Dietary phenolic compounds are often transformed before absorption. This transformation modulates their biological activity. Different studies have been carried out to understand gut microbiota ...transformations of particular polyphenol types and identify the responsible microorganisms. Although there are potentially thousands of different phenolic compounds in the diet, they are typically transformed to a much smaller number of metabolites. The aim of this review was to discuss the current information about the microbial degradation metabolites obtained from different phenolics and their formation pathways, identifying their differences and similarities. The modulation of gut microbial population by phenolics was also reviewed in order to understand the two-way phenolic−microbiota interaction. Clostridium and Eubacterium genera, which are phylogenetically associated, are other common elements involved in the metabolism of many phenolics. The health benefits from phenolic consumption should be attributed to their bioactive metabolites and also to the modulation of the intestinal bacterial population.
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(Poly)phenols (PPs) constitute a large family of phytochemicals with high chemical diversity that are known to be active principles of plant-derived nutraceuticals and herbal ...medicinal products. Their pharmacological activity, however, is difficult to demonstrate due to their mild physiological effects, and to the large inter-individual variability observed. Many PPs have little bioavailability and reach the colon almost unaltered. There they encounter the gut microbes resulting in a two-way interaction in which PPs modulate the gut microbiota composition, and the intestinal microbes catabolize the ingested PPs to release metabolites that are often more active and better absorbed than the native phenolic compounds. The type and quantity of the PP metabolites produced in humans depend on the gut microbiota composition and function, and different metabotypes have been identified. However, not all the metabolites have the same biological activity, and therefore the final health effects of dietary PPs depend on the gut microbiota composition. Stratification in clinical trials according to individuals’ metabotypes is necessary to fully understand the health effects of PPs. In this review, we present and discuss the most significant and updated knowledge regarding the reciprocal interrelation of the gut microbiota with dietary PPs as a key factor that modulates the health effects of these compounds. The review will focus in those PPs that are known to be metabolized by gut microbiota resulting in bioactive metabolites.
Scope
The cardioprotective role of resveratrol as part of the human diet is not yet clear. Our aim was to investigate the effect of a grape supplement containing 8 mg resveratrol in oxidized LDL ...(LDLox), apolipoprotein‐B (ApoB), and serum lipids on statin‐treated patients in primary cardiovascular disease prevention (PCP).
Methods and results
A triple‐blind, randomized, placebo‐controlled trial was conducted. Seventy‐five patients (three parallel arms) consumed one capsule (350 mg) daily for 6 months containing resveratrol‐enriched grape extract (GE‐RES, Stilvid®), grape extract (GE, similar polyphenolic content but no resveratrol), or placebo (maltodextrin). After 6 months, no changes were observed in the placebo group and only LDL cholesterol (LDLc) decreased by 2.9% (p = 0.013) in the GE group. In contrast, LDLc (−4.5%, p = 0.04), ApoB (−9.8%, p = 0.014), LDLox (−20%, p = 0.001), and LDLox/ApoB (−12.5%, p = 0.000) decreased in the Stilvid® group, whereas the ratio non‐HDLc (total atherogenic cholesterol load)/ApoB increased (8.5%, p = 0.046). No changes were observed in hepatic, thyroid, and renal function. No adverse effects were observed in any of the patients.
Conclusion
This GE‐RES reduced atherogenic markers and might exert additional cardioprotection beyond the gold‐standard medication in patients from PCP. The presence of resveratrol in the GE was necessary to achieve these effects.
Urolithins are dibenzob,dpyran‐6‐one derivatives that are produced by the human gut microbiota from ellagitannins and ellagic acid (EA). These metabolites are much better absorbed than their ...precursors and have been suggested to be responsible for the health effects attributed to ellagitannins and EA that occur in food products as berries and nuts. In the present review, the role and potential of urolithins in human health are critically reviewed, and a perspective of the research approach needed to demonstrate these health effects is presented, based on the existing knowledge. The analytical methods available for urolithin analysis, their occurrence in different tissues and biological fluids, and their metabolism by human gut microbiota are considered. In addition, the interindividual variability observed for the production of urolithins (metabotypes) and its relationship with health status and dysbiosis are also reviewed. The potential mechanisms of action of urolithins are also critically discussed, paying attention to the concentration and the type of metabolites used in the in vitro and in vivo assays and the physiological significance of the results obtained. The gut microbiota metabolism of EA to urolithins and that of daidzein to equol, their individual variations, and the effects on health are also compared.
The role of urolithins in human health after the consumption of dietary ellagitannins (ETs) is reviewed. The review shows preclinical evidence and in vitro mechanistic studies indicating that ETs can have anti‐inflammatory effects. However, no clinical studies have confirmed this effect yet. The recent finding that urolithins can reach the brain has increased the relevance of preclinical studies indicating that urolithins might have a role in protecting against neurodegenerative diseases.
Biological invasions are a major threat to biodiversity and as such understanding their impacts is a research priority. Ecological networks provide a valuable tool to explore such impacts at the ...community level, and can be particularly insightful for planning and monitoring biocontrol programmes, including the potential for their seldom evaluated indirect non-target effects. Acacia longifolia is among the worst invasive species in Portugal, and has been recently targeted for biocontrol by a highly specific gall-wasp. Here we use an ambitious replicated network approach to: (1) identify the mechanisms by which direct and indirect impacts of A. longifolia can cascade from plants to higher trophic levels, including gallers, their parasitoids and inquilines; (2) reveal the structure of the interaction networks between plants, gallers, parasitoids and inquilines before the biocontrol; and (3) explore the potential for indirect interactions among gallers, including those established with the biocontrol agent, via apparent competition. Over a 15-month period, we collected 31,737 galls from native plants and identified all emerging insects, quantifying the interactions between 219 plant-, 49 galler-, 65 parasitoid- and 87 inquiline-species—one of the largest ecological networks to date. No galls were found on any of the 16 alien plant species. Invasion by A. longifolia caused an alarming simplification of plant communities, with cascading effects to higher trophic levels, namely: a decline of overall gall biomass, and on the richness, abundance and biomass of galler insects, their parasitoids, and inquilines. Correspondingly, we detected a significant decline in the richness of interactions between plants and galls. The invasion tended to increase overall interaction evenness by promoting the local extinction of the native plants that sustained more gall species. However, highly idiosyncratic responses hindered the detection of further consistent changes in network topology. Predictions of indirect effects of the biocontrol on native gallers via apparent competition ranged from negligible to highly significant. Such scenarios are incredibly hard to predict, but even if there are risks of indirect effects it is critical to weigh them carefully against the consequences of inaction and invasive species spread.
Three phenotypes for urolithin production after ellagitannin and ellagic acid intake are consistently observed in different human intervention trials. Subjects can be stratified into three ...urolithin-producing groups. “Phenotype A” produced only urolithin A conjugates, which included between 25 and 80% of the volunteers in the different trials. “Phenotype B” produced isourolithin A and/or urolithin B in addition to urolithin A, this being the second relevant group (10–50%). “Phenotype 0” (5–25%) was that in which these urolithins were not detected. The three phenotypes were observed independently of the volunteers’ health status and demographic characteristics (age, gender, body mass index (BMI)) and of the amount or type of ellagitannin food source ingested (walnuts and other nuts, strawberries, raspberries, and other berries or pomegranates). Interestingly, a higher percentage of phenotype B was observed in those volunteers with chronic illness (metabolic syndrome or colorectal cancer) associated with gut microbial imbalance (dysbiosis). These urolithin phenotypes could show differences in the human gut microbiota and should be considered in intervention trials dealing with health benefits of ellagitannins or ellagic acid. Whether this phenotypic variation could be a biomarker related to differential health benefits or illness predisposition deserves further research.
The ellagitannin composition and the total content of ellagitannins in different types of tea were studied by high-performance liquid chromatography/ion-trap mass spectrometry. Strictinin and seven ...other isomers, tellimagrandin I, and ellagic acid were identified from tea infusions. The ellagitannin content in tea infusions was determined after acid hydrolysis and ranged from 0.15 to 4.46 mg of ellagic acid equivalent/g of tea in the infusions. The intake of ellagic acid after drinking a cup of tea brewed with 4 g of tea could range between 0.59 and 17.89 mg. These results indicate that tea can be a significant contributor to the dietary intake of ellagitannins. Urolithins, the gut microbiota metabolites produced in vivo from ellagic acid and ellagitannins, were detected in human urine after dietary tea beverage intake. Urolithin metabotypes A, B, and 0 were identified in volunteers after tea intake. These results suggest that the daily intake of ellagitannins from tea can have a role in tea health effects.
SCOPE: MicroRNAs (miRs) are proposed as colorectal cancer (CRC) biomarkers. Pomegranate ellagic acid and their microbiota metabolites urolithins exert anticancer effects in preclinical CRC models, ...and target normal and malignant colon tissues in CRC patients. Herein, we investigated whether the intake of pomegranate extract (PE) modified miRs expression in surgical colon tissues versus biopsies from CRC patients. METHODS AND RESULTS: We conducted a randomized, double‐blind, controlled trial. Thirty‐five CRC patients consumed 900 mg PE daily before surgery. Control CRC patients (no PE intake, n = 10) were included. Our results revealed: (1) significant differences for specific miRs between malignant and normal tissues modifiable by the surgical protocols; (2) opposed trends between ‐5p and ‐3p isomolecules; (3) general induction of miRs attributable to the surgery; (4) moderate modulation of various miRs following the PE intake, and (5) no association between tissue urolithins and the observed miRs changes. CONCLUSION: PE consumption appears to affect specific colon tissue miRs but surgery critically alters miRs levels hindering the discrimination of significant changes caused by dietary factors and the establishment of genuine differences between malignant and normal tissues as biomarkers. The components responsible for the PE effects and the clinical relevance of these observations deserve further research.
Polyphenols and Health: Current State and Progress Tomás-Barberán, Francisco A; Andrés-Lacueva, Cristina
Journal of agricultural and food chemistry,
09/2012, Letnik:
60, Številka:
36
Journal Article
Recenzirano
During the 5th International Conference on Polyphenols and Health that was held in Sitges (Spain) in October 2011, the latest advances in this area of active research were presented. Sessions on ...polyphenol effects on cardiovascular disease, polyphenols as ingredients of functional foods, the role of polyphenols in preventing obesity and diabetes, the interaction of polyphenols with gut microbiota, bioavailability and metabolism of polyphenols in humans, the mechanisms of action of these metabolites in different models, new methodologies for the study of the role of polyphenols in health, polyphenols and cancer, recent developments in phenolic compounds and neuroscience, and polyphenols in epidemiology and public health were organized. This highlight issue presents a selection of papers from invited speakers, oral presentations, and poster prize winners. The perspectives for this exciting area of very active research were also discussed at the meeting and are summarized in this introductory paper.
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