Recommendations for standardizing nomenclature for dietary (poly)phenol catabolites

Chronic consumption of a bergamot-based beverage does not affect glucose, lipid and inflammatory biomarkers of cardiometabolic risk in healthy subjects: a randomised controlled intervention study

Background: Pure bergamot juice exerts lipid lowering effects in dyslipidemic subjects. It is unknown whether bergamot-based beverages exert similar effects in healthy subjects. Aim: To assess the effects, if any, of a bergamot-based beverage (BBB, bergamot juice ≤25%) on lipid, metabolic and inflammatory biomarkers. Methods: Forty-five healthy subjects were randomised 1 : 1 to BBB intake (400 mL day-1) (55.5%) or control (44.5%) for 12 weeks. Anthropometric (waist circumference, body mass index (BMI)) and clinical (blood pressure) parameters, blood samples (glucose, glycated haemoglobin, insulinemia, lipid profile, liver and renal function, inflammatory biomarkers) and 24-h urine for the analysis of (poly)phenol metabolites were collected at the baseline and at 12 weeks. Intakes of energy, nutrients and food groups were assessed by a 7-day dietary record. Results: Both groups exhibited a time-related significant decrease in total cholesterol (p = 0.02), fasting plasma glucose (p = 0.016), insulin (p = 0.034), BMI (p < 0.001) and waist circumference (p = 0.04), but with no significant between-arm difference. The urinary profile of metabolites from the BBB-derived (poly)phenols well discriminated the two study groups, documenting good compliance in the intervention arm. Notably, urinary bergamot 3-hydroxy-3-methylglutaryl (HMG) -containing flavanones or derived HMG-containing metabolites were not detectable. BBB was well tolerated and no adverse events were recorded. Conclusion: This first randomized controlled trial of BBB consumption in healthy subjects showed no effects of BBB on the cardiometabolic risk profile. BBB consumption is a safe nutritional adjunct in the context of a well balanced diet.

Seasonal and Morphology Effects on Bioactive Compounds, Antioxidant Capacity, and Sugars Profile of Black Carrot (Daucus carota ssp. sativus var. atrorubens Alef.)

Black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) is widely recognized for its bioactive compounds and antioxidant properties. The black carrot of Cuevas Bajas (Málaga) is a local variety characterized by a black/purple core, which differs from other black carrot varieties. Therefore, this autochthonous variety was characterized according to the root size and the harvesting season by means of a study of its antioxidant capacity analyzed by three methods, its total carotenoids content, and its sugars and phenolic compounds profile by ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-MS). A total of 20 polyphenolic compounds were quantified in 144 samples analyzed. The anthocyanidins group was observed to be the most abundant, followed by the hydroxycinnamic acids group. Moreover, pelargonidin 3-sambubioside was observed in black carrot for the first time. The medium-sized carrots presented the highest content of phenolic compounds, largely due to their significantly higher anthocyanidins content. Comparatively, the small carrots showed a higher content of simple sugars than the large ones. Regarding the influence of season, significantly higher quantities of glucose and fructose were observed in the late-season carrots, while sucrose was the main sugar in early-season samples. No significant differences were observed in the total carotenoid content of black carrot.

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.

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.

Factors driving the inter-individual variability in the metabolism and bioavailability of (poly)phenolic metabolites: A systematic review of human studies

This systematic review provides an overview of the available evidence on the inter-individual variability (IIV) in the absorption, distribution, metabolism, and excretion (ADME) of phenolic metabolites and its determinants. Human studies were included investigating the metabolism and bioavailability of (poly)phenols and reporting IIV. One hundred fifty-three studies met the inclusion criteria. Inter-individual differences were mainly related to gut microbiota composition and activity but also to genetic polymorphisms, age, sex, ethnicity, BMI, (patho)physiological status, and physical activity, depending on the (poly)phenol sub-class considered. Most of the IIV has been poorly characterised. Two major types of IIV were observed. One resulted in metabolite gradients that can be further classified into high and low excretors, as seen for all flavonoids, phenolic acids, prenylflavonoids, alkylresorcinols, and hydroxytyrosol. The other type of IIV is based on clusters of individuals defined by qualitative differences (producers vs. non-producers), as for ellagitannins (urolithins), isoflavones (equol and O-DMA), resveratrol (lunularin), and preliminarily for avenanthramides (dihydro-avenanthramides), or by quali-quantitative metabotypes characterized by different proportions of specific metabolites, as for flavan-3-ols, flavanones, and even isoflavones. Future works are needed to shed light on current open issues limiting our understanding of this phenomenon that likely conditions the health effects of dietary (poly)phenols.

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.

Industrial and culinary treatments applied to Piquillo pepper (Capsicum annuum cv. Piquillo) impact positively on (poly)phenols' bioaccessibility and gut microbiota catabolism

Thermal treatments applied to plant-based foods prior to consumption might influence (poly)phenols' bioaccessibility and the metabolization of these compounds by the gut microbiota. In the present research, the impact of industrial (grilling and canning) and culinary (microwaving and frying) treatments on the bioaccessibility and colonic biotransformations of (poly)phenols from Piquillo pepper (Capsicum annum cv. Piquillo) were evaluated by in vitro gastrointestinal digestion and colonic fermentation models and HPLC-ESI-MS/MS. The application of industrial treatments impacted positively on (poly)phenols' bioaccessibility compared to raw pepper. Microwaving also exerted a positive effect on (poly)phenols' bioaccessibility compared to canning whereas the addition of oil for frying seemed to negatively affect (poly)phenols' release from the food matrix. Throughout the 48 hours of the colonic fermentation process (poly)phenolic compounds were catabolized into different (poly)phenol derivatives whose formation was also positively affected by industrial and culinary treatments. Based on the concentration and time of appearance of these derivatives, catabolic pathways of (poly)phenols from Piquillo pepper were proposed. The major (poly)phenol derivatives identified (3-(3'-hydroxyphenyl)propanoic acid, 4-hydroxy-3-methoxyphenylacetic acid and benzene-1,2-diol) are considered of great interest for the study of their bioactivity and the potential effect on human health.

Flavonoids and phenolic acids from sugarcane: Distribution in the plant, changes during processing, and potential benefits to industry and health

Sugarcane (Saccharum sp.) plants are grown in warmer climates throughout the world and processed to produce sugar as well as other useful byproducts such as molasses and bagasse. Sugarcane is rich in (poly)phenols, but there has been no attempt to critically evaluate the published information based on the use of suitable methodologies. The objective of this review is to evaluate the quantitative and qualitative (poly)phenolic profiles of individual parts of the sugarcane plant and its multiple industrial products, which will help develop new processes and uses for sugarcane (poly)phenols. The quantitative analysis involves the examination of extraction, concentration, and analytical techniques used in each study for each plant part and product. The qualitative analysis indicates the identification of various (poly)phenols throughout the sugarcane processing chain, using only compounds elucidated through robust analytical methodologies such as mass spectrometry or nuclear magnetic resonance. In conclusion, sugarcane (poly)phenols are predominantly flavonoids and phenolic acids. The main flavonoids, derivatives of apigenin, luteolin, and tricin, with a substantial proportion of C-glycosides, are consistently found across all phases of sugarcane processing. The principal phenolic acids reported throughout the process include chlorogenic acids, as well as ferulic and caffeic acids mostly observed after hydrolysis. The derivation of precise quantitative information across publications is impeded by inconsistencies in analytical methodologies. The presence of multiple (poly)phenols with potential benefits for industrial applications and for health suggests sugarcane could be a useful provider of valuable compounds for future use in research and industrial processes.

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.

A critical examination of human data for the biological activity of quercetin and its phase-2 conjugates

This critical review examines evidence for beneficial effects of quercetin phase-2 conjugates from clinical intervention studies, volunteer feeding trials, and in vitro work. Plasma concentrations of quercetin-3-O-glucuronide (Q3G) and 3'-methylquercetin-3-O-glucuronide (3'MQ3G) after supplementation may produce beneficial effects in macrophages and endothelial cells, respectively, especially if endogenous deglucuronidation occurs, and lower blood uric acid concentration via quercetin-3'-O-sulfate (Q3'S). Unsupplemented diets produce much lower concentrations (<50 nmol/l) rarely investigated in vitro. At 10 nmol/l, Q3'S and Q3G stimulate or suppress, respectively, angiogenesis in endothelial cells. Statistically significant effects have been reported at 100 nmol/l in breast cancer cells (Q3G), primary neuron cultures (Q3G), lymphocytes (Q3G and3'MQ3G) and HUVECs (QG/QS mixture), but it is unclear whether these translate to a health benefit in vivo. More sensitive and more precise methods to measure clinically significant endpoints are required before a conclusion can be drawn regarding effects at normal dietary concentrations. Future requirements include better understanding of inter-individual and temporal variation in plasma quercetin phase-2 conjugates, their mechanisms of action including deglucuronidation and desulfation both in vitro and in vivo, tissue accumulation and washout, as well as potential for synergy or antagonism with other quercetin metabolites and metabolites of other dietary phytochemicals.

Metabolomic profiling and quantification of polyphenols from leaves of seven Acacia species by UHPLC-QTOF-ESI-MS

The genus Acacia (Fabaceae) comprises >1350 species and has been used in traditional medicine as infusions and decoctions to treat wounds, sores, headaches, diarrhea, and cough. The leaf methanolic extracts of seven Acacia species growing in Egypt namely: Acacia saligna, Acacia seyal, Acacia xanthophloea, Acacia tortilis subsp. raddiana., Acacia tortilis, Acacia laeta, Acacia albida were analyzed using UPLC-QTOF-ESI-MS. A total of 37 polyphenols were identified and discussed in detail. They included phenolic acids, flavonoids, and procyanidins, among which sixteen polyphenols were identified in Acacia for the first time. Folin-ciocalteau assay and ferric reducing antioxidant power, cupric reducing antioxidant capacity, 2,20 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) cation radical and the scavenging capacity against 2,2-diphenyl-1- picrylhydrazyl radical were performed to investigate the total phenolic content and the antioxidant activity of the Acacia extracts, respectively. Furthermore, the absolute quantification of eighteen polyphenols common to most of the species was performed using UPLC-MS. It was evident that the differences in the chemical composition among the species accounted for the difference in antioxidant activity which was in line together with the total phenolic content.

Unbiased and biased chemometric analysis of LC-MS data from human urine following coffee intake

We carried out a human volunteer study with 14 participants, eight of whom were asked to consume one cup of coffee at four different time points. Urine samples were collected at eight time points and analyzed by HPLC-MS analysis. The LC-MS data were subjected to unsupervised multivariate statistical analysis (principal component analysis) followed by supervised multivariate analysis (linear discriminant analysis). In an unbiased approach, in the absence of data preselection and filtering, the most important features explaining differences between coffee consumers and the control group observed showed variations in endogenous human hormonal steroid metabolites as well as xanthine derivatives. Only after a biased data treatment data revealed differences between the sample groups based on literature reported chlorogenic acid metabolites resulting directly from coffee intake. Such analysis could confirm the presence of 21 previously reported chlorogenic acid plasma metabolites as urinary metabolites. The application of tandem MS molecular networking revealed the presence of five bioavailable chlorogenic acid derivatives in urine previously not reported, including both quinic acid lactone and dimethoxy caffeoyl esters. Selected cinnamic acids were quantified in urine.

Unravelling phenolic metabotypes in the frame of the COMBAT study, a randomized, controlled trial with cranberry supplementation

Cranberry (poly)phenols may have potential health benefits. Circulating (poly)phenol metabolites can act as mediators of these effects, but they are subjected to an extensive inter-individual variability. This study aimed to quantify both plasma and urine (poly)phenol metabolites following a 12-week intake of a cranberry powder in healthy older adults, and to investigate inter-individual differences by considering the existence of urinary metabotypes related to dietary (poly)phenols. Up to 13 and 67 metabolites were quantified in plasma and urine respectively. Cranberry consumption led to changes in plasma metabolites, mainly hydroxycinnamates and hippuric acid. Individual variability in urinary metabolites was assessed using different data sets and a combination of statistical models. Three phenolic metabotypes were identified, colonic metabolism being the main driver for subject clustering. Metabotypes were characterized by quali-quantitative differences in the excretion of some metabolites such as phenyl-γ-valerolactones, hydroxycinnamic acids, and phenylpropanoic acids. Metabotypes were further confirmed when applying a model only focused on flavan-3-ol colonic metabolites. 5-(3',4'-dihydroxyphenyl)-γ-valerolactone derivatives were the most relevant metabolites for metabotyping. Metabotype allocation was well preserved after 12-week intervention. This metabotyping approach for cranberry metabolites represents an innovative step to handle the complexity of (poly)phenol metabolism in free-living conditions, deciphering the existence of metabotypes derived from the simultaneous consumption of different classes of (poly)phenols. These results will help contribute to studying the health effects of cranberries and other (poly)phenol-rich foods, mainly considering gut microbiota-driven individual differences.

Characterization of the Interindividual Variability Associated with the Microbial Metabolism of (-)-Epicatechin

Although the relationship between gut microbiota and flavan-3-ol metabolism differs greatly between individuals, the specific metabolic profiles, known as metabotypes, have not yet been clearly defined. In this study, fecal batch fermentations of 34 healthy donors inoculated with (-)-epicatechin were stratified into groups based on their conversion rate of (-)-epicatechin and their quali-quantitative metabolic profile. Fast and slow converters of (-)-epicatechin, high producers of 1-(3'-hydroxyphenyl)-3-(2″,4″,6″-trihydroxyphenyl)-propan-2-ol (3-HPP-2-ol) and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone (3,4-DHPVL) were identified. Fecal microbiota analysis revealed that fast conversion of (-)-epicatechin was associated with short-chain fatty acid (SCFA)-producing bacteria, such as Faecalibacterium spp. and Bacteroides spp., and higher levels of acetate, propionate, butyrate, and valerate were observed for fast converters. Other bacteria were associated with the conversion of 1-(3',4'-dihydroxyphenyl)-3-(2″,4″,6″-trihydroxyphenyl)-propan-2-ol into 3-HPP-2-ol (Lachnospiraceae UCG-010 spp.) and 3,4-DHPVL (Adlercreutzia equolifaciens). Such stratification sheds light on the mechanisms of action underlying the high interindividual variability associated with the health benefits of flavan-3-ols.

Dual targeting in prostate cancer with phytoconstituents as a potent lead: a computational approach for novel drug discovery

Prostate Cancer (PCa) is an abnormal cell growth within the prostate. This condition is the second most widespread malignancy in elderly males and one of the most frequently diagnosed life-threatening conditions. The Androgen receptor signaling pathway played a crucial role in the initiation and spread to increase the risk of PCa. Hence, targeting the AR receptor signaling pathway is a key strategy for a therapeutic plan for PCa. Our study focuses on recognizing potential inhibitors for dual targeting in PCa by using the in-silico approach. In this study, we target the two enzymes that are CYP17A1 (3RUK) and 5α-reductase (3G1R) responsible for PCa, with the help of phytoconstituents. The natural plant contains various phytochemical types produced from secondary metabolites and used as a medical treatment. The in-silico investigation of phytoconstituents and enzymes was done by approaching molecular docking, ADMET analysis, and high-level molecular dynamic simulation used to assess the stability and binding affinities of the protein-ligand complex. Some phytoconstituents, such as Peonidin, Pelargonidin, Malvidin and Berberine show complex has good molecular interaction with protein. The reliability of the docking scores was examined using a molecular dynamic simulation, which revealed that the complex remained stable throughout the simulation, which ranged from 0 to 200 ns. The selected hits may be effective against CYP17A1 (3RUK) and 5α-reductase (3G1R) (PCa) using a computer-aided drug design (CADD) method, which further enables researchers for upcoming in-vivo and in-vitro research, according to our in-silico approach.Communicated by Ramaswamy H. Sarma.

UHPLC-HRMS Spectrometric Analysis: Method Validation and Plasma and Urinary Metabolite Identification after Mango Pulp Intake

After an acute intake of 300 g of mango purée by 10 subjects, 0 and 24 h urine and plasma samples were analyzed by high-performance liquid chromatography-high-resolution mass spectrometry. The method was first validated for 44 reference polyphenols in terms of linearity, specificity, limits of detection and quantification, intra-day and inter-day precision, recovery, and matrix effects in two biological matrices. After method validation, a total of 94 microbial-derived phenolic catabolites, including 15 cinnamic acids, 3 phenylhydracrylic acids, 14 phenylpropanoic acids, 12 phenylacetic acids, 28 benzoic acids, 2 mandelic acids, 15 hydroxybenzenes, and 5 hippuric acid derivatives, were identified or tentatively identified in urine and/or plasma. These results establish the value of the UHPLC-HRMS protocol and the use of authentic standards to obtain a detailed and accurate picture of mango polyphenol metabolites, together with their phase II conjugated metabolites, in human bioavailability studies.

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.

LC-MS/MS Analysis Elucidates the Different Effects of Industrial and Culinary Processing on Total and Individual (Poly)phenolic Compounds of Piquillo Pepper (Capsicum annuum cv. Piquillo)

Pepper constitutes an important source of (poly)phenols, mainly flavonoids. Nevertheless, heat treatments applied prior to consumption may have an impact on these antioxidants, and thus may also affect their potential bioactivity. In this study, the effect of industrial and culinary treatments on the total and individual (poly)phenolic content of Piquillo pepper (Capsicum annuum cv. Piquillo) was thoroughly evaluated by high-performance liquid chromatography coupled to tandem mass spectrometry. A total of 40 (poly)phenols were identified and quantified in raw pepper. Flavonoids (10 flavonols, 15 flavones, and 2 flavanones) were the major compounds identified (62.6%). Among the 13 phenolic acids identified in raw samples, cinnamic acids were the most representative. High temperatures applied and subsequent peeling during industrial grilling drastically decreased the total (poly)phenolic content from 2736.34 to 1099.38 μg/g dm (59.8% reduction). In particular, flavonoids showed a higher reduction of 87.2% after grilling compared to nonflavonoids which only decreased by 14%. Moreover, 9 nonflavonoids were generated during grilling, modifying the (poly)phenolic profile. After culinary treatments, specifically frying, (poly)phenols appear to be better released from the food matrix, enhancing their extractability. Overall, industrial and culinary treatments differently affect both the total and individual (poly)phenolic compounds of pepper and, despite the reduction, they might also positively influence their bioaccessibility.

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

The impact of β-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 β-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 β-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.

Revisiting the bioavailability of flavan-3-ols in humans: A systematic review and comprehensive data analysis

This systematic review summarizes findings from human studies investigating the different routes of absorption, metabolism, distribution and excretion (ADME) of dietary flavan-3-ols and their circulating metabolites in healthy subjects. Literature searches were performed in PubMed, Scopus and the Web of Science. Human intervention studies using single and/or multiple intake of flavan-3-ols from food, extracts, and pure compounds were included. Forty-nine human intervention studies met inclusion criteria. Up to 180 metabolites were quantified from blood and urine samples following intake of flavan-3-ols, mainly as phase 2 conjugates of microbial catabolites (n = 97), with phenyl-γ-valerolactones being the most representative ones (n = 34). Phase 2 conjugates of monomers and phenyl-γ-valerolactones, the main compounds in both plasma and urine, reached two peak plasma concentrations (C_max) of 260 and 88 nmol/L at 1.8 and 5.3 h (T_max) after flavan-3-ol intake. They contributed to the bioavailability of flavan-3-ols for over 20%. Mean bioavailability for flavan-3-ols was moderate (31 ± 23%, n bioavailability values = 20), and it seems to be scarcely affected by the amount of ingested compounds. While intra- and inter-source differences in flavan-3-ol bioavailability emerged, mean flavan-3-ol bioavailability was 82% (n = 1) and 63% (n = 2) after (-)-epicatechin and nut (hazelnuts, almonds) intake, respectively, followed by 25% after consumption of tea (n = 7), cocoa (n = 5), apples (n = 3) and grape (n = 2). This highlights the need to better clarify the metabolic yield with which monomer flavan-3-ols and proanthocyanidins are metabolized in humans. This work clarified in a comprehensive way for the first time the ADME of a (poly)phenol family, highlighting the pool of circulating compounds that might be determinants of the putative beneficial effects linked to flavan-3-ol intake. Lastly, methodological inputs for implementing well-designed human and experimental model studies were provided.

Double-blind controlled dietary cross-over intervention with differentially fertilised intact lettuce leaves shows acute reduction in blood pressure in young adults, associated with faster uptake of nitrate than of phenolics

PURPOSE

To compare acute effects on blood pressure (BP) of ingestion of visually similar lettuce with controlled high and low content of either nitrate or phenolic compounds.

METHODS

In a randomised cross-over design, 19 healthy participants (22-31 years) received 50 g of lettuce containing either 530 mg (8.4 mmol) nitrate + 11 mg (0.03 mmol) phenolic compounds (HNLP); or 3 mg nitrate (0.05 mmol) + 77 mg (0.2 mmol) phenolic compounds (LNHP), obtained by differential fertilisation. Ambulatory BP was recorded along with plasma, salivary and urinary nitrate and nitrite and plasma concentrations of cyclic guanosine monophosphate (cGMP), phenolic metabolites, Trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP).

RESULTS

Compared with LNHP, 3 h post ingestion of HNLP, plasma nitrate increased 0.31 ± (95%CI) 0.12 mM (+ 240%), and salivary nitrate 5.5 ± 1.4 mM (+ 910%); accumulated urinary nitrate excretion increased 188 ± 72 mg (+ 296%) (all P < 0.001). Systolic BP was reduced 4.9 ± 4.2 mmHg (P = 0.031) between 3 and 6 h after ingestion of HNLP compared with LNHP; systolic BP differences were negatively correlated (P = 0.004) with differences in saliva nitrate concentrations. LNHP increased plasma phenolics at 6 h, predominantly 3'-methoxycinnamic acid-4'-glucuronide (ferulic acid-4'-glucuronide), 116%, 204 ± 138 nM more than HNLP (P = 0.001); increased cGMP 14% (P = 0.019); and reduced FRAP 3.1% (P = 0.009).

CONCLUSION

The acute BP difference within 6 h of consumption matched the plasma/saliva nitrate peak, not the slower changes of plasma phenolics. This is the first double-blind controlled dietary intervention demonstrating differential effects on human physiology by consumption of an intact plant food, where compositional differences were obtained by controlling growing conditions, indicating potential opportunities for health claims relating to precision/vertical farming.

CLINICAL TRIAL REGISTRATION

The trial was retrospectively registered on ClinicalTrials.gov, with identifier NCT02701959, on March 8, 2016.

Review of factors affecting citrus polyphenol bioavailability and their importance in designing in vitro, animal, and intervention studies

Evidence from in vitro, animal, and human studies links citrus fruit consumption with several health-promoting effects. However, many in vitro studies disregard bioavailability data, a key factor determining responses in humans. Citrus (poly)phenol metabolism and bioavailability follow specific pathways that vary widely among individuals and are affected by several intrinsic (age, sex, gut microbiota, metabolic state, genetic polymorphisms) and extrinsic (food matrix, co-consumed food, (poly)phenol solubility, dose, food processing, lifestyle) factors. The gut microbiota is crucial to both absorption of citrus (poly)phenols and the production of catabolites, and absorption of both takes place mostly in the colon. Citrus (poly)phenol absorption can reach up to 100% in some individuals when the sum of the gut microbiota products are taken into account. This review emphasizes the importance of understanding citrus (poly)phenol absorption, metabolism, and bioavailability using evidence primarily derived from human studies in designing in vitro, animal, and further human clinical studies.

Effects of Polyphenols on Glucose-Induced Metabolic Changes in Healthy Human Subjects and on Glucose Transporters

Dietary polyphenols interact with glucose transporters in the small intestine and modulate glucose uptake after food or beverage consumption. This review assesses the transporter interaction in vitro and how this translates to an effect in healthy volunteers consuming glucose. As examples, the apple polyphenol phlorizin inhibits sodium-glucose linked transporter-1; in the intestinal lumen, it is converted to phloretin, a strong inhibitor of glucose transporter-2 (GLUT2), by the brush border digestive enzyme lactase. Consequently, an apple extract rich in phlorizin attenuates blood glucose and insulin in healthy volunteers after a glucose challenge. On the other hand, the olive phenolic, oleuropein, inhibits GLUT2, but the strength of the inhibition is not enough to modulate blood glucose after a glucose challenge in healthy volunteers. Multiple metabolic effects and oxidative stresses after glucose consumption include insulin, incretin hormones, fatty acids, amino acids, and protein markers. However, apart from acute postprandial effects on glucose, insulin, and some incretin hormones, very little is known about the acute effects of polyphenols on these glucose-induced secondary effects. In summary, attenuation of the effect of a glucose challenge in vivo is only observed when polyphenols are strong inhibitors of glucose transporters.

A Screening of Native (Poly)phenols and Gut-Related Metabolites on 3D HCT116 Spheroids Reveals Gut Health Benefits of a Flavan-3-ol Metabolite

SCOPE

Epidemiological evidence suggests that a reduced risk of colorectal cancer (CRC) is correlated with high consumption of fruits and vegetables, which are major sources of fiber and phytochemicals, such as flavan-3-ols. However, it remains unknown how these phytochemicals and their specific gut-related metabolites may alter cancer cell behavior.

METHODS AND RESULTS

A focused screening using native (poly)phenols and gut microbial metabolites (GMMs) on 3D HCT116 spheroids is carried out using a high-throughput imaging approach. Dose-responses, IC50 , and long-term exposure are calculated for the most promising native (poly)phenols and GMMs. As a result, this research shows that (poly)phenol catabolites may play a key role in preventing cancer propagation. Indeed, µM concentration levels of (4R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone significantly decrease spheroid size at early stages of spheroid aggregation and gene expression of matrix metalloproteinases.

CONCLUSION

A chronic exposure to (4R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone may lead to a reduced CRC risk. Daily intake of monomeric, oligomeric, and polymeric flavan-3-ols may increase the colonic concentrations of this metabolite, and, in turn, this compound may act locally interacting with intestinal epithelial cells, precancerous and cancer cells.

In Vitro Faecal Fermentation of Monomeric and Oligomeric Flavan-3-ols: Catabolic Pathways and Stoichiometry

SCOPE

The study evaluates the influence of flavan-3-ol structure on the production of phenolic catabolites, principally phenyl-γ-valerolactones (PVLs), and phenylvaleric acids (PVAs).

METHODS AND RESULTS

A set of 12 monomeric flavan-3-ols and proanthocyanidins (degree of polymerization (DP) of 2-5), are fermented in vitro for 24 h using human faecal microbiota, and catabolism is analyzed by UHPLC-ESI-MS/MS. Up to 32 catabolites strictly related to microbial catabolism of parent compounds are detected. (+)-Catechin and (-)-epicatechin have the highest molar mass recoveries, expressed as a percentage with respect to the incubated concentration (75 µmol L^-1 ) of the parent compound, for total PVLs and PVAs, both at 5 h (about 20%) and 24 h (about 40%) of faecal incubation. Only A-type dimer and B-type procyanidins underwent the ring fission step, and no differences are found in total PVL and PVA production (≃1.5% and 6.0% at 5 and 24 h faecal incubation, respectively) despite the different DPs.

CONCLUSION

The flavan-3-ol structure strongly affects the colonic catabolism of the native compounds, influencing the profile of PVLs and PVAs produced in vitro. This study opens new perspectives to further elucidate the colonic fate of oligomeric flavan-3-ols and their availability in producing bioactive catabolites.

Metabolism of phenolics in coffee and plant-based foods by canonical pathways: an assessment of the role of fatty acid β-oxidation to generate biologically-active and -inactive intermediates

ω-Phenyl-alkenoic acids are abundant in coffee, fruits, and vegetables. Along with ω-phenyl-alkanoic acids, they are produced from numerous dietary (poly)phenols and aromatic amino acids in vivo. This review addresses how phenyl-ring substitution and flux modulates their gut microbiota and endogenous β-oxidation. 3',5'-Dihydroxy-derivatives (from alkyl-resorcinols, flavanols, proanthocyanidins), and 4'-hydroxy-phenolic acids (from tyrosine, p-coumaric acid, naringenin) are β-oxidation substrates yielding benzoic acids. In contrast, 3',4',5'-tri-substituted-derivatives, 3',4'-dihydroxy-derivatives and 3'-methoxy-4'-hydroxy-derivatives (from coffee, tea, cereals, many fruits and vegetables) are poor β-oxidation substrates with metabolism diverted via gut microbiota dehydroxylation, phenylvalerolactone formation and phase-2 conjugation, possibly a strategy to conserve limited pools of coenzyme A. 4'-Methoxy-derivatives (citrus fruits) or 3',4'-dimethoxy-derivatives (coffee) are susceptible to hepatic "reverse" hydrogenation suggesting incompatibility with enoyl-CoA-hydratase. Gut microbiota-produced 3'-hydroxy-4'-methoxy-derivatives (citrus fruits) and 3'-hydroxy-derivatives (numerous (poly)phenols) are excreted as the phenyl-hydracrylic acid β-oxidation intermediate suggesting incompatibility with hydroxy-acyl-CoA dehydrogenase, albeit with considerable inter-individual variation. Further investigation is required to explain inter-individual variation, factors determining the amino acid to which C6-C3 and C6-C1 metabolites are conjugated, the precise role(s) of l-carnitine, whether glycine might be limiting, and whether phenolic acid-modulation of β-oxidation explains how phenolic acids affect key metabolic conditions, such as fatty liver, carbohydrate metabolism and insulin resistance.

A look beyond dietary (poly)phenols: The low molecular weight phenolic metabolites and their concentrations in human circulation

A large number of epidemiological studies have shown that consumption of fruits, vegetables, and beverages rich in (poly)phenols promote numerous health benefits from cardiovascular to neurological diseases. Evidence on (poly)phenols has been applied mainly to flavonoids, yet the role of phenolic acids has been largely overlooked. Such phenolics present in food combine with those resulting from gut microbiota catabolism of flavonoids and chlorogenic acids and those produced by endogenous pathways, resulting in large concentrations of low molecular weight phenolic metabolites in human circulation. Independently of the origin, in human intervention studies using diets rich in (poly)phenols, a total of 137 low molecular weight phenolic metabolites have been detected and quantified in human circulation with largely unknown biological function. In this review, we will pinpoint two main aspects of the low molecular weight phenolic metabolites: (i) the microbiota responsible for their generation, and (ii) the analysis (quali- and quantitative) in human circulation and their respective pharmacokinetics. In doing so, we aim to drive scientific advances regarding the ubiquitous roles of low molecular weight phenolic metabolites using physiologically relevant concentrations and under (patho)physiologically relevant conditions in humans.

An insight into an intriguing oxidative biotransformation pathway of 5-O-caffeoylquinic acid by a gut bacterium

Microbiota is known to play a pivotal role in generating bioavailable and bioactive low-molecular-weight metabolites from dietary polyphenols. 5-O-caffeoylquinic acid (5-CQA), one of the main polyphenols found in human diet, was submitted to a resting cell biotransformation study using three gut bacteria species Lactobacillus reuteri, Bacteroides fragilis and Bifidobacterium longum. These bacteria were selected according to their belonging to the main phyla found in human gut microbiota. Our study highlighted the ability of only one of the strains studied, L. reuteri, to bioconverse 5-CQA into various metabolites due to the expression of the cinnamoyl esterase enzyme as the first step. Interestingly, one known natural compound, esculetin, was described for the first time as a 5-CQA-derived metabolite after conversion by a gut bacterium, the other metabolites had already been reported. This evidence highlighted an interesting oxidative pathway occurring in vivo by intestinal microbiota leading to esculetin. This molecule was also identified after electrochemical and enzymatic oxidations of caffeic acid. The oxidation capacity of L. reuteri led to less diverse metabolites in comparison to those obtained either electrochemically and enzymatically where dimers and trimers were reported. Thus, esculetin may have interesting and benefical biological effects on gut microbiota, which should be further evaluated. Novel synbiotics could be formulated from the association of L. reuteri with 5-CQA.

Absorption, distribution, metabolism and excretion of apigenin and its glycosides in healthy male adults

The bioavailability of apigenin and its O-glycosides in humans was investigated with apigenin-4'-glucuronide (Ap-4'-GlcUA), apigenin-7-glucuronide and apigenin-7-sulfate being identified as in vivo metabolites. Apigenin per se was poorly absorbed with metabolites equivalent to 0.5% of intake excreted in urine 0-24 h post-intake. Consumption of a parsley drink containing apigenin-7-O-(2″-O-apiosyl)glucoside resulted in the peak plasma concentration (C_max) of Ap-4'-GlcUA occurring after 4 h, indicative of absorption in the lower gastrointestinal tract (GIT). Urinary excretion of the three metabolites corresponded to 11.2% of intake. Ingestion of dried powdered parsley leaves with yogurt extended the C_max of Ap-4'-GlcUA to 6 h. Consumption of chamomile tea containing apigenin-7'-O-glucoside resulted in a 2 h C_max of Ap-4'-GlcUA, in keeping with absorption in the upper GIT. Urinary excretion was equivalent to 34% of intake. Intake of the parsley drink provided information on intra- and inter-individual variations in the level of excretion of the apigenin metabolites. CLINICAL TRAIL REGISTRATION NUMBER: This trail was registered at clinicaltrials.gov as NCT03526081.

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

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

LC-MS Characterization and Quantification of Known and Unknown (Poly)phenol Metabolites-Possible Pitfalls and Their Avoidance

This review focuses on the LC-MS characterization and quantification of dietary (poly)phenols and their metabolites. It draws attention to errors, omissions, and misunderstandings that appear frequently in published papers, and suggests strategies for their avoidance. Aspects covered include the use of authentic standards and surrogate reference materials, the importance of collecting and archiving Total Ion Current MS data, the limitations of using on-line compilations of accurate mass MS data to assign unknown components when multiple isomers are possible, and the often understated magnitude of person-to-person variation that may significantly impact at population level any potential health benefit.

Effects of colonic fermentation on the stability of fresh and black onion bioactives

The health properties related to onion intake are attributed mainly to the presence of bioactive compounds, particularly phenolic and organosulfur compounds (OSCs). The aim of this study was to investigate, for the first time, the effect of an in vitro colonic fermentation on the stability of phenolic and OSCs of fresh and black onion by ultra-high-performance liquid chromatography coupled with mass spectrometry with a linear ion trap (UHPLC-LIT-MS). Throughout colonic fermentation, fresh onion showed an increase in the total phenolic content of 45%, mainly due to an increase in the content of the flavonoid family, while the OSCs remained stable along the fermentation. Black onion presented a different behaviour, showing significant decreases in total (poly)phenol and OSC content, 22 and 48%, respectively. The main compounds found after the in vitro colonic fermentation of fresh onion were isorhamnetin (141 μmol L^-1), quercetin (95 μmol L^-1), 3,4-dihydroxybenzoic acid (53 μmol L^-1), methionine sulfoxide (100 μmol L^-1) and S-allylcysteine (SAC) (21.7 μmol L^-1), whereas 3,4-dihydroxybenzoic acid (70 μmol L^-1), 4-hydroxyphenylacetic acid (68 μmol L^-1), methionine sulfoxide (82 μmol L^-1) and S-propylmercapto-L-cysteine (SPMC) (10.1 μmol L^-1) accounted for the highest concentrations of phenolics and OSCs in fermented black onion. These compounds, presumably present for their absorption and action at the colonic level, could be related to the health benefits of regular consumption of fresh and black onion.

(Poly)phenolic composition of tomatoes from different growing locations and their absorption in rats: A comparative study

The aim of this work was to address whether the growing location of tomato could generate a different (poly)phenol profile able to affect both in vivo absorption and (poly)phenol metabolite pattern upon tomato consumption. uHPLC-MSⁿ analyses allowed to obtain a detailed (poly)phenol profile of tomatoes from two locations in Spain, quantifying 57 (poly)phenolic compounds. However, local and non-local tomatoes showed a different concentration of their native (poly)phenols, which could be attributed to diverse cultivation origin. Rat serum was analysed after an acute tomato feeding. Seven phenolic metabolites were quantified through uHPLC-MSⁿ. Pharmacokinetic parameters were further evaluated, revealing different serum concentrations of (poly)phenolic metabolites between tomatoes. The maximum peak serum concentrations, reached mainly after 2 h after ingestion, led to suppose that serum metabolites were mostly derived from absorption in the upper gastrointestinal tract. The growing location of tomatoes affected both the content of native (poly)phenols and their in vivo absorption.

In Vitro Colonic Fermentation of (Poly)phenols and Organosulfur Compounds of Fresh and Black Garlic

The beneficial properties associated with garlic consumption have been related to the presence of bioactive compounds including (poly)phenols and organosulfur compounds (OSCs). This study aims to assess the effect of in vitro colonic fermentation on fresh and black garlic by determining the transformation of these compounds through ultrahigh-performance liquid chromatography coupled to mass spectrometry with a linear ion trap (uHPLC-LIT-MS). Colonic fermentation had a similar influence on the phenolic content of fresh and black garlic, with total respective decreases of 43.8% and 41.7%. Meanwhile, fermentation resulted in a significant decrease (33%) in OSCs in black garlic. Compounds such as 4-hydroxybenzoic acid, S-allylcysteine (SAC), and methionine sulfoxide were the phenolic compounds and OSCs with the highest concentration in fresh and black garlic after the in vitro fermentation. These compounds, potentially present at the colonic level, might be responsible for the systemic health benefits associated with the consumption of black and fresh garlic.

A wheat aleurone-rich diet improves oxidative stress but does not influence glucose metabolism in overweight/obese individuals: Results from a randomized controlled trial

BACKGROUND AND AIMS

Aleurone is the innermost layer of wheat bran, rich in fiber, minerals, vitamins, phenolic compounds, and betaine. The metabolic effects of aleurone rich foods are still unknown. Our aim was to investigate the effects of consuming a Wheat Aleurone rich diet vs. a Refined Wheat diet for 8 weeks on fasting and postprandial glycemic and lipid metabolism, inflammation, and oxidative stress in overweight/obese individuals.

METHODS AND RESULTS

According to a randomized cross-over study design, 23 overweight/obese individuals, age 56 ± 9 years (M±SD), were assigned to two isoenergetic diet - Wheat Aleurone and Refined Wheat diets - for 8 weeks. The diets were similar for macronutrient composition but different for the aleurone content (40-50 g/day in the Wheat Aleurone diet). After each diet, fasting and postprandial plasma metabolic profile, ferulic acid metabolites and 8-isoprostane concentrations in 24-h urine samples were evaluated. Compared with the Refined Wheat Diet, the Wheat Aleurone Diet increased fasting plasma concentrations of betaine by 15% (p = 0.042) and decreased the excretion of 8-isoprostane by 33% (p = 0.035). Conversely, it did not affect the fasting and postprandial glucose, insulin and triglyceride responses, homocysteine, and C-Reactive Protein concentrations, nor excretion of phenolic metabolites.

CONCLUSION

An 8-week Wheat Aleurone Diet improves the oxidative stress and increases plasma betaine levels in overweight/obese individuals with an increased cardiometabolic risk. However, further studies with longer duration and larger sample size are needed to evaluate the benefits of aleurone-rich foods on glucose and lipid metabolism in individuals with more severe metabolic abnormalities.

CLINICAL TRIAL REGISTRY NUMBER

NCT02150356, (https://clinicaltrials.gov).

A Practitioner's Dilemma Mass Spectrometry-Based Annotation and Identification of Human Plasma and Urinary Polyphenol Metabolites

The practitioner's dilemma in metabolite assignment can be described as follows: For compound and metabolite identification, should we follow strict guidelines using authentic standards only, or should we accept uncertainties in structure assignment of compounds with the certainty of consequential errors. These uncertainties arise due to limitation of software and databases in combination with the complexity of the human body fluid samples. This article is protected by copyright. All rights reserved.

Grape seed extract supplementation modulates hepatic lipid metabolism in rats. Implication of PPARβ/δ

Grape seed extract supplementationat low doses (25 mg per kg BW per day) modulates the transcriptional programs that controls the hepatic lipid metabolism in lean normolipidemic Wistar rats through PPARβ/δ activation.

Purified recombinant enzymes efficiently hydrolyze conjugated urinary (poly)phenol metabolites

Purified recombinant enzymes are efficient at hydrolyzing microbial (poly)phenol metabolite phase II conjugates, and hence, can be used to accurately quantify them using unconjugated analytical standards.

Effect of different patterns of consumption of coffee and a cocoa-based product containing coffee on the nutrikinetics and urinary excretion of phenolic compounds

BACKGROUND

Coffee consumption is associated with a reduced risk of several chronic diseases in a dose-dependent manner. Chronic intake results in the transient appearance of bioactive phenolic metabolites in the circulatory system. However, there is a lack of information on the impact of different patterns of coffee consumption on plasma and urinary profiles of phenolic metabolites.

OBJECTIVES

Plasma and urinary phenolic metabolites were investigated following regular consumption of different daily dosages of coffee or cocoa-based products containing coffee (CBPCC) under a real-life setting.

METHODS

A repeated-dose, randomized, crossover human intervention was conducted with 21 healthy volunteers. For 1 mo, participants consumed 1) 1 cup of coffee (1C), 2) 3 cups of coffee (3C), or 3) 1 cup of coffee + 2 CBPCC twice daily (PC). Plasma and urine samples were collected over a 24-h period after each treatment. The nutrikinetics and urinary excretion of native, human phase II, and colonic metabolites were assessed.

RESULTS

A total of 51 (poly)phenolic metabolites were quantified, with 41 metabolites being strictly related to coffee consumption. Significant differences were observed among treatments for most of the metabolites. The metabolites present in the highest amounts were the hydroxycinnamate, phenylpropanoic acid, benzaldehyde, and benzene classes, along with (-)-epicatechin and phenyl-γ-valerolactone derivatives after PC treatment. Daily average concentrations did not exceed 200 nmol/L and were <100 nmol/L for most of the metabolites. The excretion of coffee phenolics ranged from 40% to 70% of intake, indicating that coffee hydroxycinnamates are notably more bioavailable than previously thought. Interindividual variability was also investigated.

CONCLUSIONS

The absorption, metabolism, nutrikinetic profile, and bioavailability of coffee phenolics were established for different patterns of coffee consumption under real-life conditions. This work provides the basis for further nutritional epidemiology research and mode-of-action cell-based studies. This study was registered at clinicaltrials.gov as NCT03166540.

Administration Time Significantly Affects Plasma Bioavailability of Grape Seed Proanthocyanidins Extract in Healthy and Obese Fischer 344 Rats

SCOPE

Phenolic compounds are bioactive molecules that are associated with several health benefits. Metabolization and absorption are the main determinants of their bioavailability and bioactivity. Thus, the study of the factors that modulate these processes, such as sex or diet is essential. Recently, it has been shown that biological rhythms may also play a key role. Hence, the aim of this study is to evaluate if the bioavailability of a grape proanthocyanidin extract (GSPE) is affected by the administration time in an animal model of metabolic syndrome (MetS).

METHODS AND RESULTS

Female and male Fischer 344 rats are fed either a standard or a cafeteria diet (CAF) for 9 weeks, and an oral dose of GSPE (25 mg kg^-1 ) is daily administered either at 8:00 am (zeitgeber time (ZT)-0) or at 8:00 pm (ZT-12) during the last 4 weeks. Plasma phenolic compounds are then quantified by liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Phase-II and gut microbiota-derived phenolic metabolites are affected by ZT in all conditions or only in obese rats, respectively. CAF feeding affected the bioavailability of phenolic acids and free flavan-3-ols. Differences due to sex are also observed.

CONCLUSION

These findings demonstrate that ZT, diet, and sex are key factors influencing phenolic compounds bioavailability.

Evaluating the role of orange juice, HESPERidin in vascular HEALTH benefits (HESPER-HEALTH study): protocol for a randomised controlled trial

INTRODUCTION

Although epidemiological studies associate the consumption of sugary beverages with adverse health effects, human experimental studies have demonstrated substantially different metabolic responses when 100% fruit juices are compared with artificial beverages. Fruit juices do not just provide sugars and associated calories, but they are also rich in bioactive compounds. Flavanones are bioactives specifically and abundantly found in citrus foods, with hesperidin as the major representative in sweet oranges. Flavanone intake has been associated with a lower incidence of mortality from cardiovascular disease (CVD). However, clinical evidence are too scarce to confirm the vasculoprotective effects of 100% orange juice (OJ) presumably mediated by flavanones and thereby do not allow firm conclusions to be drawn about their efficacy.

METHODS AND ANALYSIS

The HESPER-HEALTH study aims to assess the efficacy of OJ in improving vascular function and the contribution of hesperidin to these effects. This double-blind, randomised, controlled, crossover study will be carried out in 42 volunteers predisposed to CVD, based on age and on overweight. It includes three 6-week periods of consumption of 330 mL/d of OJ versus control drinks with and without hesperidin at a dose in agreement with a daily OJ serving (approx. 200-215 mg). The primary outcome is endothelial function, assessed by flow mediated dilation, with measurements performed at fasting and postprandially in response to a challenge meal. The secondary outcomes include bioavailability and metabolism of flavanones, changes in other markers of vascular function, systemic biomarkers of cardiovascular risk, endothelial dysfunction and inflammation, vitamin C and carotenoids status, anthropometry and body composition, gut microbiota composition, nutrigenomic response and in oxylipin profiling.

ETHICS AND DISSEMINATION

This ongoing study was approved by the Ethics committee Sud-Est III, Bron, France on 17 November 2020. The trial is registered on ClinicalTrials.gov. The results will be disseminated in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04731987; Pre-results.

Defining Telehealth for Research, Implementation, and Equity (Preprint)

When the COVID-19 pandemic spurred a disruption in health care delivery, the role of telehealth shifted from an option to a near necessity to maintain access when in-person care was deemed too risky. Each state and many organizations developed temporary telehealth policies for the COVID-19 emergency, each policy with its own definitions, coverage, government cases, and regulations. As pandemic-era policies are now being replaced with more permanent guidelines, we are presented with an opportunity to reevaluate how telehealth is integrated into routine health care delivery. We believe that the timing and nature of the sequential steps for redefining telehealth are critical and that it is important to develop a clear and agreed-on definition of telehealth and its components at this time. We further suggest a necessary preliminary step is to support clear communication and interoperability throughout the development of this definition. Precise and standardized definitions could create an unambiguous environment for clinical care for both patients and providers while enabling researchers to have more precise control over their investigations of telehealth. A consensus when defining telehealth and its derivatives at this critical stage could create a consistent expectation of care for all patients and those who set the standards of care, as it has for other clinical scenarios with clear guidelines.

Metabotypes of flavan-3-ol colonic metabolites after cranberry intake: elucidation and statistical approaches

Purpose

Extensive inter-individual variability exists in the production of flavan-3-ol metabolites. Preliminary metabolic phenotypes (metabotypes) have been defined, but there is no consensus on the existence of metabotypes associated with the catabolism of catechins and proanthocyanidins. This study aims at elucidating the presence of different metabotypes in the urinary excretion of main flavan-3-ol colonic metabolites after consumption of cranberry products and at assessing the impact of the statistical technique used for metabotyping.

Methods

Data on urinary concentrations of phenyl-γ-valerolactones and 3-(hydroxyphenyl)propanoic acid derivatives from two human interventions has been used. Different multivariate statistics, principal component analysis (PCA), cluster analysis, and partial least square-discriminant analysis (PLS-DA), have been considered.

Results

Data pre-treatment plays a major role on resulting PCA models. Cluster analysis based on k-means and a final consensus algorithm lead to quantitative-based models, while the expectation–maximization algorithm and clustering according to principal component scores yield metabotypes characterized by quali-quantitative differences in the excretion of colonic metabolites. PLS-DA, together with univariate analyses, has served to validate the urinary metabotypes in the production of flavan-3-ol metabolites and to confirm the robustness of the methodological approach.

Conclusions

This work proposes a methodological workflow for metabotype definition and highlights the importance of data pre-treatment and clustering methods on the final outcomes for a given dataset. It represents an additional step toward the understanding of the inter-individual variability in flavan-3-ol metabolism.

Trial registration

The acute study was registered at clinicaltrials.gov as NCT02517775, August 7, 2015; the chronic study was registered at clinicaltrials.gov as NCT02764749, May 6, 2016.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02692-z.

Microbial Flavonoid Metabolism: A Cardiometabolic Disease Perspective

Cardiometabolic disease (CMD) is a leading cause of death worldwide and encompasses the inflammatory metabolic disorders of obesity, type 2 diabetes mellitus, nonalcoholic fatty liver disease, and cardiovascular disease. Flavonoids are polyphenolic plant metabolites that are abundantly present in fruits and vegetables and have biologically relevant protective effects in a number of cardiometabolic disorders. Several epidemiological studies underscored a negative association between dietary flavonoid consumption and the propensity to develop CMD. Recent studies elucidated the contribution of the gut microbiota in metabolizing dietary intake as it relates to CMD. Importantly, the biological efficacy of flavonoids in humans and animal models alike is linked to the gut microbial community. Herein, we discuss the opportunities and challenges of leveraging flavonoid intake as a potential strategy to prevent and treat CMD in a gut microbe-dependent manner, with special emphasis on flavonoid-derived microbial metabolites.

Design of polyphenol-rich diets in clinical trials: A systematic review

Most randomized clinical trials of polyphenols focus on individual foods. Nevertheless, due to their presence in many foods and in order to reflect a real situation, clinical trials based on polyphenol-rich diets are particularly important. This systematic review explores the characteristics of the polyphenol-rich diets used in intervention studies. The bibliography search for English-language scientific papers was performed in the Elsevier Scopus Database and PUBMED in March 2020, and focused on intervention studies with whole polyphenol-rich diets, establishing several exclusion criteria. In studies fulfilling the requirements, information on the design of the polyphenol-rich diet and associated polyphenol intake was extracted and compared. A total of 5 studies were selected. Among them, substantial differences were found in the design of the polyphenol-rich diets, regarding specific instructions and concerning the foods provided. Similarly, although a median daily polyphenol intake of 2,564 mg/day (17,945 mg/week) was obtained from the studies, which corresponds to a nutritional dose, intake values varied widely both for total polyphenols (the difference between studies reached threefold), and for individual polyphenol intake (for hydroxycinnamic acids, a tenfold difference was found between percentile 25 and percentile 75 values). These differences made the comparison of results difficult and may affected the observed health effects. Thus, despite the relevance of studying polyphenol-rich diets as a whole, this systematic review found substantial differences between the studies performed, making direct comparisons difficult.

Variation in the Methylation of Caffeoylquinic Acids and Urinary Excretion of 3'-methoxycinnamic acid-4'-Sulfate After Apple Consumption by Volunteers

INTRODUCTION

It has been reported that the phenolic metabolite 3'-methoxycinnamic acid-4'-sulfate generated from 5-O-caffeoylquinic acid may have potential benefits in human health. However, the variation in 3'- and 4'-methylation of 3',4'-dihydroxycinnamic acid and its impact on the yield of this sulfate metabolite is unclear and has been poorly studied.

METHODS AND RESULTS

To address this aim, the excreted 3'-methoxy and 4'-methoxy metabolites in urine samples (24-h) are determined in 14 volunteers after an acute intake of 80 g of red-fleshed apple (RFA) or white-fleshed apple (WFA). These methoxy metabolites are also determined in the same volunteers in a second acute intake after a 6-week sustained consumption of the same products.

CONCLUSION

Seven 3'-methoxy and seven 4'-methoxy metabolites are determined, i.e., the free cinnamic and corresponding phenylpropanoic acid, plus their sulfate, glucuronide, and glycine conjugates. In only six volunteers, five females and one male, is 4'-methylation preferred over 3'-methylation, but it is observed that an individual's 3'- : 4'-methylation ratio can change over time, and that the yield of 3'-methoxycinnamic acid-4'-sulfate is extremely variable, ranging from undetectable to 71% of the total C6 -C3 metabolites excreted, and any benefit accruing from this metabolite will not necessarily be available to all consumers.

Overview of Beneficial Effects of (Poly)phenol Metabolites in the Context of Neurodegenerative Diseases on Model Organisms

The rise of neurodegenerative diseases in an aging population is an increasing problem of health, social and economic consequences. Epidemiological and intervention studies have demonstrated that diets rich in (poly)phenols can have potent health benefits on cognitive decline and neurodegenerative diseases. Meanwhile, the role of gut microbiota is ever more evident in modulating the catabolism of (poly)phenols to dozens of low molecular weight (poly)phenol metabolites that have been identified in plasma and urine. These metabolites can reach circulation in higher concentrations than parent (poly)phenols and persist for longer periods of time. However, studies addressing their potential brain effects are still lacking. In this review, we will discuss different model organisms that have been used to study how low molecular weight (poly)phenol metabolites affect neuronal related mechanisms gathering critical insight on their potential to tackle the major hallmarks of neurodegeneration.