Cranberry Polyphenols and Prevention against Urinary Tract Infections: New Findings Related to the Integrity and Functionality of Intestinal and Urinary Barriers

This work seeks to generate new knowledge about the mechanisms underlying the protective effects of cranberry against urinary tract infections (UTI). Using Caco-2 cells grown in Transwell inserts as an intestinal barrier model, we found that a cranberry-derived digestive fluid (containing 135 ± 5 mg of phenolic compounds/L) increased transepithelial electrical resistance with respect to control (ΔTEER = 54.5 Ω cm2) and decreased FITC-dextran paracellular transport by about 30%, which was related to the upregulation of the gene expression of tight junction (TJ) proteins (i.e., occludin, zonula occludens-1 [ZO-1], and claudin-2) (∼3-4-fold change with respect to control for claudin-2 and ∼2-3-fold for occludin and ZO-1). Similar protective effects, albeit to a lesser extent, were observed when Caco-2 cells were previously infected with uropathogenic Escherichia coli (UPEC). In a urinary barrier model comprising T24 cells grown in Transwell inserts and either noninfected or UPEC-infected, treatments with the cranberry-derived phenolic metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and phenylacetic acid (PAA) (250 μM) also promoted favorable changes in barrier integrity and permeability. In this line, incubation of noninfected T24 cells with these metabolites induced positive regulatory effects on claudin-2 and ZO-1 expression (∼3.5- and ∼2-fold change with respect to control for DOPAC and ∼1.5- and >2-fold change with respect to control for PAA, respectively). Overall, these results suggest that the protective action of cranberry polyphenols against UTI might involve molecular mechanisms related to the integrity and functionality of the urothelium and intestinal epithelium.

Simulated gastrointestinal digestion of beer using the simgi® model. Investigation of colonic phenolic metabolism and impact on human gut microbiota

Beer is a source of bioactive compounds, mainly polyphenols, which can reach the large intestine and interact with colonic microbiota. However, the effects of beer consumption in the gastrointestinal function have scarcely been studied. This paper reports, for the first time, the in vitro digestion of beer and its impact on intestinal microbiota metabolism. Three commercial beers of different styles were subjected to gastrointestinal digestion using the simgi® model, and the digested fluids were further fermented in triplicate with faecal microbiota from a healthy volunteer. The effect of digested beer on human gut microbiota was evaluated in terms of microbial metabolism (short-chain fatty acids (SCFAs) and ammonium ion), microbial diversity and bacterial populations (plate counting and 16S rRNA gene sequencing). Monitoring beer polyphenols through the different digestion phases showed their extensive metabolism, mainly at the colonic stage. In addition, a higher abundance of taxa related to gut health, especially Bacteroides, Bifidobacterium, Mitsuokella and Succinilasticum at the genus level, and the Ruminococcaceae and Prevotellaceae families were found in the presence of beers. Regarding microbial metabolism, beer feeding significantly increased microbial SCFA production (mainly butyric acid) and decreased ammonium content. Overall, these results evidence the positive actions of moderate beer consumption on the metabolic activity of colonic microbiota, suggesting that the raw materials and brewing methods used may affect the beer gut effects.

A dietary polyphenol metabolite alters CA1 excitability ex vivo and mildly affects cortico-hippocampal field potential generators in anesthetized animals

Dietary polyphenols have beneficial effects in situations of impaired cognition in acute models of neurodegeneration. The possibility that they may have a direct effect on the electrical activity of neuronal populations has not been tested. We explored the electrophysiological action of protocatechuic acid (PCA) on CA1 pyramidal cells ex vivo and network activity in anesthetized female rats using pathway-specific field potential (FP) generators obtained from laminar FPs in cortex and hippocampus. Whole-cell recordings from CA1 pyramidal cells revealed increased synaptic potentials, particularly in response to basal dendritic excitation, while the associated evoked firing was significantly reduced. This counterintuitive result was attributed to a marked increase of the rheobase and voltage threshold, indicating a decreased ability to generate spikes in response to depolarizing current. Systemic administration of PCA only slightly altered the ongoing activity of some FP generators, although it produced a striking disengagement of infraslow activities between the cortex and hippocampus on a scale of minutes. To our knowledge, this is the first report showing the direct action of a dietary polyphenol on electrical activity, performing neuromodulatory roles at both the cellular and network levels.

Grape Pomace as a Cardiometabolic Health-Promoting Ingredient: Activity in the Intestinal Environment

Grape pomace (GP) is a winemaking by-product particularly rich in (poly)phenols and dietary fiber, which are the main active compounds responsible for its health-promoting effects. These components and their metabolites generated at the intestinal level have been shown to play an important role in promoting health locally and systemically. This review focuses on the potential bioactivities of GP in the intestinal environment, which is the primary site of interaction for food components and their biological activities. These mechanisms include (i) regulation of nutrient digestion and absorption (GP has been shown to inhibit enzymes such as α-amylase and α-glucosidase, protease, and lipase, which can help to reduce blood glucose and lipid levels, and to modulate the expression of intestinal transporters, which can also help to regulate nutrient absorption); (ii) modulation of gut hormone levels and satiety (GP stimulates GLP-1, PYY, CCK, ghrelin, and GIP release, which can help to regulate appetite and satiety); (iii) reinforcement of gut morphology (including the crypt-villi structures, which can improve nutrient absorption and protect against intestinal damage); (iv) protection of intestinal barrier integrity (through tight junctions and paracellular transport); (v) modulation of inflammation and oxidative stress triggered by NF-kB and Nrf2 signaling pathways; and (vi) impact on gut microbiota composition and functionality (leading to increased production of SCFAs and decreased production of LPS). The overall effect of GP within the gut environment reinforces the intestinal function as the first line of defense against multiple disorders, including those impacting cardiometabolic health. Future research on GP's health-promoting properties should consider connections between the gut and other organs, including the gut-heart axis, gut-brain axis, gut-skin axis, and oral-gut axis. Further exploration of these connections, including more human studies, will solidify GP's role as a cardiometabolic health-promoting ingredient and contribute to the prevention and management of cardiovascular diseases.

Gut Microbiota, an Additional Hallmark of Human Aging and Neurodegeneration

Gut microbiota represents a diverse and dynamic population of microorganisms harbouring the gastrointestinal tract, which influences host health and disease. Bacterial colonization of the gastrointestinal tract begins at birth and changes throughout life, with age being one of the conditioning factors for its vitality. Aging is also a primary risk factor for most neurodegenerative diseases. Among them, Alzheimeŕs disease (AD) is probably the one where its association with a state of dysbiosis of the gut microbiota has been most studied. In particular, intestinal microbial-derived metabolites have been associated with β-amyloid formation and brain amyloid deposition, tau phosphorylation, as well as neuroinflammation in AD patients. Moreover, it has been suggested that some oral bacteria increase the risk of developing AD. However, the causal connections among microbiome, amyloid-tau interaction, and neurodegeneration need to be addressed. This paper summarizes the emerging evidence in the literature regarding the link between the oral and gut microbiome and neurodegeneration with a focus on AD. Taxonomic features of bacteria as well as microbial functional alterations associated with AD biomarkers are the main points reviewed. Data from clinical studies as well as the link between microbiome and clinical determinants of AD are particularly emphasized. Further, relationships between gut microbiota and age-dependent epigenetic changes and other neurological disorders are also described. Together, all this evidence suggests that, in some sense, gut microbiota can be seen as an additional hallmark of human aging and neurodegeneration.

Deciphering the interactions between lipids and red wine polyphenols through the gastrointestinal tract

This paper investigates the mutual interactions between lipids and red wine polyphenols at different stages of the gastrointestinal tract by using the simgi® dynamic simulator. Three food models were tested: a Wine model, a Lipid model (olive oil + cholesterol) and a Wine + Lipid model (red wine + olive oil + cholesterol). With regard to wine polyphenols, results showed that co-digestion with lipids slightly affected the phenolic profile after gastrointestinal digestion. In relation to lipid bioaccessibility, the co-digestion with red wine tended to increase the percentage of bioaccessible monoglycerides, although significant differences were not found (p > 0.05). Furthermore, co-digestion with red wine tended to reduce cholesterol bioaccessibility (from 80 to 49 %), which could be related to the decrease in bile salt content observed in the micellar phase. For free fatty acids, almost no changes were observed. At the colonic level, the co-digestion of red wine and lipids conditioned the composition and metabolism of colonic microbiota. For instance, the growth [log (ufc/mL)] of lactic acid bacteria (6.9 ± 0.2) and bifidobacteria (6.8 ± 0.1) populations were significantly higher for the Wine + Lipid food model respect to the control colonic fermentation (5.2 ± 0.1 and 5.3 ± 0.2, respectively). Besides, the production of total SCFAs was greater for the Wine + Lipid food model. Also, the cytotoxicity of the colonic-digested samples towards human colon adenocarcinoma cells (HCT-116 and HT-29) was found to be significantly lower for the Wine and Wine + Lipid models than for the Lipid model and the control (no food addition). Overall, the results obtained using the simgi® model were consistent with those reported in vivo in the literature. In particular, they suggest that red wine may favourably modulate lipid bioaccessibility - a fact that could explain the hypocholesterolemic effects of red wine and red wine polyphenols observed in humans.

Polyphenols and Ulcerative Colitis: An Exploratory Study of the Effects of Red Wine Consumption on Gut and Oral Microbiome in Active-Phase Patients

SCOPE

This paper explores the effects of moderate red wine consumption on the clinical status and symptomatology of patients with ulcerative colitis (UC), including the study of the oral and intestinal microbiome.

METHODS AND RESULTS

A case control intervention study in UC patients is designed. Intervention patients (n = 5) consume red wine (250 mL day^-1 ) for 4 weeks whereas control patients (n = 5) do not. Moderate wine consumption significantly (p < 0.05) improves some clinical parameters related to serum iron, and alleviates intestinal symptoms as evaluated by the IBDQ-32 questionnaire. 16S rRNA gene sequencing indicate a non-significant (p > 0.05) increase in bacterial alpha diversity after wine intervention in both saliva and fecal microbiota. Additional comparison of taxonomic data between UC patients (n = 10) and healthy subjects (n = 8) confirm intestinal dysbiosis for the UC patients. Finally, analysis of fecal metabolites (i.e., phenolic acids and SCFAs) indicates a non-significant increase (p > 0.05) for the UC patients that consumed wine.

CONCLUSIONS

Moderate and regular red wine intake seems to improve the clinical status and symptoms of UC patients in the active phase of the disease. However, studies with a greater sample size are required to achieve conclusive results.

Artificial intelligence to estimate wine volume from single-view images

In this paper, we present a method to determine the volume of wine in different types of glass liquid containers from a single-view image. The proposed model predicts red wine volume from a photograph of the glass containing the wine. Experimental results demonstrated satisfactory performance of our image-based wine measurement system, with a Mean Absolute Error lower than 10mL. To train and evaluate our system, we introduced the WineGut_BrainUp dataset, a new dataset of glasses of wine that contains 24305 laboratory images, including a wide range of containers, volumes of wine, backgrounds, object distances, angles and lightning, with or without calibration object. The proposed methodology is a suitable analytical tool for automate measurement of red wine volume. Indeed, it has potential real life applications in diet monitoring and wine consumption studies.

Ulcerative Colitis Seems to Imply Oral Microbiome Dysbiosis

Ulcerative colitis (UC) is a recurrent pathology of complex etiology that has been occasionally associated with oral lesions, but the overall composition of the oral microbiome in UC patients and its role in the pathogenesis of the disease are still poorly understood. In this study, the oral microbiome of UC patients and healthy individuals was compared to ascertain the possible changes in the oral microbial communities associated with UC. For this, the salivary microbiota of 10 patients diagnosed with an active phase of UC and 11 healthy controls was analyzed by 16S rRNA gene sequencing (trial ref. ISRCTN39987). Metataxonomic analysis revealed a decrease in the alpha diversity and an imbalance in the relative proportions of some key members of the oral core microbiome in UC patients. Additionally, Staphylococcus members and four differential species or phylotypes were only present in UC patients, not being detected in healthy subjects. This study provides a global snapshot of the existence of oral dysbiosis associated with UC, and the possible presence of potential oral biomarkers.

Hypertension- and glycaemia-lowering effects of a grape-pomace-derived seasoning in high-cardiovascular risk and healthy subjects. Interplay with the gut microbiome

Purpose: Grape pomace (GP) is a winery by-product rich in polyphenols and dietary fibre. Some recent results suggest that GP-derived extracts could be promising additives in food, specially recommended for low-salt diets. The hypothesis tested in this paper is that the regular consumption of GP-derived seasonings could help in the control of hypertension and glycaemia. Methods: A randomized intervention study (6 weeks) was performed in high-risk cardiovascular subjects (n = 17) and in healthy subjects (n = 12) that were randomly allocated into intervention (2 g day^-1 of GP seasoning) or control (no seasoning consumed) groups. Blood samples, faeces, urine and blood pressure (BP) were taken at the baseline and at the end of the intervention. Faecal samples were analysed for microbiota composition (16S rRNA gene sequencing) and microbial-derived metabolites (short chain fatty acids and phenolic metabolites). Results: Among the clinical parameters studied, BP and fasting blood glucose significantly decreased (p < 0.05) after the seasoning intervention, but not for the control group. Notably, application of a novel approach based on ASV (Amplicon Sequence Variant) co-occurrence networks allowed us to identify some bacterial communities whose relative abundances were related with metadata. Conclusion: Our primary findings suggest that GP-seasoning may help in the modulation of cardiometabolic risk factors, mainly in the early stages. Furthermore, it evidences modulation of gut microbiota and functional bacterial communities by grape pomace, which might mediate the cardiometabolic effects of this by-product.

Gastrointestinal Digestion of a Grape Pomace Extract: Impact on Intestinal Barrier Permeability and Interaction with Gut Microbiome

Grape pomace (GP) is a winemaking by-product rich in polyphenols and fibre. Supplementation with GP extracts has shown potential benefits against oxidative stress- and inflammation-related pathologies. As a new nutritional target, this paper explores the impact of the ingestion of a grape pomace extract on intestinal barrier functionality. A GP extract was sequentially subjected to gastrointestinal and colonic digestion using the dynamic gastrointestinal simulator (simgi^®). This generated two simulated fluids: intestinal-digested extract (IDE) and colonic-digested extract (CDE). The effects of these two fluids on paracellular permeability and the expression of tight junction (TJ) proteins (i.e., zonula occludens-1 (ZO-1) and occludin) were assessed in Caco-2-cell monolayers grown in Transwell^® inserts. The IDE fluid significantly (p < 0.001) reduced the paracellular transport of FITC-dextran with respect to the control, whereas no significant differences (p > 0.05) were found for CDE, which could be due, at least partially, to the pro-leaky effect of the colonic digestion medium. Accordant slight increases in the mRNA levels of both ZO-1 and occludin were observed for IDE, but without statistical significance. Additionally, the colonic fermentation of the GP extract promoted the production of short-chain fatty acids (SCFA) and phenolic metabolites and led to changes in the relative abundance of some bacteria that might affect paracellular permeability. Overall, this paper reports first trends about the effects of grape pomace extracts on intestinal permeability that would require further confirmation in future experiments.

Effects of Wine and Its Microbial-Derived Metabolites on Intestinal Permeability Using Simulated Gastrointestinal Digestion/Colonic Fermentation and Caco-2 Intestinal Cell Models

This paper explores the effects of wine polyphenols on intestinal permeability in in vitro conditions. A red wine (2500 mg/L of gallic acid equivalents) was sequentially subjected to gastrointestinal and colonic digestion in the Dynamic Gastrointestinal Simulator (simgi^®) to obtain two simulated fluids: intestinal-digested wine (IDW) and colonic-digested wine (CDW). The two fluids were incubated with Caco-2 cell monolayers grown in Transwell^® inserts, and paracellular permeability was measured as transport of FITC-dextran. Non-significant decreases (p > 0.05) in paracellular permeability were found, which was attributed to the relatively low phenolic concentration in the solutions tested (15.6 and 7.8 mg of gallic acid equivalents/L for IDW and CDW, respectively) as quercetin (200 µM) and one of its microbial-derived phenolic metabolites, 3,4-dihydroxyphenylacetic acid (200 µM), led to significant decreases (p < 0.05). The expression of tight junction (TJ) proteins (i.e., ZO-1 and occludin) in Caco-2 cells after incubation with IDW and CDW was also determined. A slight increase in mRNA levels for occludin for both IDW and CDW fluids, albeit without statistical significance (p > 0.05), was observed. Analysis of the microbiome and microbial activity during wine colonic fermentation revealed relevant changes in the relative abundance of some families/genera (i.e., reduction in Bacteroides and an increase in Veillonella, Escherichia/Shigella and Akkermansia) as well as in the microbial production of SCFA (i.e., a significant increase in propionic acid in the presence of IDW), all of which might affect paracellular permeability. Both direct and indirect (microbiota-mediated) mechanisms might be involved in the protective effects of (wine) polyphenols on intestinal barrier integrity. Overall, this paper reinforces (wine) polyphenols as a promising dietary strategy to improve gut functionality, although further studies are needed to evaluate the effect on the intestinal barrier under different conditions.

A multi-omics approach for understanding the effects of moderate wine consumption on human intestinal health

The human gut is a highly diverse microbial ecosystem. Although showing a well-defined core of dominant taxa, an interindividual variability exists in microbiome arrangement patterns, and the presence and proportion of specific species, determining individual metabolic features-metabotypes-which govern the health effects of dietary interventions (i.e. polyphenol consumption). Starting with a 19-volunteer human intervention study, divided into low, medium, and high wine-polyphenol-metabolizers, we detected interindividual discrepancies on the effect of wine consumption in gut bacterial alpha-diversity, but a significant homogenization of beta-diversity among moderate wine consumers, independently of their metabotype. In addition, the abundance of key health-related taxa such as Akkermansia sp. increased after moderate wine intake in the group of high polyphenol-metabolizers. Regarding the metabolic activity, significant (p < 0.05) positive correlations in the production of SCFAs were observed after wine intake. Finally, we were able to correlate the microbiome and the metabolome of the three metabotypes, and to identify some metabolites-biomarker species, highlighting the genera Phascolarctobacterium, Pelotomaculum and Prevotella, as positively correlated with polyphenol concentration, and Prevotella, Zymophilus and Eubacterium as positively correlated with SCFAs concentration in faeces. Our results contribute to the evidence of the need of including the microbiome variable in personalized nutrition programs, as different metabotyes respond differently to dietary interventions.

Revalorization of Coffee Husk: Modeling and Optimizing the Green Sustainable Extraction of Phenolic Compounds

This study aimed to model and optimize a green sustainable extraction method of phenolic compounds from the coffee husk. Response surface methodology (RSM) and artificial neural networks (ANNs) were used to model the impact of extraction variables (temperature, time, acidity, and solid-to-liquid ratio) on the recovery of phenolic compounds. All responses were fitted to the RSM and ANN model, which revealed high estimation capabilities. The main factors affecting phenolic extraction were temperature, followed by solid-to-liquid ratio, and acidity. The optimal extraction conditions were 100 °C, 90 min, 0% citric acid, and 0.02 g coffee husk mL^-1. Under these conditions, experimental values for total phenolic compounds, flavonoids, flavanols, proanthocyanidins, phenolic acids, o-diphenols, and in vitro antioxidant capacity matched with predicted ones, therefore, validating the model. The presence of chlorogenic, protocatechuic, caffeic, and gallic acids and kaemferol-3-O-galactoside was confirmed by UPLC-ESI-MS/MS. The phenolic aqueous extracts from the coffee husk could be used as sustainable food ingredients and nutraceutical products.

Relationship between Wine Consumption, Diet and Microbiome Modulation in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder leading to the most common form of dementia in elderly people. Modifiable dietary and lifestyle factors could either accelerate or ameliorate the aging process and the risk of developing AD and other age-related morbidities. Emerging evidence also reports a potential link between oral and gut microbiota alterations and AD. Dietary polyphenols, in particular wine polyphenols, are a major diver of oral and gut microbiota composition and function. Consequently, wine polyphenols health effects, mediated as a function of the individual's oral and gut microbiome are considered one of the recent greatest challenges in the field of neurodegenerative diseases as a promising strategy to prevent or slow down AD progression. This review highlights current knowledge on the link of oral and intestinal microbiome and the interaction between wine polyphenols and microbiota in the context of AD. Furthermore, the extent to which mechanisms bacteria and polyphenols and its microbial metabolites exert their action on communication pathways between the brain and the microbiota, as well as the impact of the molecular mediators to these interactions on AD patients, are described.

Glutathione-Stabilized Silver Nanoparticles: Antibacterial Activity against Periodontal Bacteria, and Cytotoxicity and Inflammatory Response in Oral Cells

Silver nanoparticles (AgNPs) have been proposed as new alternatives to limit bacterial dental plaque because of their antimicrobial activity. Novel glutathione-stabilized silver nanoparticles (GSH-AgNPs) have proven powerful antibacterial properties in food manufacturing processes. Therefore, this study aimed to evaluate the potentiality of GSH-AgNPs for the prevention/treatment of oral infectious diseases. First, the antimicrobial activity of GSH-AgNPs against three oral pathogens (Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mutans) was evaluated. Results demonstrated the efficiency of GSH-AgNPs in inhibiting the growth of all bacteria, especially S. mutans (IC50 = 23.64 μg/mL, Ag concentration). Second, GSH-AgNPs were assayed for their cytotoxicity (i.e., cell viability) toward a human gingival fibroblast cell line (HGF-1), as an oral epithelial model. Results indicated no toxic effects of GSH-AgNPs at low concentrations (≤6.16 µg/mL, Ag concentration). Higher concentrations resulted in losing cell viability, which followed the Ag accumulation in cells. Finally, the inflammatory response in the HGF-1 cells after their exposure to GSH-AgNPs was measured as the production of immune markers (interleukins 6 and 8 (IL-6 and IL-8) and tumor necrosis factor-alpha (TNF-α)). GSH-AgNPs activates the inflammatory response in human gingival fibroblasts, increasing the production of cytokines. These findings provide new insights for the use of GSH-AgNPs in dental care and encourage further studies for their application.

Moderate Wine Consumption Reduces Faecal Water Cytotoxicity in Healthy Volunteers

There are some studies that suggest that moderate consumption of wine, as part of a healthy and balanced diet, has a favourable effect on intestinal health. This study evaluates the effect of moderate wine consumption on faecal water (FW) cytotoxicity as a parameter of gut health. To that end, faecal samples before and after a red wine intervention study (250 mL of wine/day, 4 weeks) in healthy volunteers (n = 8) and in a parallel control group (n = 3) were collected and assayed for in vitro FW cytotoxicity. Two reference compounds, phenol and p-cresol, were used for assessing the cytotoxicity assays using two colon epithelial cell lines (HT-29 and HCT 116) and different assay conditions (FW dilution and incubation time). For the two cell lines and all assay conditions, the means of percentage cell viability were higher (lower cytotoxicity) for samples collected after the red wine intervention than for those collected before, although significant (p < 0.05) differences were only found in certain assay conditions for both cell lines. Significant positive correlations between the percentage cell viability and the contents of some faecal metabolites (short-chain fatty acids (SCFA) and phenolic acids (PA)) were found for the more resistant cell line (HCT 116), suggesting that the reduction in FW cytotoxicity observed after moderate red wine consumption was related to the production of microbial-derived metabolites such as SCFA and PA, whose faecal contents have been shown to increase after wine consumption. FW cytotoxicity can be deemed as a holistic biomarker that involves diet, gut microbiota and host.

Current and future experimental approaches in the study of grape and wine polyphenols interacting gut microbiota

Interactions between polyphenols and gut microbiota are indeed a major issue of current interest in food science research. Knowledge in this subject is progressing as the experimental procedures and analysis techniques do. The aim of this article is to critically review the more leading-edge approaches that have been applied so far in the study of the interactions between grape/wine polyphenols and gut microbiota. This is the case of in vitro dynamic gastrointestinal simulation models that try to mitigate the limitations of simple static models (batch culture fermentations). More complex approaches include the experimentation with animals (mice, rats, pigs, lambs and chicks) and nutritional intervention studies in humans. Main advantages and limitations as well as the most relevant findings achieved by each approach in the study of how grape/wine polyphenols can modulate the composition and/or functionality of gut microbiota, are detailed. Also, common findings obtained by the three approaches (in vitro, animal models and human nutritional interventions) such as the fact that the Firmicutes/Bacteroidetes ratio tends to decrease after the feed/intake/consumption of grape/wine polyphenols are highlighted. Additionally, a nematode (Caenorhabditis elegans) model, previously used for investigating the mechanisms of processes such as aging, neurodegeneration, oxidative stress and inflammation, is presented as an emerging approach for the study of polyphenols interacting gut microbiota. © 2020 Society of Chemical Industry.

Cranberry Polyphenols and Prevention against Urinary Tract Infections: Relevant Considerations

Cranberry (Vaccinium macrocarpon) is a distinctive source of polyphenols as flavonoids and phenolic acids that has been described to display beneficial effects against urinary tract infections (UTIs), the second most common type of infections worldwide. UTIs can lead to significant morbidity, especially in healthy females due to high rates of recurrence and antibiotic resistance. Strategies and therapeutic alternatives to antibiotics for prophylaxis and treatment against UTIs are continuously being sought after. Different to cranberry, which have been widely recommended in traditional medicine for UTIs prophylaxis, probiotics have emerged as a new alternative to the use of antibiotics against these infections and are the subject of new research in this area. Besides uropathogenic Escherichia coli (UPEC), the most common bacteria causing uncomplicated UTIs, other etiological agents, such as Klebsiellapneumoniae or Gram-positive bacteria of Enterococcus and Staphylococcus genera, seem to be more widespread than previously appreciated. Considerable current effort is also devoted to the still-unraveled mechanisms that are behind the UTI-protective effects of cranberry, probiotics and their new combined formulations. All these current topics in the understanding of the protective effects of cranberry against UTIs are reviewed in this paper. Further progresses expected in the coming years in these fields are also discussed.

Interplay between Dietary Polyphenols and Oral and Gut Microbiota in the Development of Colorectal Cancer

Colorectal cancer (CRC) is the third most diagnosed type of cancer worldwide. Dietary features play an important role in its development, and the involvement of human microbial communities in this pathology has also recently been recognized. Individuals with CRC display alterations in gut bacterial composition and a notably higher abundance of putative oral bacteria in colonic tumors. Many experimental studies and preclinical evidence propose that dietary polyphenols have a relevant role in CRC development and progression, mainly attributed to their immunomodulatory activities. Furthermore, polyphenols can modulate oral and gut microbiota, and in turn, intestinal microbes catabolize polyphenols to release metabolites that are often more active and better absorbed than the original phenolic compounds. The current study aimed to review and summarize current knowledge on the role of microbiota and the interactions between dietary polyphenols and microbiota in relation to CRC development. We have highlighted the mechanisms by which dietary polyphenols and/or their microbial metabolites exert their action on the pathogenesis and prevention of CRC as modulators of the composition and/or activity of oral and intestinal microbiota, including novel screening biomarkers and possible nutritional therapeutic implications.

Silver Nanoparticles against Foodborne Bacteria. Effects at Intestinal Level and Health Limitations

Foodborne diseases are one of the factors that endanger the health of consumers, especially in people at risk of exclusion and in developing countries. The continuing search for effective antimicrobials to be used in the food industry has resulted in the emergence of nanotechnology in this area. Silver nanoparticles (Ag-NPs) are the nanomaterial with the best antimicrobial activity and therefore, with great potential of application in food processing and packing. However, possible health effects must be properly addressed to ensure food safety. This review presents a detailed description on the main applications of Ag-NPs as antimicrobial agents for food control, as well as the current legislation concerning these materials. Current knowledge about the impact of the dietary exposure to Ag-NPs in human health with special emphasis on the changes that nanoparticles undergo after passing through the gastrointestinal tract and how they alter the oral and gut microbiota, is also summarized. It is concluded that given their potential and wide properties against foodborne pathogens, research in Ag-NPs is of great interest but is not exempt from difficulties that must be resolved in order to certify the safety of their use.

Application of the dynamic gastrointestinal simulator (simgi®) to assess the impact of probiotic supplementation in the metabolism of grape polyphenols

In this paper, the Dynamic Gastrointestinal Simulator (simgi®) is used as a model to the study the metabolic activity of probiotics at the intestinal level, and in particular, to assess the impact of probiotic supplementation in the microbial metabolism of grape polyphenols. Two independent simulations using fecal samples from two healthy volunteers were carried out. Changes in microbiota composition and in metabolic activity were assessed by qPCR and 16S rRNA gene sequencing and by analyses of phenolic metabolites and ammonium ions (NH₄⁺). The strain Lactobacillus plantarum CLC 17 was successfully implanted in the colon compartments of the simgi® after daily feeding of 2 × 10¹⁰ CFU/day for 7 days. Overall, no changes in bacterial diversity were observed after probiotic implantation. In comparison to the digestion of the grape polyphenols on their own, the inclusion of L. plantarum CLC 17 in the simgi® colon compartments led to a greater formation of phenolic metabolites such as benzoic acids, probably by the breakdown of high-molecular-weight procyanidin polymers. These results provide evidence that the probiotic strain Lactobacillus plantarum CLC 17 may improve the metabolism of dietary polyphenols when used as a food ingredient.

Impact of a sustained consumption of grape extract on digestion, gut microbial metabolism and intestinal barrier in broiler chickens

The effect of dietary supplementation with grape extract (GE) at 2.5 and 5.0 g kg-1 of feed on intestinal utilization of polyphenols and gut health of broiler chickens was determined. The ileal digestibility of grape polyphenols was higher for flavan-3-ol monomers [(+)-catechin and (-)-epicatechin] than for dimers (Procyanidins B1 and B2) and galloylated compounds [(-)-epicatechingallate] and no differences among 2.5 and 5.0 g GE per kg dietary treatments were observed. The excreta concentration of benzoic, phenylacetic, phenylpropionic, and cinnamic acids and phenyl-γ-valerolactone phenolic metabolites was higher in birds fed GE, confirming hence the microbial metabolism of grape polyphenols to a relevant extent. Gut morphology and the total ileal mucin content were not modified by the dietary inclusion of GE, but a lower sialic acid concentration was observed in those birds fed a higher concentration of GE. Escherichia coli and lactic-acid bacteria ileal counts were reduced in birds fed GE. Overall, these results prove the extensive intestinal utilization and microbial metabolism of grape polyphenols in broiler chickens. Some antimicrobial and mucin-modulation effects were also observed after a sustained consumption of grape polyphenols during 21 days.

Gastrointestinal digestion of food-use silver nanoparticles in the dynamic SIMulator of the GastroIntestinal tract (simgi®). Impact on human gut microbiota

The increasing use of silver nanoparticles (AgNPs) in consumer products has led to concern about their impact on human health. This paper aims to provide new scientific evidence about the modifications and potential effects of AgNPs with food applications during their passage through the digestive tract. For that, two types of AgNPs [solid polyethylene glycol-stabilised silver nanoparticles (PEG-AgNPs 20) and liquid glutathione-stabilised silver nanoparticles (GSH-AgNPs)] were initially subjected to gut-microbial digestion simulation in an in vitro static model. Based on these experiments, digestion of GSH-AgNPs was carried out in a dynamic model (simgi^®) that simulated the different regions of the digestive tract (stomach, small intestine and the ascending, transverse and descending colon) in physiological conditions. Dynamic transport of GSH-AgNPs in the simgi^® was similar to that observed for the inert compound Cr-EDTA, which discarded any alterations in the intestinal fluid delivery due to the AgNPs. Also, feeding the simgi^® with GSH-AgNPs seemed not to induce significant changes in the composition and metabolic activity (i.e., proteolytic activity) of the gut microbiota. Concerning monitoring of AgNps, it was observed that the GSH-AgNPs underwent several transformations in the gastrointestinal fluids and appeared to expose the intestine in ways that were structurally different from the original forms. In compliance with European guidelines, the simgi^® model can be considered a useful in vitro tool to evaluate the effects of nanoparticles at the digestive level, prior to human studies, and, therefore, minimising animal testing.

Antimicrobial activity of red wine and oenological extracts against periodontal pathogens in a validated oral biofilm model

Background

Previous research findings support an antimicrobial effect of polyphenols against a variety of pathogens, but there is no evidence of this effect against periodontal pathogens in complex biofilms. The purpose of this study was to evaluate the antimicrobial activity of red wine and oenological extracts, rich in polyphenols, against the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and total bacteria growing in an in vitro oral biofilm static model.

Methods

A previously validated biofilm model, including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, F. nucleatum, P. gingivalis and A. actinomycetemcomitans was developed on sterile hydroxyapatite discs. Red wine (and dealcoholized wine), and two polyphenols-rich extracts (from wine and grape seeds) were applied to 72 h biofilms by dipping the discs during 1 and 5 min in the wine solutions and during 30 s and 1 min in the oenological extracts. Resulting biofilms were analyzed by confocal laser scanning microscopy and viable bacteria (colony forming units/mL) were measured by quantitative polymerase chain reaction combined with propidium monoazide. A generalized linear model was constructed to determine the effect of the tested products on the viable bacterial counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, as well on the total number of viable bacteria.

Results

The results showed that red wine and dealcoholized red wine caused reduction in viability of total bacteria within the biofilm, with statistically significant reductions in the number of viable P. gingivalis after 1 min (p = 0.008) and in A. actinomycetemcomitans after 5 min of exposure (p = 0.011) with red wine. No evidence of relevant antibacterial effect was observed with the oenological extracts, with statistically significant reductions of F. nucleatum after 30 s of exposure to both oenological extracts (p = 0.001).

Conclusions

Although moderate, the antimicrobial impact observed in the total bacterial counts and counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, encourage further investigations on the potential use of these natural products in the prevention and treatment of periodontal diseases.

Some New Findings Regarding the Antiadhesive Activity of Cranberry Phenolic Compounds and Their Microbial-Derived Metabolites against Uropathogenic Bacteria

Findings concerning the antiadhesive activity of cranberry phenolic compounds and their microbial-derived metabolites against Gram-negative ( Escherichia coli ATCC 53503 and DSM 10791) and Gram-positive ( Enterococcus faecalis 04-1) bacteria in T24 cells are reported. A-Type procyanidins (A2 and cinnamtannin B-1) exhibited antiadhesive activity (at concentrations ≥250 μM), a feature that was not observed for B-type procyanidins (B2). The metabolites hippuric acid and α-hydroxyhippuric acid also showed effective results at concentrations ≥250 μM. With regard to conjugated metabolites, sulfation seemed to increase the antiadhesive activity of cranberry-derived metabolites as 3-(3,4-dihydroxyphenyl)propionic acid 3- O-sulfate presented active results, unlike its corresponding nonsulfated form. In contrast, methylation decreased antiadhesive activity as 3,4-dihydroxyphenylacetic acid was found to be active but not its corresponding methylated form (4-hydroxy-3-methoxyphenylacetic acid). As a whole, this work sustains the antiadhesive activity of cranberry-derived metabolites as one of the mechanisms involved in the beneficial effects of cranberries against urinary tract infections.

Could Fecal Phenylacetic and Phenylpropionic Acids Be Used as Indicators of Health Status?

Although most of the health effects attributed to polyphenols may be linked to their phenolic-derived metabolites, the role of the intestinal derived-phenolics in human health is still far from being well understood. We determined the profile of fecal phenolic-derived metabolites, microbiota, biomarkers of oxidative stress and inflammation, and daily intake of bioactive compounds in 71 elderly volunteers. Phenylacetic and phenylpropionic acids were the main phenolic metabolites present in feces. From them, phenylacetic acid was related with a more pro-oxidant and immune stimulated status, and both were negatively associated with fecal propionate, whereas phenylpropionic acid was directly related with the fecal concentration of acetate. Moreover, phenylacetic acid was negatively associated with the Bacteroides group and Clostridium cluster XIVa and positively with Lactobacillus. These results provide a rationale to explore the potential of fecal microbial phenolic-derived metabolites as possible biomarkers of health status in future studies focused on the elderly population.

An integrative salivary approach regarding palate cleansers in wine tasting

Wine sensory sessions normally involve the tasting of several samples, to remove food residues from the mouth the use of palate cleansers (PC) is needed. Until now, there is no agreement on the best PC to use during wine tasting sessions. The aim of this work is to study the relationship between the components retained in saliva after wine tasting and the remnant sensory feeling (astringency, alcohol, and acidity). For that, different common PC (water, carbonated water, and milk) were tested and saliva samples (expectorated and scraped) from nine trained panelists were collected after wine with and without PC trials. Results showed that after palate cleansing and not cleansing, astringency, alcoholic and acidity perception were influenced by time, PC and panelist. Astringency perception showed the greatest intensity in comparison to alcoholic and acidity. Milk was the only PC which reduced quantifiable polyphenols in expectorated saliva, as well as reducing astringency feelings. Although compositions of expectorated and scraped saliva correlated between them, polyphenols accumulated in the expectorated saliva significantly more. Retained polyphenols were correlated with astringency perception, but no correlation was found with salivary proteins. These findings assessed the astringency build-up effect during wine tasting due to polyphenols accumulation in saliva, remarking the importance of an adequate PC selection. All things considered, the present work confirmed the relationship between after-swallow mouthfeel perception and mouth residues instrumentally quantified. Also, milk has proven to be the most effective of the three PC. PRACTICAL APPLICATIONS: During tasting the accumulation of residues from previous wine samples tasted, could mislead the judgment of wine sensory qualities by oenologists. Therefore, between tasting samples it is highly important to choose the right PC. However, until now the selection of PC remains empirical, therefore in this work, we proposed to study the residues in saliva by using different PC and quantifying instrumentally, the wine residues. The methodology selected to quantify the wines residues in saliva was quick and easy to use. Furthermore, instrumental results were related with the sensory feeling of mouth cleanliness without considering individual panel member's preferences of PC. In this study, to remove astringency feeling, milk was shown to be the best cleanser in comparison with water, carbonated water or nothing, but oenologist/winemakers could use this instrumental methodology in saliva to select which one is the best among their current PC used.