Using Targeted Metabolomics to Unravel Phenolic Metabolites of Plant Origin in Animal Milk

Milk holds a high nutritional value and is associated with diverse health benefits. The understanding of its composition of (poly)phenolic metabolites is limited, which necessitates a comprehensive evaluation of the subject. This study aimed at analyzing the (poly)phenolic profile of commercial milk samples from cows and goats and investigating their sterilization treatments, fat content, and lactose content. Fingerprinting of phenolic metabolites was achieved by using ultra-high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry (UHPLC-QqQ-MS/MS). Two hundred and three potential microbial and phase II metabolites of the main dietary (poly)phenols were targeted. Twenty-five metabolites were identified, revealing a diverse array of phenolic metabolites in milk, including isoflavones and their microbial catabolites equol and O-desmethylangolensin, phenyl-γ-valerolactones (flavan-3-ol microbial catabolites), enterolignans, urolithins (ellagitannin microbial catabolites), benzene diols, and hippuric acid derivates. Goat's milk contained higher concentrations of these metabolites than cow's milk, while the sterilization process and milk composition (fat and lactose content) had minimal impact on the metabolite profiles. Thus, the consumption of goat's milk might serve as a potential means to supplement bioactive phenolic metabolites, especially in individuals with limited production capacity. However, further research is needed to elucidate the potential health effects of milk-derived phenolics.

Nav1.8-expressing neurons control daily oscillations of food intake, body weight and gut microbiota in mice

Recent evidence suggests a role of sensory neurons expressing the sodium channel Nav1.8 on the energy homeostasis control. Using a murine diphtheria toxin ablation strategy and ad libitum and time-restricted feeding regimens of control or high-fat high-sugar diets, here we further explore the function of these neurons on food intake and on the regulation of gastrointestinal elements transmitting immune and nutrient sensing.The Nav1.8+ neuron ablation increases food intake in ad libitum and time-restricted feeding, and exacerbates daily body weight variations. Mice lacking Nav1.8+ neurons show impaired prandial regulation of gut hormone secretion and gut microbiota composition, and altered intestinal immunity.Our study demonstrates that Nav1.8+ neurons are required to control food intake and daily body weight changes, as well as to maintain physiological enteroendocrine and immune responses and the rhythmicity of the gut microbiota, which highlights the potential of Nav1.8+ neurons to restore energy balance in metabolic disorders.

Pathogenic NLRP3 mutants form constitutively active inflammasomes resulting in immune-metabolic limitation of IL-1β production

Cryopyrin-associated periodic syndrome (CAPS) is an autoinflammatory condition resulting from monoallelic NLRP3 variants that facilitate IL-1β production. Although these are gain-of-function variants characterized by hypersensitivity to cell priming, patients with CAPS and animal models of the disease may present inflammatory flares without identifiable external triggers. Here we find that CAPS-associated NLRP3 variants are forming constitutively active inflammasome, which induce increased basal cleavage of gasdermin D, IL-18 release and pyroptosis, with a concurrent basal pro-inflammatory gene expression signature, including the induction of nuclear receptors 4 A. The constitutively active NLRP3-inflammasome of CAPS is responsive to the selective NLRP3 inhibitor MCC950 and its activation is regulated by deubiquitination. Despite their preactivated state, the CAPS inflammasomes are responsive to activation of the NF-κB pathway. NLRP3-inflammasomes with CAPS-associated variants affect the immunometabolism of the myeloid compartment, leading to disruptions in lipids and amino acid pathways and impaired glycolysis, limiting IL-1β production. In summary, NLRP3 variants causing CAPS form a constitutively active inflammasome inducing pyroptosis and IL-18 release without cell priming, which enables the host's innate defence against pathogens while also limiting IL-1β-dependent inflammatory episodes through immunometabolism modulation.

In vitro study of potential prebiotic properties of monovarietal extra virgin olive oils

Olive oil, essential ingredient of the Mediterranean diet, is attracting a growing interest due to increasing evidence on its beneficial effects on human health. This study investigated whether extra virgin olive oil (EVOO) possess prebiotic properties. Twenty different monovarietal EVOO samples from 5 Marche region cultivars (Italy) were studied. The prebiotic activity of EVOOs was assessed monitoring the selective stimulation of gut bacterial species and the short chain fatty acids (SCFAs) production, using an in vitro fermentation system. All EVOOs selectively stimulated Lactobacillus spp., with a stronger activity than that observed in the inulin fermentation (positive control). Also, the bifidobacteria population increased; this bifidogenic stimulation was of EVOOs from Raggia cultivar. SCFAs appeared significantly higher after 24 h in all EVOO fermentations than in the control. Acetic and propionic acids production was particularly stimulated. Overall, most of the investigated EVOOs had a potential prebiotic activity, similar or stronger than inulin.

Mitophagy curtails cytosolic mtDNA-dependent activation of cGAS/STING inflammation during aging

Macroautophagy decreases with age, and this change is considered a hallmark of the aging process. It remains unknown whether mitophagy, the essential selective autophagic degradation of mitochondria, also decreases with age. In our analysis of mitophagy in multiple organs in the mito-QC reporter mouse, mitophagy is either increased or unchanged in old versus young mice. Transcriptomic analysis shows marked upregulation of the type I interferon response in the retina of old mice, which correlates with increased levels of cytosolic mtDNA and activation of the cGAS/STING pathway. Crucially, these same alterations are replicated in primary human fibroblasts from elderly donors. In old mice, pharmacological induction of mitophagy with urolithin A attenuates cGAS/STING activation and ameliorates deterioration of neurological function. These findings point to mitophagy induction as a strategy to decrease age-associated inflammation and increase healthspan.

NMR Spectroscopic Identification of Urolithin G, a Novel Trihydroxy Urolithin Produced by Human Intestinal Enterocloster Species

Urolithins are gut microbiota metabolites of ellagic acid. Here, we have identified and chemically characterized a novel urolithin produced from urolithin D (3,4,8,9-tetrahydroxy urolithin) by in vitro incubation with different human gut Enterocloster species under anaerobic conditions. Urolithin G (3,4,8-trihydroxy urolithin) was identified by 1H NMR, 13C NMR, UV, HRMS, and 2D NMR. For the identification, NMR spectra of other known urolithins were also recorded and compared. Urolithin G was present in the feces of 12% of volunteers in an overweight-obese group after consuming an ellagitannin-rich pomegranate extract. The production of urolithin G required a bacterial 9-dehydroxylase activity and was not specific to the known human urolithin metabotypes A and B. The ability to produce urolithin G could be considered an additional metabolic feature for volunteer stratification and bioactivity studies. This is the first urolithin with a catechol group in ring A while having only one hydroxyl in ring B, a unique feature not found in human and animal samples so far.

Ellagic acid and its metabolites urolithins A/B ameliorate most common disease phenotypes in cellular and mouse models for lysosomal storage disorders by enhancing extracellular vesicle secretion

Niemann Pick diseases types A (NPDA) and C (NPDC) are lysosomal storage disorders (LSDs) leading to cognitive impairment, neurodegeneration, and early death. NPDA and NPDC have different genetic origins, being caused by mutations in the acid sphingomyelinase (ASM) or the cholesterol transport protein NPC1, respectively. However, they share a common pathological hallmark in the accumulation of lipids in the endolysosomal compartment. Here, we tested the hypothesis that polyphenols reduce lipid overload in NPD cells by enhancing the secretion of extracellular vesicles (ECVs). We show that among the polyphenols tested, the ellagic acid metabolites, urolithin A and B, were the safest and most efficient in increasing ECV secretion. They reduced levels of accumulating lipids and lysosomal size and permeabilization in cultured bone marrow-derived macrophages and neurons from ASMko and NPC1 mutant mice, which mimic NPDA and NPDC, respectively. Moreover, oral treatment with ellagic acid reduced lipid levels, ameliorated lysosomal alterations, and diminished microglia activation in the brain of NPD mice. These results support the therapeutic value of ECV secretion and polyphenols for NPDs, which may also help treat other LSDs characterized by intracellular lipid overload.

Gut Bacteria Involved in Ellagic Acid Metabolism To Yield Human Urolithin Metabotypes Revealed

We aimed to elucidate the gut bacteria that characterize the human urolithin metabotypes A and B (UM-A and UM-B). We report here a new bacterium isolated from the feces of a healthy woman, capable of producing the final metabolites urolithins A and B and different intermediates. Besides, we describe two gut bacterial co-cultures that reproduced the urolithin formation pathways upon in vitro fermentation of both UM-A and UM-B. This is the first time that the capacity of pure strains to metabolize ellagic acid cooperatively to yield urolithin profiles associated with UM-A and UM-B has been demonstrated. The urolithin-producing bacteria described herein could have potential as novel probiotics and in the industrial manufacture of bioactive urolithins to develop new ingredients, beverages, nutraceuticals, pharmaceuticals, and (or) functional foods. This is especially relevant in UM-0 individuals since they cannot produce bioactive urolithins.

Separation of Isomeric Forms of Urolithin Glucuronides Using Supercritical Fluid Chromatography

Urolithins are gut microbiota metabolites produced in humans after consuming foods containing ellagitannins and ellagic acid. Three urolithin metabotypes have been reported for different individuals depending on the final urolithins produced. After absorption, they are conjugated with glucuronic acid (phase II metabolism), and these are the main circulating metabolites in plasma and reach different tissues. Different regioisomeric isomers of urolithin glucuronides have been described. Still, their identification and quantification in humans have not been properly reported due to resolution limitations in their analysis by reversed-phase high-performance liquid chromatography. In the present study, we report a novel method for separating these isomers using supercritical fluid chromatography. With this method, urolithin A 3- and 8-glucuronide, isourolithin A 3- and 9- glucuronide, and urolithin B 3-glucuronide (8-hydroxy urolithin 3-glucuronide; 3-hydroxy urolithin 8-glucuronide; 3-hydroxyurolithin 9-glucuronide; 9-hydroxyurolithin 3-glucuronide; and urolithin 3-glucuronide) were separated in less than 15 min. The proposed method was applied to successfully analyze these metabolites in urine samples from different volunteers belonging to different metabotypes.

Effect of Storage Conditions on the Stability of Polyphenols of Apple and Strawberry Purees Produced at Industrial Scale by Different Processing Techniques

During a food product's life, storage conditions affect its composition of nutrients, bioactive compounds, and sensory attributes. In this research, strawberry and apple purees were selected as a model to examine how the storage of various purees industrially produced with different technologies affect the bioactive phenolic compounds, color, and sensory attributes. Specifically, fruit products processed on an industrial scale by different technologies including freezing, thermal treatment (mild and standard), and high-pressure processing were studied, as well as storage for up to 12 months at -20, 4, and 24 °C. In strawberry puree, storage conditions had a stronger impact on phenolic compound levels, particularly on anthocyanins, whereas in apple puree, the initial processing techniques exerted a greater influence than storage conditions, mainly caused by the hot or cold crushing processes. In general, proanthocyanidins were the major phenolic group and the most stable during storage, while anthocyanins were the group most affected by both processing and storage. Apple flavonols and dihydrochalcones were quite stable, while strawberry ellagitannins suffered higher degradations during storage. Through our analysis, it is found that during storage, the stability of polyphenols in each fruit is different, and processing and storage can be either detrimental or even beneficial. The selection of the ideal storage conditions (time and temperature) is a key factor to maintaining the polyphenol content in sensitive fruits such as strawberries. However, storage conditions are in some cases more important to minimizing the polyphenol losses than how the product is processed.

Biodegradation of Punicalagin into Ellagic Acid by Selected Probiotic Bacteria: A Study of the Underlying Mechanisms by MS-Based Proteomics

Pomegranate (Punica granatum L.) is a well-known source of bioactive phenolic compounds such as ellagitannins, anthocyanins, and flavanols. Punicalagin, one of the main constituents of pomegranate, needs to be biodegraded by bacteria to yield metabolites of medicinal interest. In this work, we tested 30 lactic acid bacteria (LAB) and their capacity to transform punicalagin from a punicalagin-rich pomegranate extract into smaller bioactive molecules, namely, ellagic acid and urolithins. These were identified and quantified by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS²). Further, we evaluated the molecular mechanism governing this transformation through label-free comparative MS-based proteomics. All tested LAB strains were capable of transforming punicalagin into ellagic acid, while the biosynthesis of urolithins was not observed. Proteomic analysis revealed an increase of generic transglycosylases that might have a hydrolytic role in the target phenolic molecule, coupled with an increase in the quantity of ATP-binding cassette (ABC) transporters, which might play a relevant role in transporting the resulting byproducts in and out of the cell.

A novel combined analytical UV and MS approach for the quantification of oleuropein metabolites in human biological samples when authentic standards are not available

The beneficial health effects of phytochemicals depend on their bioavailability and the form under which they reach systemic circulation, usually as phase II metabolites. The lack of authentic standards for these metabolites makes their quantification in biological samples challenging. A new analytical approach to get a more accurate quantification of oleuropein metabolites in biological samples after ingestion of olive leaf extract was proposed. This approach was based on the calculation of a response factor in QTOF MS for each metabolite, comparing their quantification in UV and MS using urine samples concentrated in the metabolites of interest. Glucuronide and sulfate conjugates of hydroxytyrosol and homovanillyl alcohol were more accurately quantified in plasma and urine and for the first time, oleuropein aglycone conjugates and their hydroxylated and hydrogenated derivatives were quantified after consumption of olive products. This approach could be extensible to the analysis of other phenolic metabolites when authentic standards are not available, opening a valuable method for bioavailability studies.

Introduction to Novel Approaches in the Valorization of Agricultural Wastes and Their Applications

Sustainable food production, waste minimization, and valorization are critical concerns for the agricultural and food industry considering their environmental, social, and economic impacts. Foods are processed to prolong shelf life, make products available out of season, produce new products, and improve nutritional value. During processing, a significant amount of waste is generated, which attracts the attention of scientists and industrialists to valorize the value-added components, including dietary fibers, proteins, and bioactive components. This special issue focuses on the latest developments in waste valorization, covering different industries and methodologies. Within the special issue, waste valorization of some specific food groups, including fruit juice wastes, honeybee byproducts, soybean processing waste, grape pomace materials, and olive mill solid waste, are evaluated. On the other hand, novel approaches to valorizing agricultural wastes and their applications, also covering the recovery of natural pigments with potential health effects, are considered. Besides, nanotechnological and microbial bioconversion methods are used to improve the bioavailability and bioactivity of phytochemicals derived from wastes. It can be concluded that there are still some challenges in waste management and valorization concerning economic, safety, sensory, consumer acceptance, and regulative aspects, and further research is required to overcome these challenges and improve the quality and quantity of value-added products obtained from agricultural wastes and byproducts.

Novel Regioselective Synthesis of Urolithin Glucuronides─Human Gut Microbiota Cometabolites of Ellagitannins and Ellagic Acid

Urolithins (dibenzo-pyran-[b,d]-6 one derivatives) are human gut microbiota metabolites produced from the natural food antioxidant ellagic acid. Urolithins are better absorbed than ellagic acid and demonstrate biological activities that suggest that they are responsible for the health effects observed after consuming ellagitannin- and ellagic acid-containing foods. Urolithins occur in the systemic circulation as glucuronide conjugates following phase II metabolism. These phase II conjugates are essential for testing the urolithin mechanisms of action in human cell line bioassays. Urolithin glucuronides are not commercially available, and their biosynthesis leads to mixtures of regional isomers. This study describes a novel and regioselective synthesis of urolithin A (3,8-dihydroxy urolithin) 3- and 8-glucuronides and isourolithin A (3,9-dihydroxy urolithin) 3- and 9-glucuronides. The metabolites were characterized using ¹H and ¹³C NMR spectroscopy and UV spectrophotometry. The presence of these metabolites in human subjects belonging to different urolithin metabotypes was also investigated.

Production of New Microbially Conjugated Bile Acids by Human Gut Microbiota

Gut microbes have been recognized to convert human bile acids by deconjugation, dehydroxylation, dehydrogenation, and epimerization of the cholesterol core, but the ability to re-conjugate them with amino acids as an additional conversion has been recently described. These new bile acids are known as microbially conjugated bile acids (MCBAs). The aim of this study was to evaluate the MCBAs diversity produced by the gut microbiota through a metabolomics approach. In this study, fresh fecal samples from healthy donors were evaluated to explore the re-conjugation of chenodeoxycholic and 3-oxo-chenodeoxycholic acids by the human gut microbiota. No significant differences were found between the conversion trend of both BAs incubations. The in vitro results showed a clear trend to first accumulate the epimer isoursochenodeoxycholic acid and the dehydroxylated lithocholic acid derivatives in samples incubated with chenodeoxycholic and 3-oxo-chenodeoxycholic acid. They also showed a strong trend for the production of microbially conjugated dehydroxylated bile acids instead of chenodeoxycholic backbone conjugates. Different molecules and isomers of MCBAs were identified, and the new ones, valolithocholate ester and leucolithocholate ester, were identified and confirmed by MS/MS. These results document the gut microbiota’s capability to produce esters of MCBAs on hydroxyls of the sterol backbone in addition to amides at the C24 acyl site. This study opens a new perspective to study the BAs diversity produced by the human gut microbiota.

Technological and Biotechnological Processes To Enhance the Bioavailability of Dietary (Poly)phenols in Humans

The health effects of (poly)phenols (PPs) depend upon their bioavailability that, in general, is very low and shows a high interindividual variability. The low bioavailability of PPs is mainly attributed to their low absorption in the upper gastrointestinal tract as a result of their low water solubility, their presence in foods as polymers or in glycosylated forms, and their tight bond to food matrices. Although many studies have investigated how technological and biotechnological processes affect the phenolic composition of fruits and vegetables, limited information exists regarding their effects on PP bioavailability in humans. In the present review, the effect of food processing (mechanical, thermal, and non-thermal treatments), oral-delivery nanoformulations, enzymatic hydrolysis, fermentation, co-administration with probiotics, and generation of postbiotics in PP bioavailability have been overviewed, focusing in the evidence provided in humans.

Bioactive compounds in lettuce: Highlighting the benefits to human health and impacts of preharvest and postharvest practices

Lettuce is one of the most commonly consumed leafy vegetables worldwide and is available throughout the entire year. Lettuce is also a significant source of natural phytochemicals. These compounds, including glycosylated flavonoids, phenolic acids, carotenoids, the vitamin B groups, ascorbic acid, tocopherols, and sesquiterpene lactones, are essential nutritional bioactive compounds. This review aims to provide a comprehensive understanding of the composition of health-promoting compounds in different types of lettuce, the potential health benefits of lettuce in reducing the risks of chronic diseases, and the effect of preharvest and postharvest practices on the biosynthesis and accumulation of health-promoting compounds in lettuce.

High-Pressure Processing vs. Thermal Treatment: Effect on the Stability of Polyphenols in Strawberry and Apple Products

Polyphenols are important bioactive compounds that are affected by processing. The consumer's demand for minimally processed products contributes to the increase in non-thermal technologies such as high-pressure processing (HPP) in the food industry. This review is aimed at critically discussing the positive and negative effects of thermal treatment (TT) and HPP on the stability of different polyphenol families in agro-food products obtained from strawberry and apple, two of the most used fruits in food processing. Our findings show that the phenolic content was affected by processing, fruit type, polyphenol family, and storage conditions (time and temperature) of the final product. To increase shelf life, manufacturers aiming to preserve the natural content of polyphenols need to find the sweet spot between polyphenol stability and product shelf-life since the residual enzyme activity from HPP can affect polyphenols negatively.

Endocrine disruption in Crohn's disease: Bisphenol A enhances systemic inflammatory response in patients with gut barrier translocation of dysbiotic microbiota products

The relevance of environmental triggers in Crohn's disease remains poorly explored, despite the well-known association between industrialization and disease onset/progression. We have aimed at evaluating the influence of endocrine disrupting chemicals in CD patients. We performed a prospective observational study on consecutive patients diagnosed of CD. Serum levels of endocrine disruptors, short-chain fatty acids, tryptophan and cytokines were measured. Bacterial-DNA and serum endotoxin levels were also evaluated. Gene expression of ER-α, ER-β and GPER was measured in PBMCs. All patients were genotyped for NOD2 and ATG16L1 polymorphisms. A series of 200 CD patients (140 in remission, 60 with active disease) was included in the study. Bisphenol A was significantly higher in patients with active disease versus remission and in colonic versus ileal disease. GPER was significantly increased in active patients and correlated with BPA levels. BPA was significantly increased in patients with bacterial-DNA and correlated with serum endotoxin levels, (r = 0.417; P = .003). Serum butyrate and tryptophan levels were significantly lower in patients with bacterial-DNA and an inverse relationship was present between them and BPA levels (r = -0.491; P = .001) (r = -0.611; P = .001). Serum BPA levels correlated with IL-23 (r = 0.807; P = .001) and IL-17A (r = 0.743; P = .001). The multivariate analysis revealed an independent significant contribution of BPA and bacterial-DNA to serum levels of IL-23 and IL-17A. In conclusion, bisphenol A significantly affects systemic inflammatory response in CD patients with gut barrier disruption and dysbiotic microbiota secretory products in blood. These results provide evidence of an endocrine disruptor playing an actual pathogenic role on CD.

Jaboticaba berry: A comprehensive review on its polyphenol composition, health effects, metabolism, and the development of food products

Jaboticaba, a popular Brazilian berry, has been studied due to its relevant polyphenol composition, health benefits and potential use for the development of derived food products. Considering that around 200 articles have been published in recent years, this review aims to provide comprehensive and updated information, as well as a critical discussion on: (i) jaboticaba polyphenolic composition and extraction methods for their accurate determination; (ii) jaboticaba polyphenol's metabolism; (iii) biological effects of the fruit and the relationship with its polyphenols and their metabolites; (iv) challenges in the development of jaboticaba derived products. The determination of jaboticaba polyphenols should employ hydrolysis procedures during extraction, followed by liquid chromatographic analysis. Jaboticaba polyphenols, mainly anthocyanins and ellagitannins, are extensively metabolized, and their metabolites are probably the most important contributors to the relevant health effects associated with the fruit, such as antioxidant, anti-inflammatory, antidiabetic, hepatoprotective and hypolipidemic. Most of the technological processing of jaboticaba fruit and its residues is related to their application as a colorant, antioxidant, antimicrobial and source of polyphenols. The scientific literature still lacks studies on the metabolism and bioactivity of polyphenols from jaboticaba in humans, as well as the effect of technological processes on these issues.

Phytoprostanes and phytofurans modulate COX-2-linked inflammation markers in LPS-stimulated THP-1 monocytes by lipidomics workflow

Inflammation is a fundamental pathophysiological process which occurs in the course of several diseases. The present work describes the capacity of phytoprostanes (PhytoPs) and phytofurans (PhytoFs) (plant oxylipins), present in plant-based foods, to modulate inflammatory processes mediated by prostaglandins (PGs, human oxylipins) in lipopolysaccharide (LPS)-stimulated THP-1 monocytic cells, through a panel of 21 PGs and PG's metabolites, analyzed by UHPLC-QqQ-ESI-MS/MS. Also, the assessment of the cytotoxicity of PhytoPs and PhytoFs on THP-1 cells evidenced percentages of cell viability higher than 90% when treated with up to 100 μM. Accordingly, 50 μM of the individual PhytoPs and PhytoFs 9-F_1t-PhytoP, 9-epi-9-F_1t-PhytoP, ent-16-F_1t-PhytoP, ent-16-epi-16-F_1t-PhytoP, ent-9-D_1t-PhytoP, 16-B₁-PhytoP, 9-L₁-PhytoP, ent-16(RS)-9-epi-ST-Δ¹⁴-10-PhytoF, ent-9(RS)-12-epi-ST-Δ¹⁰-13-PhytoF, and ent-16(RS)-13-epi-ST-Δ¹⁴-9-PhytoF were evaluated on their capacity to modulate the expression of inflammatory markers. The results obtained demonstrated the presence of 7 metabolites (15-keto-PGF_2α, PGF_2α, 11β-PGF_2α, PGE₂, PGD₂, PGDM, and PGF_1α) in THP-1 monocytic cells, which expression was significantly modulated when exposed to LPS. The evaluation of the capacity of the individual PhytoPs and PhytoFs to revert the modification of the quantitative profile of PGs induced by LPS revealed the anti-inflammatory ability of 9-F_1t-PhytoP, ent-9-D_1t-PhytoP, 16-B₁-PhytoP, 9-L₁-PhytoP, and ent-9(RS)-12-epi-ST-Δ¹⁰-13-PhytoF, as evidenced by their capacity to prevent the up-regulation of 15-keto-PGF_2α, PGF_2α, PGE₂, PGF_1α, PGDM, and PGD₂ induced by LPS. These results indicated that specific plant oxylipins can protect against inflammatory events, encouraging further investigations using plant-based foods rich in these oxylipins or enriched extracts, to identify specific bioactivities of the diverse individual molecules, which can be useful for nutrition and health in the frame of well-defined pathophysiological processes.

Novel Urinary Biomarkers of Orange Juice Consumption, Interindividual Variability, and Differences with Processing Methods

Untargeted metabolomics identified urinary biomarkers able to discriminate between the intake of fresh hand-squeezed and industrially processed orange juices. Processing led to an upregulation in the excretion of hydroxy-polymethoxyflavone sulfates, abscisic acid, and sinapic acid 4'-glucuronide. The demethylated polymethoxyflavone metabolites were produced with a significant interindividual variability suggesting that they could originate from gut microbiota metabolism. No correlation between the excretion levels of flavanone and polymethoxyflavone metabolites was observed, showing that gut microbiota metabolism differences could be behind the interindividual variability. Subjects with a high excretion level of hesperetin conjugates could be low or high polymethoxyflavone excretors. Flavanone phase II metabolites were primarily glucuronides, while those of demethylated polymethoxyflavones were mainly sulfates. A comparative study with the available demethylated polymethoxyflavone standards suggested that the metabolites produced in humans could be tentatively 4'-hydroxy- and/or 3'-hydroxy-polymethoxyflavone sulfates. This study is the first to describe the bioavailability and metabolism of citrus juice polymethoxyflavones in humans.

Stratification of Volunteers According to Flavanone Metabolite Excretion and Phase II Metabolism Profile after Single Doses of 'Pera' Orange and 'Moro' Blood Orange Juices

Large interindividual variations in the biological response to citrus flavanones have been observed, and this could be associated with high variations in their bioavailability. The aim of this study was to identify the main determinants underlying interindividual differences in citrus flavanone metabolism and excretion. In a randomized cross-over study, non-obese and obese volunteers, aged 19-40 years, ingested single doses of Pera and Moro orange juices, and urine was collected for 24 h. A large difference in the recovery of the urinary flavanone phase II metabolites was observed, with hesperetin-sulfate and hesperetin-sulfo-O-glucuronide being the major metabolites. Subjects were stratified according to their total excretion of flavanone metabolites as high, medium, and low excretors, but the expected correlation with the microbiome was not observed at the genus level. A second stratification was proposed according to phase II flavanone metabolism, whereby participants were divided into two excretion groups: Profiles A and B. Profile B individuals showed greater biotransformation of hesperetin-sulfate to hesperetin-sulfo-O-glucuronide, as well as transformation of flavanone-monoglucuronide to the respective diglucuronides, suggestive of an influence of polymorphisms on UDP-glucuronosyltransferase. In conclusion, this study proposes a new stratification of volunteers based on their metabolic profiles. Gut microbiota composition and polymorphisms of phase II enzymes may be related to the interindividual variability of metabolism.

Urolithins in Human Breast Milk after Walnut Intake and Kinetics of Gordonibacter Colonization in Newly Born: The Role of Mothers' Urolithin Metabotypes

The maternal-infant transmission of several urolithins through breast milk and the gut colonization of infants by the urolithin-producing bacterium Gordonibacter during their first year of life were explored. Two trials (proof-of-concept study: n = 11; validation study: n = 30) were conducted, where breastfeeding mothers consumed walnuts as a dietary source of urolithin precursors. An analytical method was developed and validated to characterize the urolithin profile in breast milk. Total urolithins ranged from 8.5 to 176.9 nM, while they were not detected in breast milk of three mothers. The mothers' urolithin metabotypes governed the urolithin profile in breast milk, which might have biological significance on infants. A specific quantitative polymerase chain reaction method allowed monitoring the gut colonization of infants by Gordonibacter during their first year of life, and neither breastfeeding nor vaginal delivery was essential for this. The pattern of Gordonibacter establishment in babies was conditioned by their mother's urolithin metabotype, probably because of mother-baby close contact.

Human Gut Microbiota Metabolism of Dietary Sesquiterpene Lactones: Untargeted Metabolomics Study of Lactucopicrin and Lactucin Conversion In Vitro and In Vivo

SCOPE

Gut microbiota converts dietary phytochemicals into metabolites and modulates their health effects. The microbial metabolism of dietary terpenoids, as the sesquiterpene lactones of leafy vegetables, is unknown.

METHODS AND RESULTS

In vitro fermentation of lactucopicrin, lactucin, and romaine lettuce with gut microbiota from independent donors, show their extensive metabolism through untargeted metabolomics of the fecal incubations. Dehydroxylations and double bond hydrogenations are the main catabolic reactions. Isomers of dihydrolactucopicrin, tetrahydrolactucopicrin, and deoxylactucin, are observed after lactucopicrin metabolism. Tetrahydrolactucin and hexahydrolactucin are also found after lactucin metabolism. Lettuce fermentation shows similar metabolic conversions. Phase II conjugates of most of these metabolites are detected in the urine of healthy volunteers after escarole salad intake. Glucuronides, and sulfates, of dihydrolactucopicrin, tetrahydrolactucopicrin, dihydrolactucin, and deoxylactucin, are detected in the urine although with large inter-subject variability.

CONCLUSION

This is the first report on the gut microbiota metabolism of sesquiterpene lactones in humans, and one of the first reports to describe that dietary terpenoids of widely consumed leafy vegetables are extensively catabolized by human gut microbiota. A large inter-subject variation in the metabolism of sesquiterpene lactones also reflects differences in gut microbiota composition. It suggests that inter-individual differences in their health effects should be expected.

Can we trust biomarkers identified using different non-targeted metabolomics platforms? Multi-platform, inter-laboratory comparative metabolomics profiling of lettuce cultivars via UPLC-QTOF-MS

INTRODUCTION

Data analysis during UPLC-MS non-targeted metabolomics introduces variation as different manufacturers use specific algorithms for data treatment and this makes untargeted metabolomics an application for the discovery of new biomarkers with low confidence in the reproducibility of the results under the use of different metabolomics platforms.

OBJECTIVES

This study compared the ability of two platforms (Agilent UPLC-ESI-QTOF-MS and Waters UPLC-IMS-QTOF-MS) to identify biomarkers in butterhead and romaine lettuce cultivars.

METHODS

Two case studies by different metabolomics platforms: (1) Waters and Agilent datasets processed by the same data pre-processing software (Progenesis QI), and (2) Datasets processed by different data pre-processing software.

RESULTS

A higher number of candidate biomarkers shared between sample groups in case 2 (101) than in case 1 (26) was found. Thirteen metabolites were common to both cases. Romaine lettuce was characterised by phenolic compounds including flavonoids, hydroxycinnamate derivatives, and 9-undecenal, while Butterhead showed sesquiterpene lactones and xanthosine. This study demonstrates that high percentages of the most discriminatory entities can be obtained by using the manufacturers' embedded pre-processing software and following the recommended processing data guidelines using commercial software to normalise the data matrix.

Metabolism of different dietary phenolic compounds by the urolithin-producing human-gut bacteria Gordonibacter urolithinfaciens and Ellagibacter isourolithinifaciens

Gordonibacter urolithinfaciens and Ellagibacter isourolithinifaciens are two human gut bacterial species that convert ellagic acid into urolithins. Urolithins are bioactive postbiotics produced by dehydroxylation reactions catalyzed by different catechol-dehydroxylases. The metabolic ability of these anaerobic bacteria on other dietary-phenolic compounds is unknown. In the present study, we evaluated the metabolism of flavonoids (quercetin, hesperetin, hesperidin, nobiletin, catechin, isoxanthohumol), isoflavonoids (daidzein), coumarins (esculetin, umbelliferone, scoparone), phenylpropanoids [caffeic acid; 3-(3',4'-dihydroxyphenyl)propanoic acid (dihydrocaffeic acid); rosmarinic acid, and chlorogenic acid], benzoic acid derivatives (gallic acid, ellagic acid), lignans (secoisolariciresinol diglucoside), stilbenes (resveratrol), and secoiridoids (oleuropein) by G. urolithinfaciens DSM 27213^T and E. isourolithinifaciens DSM 104140^T. Both strains metabolized ellagic acid leading to the characteristic urolithins. They also metabolized caffeic, dihydrocaffeic, rosmarinic, and chlorogenic acids. The rest of the phenolic compounds were not transformed. Catechol dehydroxylation and double bond reduction were prominent transformations observed during the incubations. The enzymatic activities seem to have a narrow substrate scope as many catechol- (quercetin, catechin, esculetin, gallic acid) and double bond-containing (resveratrol, esculetin, scoparone, umbelliferone) phenolics were not metabolized. The catechol-dehydroxylase activity was more efficient in E. isourolithinifaciens, while the reductase activity was more relevant in G. urolithinfaciens.

Anti-Inflammatory and Antioxidant Effects of Regular Consumption of Cooked Ham Enriched with Dietary Phenolics in Diet-Induced Obese Mice

Oxidative damage and chronic inflammation have been proven as one of the major factors associated with obesity, which increases the incidence of non-communicable chronic diseases. In this sense, the development of new functional products aiming at the palliation of oxidative stress and inflammatory disruption can be a determining factor for public health as seen in previous researches. In this study, a blend of potentially bioavailable dietary phenolics was added to low sodium and low-fat cooked ham. A diet-induced obesity model in C57/BL6J mice has been used for testing the effectiveness of the phenolic blend and the new functionalized product, which bioavailability was tested by UPLC-ESI-QTOF-MS. After obesity induction, different oxidative and inflammatory biomarkers were evaluated. Results in the murine induced obesity model, demonstrate a robust statistically significant improvement in key parameters related with obesity risk in the groups feed with a phenolic-enriched diets (P) + high-fat diet (HFD) and phenolic enriched cooked ham (PECH) + HFD. In both groups there was an improvement in body composition parameters, inflammatory biomarkers and antioxidant enzymes levels. Specifically in the group feed with the phenolic enriched cooked ham (PECH + HFD) there was an improvement of total fat volume (23.08% reduction), spleen index (22.04% of reduction), plasmatic MCP-1 (18% reduction), IL-6 (38.94% reduction), IL-10 (13.28% reduction), TNF-α (21.32% reduction), gut IL-1β (10.86% reduction), gut IL-6 (13.63% reduction) and GPx (60.15% increase) and catalase (91.37% increase) enzymes. Thus, the functionalized ham could be considered an appropriate dietary polyphenol source, which might improve the oxidative and inflammatory status and could finally result in the potential decrease of the risk of certain non-communicable chronic diseases.

Polyphenol characterisation of Phoenix dactylifera L. (date) seeds using HPLC-mass spectrometry and its bioaccessibility using simulated in-vitro digestion/Caco-2 culture model

The polyphenolic content in date seeds, a promising functional ingredient for food, was characterised in three forms viz., date seed powder (DSP), date seed pita bread (DSB) and date seed extract (DSE). Bioaccessibility of the polyphenols from the samples was assessed by in-vitro digestion coupled with transport using Caco-2 cells. HPLC-ESI-UV/MS/MS-(IT) analysis recorded the presence of phenolic acids, flavanols, flavonols and flavones. Flavan-3-ols was the most significant group with the highest concentration in DSP, 47.91 ± 0.13 g/kg, after depolymerisation. Phenolic acids such as protocatechuic acid, vanillic acid and caffeoylshikimic acid were recovered from DSP and DSE after in-vitro digestion. In comparison, the recovery was significantly lower in the bread sample. Similarly, transport of protocatechuic acid, p-hydroxybenzoic acid, caffeoylshikimic acid, p-coumaric acid, syringic acid hexoside and diosmin through Caco-2 monolayer was observed in DSP and DSE, while protocatechuic acid and p-hydroxybenzoic acid were the only polyphenols transported from digested DSB.

Improving the reporting quality of intervention trials addressing the inter-individual variability in response to the consumption of plant bioactives: quality index and recommendations

PURPOSE

The quality of the study design and data reporting in human trials dealing with the inter-individual variability in response to the consumption of plant bioactives is, in general, low. There is a lack of recommendations supporting the scientific community on this topic. This study aimed at developing a quality index to assist the assessment of the reporting quality of intervention trials addressing the inter-individual variability in response to plant bioactive consumption. Recommendations for better designing and reporting studies were discussed.

METHODS

The selection of the parameters used for the development of the quality index was carried out in agreement with the scientific community through a survey. Parameters were defined, grouped into categories, and scored for different quality levels. The applicability of the scoring system was tested in terms of consistency and effort, and its validity was assessed by comparison with a simultaneous evaluation by experts' criteria.

RESULTS

The "POSITIVe quality index" included 11 reporting criteria grouped into four categories (Statistics, Reporting, Data presentation, and Individual data availability). It was supported by detailed definitions and guidance for their scoring. The quality index score was tested, and the index demonstrated to be valid, reliable, and responsive.

CONCLUSIONS

The evaluation of the reporting quality of studies addressing inter-individual variability in response to plant bioactives highlighted the aspects requiring major improvements. Specific tools and recommendations favoring a complete and transparent reporting on inter-individual variability have been provided to support the scientific community on this field.

Targeting the delivery of dietary plant bioactives to those who would benefit most: from science to practical applications

Background

A healthy diet and optimal lifestyle choices are amongst the most important actions for the prevention of cardiometabolic diseases. Despite this, it appears difficult to convince consumers to select more nutritious foods. Furthermore, the development and production of healthier foods do not always lead to economic profits for the agro-food sector. Most dietary recommendations for the general population represent a “one-size-fits-all approach” which does not necessarily ensure that everyone has adequate exposure to health-promoting constituents of foods. Indeed, we now know that individuals show a high variability in responses when exposed to specific nutrients, foods, or diets.

Purpose

This review aims to highlight our current understanding of inter-individual variability in response to dietary bioactives, based on the integration of findings of the COST Action POSITIVe. We also evaluate opportunities for translation of scientific knowledge on inter-individual variability in response to dietary bioactives, once it becomes available, into practical applications for stakeholders, such as the agro-food industry. The potential impact from such applications will form an important impetus for the food industry to develop and market new high quality and healthy foods for specific groups of consumers in the future. This may contribute to a decrease in the burden of diet-related chronic diseases.

Individual differences in ADME (Absorption, Digestion, Metabolism and Excretion) is believed to underpin much of the inter-individual variation in responses.

Recent developments in the area of food metabolome databases and fast improvements in innovative metabotyping technologies hold great promise for improved profiling of dietary intake, exposure to individual ingredients, foods and dietary patterns, as well as our ability to identify individual responsiveness.

The food industry needs well-defined population clusters or targets in order to be able to design “personalized products”.

There are indeed excellent industrial opportunities for foods that modulate gut microbiota, and thereby enable the delivery of food bioactive metabolites.

It is currently not clear whether knowledge on individual nutrient needs, based on genetic or metagenomic data, would affect long-term dietary and health behaviours.

Data to support the development of dietary recommendations may need to be generated by new n-of-1-based study designs in the future.

Identification of Novel Urolithin Metabolites in Human Feces and Urine after the Intake of a Pomegranate Extract

Urolithins are bioactive gut microbiota metabolites of ellagic acid. Here, we have identified four unknown urolithins in human feces after the intake of a pomegranate extract. The new metabolites occurred only in 19% of the subjects. 4,8,9,10-Tetrahydroxy urolithin, (urolithin M6R), was unambiguously identified by ¹H NMR, UV, and HRMS. Three metabolites were tentatively identified by the UV, HRMS, and chromatographic behavior, as 4,8,10-trihydroxy (urolithin M7R), 4,8,9-trihydroxy (urolithin CR), and 4,8-dihydroxy (urolithin AR) urolithins. Phase II conjugates of the novel urolithins were detected in urine and confirmed their absorption, circulation, and urinary excretion. The production of the new urolithins was not specific of any of the known urolithin metabotypes A and B. The new metabolites needed a bacterial 3-dehydroxylase activity for their production, and this is a novel feature as all the previously known urolithins maintained the hydroxyl at 3 position. The ability of production of these "R" urolithins can be considered an additional metabolic feature for volunteer stratification.

Pomegranate Fruit and Juice (cv. Mollar), Rich in Ellagitannins and Anthocyanins, Also Provide a Significant Content of a Wide Range of Proanthocyanidins

Proanthocyanidins (PAs) were characterized in husk, membranes, arils, and seeds of 'Mollar de Elche' pomegranate cultivar using liquid chromatography-electrospray ionization-ion-trap tandem mass spectrometry after acid catalysis in the presence of phloroglucinol (phloroglucinolysis). PAs were also evaluated in commercial juice and in the juice made in the laboratory by pressing fresh arils. Pomegranate PAs were composed of a very rich mixture of flavan-3-ols: catechin, epicatechin, gallocatechin, epigallocatechin, epigallocatechin gallate, and epicatechin gallate. Catechins and gallocatechins were the most abundant units, while galloylated flavanols were detected at lower concentrations. The highest PA content was found in husk (1840.5 μg/g), followed by seeds (316.2 μg/g) and membranes (51.4 μg/g). With regard to the pomegranate edible parts, arils showed concentrations of 34.4 μg/g and pressed aril juice of 21.3 mg/L, lower than those found in other traditional PA-containing food and beverages, such as apple, grapes, chocolate, red wine, or tea. Higher concentrations similar to those found in red wine were observed in commercial whole fruit pressed pomegranate juice (146.9 mg/L). These PA concentrations represented between 0.1 and 7% of the total polyphenol content in the different pomegranate samples, which were richer in ellagitannins and anthocyanins. The mean degree of polymerization (1.2-2.1) revealed that PAs in Mollar pomegranate samples are constituted mainly of monomers and dimers, which may influence in better absorption and bioavailability of these compounds.

Circulating levels of butyrate are inversely related to portal hypertension, endotoxemia, and systemic inflammation in patients with cirrhosis

Short-chain fatty acids (SCFAs) are gut microbiota-derived products that participate in maintaining the gut barrier integrity and host's immune response. We hypothesize that reduced SCFA levels are associated with systemic inflammation, endotoxemia, and more severe hemodynamic alterations in cirrhosis. Patients with cirrhosis referred for a hepatic venous pressure gradient (HVPG) measurement (n = 62) or a transjugular intrahepatic portosystemic shunt placement (n = 12) were included. SCFAs were measured in portal (when available), hepatic, and peripheral blood samples by GC-MS. Serum endotoxins, proinflammatory cytokines, and NO levels were quantified. SCFA levels were significantly higher in portal vs. hepatic and peripheral blood. There were inverse relationships between SCFAs and the severity of disease. SCFAs (mainly butyric acid) inversely correlated with the model for end-stage liver disease score and were further reduced in patients with history of ascites, hepatic encephalopathy, and spontaneous bacterial peritonitis. There was an inverse relationship between butyric acid and HVPG values. SCFAs were directly related with systemic vascular resistance and inversely with cardiac index. Butyric acid inversely correlated with inflammatory markers and serum endotoxin. A global reduction in the blood levels of SCFA in patients with cirrhosis is associated with a more advanced liver disease, suggesting its contribution to disease progression.-Juanola, O., Ferrusquía-Acosta, J., García-Villalba, R., Zapater, P., Magaz, M., Marín, A., Olivas, P., Baiges, A., Bellot, P., Turon, F., Hernández-Gea, V., González-Navajas, J. M., Tomás-Barberán, F. A., García-Pagán, J. C., Francés, R. Circulating levels of butyrate are inversely related to portal hypertension, endotoxemia, and systemic inflammation in patients with cirrhosis.

The effects of polyphenols and other bioactives on human health

Although deficiencies in polyphenol intake do not result in specific deficiency diseases, adequate intake of polyphenols could confer health benefits, especially with regard to chronic diseases. Tea, cocoa, fruits, and berries, as well as vegetables, are rich in polyphenols. Flavan-3-ols from cocoa have been found to be associated with a reduced risk of stroke, myocardial infarction, and diabetes, as well as improvements in lipids, endothelial-dependent blood flow and blood pressure, insulin resistance, and systemic inflammation. The flavonoid quercetin and the stilbene resveratrol have also been associated with cardiometabolic health. Although polyphenols have been associated with improved cerebral blood flow, evidence of an impact on cognition is more limited. The ability of dietary polyphenols to produce clinical effects may be due, at least in part, to a bi-directional relationship with the gut microbiota. Polyphenols can impact the composition of the gut microbiota (which are independently associated with health benefits), and gut bacteria metabolize polyphenols into bioactive compounds that produce clinical benefits. Another critical interaction is that of polyphenols with other phytochemicals, which could be relevant to interpreting the health parameter effects of polyphenols assayed as purified extracts, whole foods, or whole food extracts.

Targeted Metabolomics Analysis and Identification of Biomarkers for Predicting Browning of Fresh-Cut Lettuce

The metabolism of phenolic compounds is a key factor in the development of wound-induced enzymatic browning of fresh-cut lettuce. In the present study, the lettuce midribs discriminant metabolites, selected in a previous untargeted metabolomics study, were thoroughly identified. Our results showed that their basal contents correlated with browning developed after 5 days of storage. 5- trans-Chlorogenic acid and 5- cis-chlorogenic acid were positively correlated with browning, while sinapaldehyde and its 4-β-d-glucoside and 4-(6'-malonyl)-β-d-glucoside conjugates were negatively correlated. Using targeted metabolomics, the metabolites were analyzed in lettuce heads with different degrees of development and different browning susceptibility and these biomarkers were confirmed. Despite the large variability in the browning process of lettuce, the chlorogenic acids/sinapaldehyde derivatives ratio showed a linear correlation ( r2 = 0.79) with the fresh-cut lettuce browning developed in 24 Romaine lettuce cultivars, validating the relevance of these biomarkers. These results show that the analysis of the basal content of these metabolites could be used in lettuce breeding programs to select cultivars that are more appropriate for the fresh-cut industry.

Tea Is a Significant Dietary Source of Ellagitannins and Ellagic Acid

The ellagitannin composition and the total content of ellagitannins in different types of tea were studied by high-performance liquid chromatography/ion-trap mass spectrometry. Strictinin and seven other isomers, tellimagrandin I, and ellagic acid were identified from tea infusions. The ellagitannin content in tea infusions was determined after acid hydrolysis and ranged from 0.15 to 4.46 mg of ellagic acid equivalent/g of tea in the infusions. The intake of ellagic acid after drinking a cup of tea brewed with 4 g of tea could range between 0.59 and 17.89 mg. These results indicate that tea can be a significant contributor to the dietary intake of ellagitannins. Urolithins, the gut microbiota metabolites produced in vivo from ellagic acid and ellagitannins, were detected in human urine after dietary tea beverage intake. Urolithin metabotypes A, B, and 0 were identified in volunteers after tea intake. These results suggest that the daily intake of ellagitannins from tea can have a role in tea health effects.

Bioactive Components and Antioxidant and Antibacterial Activities of Different Varieties of Honey: A Screening Prior to Clinical Application

This study assessed 16 different honey samples in order to select the best one for therapeutic purposes. First, a study of honey's main bioactive compounds was carried out. Then phenolic profiles were determined and specific compounds quantified using a HPLC system coupled to a mass spectrometer. Then, antioxidant activity, by three in vitro methods, and antibacterial activity against reference strains and clinical isolates were evaluated. Great variability among samples was observed regarding ascorbic acid (between 0.34 ± 0.00 and 75.8 ± 0.41 mg/100 g honey; p < 0.001), total phenolic compounds (between 23.1 ± 0.83 and 158 ± 5.37 mg/100 g honey; p < 0.001), and total flavonoid contents (between 1.65 ± 0.11 and 5.93 ± 0.21 mg/100 g honey; p < 0.001). Forty-nine different phenolic compounds were detected, but only 46 of them were quantified by HPLC. The concentration of phenolic compounds and the phenolic profiles varied widely among samples (between 1.06 ± 0.04 and 18.6 ± 0.73 mg/100 g honey; p < 0.001). Antioxidant activity also varied significantly among the samples. All honey varieties exhibited antibacterial activity against both reference and clinical strains (effective concentrations ranged between 0.05 and 0.40 g/mL depending on the honey sample and bacteria tested). Overall, samples with better combinations of bioactive properties were avocado and chestnut honeys.

Effect of Food Structure and Processing on (Poly)phenol-Gut Microbiota Interactions and the Effects on Human Health

The two-way interaction of food (poly)phenols with the human gut microbiota has been studied throughout the past ten years. Research has shown that this interaction can be relevant to explain the health effects of these phytochemicals. The effect of the food matrix and food processing on this interaction has only been partially studied. In this article, the studies within this field have been critically reviewed, with a special focus on the following groups of phenolic metabolites: citrus flavanones, pomegranate ellagitannins, and cocoa proanthocyanidins. The available research shows that both the food matrix and food processing can be relevant factors for gut microbiota reshaping to reach a healthier microbial ecology and for the conversion of polyphenols to bioactive and bioavailable metabolites. There are, however, some research gaps that indicate a more comprehensive research approach is needed to reach valid conclusions regarding the gut microbiota-mediated effects of polyphenols on human health.

The gut microbiota urolithin metabotypes revisited: the human metabolism of ellagic acid is mainly determined by aging

Understanding individuals' response to dietary bioactives is crucial for personalized nutrition. We report here for the first time in a Caucasian cohort (5-90 years, n = 839) that aging is the main factor that determines the gut microbiota involved in the ellagic acid-ellagitannin metabolism (urolithin metabotypes), with potential consequences for human health.

Regulatory T Cells Restrict Permeability to Bacterial Antigen Translocation and Preserve Short-Chain Fatty Acids in Experimental Cirrhosis

Intestinal permeability to translocation of bacterial products is increased in cirrhosis. Regulatory T cells (Tregs) remain central to the interplay between the host and microbial milieu. We propose that Tregs are involved in promoting gut barrier integrity and a balanced interaction with gut microbiota–derived short‐chain fatty acids (SCFAs). Carbon tetrachloride cirrhosis was induced in wild‐type and recombination activating gene 1 (Rag1)^‐/‐ mice. Naive T cells and Treg cells were transferred into Rag1^‐/‐ mice. Intestinal permeability was assessed in vivo after lipopolysaccharide (LPS) oral administration, and bacterial DNA presence was evaluated in mesenteric lymph nodes. Transcript and protein levels of tight‐junction (TJ) proteins were measured in colonic tissue. Intestinal T helper profile in response to Escherichia coli (E. coli) was determined by flow cytometry. SCFAs were measured by gas chromatography–mass spectrometry in colonic content before and after E. coli challenge. Rag1^‐/‐ mice showed significantly increased permeability to LPS and bacterial DNA translocation rate compared with control mice. Naive T and Treg cotransfer significantly reduced gut permeability to bacterial antigen translocation and restored TJ protein expression in Rag1^‐/‐ mice. Naive T and Treg replenishment in Rag1^‐/‐ mice restrained proinflammatory differentiation of intestinal lymphocytes in response to E. coli. The main SCFA concentration resulted in significant reduction in Rag1^‐/‐ mice after E. coli administration but remained unaltered after naive T and Tregs cotransfer. The reduced expression of SCFA receptors induced by E. coli was reestablished following naive T and Treg reconstitution in Rag1^‐/‐ mice. Conclusion: The restriction of gut permeability, local inflammatory differentiation, and loss of bacteria‐derived SCFAs foster the value of Tregs in preventing bacterial translocation in cirrhosis.

Ellagibacter isourolithinifaciens gen. nov., sp. nov., a new member of the family Eggerthellaceae, isolated from human gut

Urolithins are gut microbial metabolites that exert health benefits in vivo and are generated from ellagic acid (EA) and ellagitannin-containing foods such as strawberries, pomegranates and walnuts. Gordonibacter species produce some intermediary urolithins but the micro-organisms responsible for the transformation of EA into the final and more bioactive urolithins, such as urolithin A and isourolithin A, are unknown. We report here a new bacterium, capable of metabolizing EA into isourolithin A, isolated from healthy human faeces and characterized by determining phenotypic, biochemical and molecular methods. Strain CEBAS 4A belongs to the Eggerthellaceae family and differed from other genera of this family, both phylogenetically and phenotypically. Based on 16S rRNA gene sequence similarity, the strain was related to Enterorhabdus musicola DSM 19490^T (92.9 % similarity), Enterorhabdus caecimuris DSM 21839^T (92.7 % similarity), Adlercreutzia equolifaciens DSM 19450^T (92.5 % similarity), Asaccharobacter celatus DSM 18785^T (92.5 % similarity) and Parvibacter caecicola DSM 22242^T (91.2 % similarity). This strain was strictly anaerobic and Gram-stain-positive. The whole-cell fatty acids were saturated (98.3 %), a very high percentage that differs from the nearest genera ranging from 62 to 73 %. The major respiratory lipoquinone was menaquinone-7 and the diamino acid in the peptidoglycan was meso-diaminopimelic acid. Diphosphatidylglycerol and phosphatidylglycerol comprised the main polar lipid profile in addition to several phosphoglycolipids (PGL1-2), phospholipids (PL1-4), glycolipids (GL1-6) and lipids. Based on these data, a new genus, Ellagibacter gen. nov. is proposed with one species, Ellagibacter isourolithinifaciens sp. nov. The type strain of Ellagibacter isourolithinifaciens is CEBAS 4A^T (=DSM 104140^T=CCUG 70284^T).

A novel integrated non-targeted metabolomic analysis reveals significant metabolite variations between different lettuce (Lactuca sativa. L) varieties

Lettuce is an important leafy vegetable that represents a significant dietary source of antioxidants and bioactive compounds. However, the levels of metabolites in different lettuce cultivars are poorly characterized. In this study, we used combined GC × GC-TOF/MS and UPLC-IMS-QTOF/MS to detect and relatively quantify metabolites in 30 lettuce cultivars representing large genetic diversity. Comparison with online databases, the published literature, standards as well using collision cross-section values enabled putative identification of 171 metabolites. Sixteen of these 171 metabolites (including phenolic acid derivatives, glycosylated flavonoids, and one iridoid) were present at significantly different levels in leaf and head type lettuces, which suggested the significant metabolomic variations between the leaf and head types of lettuce are related to secondary metabolism. A combination of the results and metabolic network analysis techniques suggested that leaf and head type lettuces contain not only different levels of metabolites but also have significant variations in the corresponding associated metabolic networks. The novel lettuce metabolite library and novel non-targeted metabolomics strategy devised in this study could be used to further characterize metabolic variations between lettuce cultivars or other plants. Moreover, the findings of this study provide important insight into metabolic adaptations due to natural and human selection, which could stimulate further research to potentially improve lettuce quality, yield, and nutritional value.

Clustering according to urolithin metabotype explains the interindividual variability in the improvement of cardiovascular risk biomarkers in overweight-obese individuals consuming pomegranate: A randomized clinical trial

SCOPE

The pomegranate lipid-lowering properties remain controversial, probably due to the interindividual variability in polyphenol (ellagitannins) metabolism.

OBJECTIVE

We aimed at investigating whether the microbially derived ellagitannin-metabolizing phenotypes, i.e. urolithin metabotypes A, (UM-A), B (UM-B), and 0 (UM-0), influence the effects of pomegranate extract (PE) consumption on 18 cardiovascular risk biomarkers in healthy overweight-obese individuals.

METHODS AND RESULTS

A double-blind, crossover, dose-response, randomized, placebo-controlled trial was conducted. The study (POMEcardio) consisted of two test phases (dose-1 and dose-2, lasting 3 weeks each) and a 3-week washout period between each phase. Forty-nine participants (BMI > 27 kg/m² ) daily consumed one (dose-1, 160 mg phenolics/day) or four (dose-2, 640 mg phenolics/day) PE or placebo capsules. Notably, UM-B individuals showed the highest baseline cardiovascular risk. After dose-2, total cholesterol (-15.5 ± 3.7%), LDL-cholesterol (-14.9 ± 2.1%), small LDL-cholesterol (-47 ± 7%), non-HDL-cholesterol (-11.3 ± 2.5%), apolipoprotein-B (-12 ± 2.2%), and oxidized LDL-cholesterol -24 ± 2.5%) dose dependently decreased (P < 0.05) but only in UM-B subjects. These effects were partially correlated with urolithin production and the increase in Gordonibacter levels. Three (50%) nonproducers (UM-0) became producers following PE consumption.

CONCLUSIONS

UM clustering suggests a personalized effect of ellagitannin-containing foods and could explain the controversial pomegranate benefits. Research on the specific role of urolithins and the microbiota associated with each UM is warranted.

Pomegranate juice, but not an extract, confers a lower glycemic response on a high-glycemic index food: randomized, crossover, controlled trials in healthy subjects

Background: Low-glycemic index diets have demonstrated health benefits associated with a reduced risk of developing type 2 diabetes.Objectives: We tested whether pomegranate polyphenols could lower the glycemic response of a high-glycemic index food when consumed together and the mechanism by which this might occur.Design: We compared the acute effect of a pomegranate juice and a polyphenol-rich extract from pomegranate (supplement) on the bread-derived postprandial blood glucose concentration in 2 randomized, crossover, controlled studies (double-blinded for the supplements), each on 16 healthy volunteers. An additional randomized, crossover, controlled study on 16 volunteers consuming constituent fruit acids in a pH-balanced solution (same pH as pomegranate) and bread was conducted to determine any contributions to postprandial responses caused by acidic beverages.Results: As primary outcome, the incremental area under the curve for bread-derived blood glucose (-33.1% ± 18.1%, P = 0.000005) and peak blood glucose (25.4% ± 19.3%, P = 0.0004) were attenuated by pomegranate juice, compared with a control solution containing the equivalent amount of sugars. In contrast, the pomegranate supplement, or a solution containing the malic and citric acid components of the juice, was ineffective. The pomegranate polyphenol punicalagin was a very effective inhibitor of human α-amylase in vitro, comparable to the drug acarbose. Neither the pomegranate extract nor the individual component polyphenols inhibited ¹⁴C-D-glucose transport across differentiated Caco-2/TC7 cell monolayers, but they inhibited uptake of ¹⁴C-glucose into Xenopus oocytes expressing the human glucose transporter type 2. Further, some of the predicted pomegranate gut microbiota metabolites modulated ¹⁴C-D-glucose and ¹⁴C-deoxy-D-glucose uptake into hepatic HepG2 cells.Conclusions: These data indicate that pomegranate polyphenols, when present in a beverage but not in a supplement, can reduce the postprandial glycemic response of bread, whereas microbial metabolites from pomegranate polyphenols exhibit the potential to further modulate sugar metabolism much later in the postprandial period. This trial was registered at clinicaltrials.gov as NCT02486978, NCT02624609, and NCT03242876.