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The risk to human health from bacterial foodborne infection is presently controlled by the addition of antimicrobial preservatives to food. However, the use of chemical preservatives such as sodium nitrite poses a health risk in themselves with concerns around carcinogenic effects. This makes the development of improved preservatives a priority for the food industry.One promising source of novel antimicrobial compounds can be found in nature; phytochemicals, in particular polyphenols are secondary metabolites produced by plants for numerous purposes including antimicrobial defence. There has been significant study of phytochemicals; including quantifying their antimicrobial activity, potential to synergise with current antibiotics and the feasibility of their application as natural food preservatives. However, there remains significant uncertainty about the relative antimicrobial efficacy of different phytochemicals, their mechanisms of action (MOA) and the potential for emergence of bacterial resistance to their effects. This review summarizes recent work relevant to the potential development of phytochemicals as antimicrobial agents.

Junctional adhesion molecules (JAMs; comprising JAM-A, -B and -C) act as receptors for viruses, mediate cell permeability, facilitate leukocyte migration during sterile and non-sterile inflammation and are important for the maintenance of epithelial barrier integrity. As such, they are implicated in the development of both communicable and non-communicable chronic diseases. Here, we investigated the expression and regulation of JAM-B in leukocytes under pathogen- and host-derived inflammatory stimuli using immunoassays, qPCR and pharmacological inhibitors of inflammatory signalling pathways. We show that JAM-B is expressed at both the mRNA and protein level in leukocytes. JAM-B protein is localised to the cytoplasm, Golgi apparatus and in the nucleus around ring-shaped structures. We also provide evidence that JAM-B nuclear localisation occurs via the classical importin-α/β pathway, which is likely mediated through JAM-B protein nuclear localisation signals (NLS) and export signals (NES). In addition, we provide evidence that under both pathogen- and host-derived inflammatory stimuli, JAM-B transcription is regulated via the NF-κB-dependent pathways, whereas at the post-translational level JAM-B is regulated by ubiquitin-proteosome pathways. Anaphase-promoting ubiquitin ligase complex (APC/C) and herpes simplex virus-associated ubiquitin-specific protease (HAUSP/USP) were identified as candidates for JAM-B ubiquitination and de-ubiquitination, respectively. The expression and regulation of JAM-B in leukocytes reported here is a novel observation and contrasts with previous reports. The data reported here suggest that JAM-B expression in leukocytes is under the control of common inflammatory pathways.

Formulating poorly soluble drugs with polymers in the form of solid dispersions has been widely used for improving drug dissolution. Endogenous surface-active species present in the gut, such as bile salts, lecithin and other phospholipids, have been shown to play a key role in facilitating lipids and poorly soluble drugs solubilisation in the gut. In this study, we examined the possible occurrence of interactions between a model bile salt, sodium taurocholate (NaTC), and model spray dried solid dispersions comprising piroxicam and Hydroxypropyl Methylcellulose (HPMC), a commonly used hydrophilic polymer for solid dispersion preparation. Solubility measurements revealed the good solubilisation effect of NaTC on the crystalline drug, which was enhanced by the addition of HPMC, and further boosted by the drug formulation into solid dispersion. The colloidal behaviour of the solid dispersions upon dissolution in biorelevant media, with and without NaTC, revealed the formation of NaTC-HPMC complexes and other mixed colloidal species. Cellular level drug absorption studies obtained using Caco-2 monolayers confirmed that the combination of drug being delivered by solid dispersion and the presence of bile salt and lecithin significantly contributed to the improved drug absorption. Together with the role of NaTC-HPMC complexes in assisting the drug solubilisation, our results also highlight the complex interplay between bile salts, excipients and drug absorption.

Purpose Plasma trimethylamine-N-oxide (TMAO) levels have been shown to correlate with increased risk of metabolic diseases including cardiovascular diseases. TMAO exposure predominantly occurs as a consequence of gut microbiota-dependent trimethylamine (TMA) production from dietary substrates including choline, carnitine and betaine, which is then converted to TMAO in the liver. Reducing microbial TMA production is likely to be the most effective and sustainable approach to overcoming TMAO burden in humans. Current models for studying microbial TMA production have numerous weaknesses including the cost and length of human studies, differences in TMA(O) metabolism in animal models and the risk of failing to replicate multi-enzyme/multi-strain pathways when using isolated bacterial strains. The purpose of this research was to investigate TMA production from dietary precursors in an in-vitro model of the human colon. Methods TMA production from choline, l-carnitine, betaine and γ-butyrobetaine was studied over 24–48 h using an in-vitro human colon model with metabolite quantification performed using LC–MS. Results Choline was metabolised via the direct choline TMA-lyase route but not the indirect choline–betaine-TMA route, conversion of l-carnitine to TMA was slower than that of choline and involves the formation of the intermediate γ-BB, whereas the Rieske-type monooxygenase/reductase pathway for l-carnitine metabolism to TMA was negligible. The rate of TMA production from precursors was choline > carnitine > betaine > γ-BB. 3,3-Dimethyl-1-butanol (DMB) had no effect on the conversion of choline to TMA. Conclusion The metabolic routes for microbial TMA production in the colon model are consistent with observations from human studies. Thus, this model is suitable for studying gut microbiota metabolism of TMA and for screening potential therapeutic targets that aim to attenuate TMA production by the gut microbiota. Trial registration number NCT02653001 (http://www.clinicaltrials.gov), registered 12 Jan 2016.

Spot urinary polyphenols have potential as a biomarker of polyphenol-rich food intakes. The aim of this study is to explore the relationship between spot urinary polyphenols and polyphenol intakes from polyphenol-rich food sources. Young adults (18–24 years old) were recruited into a sub-study of an online intervention aimed at improving diet quality. Participants’ intake of polyphenols and polyphenol-rich foods was assessed at baseline and 3 months using repeated 24-h recalls. A spot urine sample was collected at each session, with samples analysed for polyphenol metabolites using LC-MS. To assess the strength of the relationship between urinary polyphenols and dietary polyphenols, Spearman correlations were used. Linear mixed models further evaluated the relationship between polyphenol intakes and urinary excretion. Total urinary polyphenols and hippuric acid (HA) demonstrated moderate correlation with total polyphenol intakes (rs = 0·29–0·47). HA and caffeic acid were moderately correlated with polyphenols from tea/coffee (rs = 0·26–0·46). Using linear mixed models, increases in intakes of total polyphenols or polyphenols from tea/coffee or oil resulted in a greater excretion of HA, whereas a negative relationship was observed between soya polyphenols and HA, suggesting that participants with higher intakes of soya polyphenols had a lower excretion of HA. Findings suggest that total urinary polyphenols may be a promising biomarker of total polyphenol intakes foods and drinks and that HA may be a biomarker of total polyphenol intakes and polyphenols from tea/coffee. Caffeic acid warrants further investigation as a potential biomarker of polyphenols from tea/coffee.

New Findings: What is the topic of this review? The role of the gut microbiome in physiology and how it can be targeted as an effective strategy against two of the most important global medical challenges of our time, namely, metabolic diseases and antibacterial resistance. What advances does it highlight? The critical roles of the microbiome in regulating host physiology and how microbiome analysis is useful for disease stratification to enable informed clinical decisions and develop interventions such as faecal microbiota transplantation, prebiotics and probiotics. Also, the limitations of microbiome modulation, including the potential for probiotics to enhance antimicrobial resistance gene reservoirs, and that currently a ‘healthy microbiome’ that can be used as a biobank for transplantation is yet to be defined. Abstract: The human gut microbiome is a key factor in the development of metabolic diseases and antimicrobial resistance, which are among the greatest global medical challenges of the 21st century. A recent symposium aimed to highlight state-of-the-art evidence for the role of the gut microbiome in physiology, from childhood to adulthood, and the impact this has on global disease outcomes, ageing and antimicrobial resistance. Although the gut microbiome is established early in life, over time the microbiome and its components including metabolites can become perturbed due to changes such as dietary habits, use of antibiotics and age. As gut microbial metabolites, including short-chain fatty acids, secondary bile acids and trimethylamine-N-oxide, can interact with host receptors including G protein-coupled receptors and can alter host metabolic fluxes, they can significantly affect physiological homoeostasis leading to metabolic diseases. These metabolites can be used to stratify disease phenotypes such as irritable bowel syndrome and adverse events after heart failure and allow informed decisions on clinical management and treatment. While strategies such as use of probiotics, prebiotics and faecal microbiota transplantation have been proposed as interventions to treat and prevent metabolic diseases and antimicrobial resistance, caution must be exercised, first due to the potential of probiotics to enhance antimicrobial resistance gene reservoirs, and second, a ‘healthy gut microbiome’ that can be used as a biobank for transplantation is yet to be defined. We highlight that sampling other parts of the gastrointestinal tract may produce more representative data than the faecal microbiome alone.

Purpose Aging can be characterized by increased systemic low-grade inflammation, altered gut microbiota composition, and increased intestinal permeability (IP). The intake of polyphenol-rich foods is proposed as a promising strategy to positively affect the gut microbiota-immune system-intestinal barrier (IB) axis. In this context, we tested the hypothesis that a PR-dietary intervention would affect the presence of bacterial factors in the bloodstream of older adults. Methods We collected blood samples within a randomized, controlled, crossover intervention trial in which older volunteers (n = 51) received a polyphenol-enriched and a control diet. We quantified the presence of bacterial DNA in blood by qPCR targeting the 16S rRNA gene (16S; bacterial DNAemia). Blood DNA was taxonomically profiled via 16S sequencing. Results Higher blood 16S levels were associated with higher BMI and markers of IP, inflammation, and dyslipidemia. PR-intervention did not significantly change bacterial DNAemia in the older population (P = 0.103). Nonetheless, the beneficial changes caused by the polyphenol-enriched diet were greatest in participants with higher bacterial DNAemia, specifically in markers related to IP, inflammation and dyslipidemia, and in fecal bacterial taxa. Finally, we found that the bacterial DNA detected in blood mostly belonged to γ-Proteobacteria, whose abundance significantly decreased after the polyphenol-rich diet in subjects with higher bacterial DNAemia at baseline. Conclusions This study shows that older subjects with higher bacterial DNAemia experienced a beneficial effect from a polyphenol-rich diet. Bacterial DNAemia may be a further relevant marker for the identification of target populations that could benefit more from a protective dietary treatment. Registration This trial was retrospectively registered at www.isrctn.org (ISRCTN10214981) on April 28, 2017.

Dietary polyphenols can alter the gut microbiota (GM) and promote the production of bioactive metabolites. Several indoles result of GM metabolism of dietary tryptophan have been associated with intestinal barrier integrity. Our aim is to study the changes in GM-derived indoles during a polyphenol-rich (PR) diet intervention in older adults.Randomized, controlled, crossover trial in adults ≥ 60 years living in a residential care facility during an 8-week PR versus control diet (n = 51). Seven GM-tryptophan metabolites are measured in serum, and metataxonomic analysis of GM is performed on fecal samples. Exploratory subgroup analyses are performed based on renal function (RF). The PR-diet significantly increases serum indole 3-propionic acid (IPA) in subjects with normal RF, but not in subjects with impaired RF. Other GM-tryptophan metabolites are not affected. Comparison of baseline GM composition shows shifts in Bacteroidales order members as well as higher abundance of Clostridiales in participants with normal RF. During the trial, variations of IPA are associated with changes in C-reactive protein (β = 0.32, p = 0.010) and GM, particularly with the Clostridiales (r = 0.35, p0.001) and Enterobacteriales (r = -0.15, p0.05) orders.A PR diet increases the serum concentration of IPA in older adults with normal RF. Our findings may be important when defining appropriate dietary interventions for older adults.ISRCTN10214981 (https://doi.org/10.1186/ISRCTN10214981).

A polyphenol-rich diet reduced intestinal permeability (IP) in older adults. Our aim was to evaluate if participants categorized according to urolithin metabotypes (UMs) exhibited different responses in the MaPLE trial. Fifty-one older adults (mean age: 78 years) completed an 8-week randomized-controlled-crossover trial comparing the effects of a polyphenol-rich vs. a control diet on IP, assessed through zonulin levels. Plasma and urinary metabolomics were evaluated with a semi-targeted UHPLC-MS/MS method. Gut microbiota was characterized by 16S rRNA gene profiling. UMs were determined according to urolithin excretion in 24 h urine samples. Multivariate statistics were used to characterize the differences in metabolomic and metataxonomic responses across UMs. Thirty-three participants were classified as urolithin metabotype A (UMA), 13 as urolithin metabotype B (UMB), and 5 as urolithin metabotype 0 (UM0) according to their urinary excretion of urolithins. Clinical, dietary, and biochemical characteristics at baseline were similar between UMs (all p > 0.05). After the polyphenol-rich diet, UMB vs. UMA participants showed a 2-fold higher improvement of zonulin levels (p for interaction = 0.033). Moreover, UMB vs. UMA participants were characterized for alterations in fatty acid metabolism, kynurenine pathway of tryptophan catabolism, and microbial metabolization of phenolic acids. These changes were correlated with the reduction of zonulin levels and modifications of gut microbes (increased Clostridiales, including, R. lactaris, and G. formicilis). In conclusion, urolithin-based metabotyping identified older adults with a higher improvement of IP after a polyphenol-rich diet. Our results reinforce the concept that UMs may contribute to tailor personalized nutrition interventions.

Background &aim: The MaPLE study was a randomized, controlled, crossover trial involving adults 60 y.o. (n ¼ 51) living in a residential care facility during an 8-week polyphenol-rich (PR)-diet. Results from the MaPLE trial showed that the PR-diet reduced the intestinal permeability (IP) in older adults by inducing changes to gut microbiota (GM). The present work aimed at studying the changes in serum metabolome in the MaPLE trial, as a further necessary step to depict the complex crosstalk between dietary polyphenols, GM, and intestinal barrier. Methods: Serum metabolome was monitored using a semi-targeted UHPLC-MS/MS analysis. Metataxonomic analysis (16S rRNA gene profiling) of GM was performed on faecal samples. Clinical characteristics and serum levels of the IP marker zonulin were linked to GM and metabolomics data in a multi-omics network. Results: Compared to the control diet, the PR-diet increased serum metabolites related to polyphenols and methylxanthine intake. Theobromine and methylxanthines, derived from cocoa and/or green tea, were positively correlated with butyrate-producing bacteria (the order Clostridiales and the genera Roseburia, Butyricicoccus and Faecalibacterium) and inversely with zonulin. A direct correlation between polyphenol metabolites hydroxyphenylpropionic acid-sulfate, 2-methylpyrogallol-sulfate and catecholsulfate with Butyricicoccus was also observed, while hydroxyphenylpropionic acid-sulfate and 2- methylpyrogallol-sulfate negatively correlated with Methanobrevibacter. The multi-omics network indicated that participant's age, baseline zonulin levels, and changes in Porphyromonadaceae abundance were the main factors driving the effects of a PR-diet on zonulin. Conclusion: Overall, these results reveal the complex relationships among polyphenols consumption, intestinal permeability, and GM composition in older adults, and they may be important when setting personalized dietary interventions for older adults. Trial registration number: ISRCTN10214981. © 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license

Scope Pro‐inflammatory stimuli such as hyperglycemia and cytokines have been shown to negatively affect endothelial cell functions. The aim of this study is to assess the potential of quercetin and its human metabolites to overcome the deleterious effects of hyperglycemic or inflammatory conditions on the vascular endothelium by modulating endothelial cell metabolism. Methods and results A metabolomics approach enabled identification and quantification of 27 human umbilical vein endothelial cell (HUVEC) metabolites. Treatment of HUVECs with high‐glucose concentrations causes significant increases in lactate and glutamate concentrations. Quercetin inhibits glucose‐induced increases in lactate and adenosine 5′‐triphosphate (ATP) and also increased inosine concentrations. Tumor necrosis factor α‐treatment (TNFα) of HUVECs causes increases in asparagine and decreases in aspartate concentrations. Co‐treatment with quercetin reduces pyruvate concentrations compared to TNFα‐only treated controls. Subsequently, it was shown that quercetin and its HUVEC phase‐2 conjugates inhibit adenosine deaminase, xanthine oxidase and 5′nucleotidase (CD73) but not ectonucleoside triphosphate diphosphohydrolase‐1 (CD39) or purine nucleoside phosphorylase activities. Conclusion Quercetin was shown to alter the balance of HUVEC metabolites towards a less inflamed phenotype, both alone and in the presence of pro‐inflammatory stimuli. These changes are consistent with the inhibition of particular enzymes involved in purine metabolism by quercetin and its HUVEC metabolites., Pro‐inflammatory stimuli such as hyperglycemia and cytokines have been shown to negatively affect endothelial cell functions. In the present study, quercetin is shown to alter the balance of HUVEC metabolites towards a less inflamed phenotype, both alone and in the presence of pro‐inflammatory stimuli. These changes are consistent with inhibition of particular enzymes involved in purine metabolism by quercetin and its HUVEC metabolites.

Some dietary interventions with berry fruits, berry fruit extracts, and purified anthocyanins have been reported to beneficially alter lipoprotein profiles in hyperlipidemic participants. The major anthocyanins in human diets are glycosides of cyanidin and delphinidin, and structure can influence both absorption and bioactivity. The aim of this study is to determine the effects of two major types of anthocyanins on low-density lipoprotein cholesterol and other cardiometabolic markers for cardiovascular disease (CVD) risk in hyperlipidemic individuals.Fifty-two hyperlipidemic participants complete this randomized, placebo-controlled, double-blind, three arm crossover trial. Participants ingest capsules containing 320 mg of anthocyanins (bilberry trihydroxy-type or black rice dihydroxy-type) or placebo once daily for 28 days. Biomarkers of CVD risk are measured before and after the intervention period. Compared to the placebo, neither anthocyanin treatment significantly (p0.05) changes circulating levels of lipoproteins (total-/high-density lipoprotein (HDL)-/low-density lipoprotein (LDL)-cholesterol, triglycerides, Apolipoprotein B (ApoB)), biomarkers of glycemic control (fasting glucose, fructosamine), biomarkers of HDL function (ApoA1, HDL3, paraoxonase-1 (PON1) arylesterase, and lactonase activities), or plasma bile acids.These data do not support the notion that regular consumption of anthocyanins beneficially affects glycemic control or lipoprotein profiles or functions. It is possible the no effect observation is due to the relatively short duration of treatments.

Background: Previous research demonstrated that a high dose of phlorizin-rich apple extract (AE) can markedly inhibit early-phase postprandial glycemia, but efficacy of lower doses of the AE is unclear. Objective: To determine whether lower AE doses reduce early-phase postprandial glycemia in healthy adults and investigate mechanisms. Design: In a randomized, controlled, double-blinded, cross-over acute trial, drinks containing 1.8 g (HIGH), 1.35 g (MED), 0.9 g (LOW), or 0 g (CON) of a phlorizin-rich AE were consumed before 75 g starch/sucrose meal. Postprandial blood glucose, insulin, C-peptide, glucose-dependent insulinotropic polypeptide (GIP) and polyphenol metabolites concentrations were measured 0–240 min, acetaminophen concentrations to assess gastric emptying rate, and 24 h urinary glucose excretion. Effects of AE on intestinal glucose transport were investigated in Caco-2/TC7 cells. Results: AE significantly reduced plasma glucose iAUC 0–30 min at all doses: mean differences (95% CI) relative to CON were −15.6 (−23.3, −7.9), −11.3 (−19.6, −3.0) and −8.99 (−17.3, −0.7) mmol/L per minute for HIGH, MEDIUM and LOW respectively, delayed T max (HIGH, MEDIUM and LOW 45 min vs. CON 30 min), but did not lower C max. Similar dose-dependent treatment effects were observed for insulin, C-peptide, and GIP. Gastric emptying rates and urinary glucose excretion did not differ. Serum phloretin, quercetin and epicatechin metabolites were detected postprandially. A HIGH physiological AE dose equivalent decreased total glucose uptake by 48% in Caco-2/TC7 cells. Conclusions: Phlorizin-rich AE, even at a low dose, can slightly delay early-phase glycemia without affecting peak and total glycemic response.

Urinary polyphenol metabolites are potential biomarkers of dietary polyphenol intake. The current study aims to evaluate associations between total diet, vegetable and fruit polyphenol intakes with urinary polyphenol metabolite concentrations in a sample of adults prescribed a diet rich in vegetables and fruit. Thirty-four participants completed a 10-week pre-post study. Participants were asked to consume Australian recommended daily vegetable and fruit serves and attend measurement sessions at baseline and at weeks 2 and 10. Two 24-h diet recalls were collected at each time-point and polyphenol intakes were calculated using the Phenol-Explorer database. Spot urine samples, collected at each time-point, were analyzed for 15 polyphenol metabolites using liquid chromatography-mass spectroscopy. Spearman&rsquo, s correlation analyzes assessed the strength of relationships between urinary and dietary polyphenols. Linear mixed models were used to investigate relationships between polyphenol excretion and intake. Total urinary polyphenols were significantly correlated with total polyphenol intakes at week 10 (rs = 0.47) and fruit polyphenols at week 2 (rs = 0.38). Hippuric acid was significantly correlated with vegetable polyphenols at baseline (rs = 0.39). Relationships were identified between individual polyphenol metabolites and vegetable and fruit polyphenols. Linear mixed model analyzes identified that for every 1 mg increase in polyphenol intakes, urinary polyphenol excretion increased by 16.3 nmol/g creatinine. Although the majority of relationships were not sufficiently strong or consistent at different time-points, promising relationships were observed between total urinary polyphenols and total polyphenol intakes, and hippuric acid and vegetable polyphenols.

International audience; There is ample evidence in the epidemiological literature that polyphenols, the major non-vitamin antioxidants in plant foods and beverages, have a beneficial effect on heart disease. Until recently other mechanisms which polyphenols exhibit such as cell signaling and regulating nitric oxide bioavailability have been investigated. The oxidation theory of atherosclerosis implicates LDL oxidation as the beginning step in this process. Nine polyphenols from eight different classes and several of their O-methylether, O-glucuronide and O-sulfate metabolites have been shown in this study to bind to the lipoproteins and protect them from oxidation at lysosomal/inflammatory pH (5.2), and physiological pH (7.4). Polyphenols bind to the apoprotein at pH 7.4 with Kb > 106M- 1 and the number of molecules of polyphenols bound per LDL particle under saturation conditions varied from 0.4 for ferulic acid to 13.1 for quercetin. Competition studies between serum albumin and LDL show that substantial lipoprotein binding occurs even in the presence of a great molar excess of albumin, the major blood protein. These in vitro results are borne out by published human supplementation studies showing that polyphenol metabolites from red wine, olive oil and coffee are found in LDL even after an overnight fast. A single human supplementation with various fruit juices, coffee and tea also produced an ex vivo protection against lipoprotein oxidation under postprandial conditions. This in vivo binding is heart-protective based on published olive oil consumption studies. Relevant to heart disease, we hypothesize that the binding of polyphenols and metabolites to LDL functions as a transport mechanism to carry these antioxidants to the arterial intima, and into endothelial cells and macrophages. Extracellular and intracellular polyphenols and their metabolites are heartprotective by many mechanisms and can also function as potent “intraparticle” and intracellular antioxidants due to their localized concentrations that can reach as high as the micromolar level. Low plasma concentrations makepolyphenols and their metabolites poor plasma antioxidants but their concentration in particles such as lipoproteins and cells is high enough for polyphenols to provide cardiovascular protection by direct antioxidant effects and by other mechanisms such as cell signaling.

Quercetin is a flavonoid, its glycosides and aglycone are found in significant amounts in several plants and dietary supplements. Because of the high presystemic biotransformation of quercetin, mainly its conjugates appear in circulation. As has been reported in previous studies, quercetin can interact with several proteins of pharmacokinetic importance. However, the interactions of its metabolites with biotransformation enzymes and drug transporters have barely been examined. In this study, the inhibitory effects of quercetin and its most relevant methyl, sulfate, and glucuronide metabolites were tested on cytochrome P450 (CYP) (2C19, 3A4, and 2D6) enzymes as well as on organic anion-transporting polypeptides (OATPs) (OATP1A2, OATP1B1, OATP1B3, and OATP2B1) and ATP (adenosine triphosphate) Binding Cassette (ABC) (BCRP and MRP2) transporters. Quercetin and its metabolites (quercetin-3&prime, sulfate, quercetin-3-glucuronide, isorhamnetin, and isorhamnetin-3-glucuronide) showed weak inhibitory effects on CYP2C19 and 3A4, while they did not affect CYP2D6 activity. Some of the flavonoids caused weak inhibition of OATP1A2 and MRP2. However, most of the compounds tested proved to be strong inhibitors of OATP1B1, OATP1B3, OATP2B1, and BCRP. Our data demonstrate that not only quercetin but some of its conjugates, can also interact with CYP enzymes and drug transporters. Therefore, high intake of quercetin may interfere with the pharmacokinetics of drugs.

The increased presence of bacteria in blood is a plausible contributing factor in the development and progression of aging-associated diseases. In this context, we performed the quantification and the taxonomic profiling of the bacterial DNA in blood samples collected from a group of forty-three older subjects enrolled in a nursing home. Quantitative PCR targeting the 16S rRNA gene revealed that all the older volunteers contained detectable amounts of bacterial DNA in their blood. The total amount of 16S rRNA gene copies varied considerably between subjects. Correlation analyses revealed that the bacterial DNAemia (expressed as concentration of 16S rRNA gene copies in blood) significantly correlated with the serum levels of zonulin, an emerging marker of intestinal permeability. This result was confirmed by the analysis of a second set of blood samples collected after approximately four months from the same subjects. Analyses of 16S rRNA gene profiling revealed that most of the bacterial DNA detected in blood was ascribable to the phylum Proteobacteria with a predominance of Pseudomonadaceae and Enterobacteriaceae. Several control samples were also analyzed to assess the influence exerted by contaminant bacterial DNA potentially originating from reagents and materials. The date reported here suggest that para-cellular permeability of epithelial (and potentially also endothelial) cell layers may play an important role in bacterial migration into the bloodstream. Bacterial DNAemia is likely to impact on several aspects of host physiology and could underpin the development and prognosis of various diseases in older subjects.

Scope The majority of ingested flavanols reach the colon where they are catabolized by the microbiota to form hydroxyphenyl‐γ‐valerolactones (HGVLs). It is not known if the HGVLs are catabolic products of monomeric (epi)catechins (EPC), oligomeric procyanidins (OPCs), or both. Using data from a randomized, double‐blind, placebo‐controlled crossover trial the relative contributions of catechins and OPC to the bioavailable pool of HGVLs are estimated. Methods and results Participants ingested an apple extract once daily for 28 days that delivered the following: i) 70 mg EPC and 65 mg OPC (low dose EPC), ii) 140 mg EPC and 130 mg OPC (high dose EPC), iii) 6 mg EPC and 130 mg OPC (OPC), and iv) a placebo control. Urine is collected over a 24‐h period before and after treatments. The median urinary excretion of HGVLs after ingestion of the high dose EPC is tenfold higher than that excreted after ingestion of the OPC that provided an equivalent dose of PC. Approximately 22% of catechins are converted to HGVLs in contrast to PC, for which there is limited conversion. Conclusion Monomeric catechins are efficiently converted to derived HGVLs that are absorbed and excreted in human urine, whereas oligomeric PCs are much less efficiently converted., Apples are a rich dietary source of the flavanols (‐)‐epicatechin and procyanidins. There is limited information regarding the type of flavanol that forms hydroxyphenyl‐γ‐valerolactones (HGVLs). After 28 days ingestion of an apple extract containing different doses of epicatechin and procyanidins, it is shown that ≈22% of catechins are converted to HGLVs compared with procyanidins, for which there is limited conversion.

Background During aging, alterations of the intestinal microbial ecosystem can occur contributing to immunosenescence, inflamm-aging and impairment of intestinal barrier function (increased intestinal permeability; IP). In the context of a diet-microbiota-IP axis in older subjects, food bioactives such as polyphenols may play a beneficial modulatory role. Methods MaPLE is a project centered on a randomized, controlled cross-over dietary intervention trial [polyphenol-rich diet (PR-diet) versus control diet (C-diet)] targeted to older people (≥ 60 y) living in a well-controlled setting (i.e. nursing home). The 8-week interventions are separated by an 8-week wash-out period. Three small portions per day of selected polyphenol-rich foods are consumed during intervention in substitution of other comparable products within the C-diet. Biological samples are collected before and after each treatment period to evaluate markers related to IP, inflammation, vascular function, oxidative stress, gut and blood microbiomics, metabolomics. A sample size of 50 subjects was defined based on IP as primary outcome. Discussion Evidence that increasing the consumption of polyphenol-rich food products can positively affect intestinal microbial ecosystem resulting in reduced IP and decreased translocation of inflammogenic bacterial factors into the bloodstream will be provided. The integration of data from gut and blood microbiomics, metabolomics and other IP-related markers will improve the understanding of the beneficial effect of the intervention in the context of polyphenols−microbiota−IP interactions. Finally, findings obtained will provide a proof of concept of the reliability of the dietary intervention, also contributing to future implementations of dietary guidelines directed to IP management in the older and other at risk subjects. Trial registration The trial is registered at (ISRCTN10214981); April 28, 2017.

Isoflavones and isoflavandiols have shown many health benefits, such as reducing cardiovascular disease, cancer, age-related disease, and osteoporosis. However, to investigate the relationships between consumption of isoflavones and their health benefits, it is important to be able to accurately quantify exposure in the large numbers of samples typically produced in association studies (i.e., several thousands). Current methods rely on solid-phase extraction protocols for sample cleanup, resulting in protracted extraction and analysis times. Here, we describe a fast and easy sample preparation method of human urine samples for subsequent quantification of daidzein, genistein (isoflavones), and equol (isoflavandiol) using LC-MS/MS. Sample preparation involves only the addition of dimethylformamide (DMF) and formic acid (FA) after enzymatic hydrolysis of their metabolites by a β-glucuronidase and sulfatase mixture. The method was validated by precision, linearity, accuracy, recoveries, limit of detection (LOD), and limit of quantification (LOQ). Linear calibration curves have been shown by daidzein, genistein, and equol. The correlation coefficients values are r2 > 0.99 for daidzein, genistein, and equol. LOD for daidzein and genistein was 1 ng/ml and equol was 2 ng/ml. Recoveries were >90%, and the relative standard deviation for intraday (

International audience; Cholesterol is one of the triggers of oxidative stress in the pancreatic-β cell, generating high levels of reactive oxygen species, which leads to impairment of insulin synthesis and secretion. Bioactive compounds, such as citrus flavanones, which possess anti-inflammatory and antioxidant activities, could reduce oxidative stress in β-cells and improve their function. We describe for the first time the protective effects of the phase-II flavanone metabolites [naringenin 7-O-glucuronide, hesperetin 3′-O-glucuronide, and hesperetin 7-O-glucuronide], and two flavanones-catabolites derived from gut microbiota metabolism [hippuric acid and 3-(4-hydroxyphenyl)propionic acid], on pancreatic β-cell line MIN6 under oxidative stress, at physiologically relevant concentration. Cholesterol reduced cell viability in a dose and time-dependent manner, with an improvement in the presence of the metabolites. Moreover, flavanone metabolites attenuated oxidative stress by reducing levels of lipid peroxides, superoxide anions, and hydrogen peroxide. In response to the reduction of reactive oxygen species, a decrease in superoxide dismutase and glutathione peroxidase activities was observed; these activities were elevated by cholesterol. Moreover, all the flavanone metabolites improved mitochondrial function and insulin secretion, and reduced apoptosis. Flavanone metabolites were found uptake by β-cells, and therefore could be responsible for the observed protective effects. These results demonstrated that circulating phase-II hesperetin and naringenin metabolites, and also phenolics derived from gut microbiota, protect pancreatic-β cells against oxidative stress, leading to an improvement in β-cell function and could be the bioactive molecules derived from the citrus consumption.

The evaluation of food intake in older subjects is crucial in order to be able to verify adherence to nutritional recommendations. In this context, estimation of the intake of specific dietary bioactives, such as polyphenols, although particularly challenging, is necessary to plan possible intervention strategies to increase their intake. The aims of the present study were to: (i) evaluate the nutritional composition of dietary menus provided in a residential care setting, (ii) estimate the actual intake of nutrients and polyphenols in a group of older subjects participating in the MaPLE study, and (iii) investigate the impact of an eight-week polyphenol-rich dietary pattern, compared to an eight-week control diet, on overall nutrient and polyphenol intake in older participants. The menus served to the participants provided ~770 mg per day of total polyphenols on average with small variations between seasons. The analysis of real consumption, measured using weighed food diaries, demonstrated a lower nutrient (~20%) and polyphenol intake (~15%) compared to that provided by the menus. The feasibility of dietary patterns that enable an increase in polyphenol intake with putative health benefits for age-related conditions is discussed, with a perspective to developing dietary guidelines for this target population.

Polyphenols have great potential in regulating intestinal health and ameliorating pathological conditions related to increased intestinal permeability (IP). However, the efficacy of dietary interventions with these phytochemicals may significantly be influenced by interindividual variability factors affecting their bioavailability and consequent biological activity. In the present study, urine samples collected from older subjects undergoing a crossover intervention trial with polyphenol-rich foods were subjected to metabolomics analysis for investigating the impact of increased IP on the bioavailability of polyphenols. Interestingly, urinary levels of phase II and microbiota-derived metabolites were significantly different between subjects with healthier intestinal barrier integrity and those with increased IP disruption. Our results support that this IP-dependent impaired bioavailability of polyphenols could be attributed to disturbances in the gut microbial metabolism and phase II methylation processes. Furthermore, we also observed that microbiota-derived metabolites could be largely responsible for the biological activity elicited by dietary polyphenols against age-related disrupted IP.

In recent years, research has been focusing on strategies to counteract inflammatory processes and age-related diseases(1). During ageing, a low-grade systemic inflammation is often associated to an altered intestinal permeability (IP) a condition that has been shown to promote inflammation possibly through the translocation of dietary and bacterial factors into the blood stream that activates the immune system(2).In this regard, dietary pattern and environmental factors could play a fundamental role because of their potential ability to modulate inflammation, IP and the gut microbial ecosystem (GME). Moreover, it has been hypothesized that bioactive compounds such as polyphenols may affect IP and GME(3).The MaPLE project (Microbiome mAnipulation through Polyphenols for managing gut Leakiness in the Elderly) aimed to investigate the hypothesis that a polyphenol-rich diet can improve IP condition in a target population with beneficial changes at intestine and systemic level. To this aim, a randomised, controlled, cross-over dietary intervention study (8-week polyphenol-rich diet versus 8-week control diet, separated by a wash-out period) was carried out in a group of older subjects (> 60 years) living in a well-controlled setting (i.e. nursing home). Markers related with IP, inflammation, oxidative stress, vascular function and intestinal microbial ecosystem were investigated in serum, urine and/or fecal samples. Moreover, blood bacteria DNAemia, and serum/urine metabolomics has been assessed. Moreover, a consistent nutritional evaluation of the standard menu (provided by the nursing home) and of weighed food diaries was performed, providing also data on actual polyphenol intake during the intervention. The results show there were higher levels of IP in the older subjects, and that the polyphenol-enriched diet changed the levels of serum zonulin, a marker of IP. In addition, an association between zonulin and blood bacterial load was demonstrated. Ongoing in vitro and in vivo experiments are exploring the potential effects of different polyphenols on IP and the mechanisms involved. The MaPLE project will generate new data to improve the understanding on the role of polyphenols in the modulation of intestinal microbiome and its interactions with the host.

Background: The reported effects of flavanol-rich foods such as cocoa, dark chocolate, and apples on blood pressure and endothelial function may be due to the monomeric flavanols [mainly (–)-epicatechin (EC)], the oligomeric flavanols [procyanidins (PCs)], or other components. Reports of well-controlled intervention studies that test the effects of isolated oligomeric flavanols on biomarkers of cardiovascular health are lacking. Objective: We studied the acute and chronic effects of an EC-rich apple flavanol extract and isolated apple PCs on systolic blood pressure (BP) and other cardiometabolic biomarkers. Design: Forty-two healthy men and women with moderately elevated BP completed this randomized, double-blind, placebo-controlled, 4-arm crossover trial. Participants ingested a single dose of an apple flavanol extract (70 mg monomeric flavanols, 65 mg PCs), a double dose of this extract (140 mg monomeric flavanols, 130 mg PCs), an apple PC extract (130 mg PCs, 6.5 mg monomeric flavanols), or placebo capsules once daily for 4 wk, in random order. Biomarkers of cardiovascular disease risk and vascular function were measured before and 2 h after ingestion of the first dose and after the 4-wk intervention. Results: Compared with placebo, none of the isolated flavanol treatments significantly (P < 0.05) changed systolic or diastolic BP (peripheral and aortic), plasma nitric oxide (NO) reaction products, or measures of arterial stiffness (carotid femoral pulse-wave velocity, brachial-ankle pulse-wave velocity, or Augmentation Index) after 2 h or 4 wk of the intervention. There were no changes in plasma endogenous metabolite profiles or circulating NO; endothelin 1; total, HDL, or LDL cholesterol; triglycerides; fasting glucose; fructosamine; or insulin after 4 wk of the intervention. Conclusions: Our data suggest that, in isolation, neither monomeric flavanols nor PCs affect BP, blood lipid profiles, endothelial function, or glucose control in individuals with moderately elevated BP. The reported benefits of consuming flavanol-rich cocoa, chocolate, and apple products appear to be dependent on other components, which may work in combination with monomeric flavanols and PCs. This trial was registered at www.clinicaltrials.gov as NCT02013856.

Graphical abstract, Highlights • A process for incorporating phytochemical-rich vegetables into potato snacks was developed. • Highest phytochemical concentrations were achieved using freeze-dried vegetables. • There was excellent retention of flavonoids and glucosinolates in the final snack product. • Bioavailability of phytochemicals from the snack was similar to that of cooked vegetables., The aim was to incorporate vegetables containing the phytochemicals quercetin, apigenin, glucoraphanin and carotenoids into a processed potato-based snack and assess their bioaccessibility and bioavailability. Three different processing routes were tested for incorporation and retention of phytochemicals in snacks using individually quick frozen or freeze-dried vegetables. No significant differences in the uptake or transport of quercetin or apigenin between a vegetable mix or snacks were observed using the CaCo-2 transwell model. Simulated in vitro digestions predicted a substantial release of quercetin and apigenin, some release of glucoraphanin but none for carotenes from either the snack or equivalent steamed vegetables. In humans, there were no significant differences in the bioavailability of quercetin, apigenin or glucoraphanin from the snack or equivalent steamed vegetables. We have shown that significant quantities of freeze-dried vegetables can be incorporated into snacks with good retention of phytochemicals and with similar bioavailability to equivalent steamed vegetables.

Numerous studies support the protective role of bioactive peptides against cardiovascular diseases. Cereals represent the primary source of carbohydrates, but they also contain substantial amounts of proteins, therefore representing a potential dietary source of bioactive peptides with nutraceutical activities. The analysis of wheat extracts purified by chromatographic techniques by means of HPLC‐UV/nanoLC‐nanoESI‐QTOF allowed the identification of a signal of about 7 kDa which, following data base searches, was ascribed to a nonspecific lipid‐transfer protein (nsLTP) type 2 from Triticum aestivum(sequence coverage of 92%). For the first time nsLTP2 biological activities have been investigated. In particular, in experiments with human umbilical vein endothelial cells (HUVEC), nsLTP2 displayed antioxidant and cytoprotective activities, being able to significantly decrease reactive oxygen species (ROS) levels and to reduce lactate dehydrogenase (LDH) release, generated following oxidative (hydrogen peroxide) and inflammatory (tumor necrosis factor α, interleukin‐1β, and lipopolysaccharide) stimulation. The obtained promising results suggest potential protective role of nsLTP2 in vascular diseases prevention. nsLTP 2 peptide is resistant to proteases throughout the gastrointestinal tract and exerts antioxidant and cytoprotective activities. These characteristics could be exploited in vascular diseases prevention.

Elevated circulating cholesterol levels are a risk factor for CVD which is also associated with sub-optimal vascular function. There is emerging evidence that anthocyanins can cause beneficial cardio-protective effects by favourably modulating lipoprotein profiles. We compared the effects of blood orange juice which is rich in anthocyanins and blonde orange juice without anthocyanins on LDL-cholesterol and other biomarkers of CVD risk, vascular function and glycaemia. In all, forty-one participants (aged 25–84 years) with a waist circumference >94 cm (men) and >80 cm (women) completed a randomised, open label, two-arm cross-over trial. For 28 d participants ingested (i) 500 ml blood orange juice providing 50 mg anthocyanins/d and (ii) 500 ml blonde orange juice without anthocyanins. There was a minimum 3-week washout period between treatments. LDL-cholesterol and other biomarkers associated with CVD risk and glycaemia were assessed at the start and end of each treatment period. No significant differences were observed in total, HDL- and LDL-cholesterol, TAG, glucose, fructosamine, nitric oxide, C-reactive protein, aortic systolic blood pressure and diastolic blood pressure or carotid-femoral and brachial-ankle pulse wave velocity after 28 d ingestion of blood orange juice compared with standard orange juice. The lack of effect on LDL-cholesterol may be due to the modest concentration of anthocyanins in the blood orange juice.

Quercetin is one of the most commonly occurring flavonoids in nature. Although, quercetin and its metabolites express negligible fluorescence, the albumin-bound form of quercetin has a strong fluorescence property. Considering the structural variance of different albumins, we hypothesized that the fluorescence of albumin complexes of quercetin and its metabolites may vary significantly. Therefore, in this study the fluorescence enhancement of quercetin and some of its major metabolites in the presence of bovine (BSA), human (HSA), porcine (PSA), and rat serum albumins (RSA) were investigated by steady-state fluorescence spectroscopy in PBS buffer (pH 7.4). Among the tested quercetin metabolites, significant fluorescence signal was shown by albumin complexes of quercetin, isorhamnetin, and quercetin-3′-sulfate, while other metabolites (tamarixetin, quercetin-3-glucuronide, and isorhamnetin-3-glucuronide) expressed negligible fluorescence. BSA was the most potent enhancer of quercetin-3′-sulfate but it showed poor effects regarding other flavonoids. The strongest enhancement of isorhamnetin was caused by HSA, while it was less effective enhancer of quercetin and quercetin-3′-sulfate. PSA showed a strong fluorescence enhancement of quercetin and quercetin-3′-sulfate but it was poorly effective regarding isorhamnetin. RSA was the most potent enhancer of quercetin but it caused only a weak enhancement of isorhamnetin and quercetin-3′-sulfate. Large changes of the pH (such as pH 5.0 and pH 10.0) almost completely abolished the fluorescence signals of the complexes. Nevertheless, slight decrease (pH 7.0) reduced and slight increase (pH 7.8) generally enhanced the fluorescence of flavonoid-albumin complexes (only exceptions were quercetin-PSA and quercetin-RSA). Complex formations were also investigated by fluorescence quenching studies. Based on our results, the formations of quercetin-BSA, quercetin-HSA, isorhamnetin-BSA, isorhamnetin-HSA, isorhamnetin-PSA, and quercetin-3′-sulfate – HSA complexes followed 1:1 stoichiometry, while the presence of a secondary binding site of flavonoids was assumed regarding other tested albumin complexes. Our study highlights that albumins can induce significantly different fluorescence enhancement of flavonoids, and even the stoichiometry of flavonoid-albumin complexes may differ.

Flavan-3-ols and methylxanthines have potential beneficial effects on human health including reducing cardiovascular risk. We performed a randomized controlled crossover intervention trial to assess the acute effects of consumption of flavan-3-ol-enriched dark chocolate, compared with standard dark chocolate and white chocolate, on the human metabolome. We assessed the metabolome in urine and blood plasma samples collected before and at 2 and 6 h after consumption of chocolates in 42 healthy volunteers using a nontargeted metabolomics approach. Plasma samples were assessed and showed differentiation between time points with no further separation among the three chocolate treatments. Multivariate statistics applied to urine samples could readily separate the postprandial time points and distinguish between the treatments. Most of the markers responsible for the multivariate discrimination between the chocolates were of dietary origin. Interestingly, small but significant level changes were also observed for a subset of endogenous metabolites. H-1 NMR revealed that flavan-3-ol-enriched dark chocolate and standard dark chocolate reduced urinary levels of creatinine, lactate, some amino acids, and related degradation products and increased the levels of pyruvate and 4-hydroxyphenylacetate, a phenolic compound of bacterial origin. This study demonstrates that an acute chocolate intervention can significantly affect human metabolism.

There is a lack of data for individual oligomeric procyanidins in apples and apple extracts. Our aim was to develop, validate and evaluate an analytical method for the separation, identification and quantification of monomeric and oligomeric flavanols in apple extracts. To achieve this, we prepared two types of flavanol extracts from freeze-dried apples; one was an epicatechin-rich extract containing ∼30% (w/w) monomeric (−)-epicatechin which also contained oligomeric procyanidins (Extract A), the second was an oligomeric procyanidin-rich extract depleted of epicatechin (Extract B). The parameters considered for method optimisation were HPLC columns and conditions, sample heating, mass of extract and dilution volumes. The performance characteristics considered for method validation included standard linearity, method sensitivity, precision and trueness. Eight laboratories participated in the method evaluation. Chromatographic separation of the analytes was best achieved utilizing a Hilic column with a binary mobile phase consisting of acidic acetonitrile and acidic aqueous methanol. The final method showed linearity for epicatechin in the range 5–100 μg/mL with a correlation co-efficient >0.999. Intra-day and inter-day precision of the analytes ranged from 2 to 6% and 2 to 13% respectively. Up to dp3, trueness of the method was >95% but decreased with increasing dp. Within laboratory precision showed RSD values, This research has received funding from the European Community’s Seventh Framework Programme (FP7 under agreement no. 312090, project BACCHUS) and the Biotechnology and Biological Sciences Research Council (UK) through an Institute Strategic Programme Grant (‘Food and Health’; Grant No: BB/J004545/1) to the Institute of Food Research.

Flavonoids are ubiquitous molecules in nature with manifold pharmacological effects. Flavonoids interact with several proteins, and thus potentially interfere with the pharmacokinetics of various drugs. Though much is known about the protein binding characteristics of flavonoid aglycones, the behaviour of their metabolites, which are extensively formed in the human body has received little attention. In this study, the interactions of the flavonoid aglycone quercetin and its main metabolites with the albumin binding of the oral anticoagulant warfarin were investigated by fluorescence spectroscopy and ultrafiltration. Furthermore, the inhibitory effects of these flavonoids on CYP2C9 enzyme were tested because the metabolic elimination of warfarin is catalysed principally by this enzyme. Herein, we demonstrate that each tested flavonoid metabolite can bind to human serum albumin (HSA) with high affinity, some with similar or even higher affinity than quercetin itself. Quercetin metabolites are able to strongly displace warfarin from HSA suggesting that high quercetin doses can strongly interfere with warfarin therapy. On the other hand, tested flavonoids showed no or weaker inhibition of CYP2C9 compared to warfarin, making it very unlikely that quercetin or its metabolites can significantly inhibit the CYP2C9-mediated inactivation of warfarin.

Polyphenols are beneficial for health, but are metabolised after consumption. We compared the vasorelaxant capacity of twenty-one physiologically relevant polyphenol metabolites in isolated mouse arteries. Hesperetin, urolithins and ferulic acid-4-O-sulfate - not their glucuronidated forms or ferulic acid - caused vasorelaxation. Therefore, we advise the use of relevant conjugates in future mechanistic research.

High circulating HDL concentrations and measures of various HDL functions are inversely associated with cardiovascular disease (CVD) risk. Paraoxonase 1 (PON1) contributes to many of the athero-protective functions of HDL, such as promoting the reverse cholesterol transport process and reducing the levels of oxidized LDL. PON1 activities are influenced by several factors, the most important being diet and genetic polymorphisms. Reported data from randomized controlled trials have shown that anthocyanin consumption increased PON1 activity. However, the underlying molecular mechanisms by which anthocyanins increase PON1 activity are not understood. Therefore, the aim of this research was to investigate the ability of anthocyanins and their metabolites to increase PON1 gene expression and/or enzyme activities as potential mechanisms. The effect of the two predominant dietary anthocyanins and 18 of their recently identified microbial metabolites including their phase-II conjugates on PON1 gene expression was studied using a PON1-Huh7 stably-transfected cell line and reporter gene assay. The effects of these compounds on PON1 arylesterase and lactonase activities were investigated using two isoforms of the PON1 enzyme that are the phenotypes of the 192Q/R polymorphism. None of the compounds caused even modest changes in PON1 promoter activity (p &ge, 0.05). Further, none of the compounds at physiological concentrations caused any significant changes in the arylesterase or lactonase activity of either of the iso-enzymes. Cyanidin reduced the lactonase activity of the PON1-R192R enzyme at high concentrations (&minus, 22%, p &lt, 0.001), but not at physiologically achievable concentrations. In conclusion, none of the data reported here support the notion that anthocyanins or their metabolites affect PON1 transactivation or enzyme activities.

Atherosclerosis, the main contributor to coronary heart disease, is characterised by an accumulation of lipids such as cholesterol in the arterial wall. Reverse cholesterol transport (RCT) reduces cholesterol via its conversion into bile acids (BAs). During RCT in non-hepatic peripheral tissues, cholesterol is transferred to high-density lipoprotein (HDL) particles and returned to the liver for conversion into BAs predominantly via the rate-limiting enzyme, cholesterol 7 α-hydroxylase (CYP7A1). Numerous reports have described that polyphenol induced increases in BA excretion and corresponding reductions in total and LDL cholesterol in animal and in-vitro studies, but the process whereby this occurs has not been extensively reviewed. There are three main mechanisms by which BA excretion can be augmented: (1) increased expression of CYP7A1; (2) reduced expression of intestinal BA transporters; and (3) changes in the gut microbiota. Here we summarise the BA metabolic pathways focusing on CYP7A1, how its gene is regulated via transcription factors, diurnal rhythms, and microRNAs. Importantly, we will address the following questions: (1) Can polyphenols enhance BA secretion by modulating the CYP7A1 biosynthetic pathway? (2) Can polyphenols alter the BA pool via changes in the gut microbiota? (3) Which polyphenols are the most promising candidates for future research? We conclude that while in rodents some polyphenols induce CYP7A1 expression predominantly by the LXRα pathway, in human cells, this may occur through FXR, NF-KB, and ERK signalling. Additionally, gut microbiota is important for the de-conjugation and excretion of BAs. Puerarin, resveratrol, and quercetin are promising candidates for further research in this area.

Increasing evidence links intestinal permeability (IP), a feature of the intestinal barrier, to several pathological or dysfunctional conditions. Several host and environmental factors, including dietary factors, can affect the maintenance of normal IP. In this regard, food bioactives, such as polyphenols, have been proposed as potential IP modulators, even if the mechanisms involved are not yet fully elucidated. The aim of the present paper is to provide a short overview of the main evidence from in vitro and in vivo studies supporting the role of polyphenols in modulating IP and briefly discuss future perspectives in this research area.

Quercetin is an abundant flavonoid in nature and is used in several dietary supplements. Although quercetin is extensively metabolized by human enzymes and the colonic microflora, we have only few data regarding the pharmacokinetic interactions of its metabolites. Therefore, we investigated the interaction of human and microbial metabolites of quercetin with the xanthine oxidase enzyme. Inhibitory effects of five conjugates and 23 microbial metabolites were examined with 6-mercaptopurine and xanthine substrates (both at 5 &mu, M), employing allopurinol as a positive control. Quercetin-3&prime, sulfate, isorhamnetin, tamarixetin, and pyrogallol proved to be strong inhibitors of xanthine oxidase. Sulfate and methyl conjugates were similarly strong inhibitors of both 6-mercaptopurine and xanthine oxidations (IC50 = 0.2&ndash, 0.7 &mu, M), however, pyrogallol inhibited xanthine oxidation (IC50 = 1.8 &mu, M) with higher potency vs. 6-MP oxidation (IC50 = 10.1 &mu, M). Sulfate and methyl conjugates were approximately ten-fold stronger inhibitors (IC50 = 0.2&ndash, 0.6 &mu, M) of 6-mercaptopurine oxidation than allopurinol (IC50 = 7.0 &mu, M), and induced more potent inhibition compared to quercetin (IC50 = 1.4 &mu, M). These observations highlight that some quercetin metabolites can exert similar or even a stronger inhibitory effect on xanthine oxidase than the parent compound, which may lead to the development of quercetin&ndash, drug interactions (e.g., with 6-mercaptopurin or azathioprine).

Accurate dietary assessment is a challenge in nutritional research, needing powerful and robust tools for reliable measurement of food intake biomarkers. In this work, we have developed a novel quantitative dietary fingerprinting (QDF) approach, which enables for the first time the simultaneous quantitation of about 350 urinary food-derived metabolites, including (poly)phenolic aglycones, phase II metabolites, and microbial-transformed compounds, as well as other compounds (e.g., glucosinolates, amino acid derivatives, methylxanthines, alkaloids, and markers of alcohol and tobacco consumption). This method was fully validated for 220 metabolites, yielding good linearity, high sensitivity and precision, accurate recovery rates, and negligible matrix effects. Furthermore, 127 additional phase II metabolites were also included in this method after identification in urines collected from acute dietary interventions with various foods. Thus, this metabolomic approach represents one-step further toward precision nutrition and the objective of improving the accurateness and comprehensiveness in the assessment of dietary patterns and lifestyles.

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., Key messages 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.