Investigating the transport dynamics of anthocyanins from unprocessed fruit and processed fruit juice from sour cherry (Prunus cerasus L.) across intestinal epithelial cells

Fruit vinegar as a promising source of natural anti-inflammatory agents: an up-to-date review

OBJECTIVES

Fruit vinegar is one of the most famous fruit byproducts worldwide with several unique properties. There are two types of fruit vinegar, artisanal and industrial, for consumers to choose from. This review aims to assess for the first time the phytochemistry of fruit vinegar and its anti-inflammatory effects.

METHOD

The present work was conducted based on a literature search that selected the relevant papers from indexed databases such as Scopus, Science Direct, MDPI, PubMed, Hindawi, and Web of Science. We used numerous terms to assure a good search in different databases, including fruit vinegar, phytochemistry, bioavailability and bioaccessibility, and anti-inflammatory effect. All articles were selected based on their relevance, quality, and problematic treatment.

RESULTS

Literature data have shown that vinegar has a long medicinal history and has been widely used by different civilizations, due to its richness in bioactive molecules, vinegar plays an important role in the prevention and treatment of various inflammatory diseases, including atopic dermatitis, mastitis, asthma, arthritis, acute pancreatitis, and colitis. Fruit vinegar consumption benefit is highly dependent on its chemical composition, especially organic acids and antioxidants, which can act as nutraceuticals.

CONCLUSION

Fruit vinegar has a rich chemical composition, including organic acids that can be transformed in the digestive system into compounds that play an important role in health-promoting features such as anti-inflammatory effects throughout the control of intestinal microbiota and pro-inflammatory cytokine production.

Plant-derived polyphenolic compounds: nanodelivery through polysaccharide-based systems to improve the biological properties

Plant-derived polyphenols are naturally occurring compounds widely distributed in plants. They have received greater attention in the food and pharmaceutical industries due to their potential health benefits, reducing the risk of some chronic diseases due to their antioxidant, anti-inflammatory, anticancer, cardioprotective, and neuro-action properties. Polyphenolic compounds orally administered can be used as adjuvants in several treatments but with restricted uses due to chemical instability. The review discusses the different structural compositions of polyphenols and their influence on chemical stability. Despite the potential and wide applications, there is a need to improve the delivery of polyphenolics to target the human intestine without massive chemical modifications. Oral administration of polyphenols is unfeasible due to instability, low bioaccessibility, and limited bioavailability. Nano-delivery systems based on polysaccharides (starch, pectin, chitosan, and cellulose) have been identified as a viable option for oral ingestion, potentiate biological effects, and direct-controlled delivery in specific tissues. The time and dose can be individualized for specific diseases, such as intestinal cancer. This review will address the mechanisms by which polysaccharides-based nanostructured systems can protect against degradation and enhance intestinal permeation, oral bioavailability, and the potential application of polysaccharides as nanocarriers for the controlled and targeted delivery of polyphenolic compounds.

Valorization of polyphenolic compounds from food industry by-products for application in polysaccharide-based nanoparticles

In the last decades, evidence has indicated the beneficial properties of dietary polyphenols. In vitro and in vivo studies support that the regular intake of these compounds may be a strategy to reduce the risks of some chronic non-communicable diseases. Despite their beneficial properties, they are poorly bioavailable compounds. Thus, the main objective of this review is to explore how nanotechnology improves human health while reducing environmental impacts with the sustainable use of vegetable residues, from extraction to the development of functional foods and supplements. This extensive literature review discusses different studies based on the application of nanotechnology to stabilize polyphenolic compounds and maintain their physical-chemical stability. Food industries commonly generate a significant amount of solid waste. Exploring the bioactive compounds of solid waste has been considered a sustainable strategy in line with emerging global sustainability needs. Nanotechnology can be an efficient tool to overcome the challenge of molecular instability, especially using polysaccharides such as pectin as assembling material. Complex polysaccharides are biomaterials that can be extracted from citrus and apple peels (from the juice industries) and constitute promising wall material stabilizing chemically sensitive compounds. Pectin is an excellent biomaterial to form nanostructures, as it has low toxicity, is biocompatible, and is resistant to human enzymes. The potential extraction of polyphenols and polysaccharides from residues and their inclusion in food supplements may be a possible application to reduce environmental impacts and constitutes an approach for effectively including bioactive compounds in the human diet. Extracting polyphenolics from industrial waste and using nanotechnology may be feasible to add value to food by-products, reduce impacts on nature and preserve the properties of these compounds.

The Effect of Ferulic Acid-Grafted Chitosan (FA-g-CS) on the Transmembrane Transport of Anthocyanins by sGLT1 and GLUT2

This work aims to evaluate the effect of ferulic acid-grafted chitosan (FA-g-CS) on the interaction between anthocyanin (ANC) and sGLT1/GLUT2 and their functions in ANC transmembrane transport using Caco-2 cells. The transmembrane transport experiments of ANC showed its low transport efficiency (Papp < 10⁻⁶ cm/s), whereas the phenomenon of a significantly rise in anthocyanins transport efficiency was observed with the incubation of FA-g-CS (p < 0.05). In order to investigate the mechanism of FA-g-CS improving ANC transmembrane transport, Caco-2 cells were transfected with small interfering RNA (siRNA) specific for transporters sGLT1 and GLUT2, and incubated with ANC, FA-g-CS, or their combination. Subsequently, Western blot analyses and immunofluorescence staining were carried out to monitor the intracellular sGLT1 and GLUT2 levels. These siRNA-transfected cells, incubated with compounds, indicate that sGLT1 and GLUT2 participated in the ANC transmembrane transport and that FA-g-CS, ANC, or their combination enhance sGLT1/GLUT2 expression. In particular, Caco-2 cells incubated with both FA-g-CS and ANC show significantly increased sGLT1 or GLUT2 expression (>80%) compared with exclusively using FA-g-CS or ANC (<60%). Molecular docking results demonstrate that there is a good binding between FA-g-CS/ANC and sGLT1 or GLUT2. These results highlight that FA-g-CS promotes the transmembrane transport of ANC by influencing the interaction between ANC and sGLT1/GLUT2; the interaction between FA-g-CS and ANC could be another key factor that improves the bioavailability of ANC.

Nanoencapsulated anthocyanin as a functional ingredient: Technological application and future perspectives

Anthocyanins are an important group of phenolic compounds responsible for pigmentation in several plants, and regular consumption is associated with a reduced risk of several diseases. However, the application of anthocyanins in foods represents a challenge due to molecular instability. The encapsulation of anthocyanins in nanostructures is a viable way to protect from the factors responsible for degradation and enable the industrial application of these compounds. Nanoencapsulation is a set of techniques in which the bioactive molecules are covered by resistant biomaterials that protect them from chemical and biological factors during processing and storage. This review comprehensively summarizes the existing knowledge about the structure of anthocyanins and molecular stability, with a critical analysis of anthocyanins' nanoencapsulation, the main encapsulating materials (polysaccharides, proteins, and lipids), and techniques used in the formation of nanocarriers to protect anthocyanins. Some studies point to the effectiveness of nanostructures in maintaining anthocyanin stability and antioxidant activity. The main advantages of the application of nanoencapsulated anthocyanins in foods are the increase in the nutritional value of the food, the addition of color, the increase in food storage, and the possible increase in bioavailability after oral ingestion. Nanoencapsulation improves stability for anthocyanin, thus demonstrating the potential to be included in foods or used as dietary supplements, and current limitations, challenges, and future directions of anthocyanins' have also been discussed.

Bioavailability of Rosehip (Rosa canina L.) Infusion Phenolics Prepared by Thermal, Pulsed Electric Field and High Pressure Processing

In this study, the in vitro bioavailability of rosehip infusion phenolics, mainly catechin, as a response to conventional and non-thermal treatments by combining gastrointestinal digestion and a Caco-2 cell culture model, was investigated. After application of thermal treatment (TT, 85 °C/10 min), high pressure (HPP, 600 MPa/5 min) or pulsed electric field (PEF, 15 kJ/kg) processing, all samples were subjected to simulated gastrointestinal digestion. Then, the amount of maximum non-toxic digest ratio was determined by the cytotoxicity sulforhodamine B (SRB) assay. Next, Caco-2 cells were exposed to 1:5 (v/v) times diluted digests in order to simulate the transepithelial transportation of catechin. Results showed that non-thermally processed samples (5.19 and 4.62% for HPP and PEF, respectively) exhibited greater transportation across the epithelial cell layer compared to than that of the TT-treated sample (3.42%). The present study highlighted that HPP and PEF, as non-thermal treatments at optimized conditions for infusions or beverages, can be utilized in order to enhance the nutritional quality of the final products.

Investigating the effects of supercritical antisolvent process and food models on antioxidant capacity, bioaccessibility and transepithelial transport of quercetin and rutin

In the present study, the effects of the Supercritical Anti-Solvent (SAS) process and food models on the antioxidant capacity, bioaccessibility and transport dynamics of flavonol-loaded polyvinylpyrrolidone (PVP) based microparticles were investigated using a combined in vitro gastrointestinal digestion/Caco-2 cell culture model. SAS-processed and unprocessed flavonols were supplied in two different food models: 10% ethanol for an aqueous hydrophilic food simulant and 3% acetic acid for an acidic food simulant. The SAS processing of quercetin and rutin resulted in a much higher recovery of these bioactives as well as greater retention of antioxidant capacity after gastrointestinal digestion in both hydrophilic and acidic food models. The present study also demonstrates that SAS coprecipitation has a positive effect on the stability and transport of bioactives across the epithelial cell layer. It can be deduced from the results that the SAS process can be a useful method in pharmaceutical and nutraceutical applications with high stability, bioaccessibility, bioavailability and thus enhanced nutritional value.

Impact of Drug Metabolism/Pharmacokinetics and their Relevance Upon Traditional Medicine-based anti-COVID-19 Drug Research

BACKGROUND

The representative anti-COVID-19 herbs, i.e. Poria cocos, Pogostemon, Prunus, and Glycyrrhiza plants, are commonly used in the prevention and treatment of COVID-19, a pandemic caused by SARS-CoV-2. Diverse medicinal compounds with favorable anti-COVID-19 activities are abundant in these plants, and their unique pharmacological/pharmacokinetic properties are being revealed. However, the current trends of drug metabolism/pharmacokinetic (DMPK) investigations of anti-COVID-19 herbs have not been systematically summarized.

METHODS

Here, the latest awareness, as well as the perception gaps of DMPK attributes, in the anti-COVID-19 drug development and clinical usage was elaborated and critically commented.

RESULTS

The extracts and compounds of P. cocos, Pogostemon, Prunus, and Glycyrrhiza plants show distinct and diverse absorption, distribution, metabolism, excretion and toxicity (ADME/T) properties. The complicated herb-herb interactions (HHIs) and herb-drug interactions (HDIs) of anti-COVID-19 Traditional Chinese Medicine (TCM) herb pair/formula dramatically influence the PK/pharmacodynamic (PD) performance of compounds thereof, which may inspire researchers to design innovative herbal/compound formulas for optimizing the therapeutic outcome of COVID-19 and related epidemic diseases. The ADME/T of some abundant compounds in anti-COVID-19 plants have been elucidated, but DMPK studies should be extended to more compounds of different medicinal parts, species and formulations, and would be facilitated by various omics platforms and computational analyses.

CONCLUSION

In the framework of systems pharmacology and pharmacophylogeny, the DMPK knowledge base would promote the translation of bench findings into the clinical practice of anti-COVID-19, and speed up the anti-COVID-19 drug discovery and development.

Nanotechnology as a Tool to Mitigate the Effects of Intestinal Microbiota on Metabolization of Anthocyanins

Anthocyanins are an important group of phenolic compounds responsible for pigmentation in several plants. For humans, a regular intake is associated with a reduced risk of several diseases. However, molecular instability reduces the absorption and bioavailability of these compounds. Anthocyanins are degraded by external factors such as the presence of light, oxygen, temperature, and changes in pH ranges. In addition, the digestion process contributes to chemical degradation, mainly through the action of intestinal microbiota. The intestinal microbiota has a fundamental role in the biotransformation and metabolization of several dietary compounds, thus modifying the chemical structure, including anthocyanins. This biotransformation leads to low absorption of intact anthocyanins, and consequently, low bioavailability of these antioxidant compounds. Several studies have been conducted to seek alternatives to improve stability and protect against intestinal microbiota degradation. This comprehensive review aims to discuss the existing knowledge about the structure of anthocyanins while discussing human absorption, distribution, metabolism, and bioavailability after the oral consumption of anthocyanins. This review will highlight the use of nanotechnology systems to overcome anthocyanin biotransformation by the intestinal microbiota, pointing out the safety and effectiveness of nanostructures to maintain molecular stability.

In Vitro Study of the Bioavailability and Bioaccessibility of the Main Compounds Present in Ayahuasca Beverages

Ayahuasca is a psychoactive beverage that contains the psychoactive compound N,N-dimethyltryptamine and β-carboline alkaloids. This study aims at determining in vitro the bioavailability and bioaccessibility of the main compounds present in decoctions of four individual plants, in a commercial mixture and in four mixtures of two individual plants used in the preparation of Ayahuasca. The samples were subjected to an in vitro digestion process, and the Caco-2 cell line was used as an absorption model. The integrity and permeability of the cell monolayer were evaluated, as well as the cytotoxicity of the extracts. After digestion and cell incubation, the compounds absorbed by the cell monolayer were quantified by high-performance liquid chromatography coupled to a diode array detector. The results showed that compounds such as N,N-dimethyltryptamine, Harmine, Harmaline, Harmol, Harmalol and Tetrahydroharmine were released from the matrix during the in vitro digestion process, becoming bioaccessible. Similarly, some of these compounds, after being incubated with the cell monolayer, were absorbed, becoming bioavailable. The extracts did not show cytotoxicity after cell incubation, and the integrity and permeability of the cell monolayer were not compromised.

Bioavailability, Absorption, and Metabolism of Pelargonidin-Based Anthocyanins Using Sprague-Dawley Rats and Caco-2 Cell Monolayers

The present study is aimed to clarify the absorption and metabolism properties of pelargonidin-based anthocyanins. Results showed that pelargonidin-3-O-rutinoside (Pg3R) was absorbed in its intact form after oral administration and reached a maximum plasma concentration of 175.38 ± 55.95 nM at 60 min. Three main metabolites were identified in plasma, including Pg3R-monoglucuronide (m/z 755.2046), Pg3R-hydroxylated (m/z 595.1644), and Pg3R-demethylated (m/z 565.1569) metabolites. The plasma concentration of the Pg3R-demethylated metabolite (57.04 ± 23.15 nM) was much higher than that of other two metabolites, indicating that demethylation was the main metabolic pathway for Pg3R, while the glucuronide conjugate was detected as the dominant metabolic form of pelargonidin-3-O-glucoside (Pg3G). The bioavailability of Pg3R (1.13%) was fourfold higher than that of Pg3G (0.28%), demonstrating that anthocyanins linked to the rutinoside may exhibit higher bioavailability than that of glucoside. In vitro transport study unveiled that passive diffusion and active efflux were involved in the absorption of Pg3R and Pg3G.

Co-Ingestion of Black Carrot and Strawberry. Effects on Anthocyanin Stability, Bioaccessibility and Uptake

Although the fate of anthocyanins along digestion has been a matter of research over the last decade, their bioaccessibility so far has been mainly assessed for single administered fruits or vegetables, which is far from the real scenario where they are co-ingested in a meal. Accordingly, the aim of this study was to evaluate the effect of simultaneous intake of fruit and vegetable on in vitro stability, bioaccessibility and uptake of anthocyanins. Black carrot and strawberry were used as food sources of anthocyanins. Anthocyanin identification and quantification were performed using HPLC-Qtof/HPLC-UV. Single matrices and mixtures thereof, were submitted to a standardized in vitro digestion procedure. Anthocyanin uptake was evaluated through an intestinal Caco-2 cell model. Our results showed an increased intestinal stability for specific anthocyanins as a consequence of co-digestion. The presence of the strawberry food matrix positively affected the bioaccessibility of the carrot associated cyanidin-based anthocyanins, whereas no reciprocal effect was observed for pelargonidin-based derivatives in the presence of the black carrot food matrix. Anthocyanin transport was maintained after co-administration. Overall, co-ingestion of black carrot and strawberry did not negatively affect the stability, bioaccessibility or uptake of cyanidin-based anthocyanins, although the effect on pelargonidin-based anthocyanins depended on the type of pelargonidin derivative.

Protective Effect of Pure Sour Cherry Anthocyanin Extract on Cytokine-Induced Inflammatory Caco-2 Monolayers

Anthocyanins have several beneficial effects, especially on inflammatory and oxidative conditions. The pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), induce damage in the intestinal barrier and participate in the pathogenesis of chronic bowel diseases. A number of fruits have high anthocyanin contents with strong biological activity which can support protective actions. Sour cherry (Prunus cerassus) is one of the richest fruits in anthocyanins; especially it has high content of cyanidins. The aim of this study was to test the biological effects of a pure sour cherry anthocyanin extract under inflammatory conditions on the intestinal barrier. Caco-2 monolayers were stimulated with 50 ng/mL TNF-α and 25 ng/mL IL-1β, and the protective effects of the anthocyanin extract were examined. We demonstrated the safety of 500, 50, 5 and 0.5 µM anthocyanin extracts through cell impedance measurements. The 50 µM anthocyanin extract inhibited the cytokine-induced Caco-2 permeability and the nuclear translocation of NF-κB p65 subunits. The extract significantly reduced the release of IL-6 and IL-8 production in intestinal cells and glutathione peroxidase activity stimulated by cytokines. We demonstrated, for the first time, the beneficial effects of pure sour cherry anthocyanin extract on inflammatory Caco-2 monolayers, indicating that this substance could be protective in inflammatory bowel diseases and is an excellent raw material for further applications and formulations.

The influence of juicing on the appearance of blueberry metabolites 2 h after consumption: a metabolite profiling approach

The consumption of berries has been linked to decreased risk of degenerative disease. Berries are regularly processed into juices. It is largely unknown how the juicing process affects the bioavailability of metabolites. As metabolomics has shown to be a valuable nutritional tool to study global metabolite differences, the aim of this study was to investigate the effect of juicing on the relative appearance of blueberry metabolites in humans using metabolomics. Nine healthy subjects consumed 250 g of fresh blueberries either as the whole fruit or after juicing, and provided blood and urine samples before and 2 h after intake in a cross-over design. Samples underwent metabolite profiling using LCMS, and data were mined with multivariate analysis. Overall, <12 % of all ions detected were significantly influenced by blueberry treatment (P<0·05). Partial least-squared discriminant analysis models of post-treatment samples revealed good discrimination. In urinary samples, whole blueberry treatment resulted in 108 ions that were significantly higher compared with juiced treatment (positive and negative mode combined), whereas only eight were significantly higher after juiced treatment. Examples of putative annotations included metabolites of ferulic and caffeic acids, several phenolic metabolites conjugated to sulphate, glycoside or glucuronide and fatty acyl derivatives, which were of higher intensity after whole blueberry treatment. In conclusion, consumption of whole blueberries resulted in a higher range of phenolic and other metabolites in plasma and urine samples 2 h after consumption. Both whole and juiced blueberries resulted in very similar metabolite profiles at 2 h, although this was the only time point measured.

Tart Cherries and health: Current knowledge and need for a better understanding of the fate of phytochemicals in the human gastrointestinal tract

Tart cherries are increasingly popular due to purported health benefits. This Prunus cesarus species is cultivated worldwide, and its market has increased significantly in the last two decades due to improvements in agricultural practices and food processing technology. Tart cherries are rich in polyphenols, with a very specific profile combining anthocyanins and flavonols (berries-like) and chlorogenic acid (coffee-like). Tart cherries have been suggested to exert several potentially beneficial health effects including: lowering blood pressure, modulating blood glucose, enhancing cognitive function, protecting against oxidative stress and reducing inflammation. Studies focusing on tart cherry consumption have demonstrated particular benefits in recovery from exercise-induced muscle damage and diabetes associated parameters. However, the bioconversion of tart cherry polyphenols by resident colonic microbiota has never been considered, considerably reducing the impact of in vitro studies that have relied on fruit polyphenol extracts. In vitro and in vivo gut microbiota and metabolome studies are necessary to reinforce health claims linked to tart cherries consumption.

Study on the pharmacokinetics of deoxyschizandrin and schizandrin in combination with epigallocatechin gallate, a component of green tea, in rats

1. Green tea is commonly used worldwide due to its potential positive health benefits. We have examined the effects of epigallocatechin gallate (EGCG), the most abundant catechin in green tea, on the pharmacokinetics of deoxyschizandrin (DSD) and schizandrin (SD), which are the representative lignans in popular traditional Chinese medicines Fructus schisandrae, in rats. 2. The effects on the transport in Caco-2 cells and metabolism in human liver microsomes (HLMs) of DSD and SD by EGCG were determined to analyze their interactions thoroughly. 3. In pharmacokinetic studies, rats were divided into four groups. Each group was orally treated with DSD alone (Group 1), DSD combined with EGCG (Group 2), SD alone (Group 3) and SD combined with EGCG (Group 4). The pharmacokinetic parameters of DSD and SD in rats were determined by UPLC-MS/MS. 4. The in vivo results indicated that EGCG had no significant influence on the pharmacokinetic behaviors of DSD or SD in rats, which were in accordance with the in vitro transport and metabolism studies. However, there were marked differences between male and female rats among C_max, AUC_0-t, AUC_0-∞ of DSD and SD. This disparity suggested that gender differences might exist in the pharmacokinetic processes of DSD or SD in rats.

Fruit Antioxidants during Vinegar Processing: Changes in Content and in Vitro Bio-Accessibility

Background: Vinegars based on fruit juices could conserve part of the health-associated compounds present in the fruits. However, in general very limited knowledge exists on the consequences of vinegar-making on different antioxidant compounds from fruit. In this study vinegars derived from apple and grape are studied. Methods: A number of steps, starting from the fermentation of the fruit juices to the formation of the final vinegars, were studied from an industrial vinegar process. The effect of each of the vinegar processing steps on content of antioxidants, phenolic compounds and flavonoids was studied, by spectroscopic methods and by high-performance liquid chromatography (HPLC). Results: The major observation was that spectrophotometric methods indicate a strong loss of antioxidant phenolic compounds during the transition from fruit wine to fruit vinegar. A targeted HPLC analysis indicates that metabolites such as gallic acid are lost in later stages of the vinegar process. Conclusion: The major conclusion of this work is that major changes occur in phenolic compounds during vinegar making. An untargeted metabolite analysis should be used to reveal these changes in more detail. In addition, the effect of vinegar processing on bio-accessibility of phenolic compounds was investigated by mimicking the digestive tract in an in vitro set up. This study is meant to provide insight into the potential of vinegar as a source of health-related compounds from fruit.

Nutraceutical Improvement Increases the Protective Activity of Broccoli Sprout Juice in a Human Intestinal Cell Model of Gut Inflammation

Benefits to health from a high consumption of fruits and vegetables are well established and have been attributed to bioactive secondary metabolites present in edible plants. However, the effects of specific health-related phytochemicals within a complex food matrix are difficult to assess. In an attempt to address this problem, we have used elicitation to improve the nutraceutical content of seedlings of Brassica oleracea grown under controlled conditions. Analysis, by LC-MS, of the glucosinolate, isothiocyanate and phenolic compound content of juices obtained from sprouts indicated that elicitation induces an enrichment of several phenolics, particularly of the anthocyanin fraction. To test the biological activity of basal and enriched juices we took advantage of a recently developed in vitro model of inflamed human intestinal epithelium. Both sprouts' juices protected intestinal barrier integrity in Caco-2 cells exposed to tumor necrosis factor α under marginal zinc deprivation, with the enriched juice showing higher protection. Multivariate regression analysis indicated that the extent of rescue from stress-induced epithelial dysfunction correlated with the composition in bioactive molecules of the juices and, in particular, with a group of phenolic compounds, including several anthocyanins, quercetin-3-Glc, cryptochlorogenic, neochlorogenic and cinnamic acids.

Inhibition of Low-Grade Inflammation by Anthocyanins after Microbial Fermentation in Vitro

The anti-inflammatory effects of anthocyanins (ACNs) on vascular functions are discussed controversially because of their low bioavailability. This study was performed to determine whether microorganism (MO)-fermented ACNs influence vascular inflammation in vitro. Therefore, MO growth media were supplemented with an ACN-rich grape/berry extract and growth responses of Escherichia coli, E. faecalis and H. alvei, as well as ACN fermentation were observed. MO supernatants were used for measuring the anti-inflammatory effect of MO-fermented ACNs in an epithelial-endothelial co-culture transwell system. After basolateral enrichment (240 min), endothelial cells were stimulated immediately or after 20 h with TNF-α. Afterwards, leukocyte adhesion, expression of adhesion molecules and cytokine release were measured. Results indicate that E. coli, E. faecalis and H. alvei utilized ACNs differentially concomitant with different anti-inflammatory effects. Whereas E. coli utilized ACNs completely, no anti-inflammatory effects of fermented ACNs were observed on activated endothelial cells. In contrast, ACN metabolites generated by E. faecalis and H. alvei significantly attenuated low-grade stimulated leukocyte adhesion, the expression of adhesion molecules E-selectin, VCAM-1 and ICAM-1 and cytokine secretion (IL-8 and IL-6), as well as NF-κB mRNA expression with a more pronounced effect of E. faecalis than H. alvei. Thus, MO-fermented ACNs have the potential to reduce inflammation.

Inhibition of low-grade inflammation by anthocyanins from grape extract in an in vitro epithelial-endothelial co-culture model

BACKGROUND

Anthocyanins (ACNs) are the most prevalent flavonoids in berries and their health promoting effects on vascular functions are still discussed. The aim of the present study was to identify the anti-inflammatory effect of ACNs on activated human umbilical vein endothelial cells (HUVECs) after their transport across an epithelial monolayer.

STUDY DESIGN

We established a transwell epithelial-endothelial co-culture system with Caco-2/HT29-B6 cells mimicking the intestinal layer and HUVECs as endothelial cells mimicking the vascular layer. Caco-2 were seeded alone (100%) or together with HT29-B6 cells (10 and 20%) on transwell inserts in order to simulate different metabolization sides of the gut. ACNs as well as malvidin-3-glucoside (M3G) were applied to the luminal compartment of the transwell-system. Transport and degradation rates were determined by high performance liquid chromatography with ultraviolet detection (HPLC-UV) or by ultra-PLC coupled to mass spectrometry (UPLC-MS). After 4 hours incubation time, co-cultured HUVECs were used immediately (short-term incubation) or after 20 hours (long-term incubation). Thereafter, HUVECs were stimulated for 3 hours with 1 ng mL(-1) TNF-α to mimic a low-grade or 10 ng mL(-1) to mimic a high-grade inflammation. Afterwards, (1.) leukocyte adhesion, (2.) expression of cell adhesion molecules (ICAM-1, VCAM-1 and E-selectin) and (3.) cytokine expression and secretion (IL-6 and IL-8) were determined using flow cytometry and real-time PCR.

RESULTS

Degradation and incubation studies revealed that ACNs were differently degraded depending on the ACN structure and the seeding densities. Incubation of ACNs and M3G to Caco-2 cells (100%) led to a fast decrease, which was not observed when HT29-B6 cells were co-cultured (10 and 20%). Concomitantly, anti-inflammatory effects were only observed using 100% Caco-2 cells, whereas mixtures of Caco-2 and HT29-B6 cells failed to induce an effect. ACN extract and M3G significantly attenuated TNF-α-stimulated low-grade leukocyte adhesion, expression of adhesion molecules E-selectin, VCAM-1 and ICAM-1 and cytokine expression and secretion (IL-8 and IL-6) as well as NF-κB mRNA expression. No effects were observed with high TNF-α (10 ng mL(-1)) or after short-term incubation (4 hours).

CONCLUSIONS

ACNs in physiological concentrations reached the serosal compartment and reduced inflammation-related parameters, which were related to the initial steps during the pathogenesis of atherosclerosis.

Anthocyanin Absorption and Metabolism by Human Intestinal Caco-2 Cells--A Review

Anthocyanins from different plant sources have been shown to possess health beneficial effects against a number of chronic diseases. To obtain any influence in a specific tissue or organ, these bioactive compounds must be bioavailable, i.e., effectively absorbed from the gut into the circulation and transferred to the appropriate location within the body while still maintaining their bioactivity. One of the key factors affecting the bioavailability of anthocyanins is their transport through the gut epithelium. The Caco-2 cell line, a human intestinal epithelial cell model derived from a colon carcinoma, has been proven to be a good alternative to animal studies for predicting intestinal absorption of anthocyanins. Studies investigating anthocyanin absorption by Caco-2 cells report very low absorption of these compounds. However, the bioavailability of anthocyanins may be underestimated since the metabolites formed in the course of digestion could be responsible for the health benefits associated with anthocyanins. In this review, we critically discuss recent findings reported on the anthocyanin absorption and metabolism by human intestinal Caco-2 cells.

Uptake and bioavailability of anthocyanins and phenolic acids from grape/blueberry juice and smoothie in vitro and in vivo

The goal of eating five servings of fruits and vegetables a day has not yet been achieved. The intake of polyphenols such as anthocyanins (ACN) could be improved by consuming smoothies and juices that are increasingly popular, especially in children; however, bioavailability data concerning food matrix effects are scarce. Thus, we conducted a randomised, cross-over, bioavailability study (n 10) to determine the bioavailability of ACN and their metabolites from an ACN-rich grape/blueberry juice (841 mg ACN/litre) and smoothie (983 mg ACN/litre) in vivo, and the uptake of a corresponding grape/blueberry extract in vitro. After the intake of beverage (0·33 litres), plasma and fractionated urine samples were collected and analysed by ultra-performance liquid chromatography coupled to MS. The most abundant ACN found in plasma and urine were malvidin and peonidin as native ACN and as glucuronidated metabolites as well as 3,4-dihydroxybenzoic acid (3,4-DHB); minor ACN (delphinidin, cyanidin and petunidin) were only detected as native glycosides. Plasma pharmacokinetics and recoveries of urinary metabolites of ACN were not different for juice or smoothie intake; however, the phenolic acid 3,4-DHB was significantly better bioavailable from juice in comparison to smoothie. In vitro data with absorptive intestinal cells indicated that despite their weak chemical stability, ACN and 3,4-DHB could be detected at the basal side in their native forms. Whether smoothies as well as juices should be recommended to increase the intake of potentially health-promoting ACN and other polyphenols requires the consideration of other ingredients such as their relatively high sugar content.