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

Changes of Barley Bound Phenolics and Their Characteristics During Simulated Gastrointestinal Digestion and Colonic Fermentation In Vitro

Phenolic compounds in cereals, known for their biological activities, are primarily found in a bound state within the bran. Their changes during digestion are linked to physiological activities. In this study, the dynamic changes and fermentation characteristics of barley bound phenolics (BBPs) were investigated through an in vitro rat gastrointestinal digestion and colonic fermentation. UPLC-HRMS revealed that the release rate of BBPs during colonic fermentation was significantly higher than that during gastric digestion (0.13%) and intestinal digestion (0.43%), reaching 5.02%. After 48 h of colonic fermentation, gallic acid and ferulic acid accounted for 35.05% and 27.84% of the total released phenolic acids, respectively. Confocal microscopy confirmed that BBPs were predominantly released in the colon. Additionally, BBPs significantly increased the content of acetate during colonic fermentation compared to the control samples, correlating with a decrease in pH value. 16S rRNA sequencing further revealed the modulatory effects of BBPs on colonic microbiota structure: BBPs significantly enhanced the Chao1 and Shannon indices of the microbiota. Notably, BBPs inhibited the growth of potentially harmful bacteria such as Proteobacteria and Enterobacteriaceae while promoting the proliferation of beneficial bacteria such as Akkermansia and Bifidobacteriaceae, thereby modulating the structure of the gut microbial community. These findings suggested that BBPs may promote gut health through prebiotic activity in the colon.

Exploratory metabolomic profiling of plasma and urine in patients with mucopolysaccharidosis type II (Hunter syndrome): A pilot study

Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is an X-linked lysosomal storage disorder. It results from a deficiency of the enzyme iduronate-2-sulfatase (I2S), leading to the accumulation of glycosaminoglycans (GAGs) in various tissues and organs. Clinical manifestations include skeletal abnormalities, facial coarsening, organ enlargement, and developmental delays. The main objective of this study was to identify neuronopathic MPS II-specific biomarkers for early detection, diagnosis, monitoring, and follow up of affected patients. We thus applied liquid chromatography-high-resolution mass spectrometry (LC-HRMS) based untargeted metabolomic approaches to identify these potential biomarkers which could discriminate patients with the neuronopathic form of MPS II from healthy controls. Secondary aims focused on a better understanding of how the disease may affect the metabolome of patients. Urine and plasma samples from 21 untreated neuronopathic MPS II patients characterized by severe clinical manifestations were compared to 23 age- and gender-matched healthy control samples using a Xevo G2-XS Qtof MS (Waters Corp.). A comprehensive metabolomic workflow and multivariate statistical analyses revealed metabolites consistently elevated in MPS II patients. These include acylaminosugars, dipeptides, amino acids and their derivatives, lipid structures, and various compounds indicating disruptions in metabolic pathways. Development and validation of quantitative methods will be done using tandem mass spectrometry. Furthermore, identifying biomarkers associated with the central nervous system (CNS) in MPS II patients would help detect the neuronopathic form of the disease early, and enable the evaluation of the effectiveness of novel therapeutic strategies.

Deciphering the importance of nanoencapsulation to improve the availability of bioactive molecules in food sources to the human body

Various bodily functions are maintained, and health benefits are provided by food-derived bioactive components. Fruits and vegetables contain numerous beneficial components, including vitamins, minerals, antioxidants, enzymes, and phytonutrients. However, the body's ability to absorb these substances at a given rate and degree frequently limits their bioavailability. If food-derived bio actives are used as therapeutic or dietary interventions, this limitation can result in low efficacy and suboptimal results. Recently, nanotechnology has been a useful method for increasing the bioavailability of bioactive compounds produced from food. Active ingredients can be delivered and absorbed more efficiently with the help of nanotechnology. By altering their size or surface properties, bioactive components can be made more soluble, permeable, and bioavailable through nanotechnology. The present review will provide an overview of the various bioactive components, the application of nanotechnology to improve the availability of bioactive molecules to humans and animals, and the challenges and safety concerns associated with nanotechnology in the production of food-derived bioactive molecules.

Functional Plant-Based Beverage Fortified with Hazelnut Cuticle Polyphenols: Antioxidant and Phenolic Content Characterization

In recent decades, there has been growing interest in the fortification of food products with antioxidants and phenolics derived from plant by-products. The present study focused on the production of a plant-based beverage enriched with hazelnut cuticle extract to characterize its antioxidant content, phenolic profile, and organoleptic characteristics. Liquid chromatography-mass spectrometry (LC-MS) enabled the identification of key polyphenols in hazelnut cuticles, including catechin, epicatechin, and quercetin derivatives, guiding the selection of a biocompatible Natural Deep Eutectic Solvent (NADES) composed of choline chloride and lactic acid for efficient extraction. The obtained phytochemical profile of the extract revealed a high concentration of bioactive compounds, with a Total Phenolic Content of 160.88 ± 14.27 mg GAE/g and Antioxidant Power measured by DPPH of 5848.2 ± 11.3 μmol TE/g. The bioaccessibility of phenolics in the fortified hazelnut-based beverage was determined after in vitro digestion, reaching a value of 89.7%, indicating excellent release and stability during digestion. Organoleptic evaluation revealed high sensory acceptability, with aftertaste scoring 3.61 ± 0.4 respect the 3.94 ± 1.3 result of reference milk, on a 5-point scale. In conclusion, this study demonstrates the potential for sustainable valorization of hazelnut cuticles, through their incorporation as NADES extracts in plant-based milk, providing an innovative solution to reduce food waste while catering to consumer demand for nutritionally enriched and eco-friendly products.

Horizontal and longitudinal targeted metabolomics in healthy pregnancy and gestational diabetes mellitus

OBJECTIVE

The objective is to investigate the differences in urinary organic acid (OA) profiles and metabolism between healthy control (HC) pregnant women and those with gestational diabetes mellitus (GDM) during the second trimester and third trimester of pregnancy.

METHODS

A total of 66 HC pregnant women and 32 pregnant women with GDM were assessed for 107 hydrophilic metabolites in urine samples collected during the second and third trimester of pregnancy using tandem mass spectrometry. The urine OA profiles for each group were obtained, and metabolomic analysis and discussion were conducted.

RESULTS

This study identified a total of 50 metabolic biomarkers. In the third trimester of pregnancy, short-chain dicarboxylic acids (DCAs) and tryptophan (Trp)-related metabolites were significantly upregulated in the urine of both the HC group and the GDM group. Comparatively, the glycine (Gly) levels and related synthetic precursor metabolites were lower in the GDM2 group. The overall dietary polyphenol metabolic intermediates level in the GDM group was lower than in the HC group. Among the pathways enriched for differentially expressed metabolites, the predominant metabolic pathway in the GDM group was the citric acid cycle. In contrast, in the HC group, it was the metabolism of alanine, aspartate, and glutamate.

CONCLUSIONS

The study reveals the differences in metabolomics between pregnant women with HC and those with GDM, identifying several metabolites associated with the occurrence and development of GDM. Demonstrating the presence of abnormal mitochondrial and peroxisomal functions at the metabolite level in GDM will contribute to future exploration of the condition.

Direct Determination of Flavanone Isomers in Citrus Juice by Paper Spray Tandem Mass Spectrometry

A novel and efficient analytical protocol based on paper spray tandem mass spectrometry was developed for the determination of isomeric O-glycoside flavanones in citrus juices and beverages. This approach significantly reduces sample preparation time and solvent consumption compared to traditional chromatographic techniques. By exploiting the unique fragmentation patterns of these compounds, accurate quantification of both diglycosides and their individual isomers (neohesperidoside and rutinose derivatives) was achieved. The method demonstrated excellent analytical performance, with high accuracy, selectivity, and reproducibility. The impact of matrix effects was mitigated through the construction of ratio calibration curves, ensuring reliable quantification in complex matrices. Finally, a simple DPPH experiment to assay the antioxidant activity of each single positional isomer was performed, indicating the superior ability of neohesperidose conjugates. This simplified method offers a valuable tool for quality control, authenticity assessment and the study of health benefits associated with citrus consumption.

Decoding polyphenol metabolism in patients with Crohn's disease: Insights from diet, gut microbiota, and metabolites

Crohn's disease (CD) is a chronic and progressive inflammatory disease that can involve any part of the gastrointestinal tract. The protective role of dietary polyphenols has been documented in preclinical models of CD. Gut microbiota mediates the metabolism of polyphenols and affects their bioactivity and physiological functions. However, it remains elusive the capacity of microbial polyphenol metabolism in CD patients and healthy controls (HCs) along with its correlation with polyphenols intake and polyphenol-derived metabolites. Thus, we aimed to decode polyphenol metabolism in CD patients through aspects of diet, gut microbiota, and metabolites. Dietary intake analysis revealed that CD patients exhibited decreased intake of polyphenols. Using metagenomic data from two independent clinical cohorts (FAH-SYSU and PRISM), we quantified abundance of polyphenol degradation associated bacteria and functional genes in CD and HCs and observed a lower capacity of flavonoids degradation in gut microbiota residing in CD patients. Furthermore, through analysis of serum metabolites and enterotypes in participants of FAH-SYSU cohort, we observed that CD patients exhibited reduced levels of serum hippuric acid (HA), one of polyphenol-derived metabolites. HA level was higher in healthier enterotypes (characterized by dominance of Ruminococcaceae and Prevotellaceae, dominant by HCs) and positively correlated with multiple polyphenols intake and abundance of bacteria engaged in flavonoids degradation as well as short-chain fatty acid production, which could serve as a biomarker for effective polyphenol metabolism by the gut microbiota and a healthier gut microbial community structure. Overall, our findings provide a foundation for future work exploring the polyphenol-based or microbiota-targeted therapeutic strategies in CD.

The role of polyphenols in modulating mitophagy: Implications for therapeutic interventions

This review rigorously assesses the burgeoning research into the role of polyphenols in modulating mitophagy, an essential cellular mechanism for the targeted removal of impaired mitochondria. These natural compounds, known for their low toxicity, are underscored for their potential in therapeutic strategies against a diverse array of diseases, such as neurodegenerative, cardiovascular, and musculoskeletal disorders. The analysis penetrates deeply into the molecular mechanisms whereby polyphenols promote mitophagy, particularly by influencing crucial signaling pathways and transcriptional regulators, including the phosphatase and tensin homolog (PTEN) induced putative kinase 1 (PINK1)/parkin and forkhead box O3 (FOXO3a) pathways. Noteworthy discoveries include the neuroprotective properties of resveratrol and curcumin, which affect both autophagic pathways and mitochondrial dynamics, and the pioneering integration of polyphenols with other natural substances to amplify therapeutic effectiveness. Furthermore, the review confronts the issue of polyphenol bioavailability and emphasizes the imperative for clinical trials to corroborate their therapeutic viability. By delivering an exhaustive synthesis of contemporary insights and recent advancements in polyphenol and mitophagy research, this review endeavors to catalyze additional research and foster the creation of innovative therapeutic modalities that exploit the distinctive attributes of polyphenols to manage and prevent disease.

Gut-Brain Axis in Focus: Polyphenols, Microbiota, and Their Influence on α-Synuclein in Parkinson's Disease

With the recognition of the importance of the gut-brain axis in Parkinson's disease (PD) etiology, there is increased interest in developing therapeutic strategies that target α-synuclein, the hallmark abhorrent protein of PD pathogenesis, which may originate in the gut. Research has demonstrated that inhibiting the aggregation, oligomerization, and fibrillation of α-synuclein are key strategies for disease modification. Polyphenols, which are rich in fruits and vegetables, are drawing attention for their potential role in this context. In this paper, we reviewed how polyphenols influence the composition and functional capabilities of the gut microbiota and how the resulting microbial metabolites of polyphenols may potentially enhance the modulation of α-synuclein aggregation. Understanding the interaction between polyphenols and gut microbiota and identifying which specific microbes may enhance the efficacy of polyphenols is crucial for developing therapeutic strategies and precision nutrition based on the microbiome.

Dietary Polyphenols, Plant Metabolites, and Allergic Disorders: A Comprehensive Review

Given the ongoing rise in the occurrence of allergic disorders, alterations in dietary patterns have been proposed as a possible factor contributing to the emergence and progression of these conditions. Currently, there is a significant focus on the development of dietary therapies that utilize natural compounds possessing anti-allergy properties. Dietary polyphenols and plant metabolites have been intensively researched due to their well-documented anti-inflammatory, antioxidant, and immunomodulatory characteristics, making them one of the most prominent natural bioactive chemicals. This study seeks to discuss the in-depth mechanisms by which these molecules may exert anti-allergic effects, namely through their capacity to diminish the allergenicity of proteins, modulate immune responses, and modify the composition of the gut microbiota. However, further investigation is required to fully understand these effects. This paper examines the existing evidence from experimental and clinical studies that supports the idea that different polyphenols, such as catechins, resveratrol, curcumin, quercetin, and others, can reduce allergic inflammation, relieve symptoms of food allergy, asthma, atopic dermatitis, and allergic rhinitis, and prevent the progression of the allergic immune response. In summary, dietary polyphenols and plant metabolites possess significant anti-allergic properties and can be utilized for developing both preventative and therapeutic strategies for targeting allergic conditions. The paper also discusses the constraints in investigating and broad usage of polyphenols, as well as potential avenues for future research.

Liver cancer wars: plant-derived polyphenols strike back

Liver cancer currently represents the leading cause of cancer-related death worldwide. The majority of liver cancer arises in the context of chronic inflammation and cirrhosis. Surgery, radiation therapy, and chemotherapy have been the guideline-recommended treatment options for decades. Despite enormous advances in the field of liver cancer therapy, an effective cure is yet to be found. Plant-derived polyphenols constitute a large family of phytochemicals, with pleiotropic effects and little toxicity. They can drive cellular events and modify multiple signaling pathways which involves initiation, progression and metastasis of liver cancer and play an important role in contributing to anti-liver cancer drug development. The potential of plant-derived polyphenols for treating liver cancer has gained attention from research clinicians and pharmaceutical scientists worldwide in the last decades. This review overviews hepatic carcinogenesis and briefly discusses anti-liver cancer mechanisms associated with plant-derived polyphenols, specifically involving cell proliferation, apoptosis, autophagy, angiogenesis, oxidative stress, inflammation, and metastasis. We focus on plant-derived polyphenols with experiment-based chemopreventive and chemotherapeutic properties against liver cancer and generalize their basic molecular mechanisms of action. We also discuss potential opportunities and challenges in translating plant-derived polyphenols from preclinical success into clinical applications.

Exploring the mechanism of probiotics in enhancing the utilization of chemical components (or polyphenols) of grape seed extract

Fecal samples from 20 healthy adults were collected for in vitro fermentation experiments to investigate the effects of combined probiotics on the utilization of grape seed extract in humans. After fermenting for 24 h, short-chain fatty acids, metabolites, and gut microbiota composition were analyzed. Short-chain fatty acids in the grape seed extract probiotics group were significantly higher than those in the grape seed extract group. Probiotics significantly enhanced the conversion and utilization of catechins and epicatechins in grape seed extract group and increased the production of 3-hydroxyphenylacetic acid. The 16S rRNA sequencing results revealed that compound probiotics significantly increased the relative abundance of Lacticaseibacillus, HT002, Bifidobacterium, and Lactobacillus and reduced that of Escherichia-Shigella. Our findings showed considerable individual variability in the metabolic utilization of grape seed extract in humans. The consumption of probiotics appears to significantly enhance the utilization.

Composition of Whole Grain Dietary Fiber and Phenolics and Their Impact on Markers of Inflammation

Inflammation is an important biological response to any tissue injury. The immune system responds to any stimulus, such as irritation, damage, or infection, by releasing pro-inflammatory cytokines. The overproduction of pro-inflammatory cytokines can lead to several diseases, e.g., cardiovascular diseases, joint disorders, cancer, and allergies. Emerging science suggests that whole grains may lower the markers of inflammation. Whole grains are a significant source of dietary fiber and phenolic acids, which have an inverse association with the risk of inflammation. Both cereals and pseudo-cereals are rich in dietary fiber, e.g., arabinoxylan and β-glucan, and phenolic acids, e.g., hydroxycinnamic acids and hydroxybenzoic acids, which are predominantly present in the bran layer. However, the biological mechanisms underlying the widely reported association between whole grain consumption and a lower risk of disease are not fully understood. The modulatory effects of whole grains on inflammation are likely to be influenced by several mechanisms including the effect of dietary fiber and phenolic acids. While some of these effects are direct, others involve the gut microbiota, which transforms important bioactive substances into more beneficial metabolites that modulate the inflammatory signaling pathways. Therefore, the purpose of this review is twofold: first, it discusses whole grain dietary fiber and phenolic acids and highlights their potential; second, it examines the health benefits of these components and their impacts on subclinical inflammation markers, including the role of the gut microbiota. Overall, while there is promising evidence for the anti-inflammatory properties of whole grains, further research is needed to understand their effects fully.

Assessment of the Effects of Roasting, Contact Grilling, Microwave Processing, and Steaming on the Functional Characteristics of Bell Pepper (Capsicum annuum L.)

Bell peppers (Capsicum annuum L.) in various stages of maturity are widely used in the diets of individuals and in the food industry; they are consumed both fresh and after thermal processing. However, every type of processing impacts the overall textural and bioactive characteristics of this plant-based food. In order to quantify the changes in the bioactive substances and color-structural characteristics that occur during selected heat treatments (contact grilling, roasting, roasting combined with microwaving, and steam cooking) of bell peppers at three maturity stages (green, yellow, and red), analyses of antioxidant activity, reducing sugar content, polyphenolic compound content, textural properties, and color coordinates in the L*a*b* system were carried out. Some of the processes used, such as contact grilling (15.43 mg GAE/g d.b.) and roasting combined with microwaving (15.24 mg GAE/g d.b.), proved to be beneficial as the total polyphenol content of green peppers (2.75 mg GAE/g d.b.) increased. The roasting (3.49 mg TE/g d.b.) and steaming (6.45 mg TE/g d.b.) methods decreased the antioxidant activity of yellow bell peppers (14.29 mg TE/g d.b.). Meanwhile, the roasting (0.88 mg Glc/g d.b.), contact-grilling (2.19 mg Glc/g d.b.), simultaneous microwaving and roasting (0.66 mg Glc/g d.b.), and steaming (1.30 mg Glc/g d.b.) methods significantly reduced the content of reducing sugars and reducing substances in red bell peppers (4.41 mg Glc/g d.b.). The studies proved that in order to preserve the antioxidant and bioactive properties of bell peppers, it is necessary to consider the use of appropriately selected heat treatments, depending on the different stages of maturity. The proper selection of adequate thermal treatment can not only increase digestibility, but also improve the bioavailability of bioactive substances from this raw material.