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.

Excretion by subjects on a low (poly)phenol diet of phenolic gut microbiota catabolites sequestered in tissues or associated with catecholamines and surplus amino acids.

Phenolic catabolites excreted by fasting subjects with a functioning colon and ileostomists on a low (poly)phenol diet have been investigated. Urine was collected over a 12 h fasting period after adherence to a low (poly)phenol diet for 36 h. UHPLC-HR-MS quantified 77 phenolics. Some were present in the urine of both groups in similar trace amounts and others were excreted in higher amounts by participants with a colon indicating the involvement of the microbiota. Most were present in sub- or low-µmol amounts, but hippuric acid dominated accounting on average for 60% of the total for both volunteer categories indicating significant production from sources other than non-nutrient dietary (poly)phenols. The potential origins of the phenolics associated with the low (poly)phenol diet, include endogenous catecholamines, surplus tyrosine and phenylalanine, and washout of catabolites derived from pre-study intakes of non-nutrient dietary (poly)phenols.

Acute effect of oat ß-glucan on the bioavailability of orange juice flavanones.

The impact of ß-glucan on the bioavailability of orange juice (OJ) flavanones was investigated in a randomised controlled trial. Volunteers consumed 500 mL of OJ without or with either 3 g (OB-3) or 6 g (OB-6) of ß-glucan. Urine samples, collected 12 h before and over a 0-24 h period post-supplementation, were analysed by high-performance liquid chromatography-high resolution mass spectrometry. The overall 0-24 h urinary excretion of the 17 flavanone metabolites identified and quantified in urine after OJ ingestion corresponded to 29.7 µmol, and 25.0 and 9.3 µmol, respectively, after OB-3 and OB-6 intake. This corresponds to 9.3, 7.9, and 2.9% recoveries of the 318 µmol of the ingested flavanones. The acute ingestion of OJ with 6 g, but not 3 g of ß-glucan led to a significant reduction (p < 0.05) in the excretion of flavanone metabolites compared with consumption of OJ alone.

In vitro catabolism of 3',4'-dihydroxycinnamic acid by human colonic microbiota.

3',4'-Dihydroxycinnamic acid (aka caffeic acid) is a common dietary component found in a variety of plant-derived food products either in a free form or esterified as in chlorogenic acids such as 5-O-caffeoylquinic acid. The dihydroxycinnamate is produced principally by hydrolysis in the colon of 5-O-caffeoylquinic acid and other caffeoylquinic acid esters, and is catabolised by the resident microbiota prior to absorption. In the present study 3',4'-dihydroxycinnamic acid was incubated in vitro, with or without glucose, under anaerobic conditions with faecal slurries obtained from five volunteers. The main resultant catabolites to accumulate were 3-(3',4'-dihydroxyphenyl)propanoic acid (aka dihydrocaffeic acid), 3-(3'-hydroxyphenyl)propanoic acid and phenylacetic acid. Both the rate of degradation of the hydroxycinnamate substrate and the catabolite profile varied between the faecal samples from the individual volunteers. Overall there was no clear cut effect when glucose was added to incubation medium.

Phenyl-γ-valerolactones and phenylvaleric acids, the main colonic metabolites of flavan-3-ols: synthesis, analysis, bioavailability, and bioactivity.

Covering: 1958 to June 2018 Phenyl-γ-valerolactones (PVLs) and their related phenylvaleric acids (PVAs) are the main metabolites of flavan-3-ols, the major class of flavonoids in the human diet. Despite their presumed importance, these gut microbiota-derived compounds have, to date, in terms of biological activity, been considered subordinate to their parent dietary compounds, the flavan-3-ol monomers and proanthocyanidins. In this review, the role and prospects of PVLs and PVAs as key metabolites in the understanding of the health features of flavan-3-ols have been critically assessed. Among the topics covered, are proposals for a standardised nomenclature for PVLs and PVAs. The formation, bioavailability and pharmacokinetics of PVLs and PVAs from different types of flavan-3-ols are discussed, taking into account in vitro and animal studies, as well as inter-individual differences and the existence of putative flavan-3-ol metabotypes. Synthetic strategies used for the preparation of PVLs are considered and the methodologies for their identification and quantification assessed. Metabolomic approaches unravelling the role of PVLs and PVAs as biomarkers of intake are also described. Finally, the biological activity of these microbial catabolites in different experimental models is summarised. Knowledge gaps and future research are considered in this key area of dietary (poly)phenol research.

Catabolism of citrus flavanones by the probiotics Bifidobacterium longum and Lactobacillus rhamnosus.

PURPOSE: Orange juice (OJ) flavanones undergo limited absorption in the upper gastrointestinal tract and reach the colon where they are transformed by the microbiota prior to absorption. This study investigated the ability of two probiotic bacteria, Bifidobacterium longum R0175 and Lactobacillus rhamnosus subsp. Rhamnosus NCTC 10302 to catabolise OJ flavanones. METHODS: The bacteria were incubated with hesperetin-7-O-rutinoside, naringenin-7-O-rutinoside, hesperetin and naringenin, and the culture medium and intracellular cell extracts were collected at intervals over a 48 h of incubation period. The flavanones and their phenolic acid catabolites were identified and quantified by HPLC-HR-MS. RESULTS: Both probiotics were able to subject hesperetin to ring fission yielding 3-(3'-hydroxy-4'-methoxyphenyl)propionic acid which was subsequently demethylated producing 3-(3',4'-dihydroxyphenyl)propionic acid and then via successive dehydroxylations converted to 3-(3'-hydroxyphenyl)propionic acid and 3-(phenyl)propionic acid. Incubation of both bacteria with naringenin resulted in its conversion to 3-(4'-hydroxyphenyl)propionic acid which underwent dehydroxylation yielding 3-(phenyl)propionic acid. In addition, only L. rhamnosus exhibited rhamnosidase and glucosidase activity and unlike B. longum, which was able to convert hesperetin-7-O-rutinoside and naringenin-7-O-rutinoside to their respective aglycones. The aglycones were then subjected to ring fission and further catabolised in a similar manner to that described above. The flavanones and their catabolites were found in the culture medium but not accumulated in the bacterial cells. CONCLUSIONS: These findings demonstrate the enzymatic potential of single strains of bifidobacterium and lactobacillus which may be involved in the colonic catabolism of OJ flavanones in vivo.

Trimethylamine-N-Oxide (TMAO)-Induced Impairment of Cardiomyocyte Function and the Protective Role of Urolithin B-Glucuronide.

One of the most recently proposed candidates as a potential trigger for cardiovascular diseases is trimethylamine-N-oxide (TMAO). Possible direct effects of TMAO on myocardial tissue, independent of vascular damage, have been only partially explored so far. In the present study, we assessed the detrimental direct effects of TMAO on cardiomyocyte contractility and intracellular calcium dynamics, and the ability of urolithin B-glucuronide (Uro B-gluc) in counteracting TMAO-induced cell damage. Cell mechanics and calcium transients were measured, and ultrastructural analysis was performed in ventricular cardiomyocytes isolated from the heart of normal adult rats. Cells were either untreated, exposed to TMAO, or to TMAO and Uro B-gluc. TMAO exposure worsened cardiomyocyte mechanics and intracellular calcium handling, as documented by the decrease in the fraction of shortening (FS) and the maximal rate of shortening and re-lengthening, associated with reduced efficiency in the intracellular calcium removal. Ultrastructurally, TMAO-treated cardiomyocytes also exhibited glycogen accumulation, a higher number of mitochondria and lipofuscin-like pigment deposition, suggesting an altered cellular energetic metabolism and a higher rate of protein oxidative damage, respectively. Uro B-gluc led to a complete recovery of cellular contractility and calcium dynamics, and morphologically to a reduced glycogen accumulation. We demonstrated for the first time a direct negative role of TMAO on cardiomyocyte functional properties and the ability of Uro B-gluc in counteracting these detrimental effects.

The Bioavailability, Transport, and Bioactivity of Dietary Flavonoids: A Review from a Historical Perspective.

Flavonoids are plant-derived dietary components with a substantial impact on human health. Research has expanded massively since it began in the 1930s, and the complex pathways involved in bioavailability of flavonoids in the human body are now well understood. In recent years, it has been appreciated that the gut microbiome plays a major role in flavonoid action, but much progress still needs to be made in this area. Since the first publications on the health effects of flavonoids, their action is understood to protect against various stresses, but the mechanism of action has evolved from the now debunked simple direct antioxidant hypothesis into an understanding of the complex effects on molecular targets and enzymes in specific cell types. This review traces the development of the field over the past 8 decades, and indicates the current state of the art, and how it was reached. Future recommendations based on this historical analysis are (a) to focus on key areas of flavonoid action, (b) to perform human intervention studies focusing on bioavailability and protective effects, and (c) to carry out cellular in vitro experiments using appropriate cells together with the chemical form of the flavonoid found at the site of action; this could be the native form of compounds found in the food for studies on digestion and the intestine, the conjugated metabolites found in the blood after absorption in the small intestine for studies on cells, or the chemical forms found in the blood and tissues after catabolism by the gut microbiota.

Chlorogenic acids and the acyl-quinic acids: discovery, biosynthesis, bioavailability and bioactivity.

Covering: 2000 up to late 2017This review is focussed upon the acyl-quinic acids, the most studied group within the ca. 400 chlorogenic acids so far reported. The acyl-quinic acids, the first of which was characterised in 1846, are a diverse group of plant-derived compounds produced principally through esterification of an hydroxycinnamic acid and 1l-(-)-quinic acid. Topics addressed in this review include the confusing nomenclature, quantification and characterisation by NMR and MS, biosynthesis and role in planta, and the occurrence of acyl-quinic acids in coffee, their transformation during roasting and delivery to the beverage. Coffee is the major human dietary source world-wide of acyl-quinic acids and consideration is given to their absorption and metabolism in the upper gastrointestinal tract, and the colon where the microbiota play a key role in the formation of catabolites. Evidence on the potential of the in vivo metabolites and catabolites of acyl-quinic acids to promote the consumer's health is evaluated.

In vivo administration of urolithin A and B prevents the occurrence of cardiac dysfunction in streptozotocin-induced diabetic rats.

BACKGROUND: Emerging evidence suggests that specific (poly)phenols may constitute new preventative strategies to counteract cell oxidative stress and myocardial tissue inflammation, which have a key role in the patho-physiology of diabetic cardiomyopathy. In a rat model of early diabetes, we evaluated whether in vivo administration of urolithin A (UA) or urolithin B (UB), the main gut microbiota phenolic metabolites of ellagitannin-rich foods, can reduce diabetes-induced microenvironmental changes in myocardial tissue, preventing cardiac functional impairment. METHODS: Adult Wistar rats with streptozotocin-induced type-1 diabetes (n = 29) were studied in comparison with 10 control animals. Diabetic rats were either untreated (n  = â€Š9) or subjected to daily i.p. injection of UA (n = 10) or UB (n = 10). After 3 weeks of hyperglycaemia, hemodynamics, cardiomyocyte contractile properties and calcium transients were measured to assess cardiac performance. The myocardial expression of the pro-inflammatory cytokine fractalkine and proteins involved in calcium dynamics (sarcoplasmic reticulum calcium ATPase, phospholamban and phosphorylated phospholamban) were evaluated by immunoblotting. Plasma, urine and tissue distribution of UA, UB and their phase II metabolites were determined. RESULTS: In vivo urolithin treatment reduced by approximately 30% the myocardial expression of the pro-inflammatory cytokine fractalkine, preventing the early inflammatory response of cardiac cells to hyperglycaemia. The improvement in myocardial microenvironment had a functional counterpart, as documented by the increase in the maximal rate of ventricular pressure rise compared to diabetic group (+18% and +31% in UA and UB treated rats, respectively), and the parallel reduction in the isovolumic contraction time (-12%). In line with hemodynamic data, both urolithins induced a recovery of cardiomyocyte contractility and calcium dynamics, leading to a higher re-lengthening rate (+21%, on average), lower re-lengthening times (-56%), and a more efficient cytosolic calcium clearing (-32% in tau values). UB treatment also increased the velocity of shortening (+27%). Urolithin metabolites accumulated in the myocardium, with a higher concentration of UB and UB-sulphate, potentially explaining the slightly higher efficacy of UB administration. CONCLUSIONS: In vivo urolithin administration may be able to prevent the initial inflammatory response of myocardial tissue to hyperglycaemia and the negative impact of the altered diabetic milieu on cardiac performance.

Identification of (poly)phenol treatments that modulate the release of pro-inflammatory cytokines by human lymphocytes.

Diets rich in fruits and vegetables (FV), which contain (poly)phenols, protect against age-related inflammation and chronic diseases. T-lymphocytes contribute to systemic cytokine production and are modulated by FV intake. Little is known about the relative potency of different (poly)phenols in modulating cytokine release by lymphocytes. We compared thirty-one (poly)phenols and six (poly)phenol mixtures for effects on pro-inflammatory cytokine release by Jurkat T-lymphocytes. Test compounds were incubated with Jurkat cells for 48 h at 1 and 30 µm, with or without phorbol ester treatment at 24 h to induce cytokine release. Three test compounds that reduced cytokine release were further incubated with primary lymphocytes at 0·2 and 1 µm for 24 h, with lipopolysaccharide added at 5 h. Cytokine release was measured, and generation of H2O2 by test compounds was determined to assess any potential correlations with cytokine release. A number of (poly)phenols significantly altered cytokine release from Jurkat cells (P<0·05), but H2O2 generation did not correlate with cytokine release. Resveratrol, isorhamnetin, curcumin, vanillic acid and specific (poly)phenol mixtures reduced pro-inflammatory cytokine release from T-lymphocytes, and there was evidence for interaction between (poly)phenols to further modulate cytokine release. The release of interferon-γ induced protein 10 by primary lymphocytes was significantly reduced following treatment with 1 µm isorhamnetin (P<0·05). These results suggest that (poly)phenols derived from onions, turmeric, red grapes, green tea and açai berries may help reduce the release of pro-inflammatory mediators in people at risk of chronic inflammation.

Nontargeted LC-MSn Profiling of Compounds in Ileal Fluids That Decrease after Raspberry Intake Identifies Consistent Alterations in Bile Acid Composition.

Ileostomy studies provide a unique insight into the digestion of foods, allowing identification of physiologically relevant dietary phytochemicals and their metabolites that are important to gut health. We previously reported an increase of components, including novel triterpenoids, in ileal fluids of 11 ileostomates following consumption of raspberries using nontargeted LC-MSn techniques in combination with data deconvolution software. The current study focused on components that consistently decreased postsupplementation. After data deconvolution, 32 components were identified that met exclusion parameters of m/z signals and which decreased significantly in ileal fluids from eight of 11 participants post-raspberry supplementation. Two-thirds of these components were identified putatively from their MS properties. Consistent decreases were observed in components that possibly reflected "washing out" of presupplementation intake of common foods/drinks including (poly)phenol metabolites. Metabolites associated with fat metabolism such as hydroxylated fatty acids and cholate-type bile acids were specifically reduced. However, more directed re-examination of the data revealed that although some cholates were consistently reduced, the more polar glyco- and tauro-linked bile acid derivatives increased consistently, by as much as 100-fold over presupplementation levels. The possible reasons for these substantial alterations in bile acid composition in ileal fluids in response to raspberry intake are discussed.

In vitro studies on the stability in the proximal gastrointestinal tract and bioaccessibility in Caco-2 cells of chlorogenic acids from spent coffee grounds.

Spent coffee grounds are a potential commercial source of substantial amounts of chlorogenic acids (CGAs). The aim of this study was to evaluate the stability of spent coffee CGAs using in vitro simulated gastroduodenal digestion and to investigate their potential absorption using an in vitro Caco-2 model of human small intestinal epithelium. During in vitro digestion, lactones were partially degraded while caffeoylquinic and feruloylquinic acids were much more stable. Transport and metabolism studies showed that 1% of the total CGAs were absorbed and transported from the apical to the basolateral side of a Caco-2 cell monolayer after 1 h. Lactones and coumaroylquinic acids showed the rate of highest absorption. Caco-2 cells possessed low metabolic activity. In conclusion, spent coffee extracts contain large amounts of CGAs, which remained bioaccessible across the intestinal barrier, albeit to a relatively low degree.

Glucuronidation does not suppress the estrogenic activity of quercetin in yeast and human breast cancer cell model systems.

Several plant-derived molecules, referred to as phytoestrogens, are thought to mimic the actions of endogenous estrogens. Among these, quercetin, one of the most widespread flavonoids in the plant kingdom, has been reported as estrogenic in some occasions. However, quercetin occurs in substantial amounts as glycosides such as quercetin-3-O-glucoside (isoquercitrin) and quercetin-3-O-rutinoside (rutin) in dietary sources. It is now well established that quercetin undergoes substantial phase II metabolism after ingestion by humans, with plasma metabolites after a normal dietary intake rarely exceeding nmol/L concentrations. Therefore, attributing phytoestrogenic activity to flavonoids without taking into account the fact that it is their phase II metabolites that enter the circulatory system, will almost certainly lead to misleading conclusions. With the aim of clarifying the above issue, the goal of the present study was to determine if plant-associated quercetin glycosides and human phase II quercetin metabolites, actually found in human biological fluids after intake of quercetin containing foods, are capable of interacting with the estrogen receptors (ER). To this end, we used a yeast-based two-hybrid system and an estrogen response element-luciferase reporter assay in an ER-positive human cell line (MCF-7) to probe the ER interaction capacities of quercetin and its derivatives. Our results show that quercetin-3-O-glucuronide, one of the main human phase II metabolites produced after intake of dietary quercetin, displays ERα- and ERß-dependent estrogenic activity, the functional consequences of which might be related to the protective activity of diets rich in quercetin glycosides.

Bioavailability, bioactivity and impact on health of dietary flavonoids and related compounds: an update.

There is substantial interest in the role of plant secondary metabolites as protective dietary agents. In particular, the involvement of flavonoids and related compounds has become a major topic in human nutrition research. Evidence from epidemiological and human intervention studies is emerging regarding the protective effects of various (poly)phenol-rich foods against several chronic diseases, including neurodegeneration, cancer and cardiovascular diseases. In recent years, the use of HPLC-MS for the analysis of flavonoids and related compounds in foods and biological samples has significantly enhanced our understanding of (poly)phenol bioavailability. These advancements have also led to improvements in the available food composition and metabolomic databases, and consequently in the development of biomarkers of (poly)phenol intake to use in epidemiological studies. Efforts to create adequate standardised materials and well-matched controls to use in randomised controlled trials have also improved the quality of the available data. In vitro investigations using physiologically achievable concentrations of (poly)phenol metabolites and catabolites with appropriate model test systems have provided new and interesting insights on potential mechanisms of actions. This article will summarise recent findings on the bioavailability and biological activity of (poly)phenols, focusing on the epidemiological and clinical evidence of beneficial effects of flavonoids and related compounds on urinary tract infections, cognitive function and age-related cognitive decline, cancer and cardiovascular disease.

Wine by-products: phenolic characterization and antioxidant activity evaluation of grapes and grape pomaces from six different French grape varieties.

Grenache, Syrah, Carignan Noir, Mourvèdre, Counoise and Alicante Bouchet grape seeds and skins, harvested in 2009 and 2010 in the Rhône valley area of France, and their respective pomaces remaining after vinification, were analyzed for their phenolic composition and antioxidant activity. The polyphenol content was quantified by HPLC and the Folin-Ciocalteu assay. The antioxidant potential was measured with four different assays: ORAC, FRAP, ABTS and DPPH. Seeds contained higher amounts of total polyphenols, up to 44.5 mg of gallic acid equivalent [GAE]/g dry weight in Alicante pomace, than skin extracts. The maximum total phenolic in skins was 31.6 mg GAE/g dry weight detected in 2010 Alicante pomace. Seeds also had the highest antioxidant capacity. HPLC analysis revealed that, despite the vinification process, pomaces still contained an appreciable amount of proanthocyanidins as well as several anthocyanin glycosides. Alicante and Syrah proved to be the varieties of most interest in terms of their potential development for nutraceutical purposes.

A Systematic Review and Comprehensive Evaluation of Human Intervention Studies to Unravel the Bioavailability of Hydroxycinnamic Acids.

Significance: Hydroxycinnamic acids (HCAs) are the main phenolic acids in the western diet. Harmonizing the available information on the absorption, distribution, metabolism, and excretion (ADME) of HCAs is fundamental to unraveling the compounds responsible for their health effects. This work systematically assessed pharmacokinetics, including urinary recovery, and bioavailability of HCAs and their metabolites, based on literature reports. Recent Advances: Forty-seven intervention studies with coffee, berries, herbs, cereals, tomato, orange, grape products, and pure compounds, as well as other sources yielding HCA metabolites, were included. Up to 105 HCA metabolites were collected, mainly acyl-quinic and C6-C3 cinnamic acids. C6-C3 cinnamic acids, such as caffeic and ferulic acid, reached the highest blood concentrations (maximum plasma concentration [Cmax] = 423 nM), with time to reach Cmax (Tmax) values ranging from 2.7 to 4.2 h. These compounds were excreted in urine in higher amounts than their phenylpropanoic acid derivatives (4% and 1% of intake, respectively), but both in a lower percentage than hydroxybenzene catabolites (11%). Data accounted for 16 and 18 main urinary and blood HCA metabolites, which were moderately bioavailable in humans (collectively 25%). Critical Issues: A relevant variability emerged. It was not possible to unequivocally assess the bioavailability of HCAs from each ingested source, and data from some plant based-foods were absent or inconsistent. Future Directions: A comprehensive study investigating the ADME of HCAs derived from their most important dietary sources is urgently required. Eight key metabolites were identified and reached interesting plasma Cmax concentrations and urinary recoveries, opening up new perspectives to evaluate their bioactivity at physiological concentrations. Antioxid. Redox Signal. 40, 510-541.

Exploring and disentangling the production of potentially bioactive phenolic catabolites from dietary (poly)phenols, phenylalanine, tyrosine and catecholamines.

Following ingestion of fruits, vegetables and derived products, (poly)phenols that are not absorbed in the upper gastrointestinal tract pass to the colon, where they undergo microbiota-mediated ring fission resulting in the production of a diversity of low molecular weight phenolic catabolites, which appear in the circulatory system and are excreted in urine along with their phase II metabolites. There is increasing interest in these catabolites because of their potential bioactivity and their use as biomarkers of (poly)phenol intake. Investigating the fate of dietary (poly)phenolics in the colon has become confounded as a result of the recent realisation that many of the phenolics appearing in biofluids can also be derived from the aromatic amino acids, l-phenylalanine and l-tyrosine, and to a lesser extent catecholamines, in reactions that can be catalysed by both colonic microbiota and endogenous mammalian enzymes. The available evidence, albeit currently rather limited, indicates that substantial amounts of phenolic catabolites originate from phenylalanine and tyrosine, while somewhat smaller quantities are produced from dietary (poly)phenols. This review outlines information on this topic and assesses procedures that can be used to help distinguish between phenolics originating from dietary (poly)phenols, the two aromatic amino acids and catecholamines.

Colon-available mango (poly)phenols exhibit mitigating effects on the intestinal barrier function in human intestinal cell monolayers under inflammatory conditions.

This study investigated the impact of in vivo available colon-mango (poly)phenols on stress-induced impairment of intestinal barrier function. Caco-2/HT29-MTX cells were incubated with six extracts of ileal fluid collected pre- and 4-8 h post-mango consumption before being subjected to inflammatory stress. (Poly)phenols in ileal fluids were analysed by UHPLC-HR-MS. Epithelial barrier function was monitored by measurement of trans-epithelial electrical resistance (TEER) and the production of selected inflammatory markers (interleukin-8 (IL-8) and nitric oxide (NO)) and the major mucin of the mucosal layer (MUC2). Post-mango intake ileal fluids contained principally benzoic acids, hydroxybenzenes and galloyl derivatives. There was a high interindividual variability in the levels of these compounds, which was reflected by the degree of variability in the protective effects of individual ileal extracts on inflammatory changes in the treated cell cultures. The 24 h treatment with non-cytotoxic doses of extracts of 4-8 h post-mango intake ileal fluid significantly reduced the TEER decrease in monolayers treated with the inflammatory cytomix. This effect was not associated with changes in IL-8 expression and secretion or claudine-7 expression. The mango derived-ileal fluid extract (IFE) also mitigated cytomix-dependent nitrite secretion, as a proxy of NO production, and the MUC2 reduction observed upon the inflammatory challenge. These insights shed light on the potential protective effect of mango (poly)phenols on the intestinal barrier exposed to inflammatory conditions.

Bioavailability of orange juice (poly)phenols: ß-glucan-rich oat bran decreases urinary excretion of flavanone phase II metabolites and enhances excretion of microbiota-derived phenolic catabolites.

The impact of ß-glucan-rich oat bran on the bioavailability of orange juice (OJ) flavanones was investigated. Volunteers consumed 500 mL of OJ with and without 22 g of oat bran containing 6 g of ß-glucan (OB-6). Urine collected 12 h prior to and over a 0-24 h period post-supplementation was analysed by UHPLC-HRMS. Sixteen flavanone metabolites and thirty-nine colon-derived phenolic catabolites were identified and quantified. The major compounds were hesperetin-3'-glucuronide, along with hippuric acids and the C6-C3 phenolic acids 3-(3'-hydroxy-4'-methoxyphenyl)hydracrylic acid and 3-(4'-hydroxy-3'-methoxyphenyl)propanoic acid. A marked reduction in the 0-24 h excretion of flavanone metabolites from 29.7 µmol (9.3% recovery) to 9.3 µmol (2.9% recovery), occurred following consumption of OB-6 compared to OJ. This appeared not to be an effect of fiber on the rate of transport in the upper gut. After consumption of OJ there was a 163 ± 15 µmol excretion of colon-derived phenolic catabolites, equivalent to 43% of (poly)phenol intake and following OB-6 intake there was a further significant 30% increase. The ß-oat bran in OB-6 contained 5.8 µmol of free and 52 µmol of bound phenolic derivatives compared to 371 µmol of OJ (poly)phenols. The elevated excretion of phenolics after OB-6 consumption appears not to be due to bound phenolics in the bran, rather it is consequence, principally, of a bran-mediated increase in the quantities of flavanones passing from the upper to the lower bowel where they were subjected to microbiota-mediated catabolism. CLINICAL TRIAL REGISTRATION NUMBER: This trial was registered at clinicaltrials.gov as NCT04867655.