying plant-derived ferritin cages in many frontier fields.

Germination-Induced Enhancement of Brown Rice Noodle Nutritional Profile and Gut Microbiota Modulation

This study explored how germination influences the starch digestion and intestinal fermentation characteristics of brown rice noodle. The study began with in vitro starch digestion tests to assess how germination affects starch digestibility in brown rice noodles, revealing an increase in rapidly digestible starch content and a decrease in resistant starch content. Subsequently, an in vitro human fecal fermentation model was used to simulate the human intestinal environment, showing that germination altered pH levels and the production of short-chain fatty acids, particularly by increasing propionate while decreasing acetate and butyrate. Additionally, the study noted a decrease in gut microbiota diversity following fermentation, accompanied by an increase in Megamonas growth and a decrease in Bacteroides and Bifidobacterium. In conclusion, these findings suggest that germination could enhance the nutritional value and intestinal probiotic properties of brown rice noodles. This research contributes valuable insights into the role of germination in improving the nutritional properties of rice-based products and provides a foundation for further exploration into the development of health-promoting rice noodles.

The Role of Gut Microbiome in Sleep Quality and Health: Dietary Strategies for Microbiota Support

Dietary components, including dietary fiber, unsaturated fatty acids, and polyphenols, along with meal timing and spacing, significantly affect the microbiota's capacity to produce various metabolites essential for quality sleep and overall health. This review explores the role of gut microbiota in regulating sleep through various metabolites such as short-chain fatty acids, tryptophan, serotonin, melatonin, and gamma-aminobutyric acid. A balanced diet rich in plant-based foods enhances the production of these sleep-regulating metabolites, potentially benefiting overall health. This review aims to investigate how dietary habits affect gut microbiota composition, the metabolites it produces, and the subsequent impact on sleep quality and related health conditions.

Fecal Microbiota Transplantation in Mice Exerts a Protective Effect Against Doxorubicin-Induced Cardiac Toxicity by Regulating Nrf2-Mediated Cardiac Mitochondrial Fission and Fusion

Aims: The relationship between the gut microbiota and cardiovascular system has been increasingly clarified. Fecal microbiota transplantation (FMT), used to improve gut microbiota, has been applied clinically for disease treatment and has great potential in combating doxorubicin (DOX)-induced cardiotoxicity. However, the application of FMT in the cardiovascular field and its molecular mechanisms are poorly understood. Results: During DOX-induced stress, FMT alters the gut microbiota and serum metabolites, leading to a reduction in cardiac injury. Correlation analysis indicated a close association between serum metabolite indole-3-propionic acid (IPA) and cardiac function. FMT and IPA achieve this by facilitating the translocation of Nfe2l2 (Nrf2) from the cytoplasm to the nucleus, thereby activating the expression of antioxidant molecules, reducing reactive oxygen species production, and inhibiting excessive mitochondrial fission. Consequently, mitochondrial function is preserved, leading to the mitigation of cardiac injury under DOX-induced stress. Innovation: FMT has the ability to modify the composition of the gut microbiota, providing not only protection to the intestinal mucosa but also influencing the generation of serum metabolites and regulating the Nrf2 gene to modulate the balance of cardiac mitochondrial fission and fusion. This study comprehensively demonstrates the efficacy of FMT in countering DOX-induced myocardial damage and elucidates the pathways linking the microbiota and the heart. Conclusion: FMT alters the gut microbiota and serum metabolites of recipient mice, promoting nuclear translocation of Nrf2 and subsequent activation of downstream antioxidant molecule expression, while inhibiting excessive mitochondrial fission to preserve cardiac integrity. Correlation analysis highlights IPA as a key contributor among differentially regulated metabolites.

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.

Exploring the Biogenic Transformation Mechanism of Polyphenols by Lactobacillus plantarum NCU137 Fermentation and Its Enhancement of Antioxidant Properties in Wolfberry Juice

This study investigated the transformation of polyphenols, including free and bound polyphenols during the fermentation of wolfberry juice by Lactobacillus plantarum NCU137. Results indicated that fermentation significantly increased the free polyphenols content and released bound polyphenols, enhancing the antioxidant activity. Analysis showed that there were 19 free polyphenols, mainly scopoletin, pyrogallol, and dihydroferulic acid, and 16 bound polyphenols, especially p-coumaric acid, feruloyl hexoside, and caffeic acid. A significant correlation was observed between the generation and degradation of polyphenols, and specific bound polyphenols peaked during the 24-48 h fermentation. Furthermore, reduced surface roughness and galacturonic acid content in wolfberry residue, along with increased pectinase activity, suggested substantial pectin degradation in the cell wall, which may be associated with the release of polyphenols, due to pectin serving as carriers for bound polyphenols. The fermentation also increased polyphenol oxidase and peroxidase activity, contributing to polyphenol breakdown. These findings provide insights for improving wolfberry juice production.

Dietary supplements: clinical cholesterol-lowering efficacy and potential mechanisms of action

This review aims to analyse the efficacy of dietary supplements in reducing plasma cholesterol levels. Focusing on evidence from meta-analyses of randomised controlled clinical trials, with an emphasis on potential mechanisms of action as supported by human, animal, and cell studies. Certain dietary supplements including phytosterols, berberine, viscous soluble dietary fibres, garlic supplements, soy protein, specific probiotic strains, and certain polyphenol extracts could significantly reduce plasma total and low-density lipoprotein (LDL) cholesterol levels by 3-25% in hypercholesterolemic patients depending on the type of supplement. They tended to be more effective in reducing plasma LDL cholesterol level in hypercholesterolemic individuals than in normocholesterolemic individuals. These supplements worked by various mechanisms, such as enhancing the excretion of bile acids, inhibiting the absorption of cholesterol in the intestines, increasing the expression of hepatic LDL receptors, suppressing the activity of enzymes involved in cholesterol synthesis, and activating the adenosine monophosphate-activated protein kinase signalling pathway.

Polysaccharides play an anti-fibrotic role by regulating intestinal flora: A review of research progress

Fibrosis is a common pathological process affecting multiple organs. It refers to an increase in fibrous connective tissue and a decrease in parenchymal cells in damaged tissues or organs. This may lead to structural damage and functional decline or even organ failure. The incidence of fibrosis is increasing worldwide, and the need for safe and effective therapeutic drugs and treatments is pivotal. The intestinal tract has a complex network of exchanging information with various tissues in the body. It contains a sizeable microbial community of which the homeostasis and metabolites are closely related to fibrosis. Polysaccharides are a class of biomolecules present in natural products; they have potential value as anti-fibrotic prebiotics. Recently, polysaccharides have been found to improve fibrosis in different organs by decreasing inflammation and modulating the immune function and intestinal microbiota. In this paper, we reviewed the progress made in research concerning polysaccharides and organ fibrosis in relation to the intestinal microbiota from the pathogenesis of fibrosis to the relationship between the intestinal flora and fibrosis. Furthermore, we provide ideas and references for future polysaccharide-drug discovery and strategies for the treatment of fibrosis.

Phenolic and Antioxidant Characterization of Fruit By-Products for Their Nutraceuticals and Dietary Supplements Valorization under a Circular Bio-Economy Approach

Agri-food by-products, obtained as waste from the food industry, negatively impact the global economy and the environment. In order to valorize waste materials from fruit juices and tomato sauces as upcycled materials rich in health-promoting compounds, they were characterized in terms of polyphenolic and protein content. The results obtained were compared with those collected for their final products. The recovery of polyphenols was performed via ultrasound-assisted extraction (UAE). A high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed and validated to depict the quali-quantitative polyphenolic profile of both the by-products and the final products. The antioxidant capacity of the resulting extracts was characterized by UV-Vis spectrophotometric assays in terms of total phenolic content (TPC) and total antioxidant status (TAS). Moreover, the protein content was assessed with the Kjeldahl method too. The results highlighted a significant quantity of polyphenols remaining in peach, apricot, and apple by-products, which were able to exert an antioxidant activity (in the range of 4.95 ± 5.69 × 10-1 to 7.06 ± 7.96 × 10-1 mmol Trolox 100 g-1 of dry weight (DW) sample). Conversely, the tomato by-products were highly rich in proteins (11.0 ± 2.00 to 14.4 ± 2.60 g of proteins 100 g-1 DW). The results proved that all by-products may potentially be sustainable ingredients with nutritional and functional value in a circular bio-economy prospect.

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.

Gut health benefits and associated systemic effects provided by functional components from the fermentation of natural matrices

Recently, the role of the gut microbiota in metabolic health, immunity, behavioral balance, longevity, and intestine comfort has been the object of several studies from scientific communities. They were encouraged by a growing interest from food industries and consumers toward novel fermented ingredients and formulations with powerful biological effects, such as pre, pro, and postbiotic products. Depending on the selected strains, the operating conditions, the addition of suitable reagents or enzymes, the equipment, and the reactor configurations, functional compounds with high bioactivity, such as short-chain fatty acids, gamma-aminobutyric acid, bioactive peptides, and serotonin, can be enhanced and/or produced through fermentation of several vegetable matrices. Otherwise, their formation can also be promoted directly in the gut after the dietary intake of fermented foods: In this case, fermentation will aim to increase the content of precursor substances, such as indigestible fibers, polyphenols, some amino acids, and resistant starch, which can be potentially metabolized by endogenous gut microorganisms and converted in healthy molecules. This review provides an overview of the main functional components currently investigated in literature and the associated gut health benefits. The current state of the art about fermentation technology as a promising functionalization tool to promote the direct or indirect formation of gut-health-enhancing components was deepened, highlighting the importance of optimizing microorganism selection, system setups, and process conditions according to the target compound of interest. The collected data suggested the possibility of gaining novel functional food ingredients or products rich in functional molecules through fermentation without performing additional extraction and purification stages, which are needed when conventional culture broths are used.

Curdlan-polyphenol complexes prepared by pH-driven effectively enhanced their physicochemical stability, antioxidant and prebiotic activities

In this study, the curdlan-polyphenol complexes were constructed by a pH-driven method. The interaction between curdlan and various hydrophobic polyphenols (curcumin, quercetin, and chlorogenic acid) was investigated. Curdlan could self-assemble into particles for loading polyphenols through hydrogen bonding and hydrophobic interactions. The three polyphenols were embedded in curdlan in an amorphous state. The curdlan-curcumin complex showed the lowest viscoelasticity but exhibited the highest curcumin loading ability (34.04 ± 1.73 mg/g). However, the curdlan-chlorogenic acid complex emerged the opposite trend, indicating that the loading capacity was associated with the hydrophobicity of polyphenols. The antioxidant activity of curdlan significantly increased after combining with polyphenols, which could be maintained during in vitro simulated gastrointestinal digestion. In particular, the curdlan-quercetin complex exhibited the highest antioxidant activity and short-chain fatty acid concentration, which could influence gut microbiota composition by promoting the proliferation of Prevotella and inhibiting the growth of Escherichia_Shigella. In conclusion, the curdlan-polyphenol complexes prepared by an alcohol-free pH-driven method could effectively enhance the gastrointestinal stability of polyphenols as well as increase the antioxidant and prebiotic activities of curdlan, which could be applied as a functional ingredient to improve gut health.

Dietary Phenolic Compounds-Wellbeing and Perspective Applications

Contemporary living is continuously leading to poor everyday choices resulting in the manifestation of various diseases. The benefits of plant-based nutrition are undeniable and research on the topic is rising. Modern man is now aware of the possibilities that plant nutrition can provide and is seeking ways to benefit from it. Dietary phenolic compounds are among the easily accessible beneficial substances that can exhibit antioxidant, anti-inflammatory, antitumor, antibacterial, antiviral, antifungal, antiparasitic, analgesic, anti-diabetic, anti-atherogenic, antiproliferative, as well as cardio-and neuroprotective activities. Several industries are exploring ways to incorporate biologically active substances in their produce. This review is concentrated on presenting current information about the dietary phenolic compounds and their contribution to maintaining good health. Additionally, this content will demonstrate the importance and prosperity of natural compounds for various fields, i.e., food industry, cosmetology, and biotechnology, among others.

Positive modulation of a new reconstructed human gut microbiota by Maitake extract helpfully boosts the intestinal environment in vitro

The human gut is a complex environment where the microbiota and its metabolites play a crucial role in the maintenance of a healthy state. The aim of the present work is the reconstruction of a new in vitro minimal human gut microbiota resembling the microbe-microbe networking comprising the principal phyla (Bacillota, Bacteroidota, Pseudomonadota, and Actinomycetota), to comprehend the intestinal ecosystem complexity. In the reductionist model, we mimicked the administration of Maitake extract as prebiotic and a probiotic formulation (three strains belonging to Lactobacillus and Bifidobacterium genera), evaluating the modulation of strain levels, the release of beneficial metabolites, and their health-promoting effects on human cell lines of the intestinal environment. The administration of Maitake and the selected probiotic strains generated a positive modulation of the in vitro bacterial community by qPCR analyses, evidencing the prominence of beneficial strains (Lactiplantibacillus plantarum and Bifidobacterium animalis subsp. lactis) after 48 hours. The bacterial community growths were associated with the production of metabolites over time through GC-MSD analyses such as lactate, butyrate, and propionate. Their effects on the host were evaluated on cell lines of the intestinal epithelium and the immune system, evidencing positive antioxidant (upregulation of SOD1 and NQO1 genes in HT-29 cell line) and anti-inflammatory effects (production of IL-10 from all the PBMCs). Therefore, the results highlighted a positive modulation induced by the synergic activities of probiotics and Maitake, inducing a tolerogenic microenvironment.

Molecular crosstalk between polyphenols and gut microbiota in cancer prevention

A growing body of evidence suggests that cancer remains a significant global health challenge, necessitating the development of novel therapeutic approaches. In recent years, the molecular crosstalk between polyphenols and gut microbiota has emerged as a promising pathway for cancer prevention. Polyphenols, abundant in many plant-based foods, possess diverse bioactive properties, including antioxidant, anti-inflammatory, and anticancer activities. The gut microbiota, a complex microbial community residing in the gastrointestinal tract, plays a crucial role in a host's health and disease risks. This review highlights cancer suppressive and oncogenic mechanisms of gut microbiota, the intricate interplay between gut microbiota modulation and polyphenol biotransformation, and the potential therapeutic implications of this interplay in cancer prevention. Furthermore, this review explores the molecular mechanisms underpinning the synergistic effects of polyphenols and the gut microbiota, such as modulation of signaling pathways and immune response and epigenetic modifications in animal and human studies. The current review also summarizes the challenges and future directions in this field, including the development of personalized approaches that consider interindividual variations in gut microbiota composition and function. Understanding the molecular crosstalk could offer new perspectives for the development of personalized cancer therapies targeting the polyphenol-gut axis. Future clinical trials are needed to validate the potential role of polyphenols and gut microbiota as innovative therapeutic strategies for cancer treatment.

(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.

Interindividual differences in aronia juice tolerability linked to gut microbiome and metabolome changes-secondary analysis of a randomized placebo-controlled parallel intervention trial

BACKGROUND

Aronia melanocarpa is a berry rich in polyphenols known for health benefits. However, the bioavailability of polyphenols has been questioned, and the individual taste acceptance of the fruit with its specific flavor varies. We recently observed substantial differences in the tolerability of aronia juice among healthy females, with half of the individuals tolerating aronia juice without complaints. Given the importance of the gut microbiome in food digestion, we investigated in this secondary analysis of the randomized placebo-controlled parallel intervention study (ClinicalTrials.gov registration: NCT05432362) if aronia juice tolerability was associated with changes in intestinal microbiota and bacterial metabolites, seeking for potential mechanistic insights into the impact on aronia polyphenol tolerance and metabolic outcomes.

RESULTS

Forty females were enrolled for this 6-week trial, receiving either 100 ml natural aronia juice (verum, V) twice daily or a polyphenol-free placebo (P) with a similar nutritional profile, followed by a 6-week washout. Within V, individuals were categorized into those who tolerated the juice well (Vt) or reported complaints (Vc). The gut microbiome diversity, as analyzed by 16S rRNA gene-based next-generation sequencing, remained unaltered in Vc but changed significantly in Vt. A MICOM-based flux balance analysis revealed pronounced differences in the 40 most predictive metabolites post-intervention. In Vc carbon-dioxide, ammonium and nine O-glycans were predicted due to a shift in microbial composition, while in Vt six bile acids were the most likely microbiota-derived metabolites. NMR metabolomics of plasma confirmed increased lipoprotein subclasses (LDL, VLDL) post-intervention, reverting after wash out. Stool samples maintained a stable metabolic profile.

CONCLUSION

In linking aronia polyphenol tolerance to gut microbiota-derived metabolites, our study explores adaptive processes affecting lipoprotein profiles during high polyphenol ingestion in Vt and examines effects on mucosal gut health in response to intolerance to high polyphenol intake in Vc. Our results underpin the importance of individualized hormetic dosing for beneficial polyphenol effects, demonstrate dynamic gut microbiome responses to aronia juice, and emphasize personalized responses in polyphenol interventions.

Novel protective aspects of dietary polyphenols against pesticidal toxicity and its prospective application in rice-fish mode: A Review

The rice fish system represents an innovative and sustainable approach to integrated farming, combining rice cultivation with fish rearing in the same ecosystem. However, one of the major challenges in this system is the pesticidal pollution resulting from various sources, which poses risks to fish health and overall ecosystem balance. In recent years, dietary polyphenols have emerged as promising bioactive compounds with potential chemo-preventive and therapeutic properties. These polyphenols, derived from various plant sources, have shown great potential in reducing the toxicity of pesticides and improving the health of fish within the rice fish system. This review aims to explore the novel aspects of using dietary polyphenols to mitigate pesticidal toxicity and enhance fish health in the rice fish system. It provides comprehensive insights into the mechanisms of action of dietary polyphenols and their beneficial effects on fish health, including antioxidant, anti-inflammatory, and detoxification properties. Furthermore, the review discusses the potential application methods of dietary polyphenols, such as direct supplementation in fish diets or through incorporation into the rice fields. By understanding the interplay between dietary polyphenols and pesticides in the rice fish system, researchers can develop innovative and sustainable strategies to promote fish health, minimize pesticide impacts, and ensure the long-term viability of this integrated farming approach. The information presented in this review will be valuable for scientists, aqua-culturists, and policymakers aiming to implement eco-friendly and health-enhancing practices in the rice fish system.

Local and Systemic Effects of Bioactive Food Ingredients: Is There a Role for Functional Foods to Prime the Gut for Resilience?

Scientific advancements in understanding the impact of bioactive components in foods on the gut microbiota and wider physiology create opportunities for designing targeted functional foods. The selection of bioactive ingredients with potential local or systemic effects holds promise for influencing overall well-being. An abundance of studies demonstrate that gut microbiota show compositional changes that correlate age and disease. However, navigating this field, especially for non-experts, remains challenging, given the abundance of bioactive ingredients with varying levels of scientific substantiation. This narrative review addresses the current knowledge on the potential impact of the gut microbiota on host health, emphasizing gut microbiota resilience. It explores evidence related to the extensive gut health benefits of popular dietary components and bioactive ingredients, such as phytochemicals, fermented greens, fibres, prebiotics, probiotics, and postbiotics. Importantly, this review distinguishes between the potential local and systemic effects of both popular and emerging ingredients. Additionally, it highlights how dietary hormesis promotes gut microbiota resilience, fostering better adaptation to stress-a hallmark of health. By integrating examples of bioactives, this review provides insights to guide the design of evidence-based functional foods aimed at priming the gut for resilience.

In vitro conversion of ellagic acid to urolithin A by different gut microbiota of urolithin metabotype A

The metabolite urolithin A, a metabolite of the dietary polyphenol ellagic acid (EA), has significant health benefits for humans. However, studies on the gut microbiota involved in ellagic acid metabolism are limited. In this study, we conducted in vitro fermentation of EA using human intestinal microbiome combined with antibiotics (vancomycin, polymyxin B sulfate, and amphotericin B). Liquid chromatography-mass spectrometry (LC-MS/MS) analysis demonstrated that the production capacity of urolithin A by gut microbiota co-treated with polymyxin B sulfate and amphotericin B (22.39 µM) was similar to that of untreated gut microbiota (24.26 µM). Macrogenomics (high-throughput sequencing) was used to analyze the composition and structure of the gut microbiota. The results showed that the abundance of Bifidobacterium longum, Bifidobacterium adolescentis, and Bifidobacterium bifidum in the gut microbiota without antibiotic treatment or co-treated with polymyxin B sulfate and amphotericin B during EA fermentation was higher than that in other antibiotic treatment gut microbiota. Therefore, B. longum, B. adolescentis, and B. bifidum may be new genera involved in the conversion of EA to urolithin A. In conclusion, the study revealed unique interactions between polyphenols and gut microbiota, deepening our understanding of the relationship between phenolic compounds like EA and the gut microbiota. These findings may contribute to the development of gut bacteria as potential probiotics for further development. KEY POINTS: • Intestinal microbiome involved in ellagic acid metabolism. • Gram-positive bacteria in the intestinal microbiome are crucial for ellagic acid metabolism. • Bifidobacterium longum, Bifidobacterium adolescentis, and Bifidobacterium bifidum participate in ellagic acid metabolism.

Germination and probiotic fermentation: a way to enhance nutritional and biochemical properties of cereals and millets

Probiotics have become increasingly popular as consumers demand balanced nutrition and health benefits from their diet. However, lactose intolerance and allergies to milk proteins may make dairy-based probiotics unsuitable for some individuals. Thus, probiotics derived from cereals and millets have shown promise as an alternative to dairy probiotics. Soaking, germination, and fermentation can reduce the anti-nutritional factors present in cereal grains and improve nutrient quality and bioactive compounds. Biochemical properties of probiotics are positively influenced by fermentation and germination. Thus, the current review provides an overview of the effect of fermentation and germination on the biochemical properties of probiotics. Further, probiotics made from non-dairy sources may prevent intestinal infections, improve lactose metabolism, reduce cholesterol, enhance immunity, improve calcium absorption, protein digestion, and synthesize vitamins. Finally, health-conscious consumers seeking non-dairy probiotic options can now choose from a wider variety of low-cost, phytochemically rich probiotics derived from germinated and fermented cereal grains.

Ameliorative potential of synbiotic combination of Lactobacillus sp. and polyphenols against Benzo[a]pyrene-induced toxicity in Caco-2 cell line

Exposure to benzo[a]pyrene (B[a]P), a major global food safety concern, is often associated with increasing incidence of colorectal cancers. This in-vitro study was focused on the identification of potential B[a]P-adsorbing Lactobacillus strains and evaluation of the ameliorative effect of synbiotic combination of selected Lactobacillus sp. and polyphenols (quercetin or resveratrol) against B[a]P-induced intestinal toxicity in Caco-2 cells. Preliminary studies lead to the selection of Lactiplantibacillus plantarum MTCC 25433 strain that showed 86% of B[a]P adsorption in 2 h as compared to L. rhamnosus GG that showed 74% of B[a]P adsorption. B[a]P adsorption by MTCC 25433 was reduced to 9%, 16% and 20% upon pre-treatment with SDS, NaIO4 and mutanolysin, attributing the involvement of cell wall proteins and polysaccharides in the adsorption. Additionally, peptidoglycan of both strains adsorbed >50% of B[a]P. In-vitro assays revealed that the selected LAB mitigated the B[a]P-induced epithelial cell damage. Among the polyphenols, quercetin, resveratrol and curcumin, varied in their potency to mitigate B[a]P-induced oxidative stress, with curcumin being least effective. Combinations of selected Lactobacillus sp. and polyphenols were more potent in averting B[a]P-induced toxicity via increase in GSH (17-30 %), SOD (50-88 %), catalase (19-45 %), and reduction in IL-8 secretion (14-28 %) and barrier dysfunction. Principal component analysis affirmed the superior potency of combination of L. plantarum MTCC 25433 and quercetin in averting B[a]P-induced toxicity. Overall, this study highlighted a novel promising strategy of synbiotic combination of Lactobacillus sp. and polyphenols (quercetin or resveratrol) in alleviating the B[a]P-induced toxicity in intestinal epithelial cells.

New horizon to the world of gut microbiome: seeds germination

The second brain of humans has been known as the microbiome. The microbiome is a dynamic network composed of commensal bacteria, archaea, viruses, and fungi colonized in the human gastrointestinal tract. They play a vital role in human health by metabolizing components, maturation of the immune system, and taking part in the treatment of various diseases. Two important factors that can affect the gut microbiome's composition and/or function are the food matrix and methods of food processing. Based on scientific research, the consumption of whole grains can make positive changes in the gut microbiota. Seeds contain different microbiota-accessible substrates that can resist digestion in the upper gastrointestinal tract. Seed germination is one of the simplest and newest food processing approaches to improve seeds' bioavailability and overall nutritional value. During germination, the dormant hydrolytic seed's enzymes have been activated and then metabolize the macromolecules. The quality and quantity of bioactive compounds like prebiotics, fiber, phenolic compounds (PC), total free amino acids, and γ-aminobutyric acid (GABA) can increase even up to 4-10 folds in some cases. These components stimulate the survival and growth of healthful bacteria like probiotics and boost their activity. This effect depends on several parameters, e.g., germination environmental conditions. This review aims to provide up-to-date and latest research about promoting bioactive components during seed germination and investigating their impacts on gut microbiota to understand the possible direct and indirect effects of seed germination on the microbiome and human health.

Chinese herbal medicines: The modulator of nonalcoholic fatty liver disease targeting oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are a natural treasure trove; their secondary metabolites participate in several pharmacological processes, making them a crucial component in the synthesis of novel pharmaceuticals and serving as a reserve resource foundation in this process. Nonalcoholic fatty liver disease (NAFLD) is associated with the risk of progression to hepatitis and liver cancer. The "Treatise on Febrile Diseases," "Compendium of Materia Medica," and "Thousand Golden Prescriptions" have listed herbal remedies to treat liver diseases.

AIM OF THE REVIEW

Chinese herbal medicines have been widely used for the prevention and treatment of NAFLD owing to their efficacy and low side effects. The production of reactive oxygen species (ROS) during NAFLD, and the impact and potential mechanism of ROS on the pathogenesis of NAFLD are discussed in this review. Furthermore, common foods and herbs that can be used to prevent NAFLD, as well as the structure-activity relationships and potential mechanisms, are discussed.

METHODS

Web of Science, PubMed, CNKI database, Google Scholar, and WanFang database were searched for natural products that have been used to treat or prevent NAFLD in the past five years. The primary search was performed using the following keywords in different combinations in full articles: NAFLD, herb, natural products, medicine, and ROS. More than 400 research papers and review articles were found and analyzed in this review.

RESULTS

By classifying and discussing the literature, we obtained 86 herbaceous plants, 28 of which were derived from food and 58 from Chinese herbal medicines. The mechanism of NAFLD was proposed through experimental studies on thirteen natural compounds (quercetin, hesperidin, rutin, curcumin, resveratrol, epigallocatechin-3-gallate, salvianolic acid B, paeoniflorin, ginsenoside Rg1, ursolic acid, berberine, honokiol, emodin). The occurrence and progression of NAFLD could be prevented by natural antioxidants through several pathways to prevent ROS accumulation and reduce hepatic cell injuries caused by excessive ROS.

CONCLUSION

This review summarizes the natural products and routinely used herbs (prescription) in the prevention and treatment of NAFLD. Firstly, the mechanisms by which natural products improve NAFLD through antioxidant pathways are elucidated. Secondly, the potential of traditional Chinese medicine theory in improving NAFLD is discussed, highlighting the safety of food-medicine homology and the broader clinical potential of multi-component formulations in improving NAFLD. Aiming to provide theoretical basis for the prevention and treatment of NAFLD.

Microbial Phenolic Metabolites Are Associated with Improved Cognitive Health

SCOPE

Diets rich in polyphenols has been associated with better cognitive performance. The aim of this study is to assess the relationship between microbial phenolic metabolites (MPM) in urine and cognition in the context of an older population at high cardiovascular risk.

METHODS AND RESULTS

A cross-sectional analysis is conducted in 400 individuals of the PREDIMED-Plus study. Liquid chromatography coupled to mass spectrometry is used to identify urinary MPM. Mediterranean diet (MedDiet) adherence is estimated with a 17-item questionnaire and cognitive function is evaluated with a battery of neuropsychological tests. Multivariable-adjusted linear regression models are fitted to assess the relationship of urinary MPM with the MedDiet and cognitive tests. Protocatechuic acid and enterolactone glucuronide are associated with higher adherence to the MedDiet. Regarding cognitive function, protocatechuic acid, vanillic acid glucuronide, 3-hydroxybenzoic acid, enterodiol glucuronide, and enterolactone glucuronide are directly associated with a global composite score of all the cognitive tests. Furthermore, protocatechuic acid and enterolactone glucuronide are associated with higher scores in the Mini-Mental State Examination, whereas enterodiol glucuronide is associated with improved Clock Drawing Test scores.

CONCLUSIONS

These results suggest that the MedDiet is linked to MPM associated with better cognitive performance in an older population.

The human gut microbiome and aging

The composition of the human gut microbiome has been observed to change over the course of an individual's life. From birth, it is shaped by mode of delivery, diet, environmental exposures, geographic location, exposures to medications, and by aging itself. Here, we present a narrative review of the gut microbiome across the lifespan with a focus on its impacts on aging and age-related diseases in humans. We will describe how it is shaped, and features of the gut microbiome that have been associated with diseases at different phases of life and how this can adversely affect healthy aging. Across the lifespan, and especially in old age, a diverse microbiome that includes organisms suspected to produce anti-inflammatory metabolites such as short-chain fatty acids, has been reported to be associated with healthy aging. These findings have been remarkably consistent across geographic regions of the world suggesting that they could be universal features of healthy aging across all cultures and genetic backgrounds. Exactly how these features of the microbiome affect biologic processes associated with aging thus promoting healthy aging will be crucial to targeting the gut microbiome for interventions that will support health and longevity.

Unlocking New Approaches to Urolithiasis Management Via Nutraceuticals

Urolithiasis, commonly known as kidney stones, is characterized by the formation of hard deposits in the urinary tract. These stones can cause severe pain and discomfort, and their management typically involves a combination of medical interventions and lifestyle modifications. According to the literature, 30% and 50% of urolithiasis cases recur. Between 9 and 12% of persons in industrialised countries are predicted to have urolithiasis at some time. Due to the high frequency of stone formation, recurrent nature, and prevalence in adults, it has a significant impact on society, the person, and the health care system. Adopting the best prophylactic measures is crucial in light of these developments to decrease the impact of urolithiasis on individuals and society. In recent years, there has been growing interest in the potential role of nutraceuticals in the management of urolithiasis. Nutraceuticals, such as herbal extracts, vitamins, minerals, and probiotics, have gained recognition for their potential in promoting urinary health and reducing the risk of urolithiasis. These compounds can aid in various ways, including inhibiting crystal formation, enhancing urine pH balance, reducing urinary calcium excretion, and supporting kidney function. Additionally, nutraceuticals can help alleviate symptoms associated with urolithiasis, such as pain and inflammation. While medical interventions remain crucial, incorporating nutraceuticals into a comprehensive management plan can offer a holistic approach to urolithiasis, improving patient outcomes and quality of life. Therefore, nutraceuticals may be a desirable choice for treating and avoiding recurring urolithiasis for patients and medical professionals. Therefore, the present study has focused on nutraceuticals' role in preventing urolithiasis.

Bifidobacterium alleviate metabolic disorders via converting methionine to 5'-methylthioadenosine

Dietary patterns and corresponding gut microbiota profiles are associated with various health conditions. A diet rich in polyphenols, primarily plant-based, has been shown to promote the growth of probiotic bacteria in the gastrointestinal tract, subsequently reducing the risk of metabolic disorders in the host. The beneficial effects of these bacteria are largely due to the specific metabolites they produce, such as short-chain fatty acids and membrane proteins. In this study, we employed a metabolomics-guided bioactive metabolite identification platform that included bioactivity testing using in vitro and in vivo assays to discover a bioactive metabolite produced from probiotic bacteria. Through this approach, we identified 5'-methylthioadenosine (MTA) as a probiotic bacterial-derived metabolite with anti-obesity properties. Furthermore, our findings indicate that MTA administration has several regulatory impacts on liver functions, including modulating fatty acid synthesis and glucose metabolism. The present study elucidates the intricate interplay between dietary habits, gut microbiota, and their resultant metabolites.

Evaluation of Olive Leaf Phenolic Compounds' Gastrointestinal Stability Based on Co-Administration and Microencapsulation with Non-Digestible Carbohydrates

The large generation of olive by-products has motivated their revalorization into high-added-value products. In this regard, olive leaves pose as an interesting source of bioactive compounds, due to their phenolic content with commonly known antioxidant, anti-inflammatory, and immunomodulatory properties, with potential application in non-communicable diseases. However, their effectiveness and applicability into functional foods is limited by their instability under gastrointestinal conditions. Thus, the development of protective formulations is essential. In this study, the spray-drying encapsulation of a phenolic-rich olive leaf extract with inulin as the encapsulating agent was optimized. Then, the behavior of the free extract under gastrointestinal conditions, its co-administration with the encapsulating agent, and the optimized microencapsulated formulation were studied through an in vitro gastrointestinal digestion process following the INFOGEST protocol. Digestion of the free extract resulted in the degradation of most compounds, whereas this was minimized in the co-administration of the non-encapsulated extract with the encapsulating agent. This protective effect, related to its interaction with inulin, was similar to the microencapsulated formulation. Thus, both approaches, co-administration and microencapsulation with inulin, could be promising strategies for the improvement of the stability of these anti-inflammatory and immunomodulatory compounds under gastrointestinal conditions, enhancing their beneficial effect.

Red Cabbage Modulates Composition and Co-Occurrence Networks of Gut Microbiota in a Rodent Diet-Induced Obesity Model

Red cabbage (RC), a cruciferous vegetable rich in various bioactive substances, can significantly reduce the risk factors of several non-communicable diseases, but the mechanism underlying the biological effects of RC remains unclear. Furthermore, mechanisms that operate through the regulation of gut microbiota also are not known. Given the relationships between diet, gut microbiota, and health, a diet-induced mice obesity model was used to elucidate the influence of RC on gut microbial composition and bacteria-bacteria interactions in mice. After 24 h of dietary intervention, a high-fat (HF) diet with the intake of RC led to increased Firmicutes/Bacteroidetes (F/B) ratios in the feces of mice. RC also reduced the relative abundance of Bifidobacteria, Lactobacillus, and Akkermansia muciniphila in mice fed a low-fat (LF) diet. After 8-weeks of dietary intervention, RC significantly changed the structure and the ecological network of the gut microbial community. Particularly, RC inhibited an HF-diet-induced increase in AF12 in mice, and this genus was positively correlated with body weight, low-density lipoprotein level, and fecal bile acid of mice. Unclassified Clostridiales, specifically increased via RC consumption, were also found to negatively correlate with hepatic free cholesterol levels in mice. Overall, our results demonstrated that RC modulating gut microbial composition and interactions are associated with the attenuation of HF-diet-induced body weight gain and altered cholesterol metabolism in mice.

Unraveling the bioactive interplay: seaweed polysaccharide, polyphenol and their gut modulation effect

Seaweed is rich in many unique bioactive compounds such as polyphenols and sulfated polysaccharides that are not found in terrestrial plant. The discovery of numerous biological activities from seaweed has made seaweed an attractive functional food source with the potential to be exploited for human health benefits. During food processing and digestion, cell wall polysaccharide and polyphenols commonly interact, and this may influence the nutritional properties of food. Interactions between cell wall polysaccharide and polyphenols in plant-based system has been extensively studied. However, similar interactions in seaweed have received little attention despite the vast disparity between the structural and chemical composition of plant and seaweed cell wall. This poses a challenge in extracting seaweed bioactive compounds with intact biological properties. This review aims to summarize the cell wall polysaccharide and polyphenols present in brown, red and green seaweed, and current knowledge on their potential interactions. Moreover, this review gives an overview of the gut modulation effect of seaweed polysaccharide and polyphenol.

Preparation, Characterization and Application of the Delivery System for Food Products

In the dynamic and evolving landscape of food science and technology, the quest to develop innovative and effective delivery systems for bioactive compounds remains a focal point of research and development [...].

Lowering glycemic levels via gastrointestinal tract factors: the roles of dietary fiber, polyphenols, and their combination

Dietary fiber (DF) and polyphenols (DP) are typical blood sugar-lowering components, and both play distinct yet interconnected roles in exerting their blood sugar-lowering effects. We comprehensively summarized the single and combined effects of DF and DP on blood glucose homeostasis through regulating the relevant factors in the upper gastrointestinal tract (UGT) and lower gastrointestinal tract (LGT). In the UGT, DF slowed down glucose metabolism by enhancing digesta viscosity and hindering enzyme-substrate interaction. DP primarily targeted enzymes and substrates. When combined, DP enhanced the adsorption capacity of DF for glucose. DF weakened DP's inhibitory effect on enzymes. Both DF and DP disrupted glucose intestinal uptake via physical or genomic modulation, but the co-consumption of DF and DP demonstrated a lower inhibitory effect on glucose uptake than DP alone. In the LGT, DF and DP showed synergistic or antagonistic effects on gut microbiota. Remarkably, whole foods exhibited potent prebiotic effects due to their compound-rich matrix, potentially enhancing glucose homeostasis and expanding dietary options for glucose regulation research.

Gut commensals and their metabolites in health and disease

Purpose of review

This review comprehensively discusses the role of the gut microbiome and its metabolites in health and disease and sheds light on the importance of a holistic approach in assessing the gut.

Recent findings

The gut microbiome consisting of the bacteriome, mycobiome, archaeome, and virome has a profound effect on human health. Gut dysbiosis which is characterized by perturbations in the microbial population not only results in gastrointestinal (GI) symptoms or conditions but can also give rise to extra-GI manifestations. Gut microorganisms also produce metabolites (short-chain fatty acids, trimethylamine, hydrogen sulfide, methane, and so on) that are important for several interkingdom microbial interactions and functions. They also participate in various host metabolic processes. An alteration in the microbial species can affect their respective metabolite concentrations which can have serious health implications. Effective assessment of the gut microbiome and its metabolites is crucial as it can provide insights into one's overall health.

Summary

Emerging evidence highlights the role of the gut microbiome and its metabolites in health and disease. As it is implicated in GI as well as extra-GI symptoms, the gut microbiome plays a crucial role in the overall well-being of the host. Effective assessment of the gut microbiome may provide insights into one's health status leading to more holistic care.

Gut microbiota metabolites, redox status, and the related regulatory effects of probiotics

Oxidative stress is a state of imbalance between oxidation and antioxidation. It is caused by excess levels of free radicals and leads to the damage of DNA, proteins, and lipids. The crucial role of gut microbiota in regulating oxidative stress has been widely demonstrated. Studies have suggested that the redox regulatory effects of gut microbiota are related to gut microbiota metabolites, including fatty acids, lipopolysaccharides, tryptophan metabolites, trimethylamine-N-oxide and polyphenolic metabolites. In recent years, the potential benefits of probiotics have been gaining increasing scientific interest owing to their ability to modulate gut microbiota and oxidative stress. In this review, we summarise the adverse health effects of oxidative stress and discuss the role of the gut microbiota and its metabolites in redox regulation. Based on the influence of gut microbiota metabolites, the roles of probiotics in preventing oxidative stress are highlighted.