Cyanidin-3-O-Glucoside Modulates the In Vitro Inflammatory Crosstalk between Intestinal Epithelial and Endothelial Cells

Recent advances on cyanidin-3-O-glucoside in preventing obesity-related metabolic disorders: A comprehensive review

Anthocyanins, found in various pigmented plants as secondary metabolites, represent a class of dietary polyphenols known for their bioactive properties, demonstrating health-promoting effects against several chronic diseases. Among these, cyanidin-3-O-glucoside (C3G) is one of the most prevalent types of anthocyanins. Upon consumption, C3G undergoes phases I and II metabolism by oral epithelial cells, absorption in the gastric epithelium, and gut transformation (phase II & microbial metabolism), with limited amounts reaching the bloodstream. Obesity, characterized by excessive body fat accumulation, is a global health concern associated with heightened risks of disability, illness, and mortality. This comprehensive review delves into the biodegradation and absorption dynamics of C3G within the gastrointestinal tract. It meticulously examines the latest research findings, drawn from in vitro and in vivo models, presenting evidence underlining C3G's bioactivity. Notably, C3G has demonstrated significant efficacy in combating obesity, by regulating lipid metabolism, specifically decreasing lipid synthesis, increasing fatty acid oxidation, and reducing lipid accumulation. Additionally, C3G enhances energy homeostasis by boosting energy expenditure, promoting the activity of brown adipose tissue, and stimulating mitochondrial biogenesis. Furthermore, C3G shows potential in managing various prevalent obesity-related conditions. These include cardiovascular diseases (CVD) and hypertension through the suppression of reactive oxygen species (ROS) production, enhancement of endogenous antioxidant enzyme levels, and inhibition of the nuclear factor-kappa B (NF-κB) signaling pathway and by exercising its cardioprotective and vascular effects by decreasing pulmonary artery thickness and systolic pressure which enhances vascular relaxation and angiogenesis. Type 2 diabetes mellitus (T2DM) and insulin resistance (IR) are also managed by reducing gluconeogenesis via AMPK pathway activation, promoting autophagy, protecting pancreatic β-cells from oxidative stress and enhancing glucose-stimulated insulin secretion. Additionally, C3G improves insulin sensitivity by upregulating GLUT-1 and GLUT-4 expression and regulating the PI3K/Akt pathway. C3G exhibits anti-inflammatory properties by inhibiting the NF-κB pathway, reducing pro-inflammatory cytokines, and shifting macrophage polarization from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype. C3G demonstrates antioxidative effects by enhancing the expression of antioxidant enzymes, reducing ROS production, and activating the Nrf2/AMPK signaling pathway. Moreover, these mechanisms also contribute to attenuating inflammatory bowel disease and regulating gut microbiota by decreasing Firmicutes and increasing Bacteroidetes abundance, restoring colon length, and reducing levels of inflammatory cytokines. The therapeutic potential of C3G extends beyond metabolic disorders; it has also been found effective in managing specific cancer types and neurodegenerative disorders. The findings of this research can provide an important reference for future investigations that seek to improve human health through the use of naturally occurring bioactive compounds.

The bioavailability of polyphenols following acute consumption of pigmented barley and wheat

Polyphenols from pigmented cereal grains exert health-promoting effects but data on their bioavailability are limited. This study investigated the acute bioavailability of polyphenols from the consumption of pigmented whole grain cereal porridges, including purple barley (PB), purple wheat (PW), and blue wheat (BW), compared to a non-pigmented regular wheat (RW). A secondary objective was to assess their effects on plasma antioxidant and inflammatory status postprandially. Phenolic characterisation and antioxidant profiling were performed on extracts from the cooked cereals. Three healthy individuals consumed 200 g of a cereal in a 4-way crossover trial with a one-week washout in between meals. Blood samples were collected at fasting baseline, 30 minutes, 1 hour, 2 hours and 4 hours postprandially. Urine samples were collected at fasting baseline and the 4-hour time point. Pigmented grains exhibited significantly higher phenolic content and antioxidant capacity (p < 0.001) compared to RW. This suggests that pigmented grains may be a better source of polyphenols and potentially offer greater health benefits. However, polyphenol bioavailability following pigmented grain consumption was reduced (less than 6%), suggesting that a substantial fraction remained unabsorbed. The bioavailable phenolic compounds detected included phenolic acids (protocatechuic and caffeic acid), hippuric acid and other phenolic metabolites. Interpersonal variability and the type of grain consumed had an impact on the absorption and excretion of phenolic acids. Only PW consumption resulted in significant (p < 0.01) increases in plasma antioxidant status but no short-term impact on the inflammatory status. This study provides valuable insights into the complex dynamics of polyphenol bioavailability from pigmented cereal consumption and warrants further investigation.

Dragon's blood attenuates LPS-induced intestinal epithelial barrier dysfunction via upregulation of FAK-DOCK180-Rac1-WAVE2-Arp3 and downregulation of TLR4/NF-κB signaling pathways

Inflammation-induced intestinal epithelial barrier (IEB) dysfunction is one of the important reasons for the occurrence and development of intestinal inflammatory-related diseases, including ulcerative colitis (UC), Crohn's disease and necrotizing enterocolitis (NEC). Dragon's blood (DB) is a traditional Chinese medicine and has been clinically used to treat UC. However, the protective mechanism of DB on intestinal inflammatory-related diseases has still not been elucidated. The present study aimed to explore the protection mechanism of DB on IEB dysfunction in rat ileum and human colorectal adenocarcinoma cells (Caco-2)/human umbilical vein endothelial cells (HUVECs) coculture system induced by lipopolysaccharide (LPS). DB could ameliorate rat ileum mucosa morphological injury, reduce the accumulation of lipid-peroxidation products and increase the expression of junction proteins. DB also alleviated LPS-induced Caco-2 cells barrier integrity destruction in Caco-2/ HUVECs coculture system, leading to increased trans-endothelial electrical resistance (TEER), reduced cell permeability, and upregulation of expressions of F-actin and junction proteins. DB contributed to the assembly of actin cytoskeleton by upregulating the FAK-DOCK180-Rac1-WAVE2-Arp3 pathway and contributed to the formation of intercellular junctions by downregulating TLR4-MyD88-NF-κB pathway, thus reversing LPS-induced IEB dysfunction. These novel findings illustrated the potential protective mechanism of DB on intestinal inflammatory-related diseases and might be useful for further clinical application of DB.

An overview on the cellular mechanisms of anthocyanins in maintaining intestinal integrity and function

Structural and functional changes of the intestinal barrier, as a consequence of a number of (epi)genetic and environmental causes, have a main role in penetrations of pathogens and toxic agents, and lead to the development of inflammation-related pathological conditions, not only at the level of the GI tract but also in other extra-digestive tissues and organs. Anthocyanins (ACNs), a subclass of polyphenols belonging to the flavonoid group, are well known for their health-promoting properties and are widely distributed in the human diet. There is large evidence about the correlation between the human intake of ACN-rich products and a reduction of intestinal inflammation and dysfunction. Our review describes the more recent advances in the knowledge of cellular and molecular mechanisms through which ACNs can modulate the main mechanisms involved in intestinal dysfunction and inflammation, in particular the inhibition of the NF-κB, JNK, MAPK, STAT3, and TLR4 proinflammatory pathways, the upregulation of the Nrf2 transcription factor and the expression of tight junction proteins and mucins.

Cyanidin-3-O-Glucoside Alleviates Alcoholic Liver Injury via Modulating Gut Microbiota and Metabolites in Mice

Alcoholic liver disease (ALD) is primarily caused by long-term excessive alcohol consumption. Cyanidin-3-O-glucoside (C3G) is a widely occurring natural anthocyanin with multiple biological activities. This study aims to investigate the effects of C3G isolated from black rice on ALD and explore the potential mechanism. C57BL/6J mice (male) were fed with standard diet (CON) and Lieber-DeCarli liquid-fed (Eth) or supplemented with a 100 mg/kg/d C3G Diet (Eth-C3G), respectively. Our results showed that C3G could effectively ameliorate the pathological structure and liver function, and also inhibited the accumulation of liver lipids. C3G supplementation could partially alleviate the injury of intestinal barrier in the alcohol-induced mice. C3G supplementation could increase the abundance of Norank_f_Muribaculaceae, meanwhile, the abundances of Bacteroides, Blautia, Collinsella, Escherichia-Shigella, Enterococcus, Prevotella, [Ruminococcus]_gnavus_group, Methylobacterium-Methylorubrum, Romboutsia, Streptococcus, Bilophila, were decreased. Spearman's correlation analysis showed that 12 distinct genera were correlated with blood lipid levels. Non-targeted metabolic analyses of cecal contents showed that C3G supplementation could affect the composition of intestinal metabolites, particularly bile acids. In conclusion, C3G can attenuate alcohol-induced liver injury by modulating the gut microbiota and metabolites, suggesting its potential as a functional food ingredient against alcoholic liver disease.

The genus Actinidia Lindl. (Actinidiaceae): A comprehensive review on its ethnobotany, phytochemistry, and pharmacological properties

ETHNOPHARMACOLOGICAL RELEVANCE

Actinidia Lindl. belongs to the family Actinidiaceae. Plants of this genus are popularly known as kiwifruits and are traditionally used to treat a wide range of ailments associated with digestive disorders, rheumatism, kidney problems, cardiovascular system, cancers, dyspepsia, hemorrhoids, and diabetes among others.

AIM

This review discusses the ethnobotanical uses, phytochemical profile, and known pharmacological properties of Actinidia plants, to understand their connotations and provide the scientific basis for future studies.

MATERIALS AND METHODS

The data were obtained by surveying journal articles, books, and dissertations using various search engines such as Google Scholar, PubMed, Science Direct, Springer Link, and Web of Science. The online databases; World Flora Online, Plants of the World Online, International Plant Names Index, and Global Biodiversity Information Facility were used to confirm the distribution and validate scientific names of Actinidia plants. The isolated metabolites from these species were illustrated using ChemBio Draw ultra-version 14.0 software.

RESULTS

Ten (10) species of Actinidia genus have been reported as significant sources of traditional medicines utilized to remedy diverse illnesses. Our findings revealed that a total of 873 secondary metabolites belonging to different classes such as terpenoids, phenolic compounds, alcohols, ketones, organic acids, esters, hydrocarbons, and steroids have been isolated from different species of Actinidia. These compounds were mainly related to the exhibited antioxidant, antimicrobial, anti-inflammatory, antidiabetic, antiproliferative, anti-angiogenic, anticinoceptive, anti-tumor, and anticancer activities.

CONCLUSION

This study assessed the information related to the ethnobotanical uses, phytochemical compounds, and pharmacological properties of Actinidia species, which indicate that they possess diverse bioactive metabolites with interesting bioactivities. Actinidia plants have great potential for applications in folklore medicines and pharmaceuticals due to their wide ethnomedicinal uses and biological activities. Traditional uses of several Actinidia species are supported by scientific evidences, qualifying them as possible modern remedies for various ailments. Nonetheless, the currently available data has several gaps in understanding the herbal utilization of most Actinidia species. Thus, further research into their toxicity, mechanisms of actions of the isolated bioactive metabolites, as well as scientific connotations between the traditional medicinal uses and pharmacological properties is required to unravel their efficacy in therapeutic potential for safe clinical application.

Anthocyanins as Immunomodulatory Dietary Supplements: A Nutraceutical Perspective and Micro-/Nano-Strategies for Enhanced Bioavailability

Anthocyanins (ACNs) have attracted considerable attention for their potential to modulate the immune system. Research has revealed their antioxidant and anti-inflammatory properties, which play a crucial role in immune regulation by influencing key immune cells, such as lymphocytes, macrophages, and dendritic cells. Moreover, ACNs contribute towards maintaining a balance between proinflammatory and anti-inflammatory cytokines, thus promoting immune health. Beyond their direct effects on immune cells, ACNs significantly impact gut health and the microbiota, essential factors in immune regulation. Emerging evidence suggests that they positively influence the composition of the gut microbiome, enhancing their immunomodulatory effects. Furthermore, these compounds synergize with other bioactive substances, such as vitamins and minerals, further enhancing their potential as immune-supporting dietary supplements. However, detailed clinical studies must fully validate these findings and determine safe dosages across varied populations. Incorporating these natural compounds into functional foods or supplements could revolutionize the management of immune-related conditions. Personalized nutrition and healthcare strategies may be developed to enhance overall well-being and immune resilience by fully understanding the mechanisms underlying the actions of their components. Recent advancements in delivery methods have focused on improving the bioavailability and effectiveness of ACNs, providing promising avenues for future applications.

Effectiveness of Anthocyanin-Rich Sour Cherry Extract on Gliadin-Induced Caco-2 Barrier Damage

Several types of gluten-related disorders are known, in which the common starting point is gluten-induced zonulin release. Zonulin results in varying degrees of increased permeability in certain gluten-related disorders but is largely responsible for the development of further pathogenic processes and symptoms. Therefore, it is important to know the barrier-modulating role of individual nutritional components and to what extent the antioxidant substance supports the protection of gliadin-induced membrane damage with its radical scavenging capacity. We investigated the pH dependence of the gliadin-anthocyanin interaction using UV photometry, during which a concentration-dependent interaction was observed at pH 6.8. The barrier modulatory effect of the anthocyanin-rich sour cherry extract (AC) was analyzed on Caco-2 cell culture with pepsin-trypsin-resistant gliadin (PT-gliadin) exposure by TEER measurement, zonula occludens-1 (ZO-1), and Occludin immunohistochemistry. In addition to the TEER-reducing and TJ-rearranging effects of PT-gliadin, NF-κB activation, an increase in cytokine (TNF-α, IFN-γ, and IL-8) release, and mitochondrial ROS levels were observed. We confirmed the anti-inflammatory, stabilizing, and restoring roles of AC extract during gliadin treatment on the Caco-2 monolayer. The extract was able to significantly reduce cytokine and ROS levels despite the known interaction of the main components of the extract with PT-gliadin.

Analysis of the interferon-γ-induced secretome of intestinal endothelial cells: putative impact on epithelial barrier dysfunction in IBD

The development of inflammatory bowel diseases (IBD) involves the breakdown of two barriers: the epithelial barrier and the gut-vascular barrier (GVB). The destabilization of each barrier can promote initiation and progression of the disease. Interestingly, first evidence is available that both barriers are communicating through secreted factors that may accordingly serve as targets for therapeutic modulation of barrier functions. Interferon (IFN)-γ is among the major pathogenesis factors in IBD and can severely impair both barriers. In order to identify factors transmitting signals from the GVB to the epithelial cell barrier, we analyzed the secretome of IFN-γ-treated human intestinal endothelial cells (HIEC). To this goal, HIEC were isolated in high purity from normal colon tissues. HIEC were either untreated or stimulated with IFN-γ (10 U/mL). After 48 h, conditioned media (CM) were harvested and subjected to comparative hyper reaction monitoring mass spectrometry (HRM™ MS). In total, 1,084 human proteins were detected in the HIEC-CM. Among these, 43 proteins were present in significantly different concentrations between the CM of IFN-γ- and control-stimulated HIEC. Several of these proteins were also differentially expressed in various murine colitis models as compared to healthy animals supporting the relevance of these proteins secreted by inflammatory activated HIEC in the inter-barrier communication in IBD. The angiocrine pathogenic impact of these differentially secreted HIEC proteins on the epithelial cell barrier and their perspectives as targets to treat IBD by modulation of trans-barrier communication is discussed in detail.

Regulation of mitotic clonal expansion and thermogenic pathway are involved in the antiadipogenic effects of cyanidin-3-O-glucoside

Introduction: Obesity is a metabolic disease with an increase both in cell size (hypertrophy) and in cell number (hyperplasia) following differentiation of new adipocytes. Adipogenesis is a well-orchestrated program in which mitotic clonal expansion (MCE) occurs in the early step followed by the late terminal differentiation one. Methods: Aim of the study was to evaluate the in vitro effects of cyanidin-3-O-glucoside (C3G), an anthocyanin present in many fruits and vegetables, in the early or late phase of 3T3-L1 preadipocytes differentiation. Results: C3G exposure in the early phase of adipogenesis process induced a more marked reduction of CCAAT/enhancer-binding protein-β (C/EBPβ), peroxisome proliferator-activated receptor γ (PPAR-ɣ) and fatty acid synthase (Fasn) expression than late phase exposure and these effects were associated to a reduced MCE with cell cycle arrest at G0/G1 phase via p21 expression. Furthermore, C3G exposure during the early phase activated AMP-activated protein kinase (AMPK) pathway better than in the late phase promoting the enhancement of beige-like adipocytes. In fact, C3G induced thermogenic biomarkers uncoupling protein-1 (Ucp1) and peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (Pgc1) and these effects were more evident during early phase exposure. Conclusion: Our data demonstrate that C3G reduces the terminal adipogenic process affecting the early phase of differentiation and inducing a thermogenic program.

Exploring the Impact of Cyanidin-3-Glucoside on Inflammatory Bowel Diseases: Investigating New Mechanisms for Emerging Interventions

Cyanidin-3-O-glucoside (C3G), the most widely distributed anthocyanin (ACN) in edible fruits, has been proposed for several bioactivities, including anti-inflammatory, neuro-protective, antimicrobial, anti-viral, anti-thrombotic and epigenetic actions. However, habitual intake of ACNs and C3G may vary widely among populations, regions, and seasons, among individuals with different education and financial status. The main point of C3G absorption occurs in the small and large bowel. Therefore, it has been supposed that the treating properties of C3G might affect inflammatory bowel diseases (IBD), such as ulcerative colitis (UC) and Crohn's disease (CD). IBDs develop through complex inflammatory pathways and sometimes may be resistant to conventional treatment strategies. C3G presents antioxidative, anti-inflammatory, cytoprotective, and antimicrobial effects useful for IBD management. In particular, different studies have demonstrated that C3G inhibits NF-κB pathway activation. In addition, C3G activates the Nrf2 pathway. On the other hand, it modulates the expression of antioxidant enzymes and cytoprotective proteins, such as NAD(P)H, superoxide dismutase, heme-oxygenase (HO-1), thioredoxin, quinone reductase-oxide 1 (NQO1), catalase, glutathione S-transferase and glutathione peroxidase. Interferon I and II pathways are downregulated by C3G inhibiting interferon-mediating inflammatory cascades. Moreover, C3G reduces reactive species and pro-inflammatory cytokines, such as C reactive protein, interferon-γ, tumor necrosis factor-α, interleukin (IL)-5, IL-9, IL-10, IL-12p70, and IL-17A in UC and CD patients. Finally, C3G modulates gut microbiota by inducing an increase in beneficial gut bacteria and increasing microbial abundances, thus mitigating dysbiosis. Thus, C3G presents activities that may have potential therapeutic and protective actions against IBD. Still, in the future, clinical trials should be designed to investigate the bioavailability of C3G in IBD patients and the proper therapeutic doses through different sources, aiming to the standardization of the exact clinical outcome and efficacy of C3G.

Phytochemicals in the treatment of inflammation-associated diseases: the journey from preclinical trials to clinical practice

Advances in biomedical research have demonstrated that inflammation and its related diseases are the greatest threat to public health. Inflammatory action is the pathological response of the body towards the external stimuli such as infections, environmental factors, and autoimmune conditions to reduce tissue damage and improve patient comfort. However, when detrimental signal-transduction pathways are activated and inflammatory mediators are released over an extended period of time, the inflammatory process continues and a mild but persistent pro-inflammatory state may develop. Numerous degenerative disorders and chronic health issues including arthritis, diabetes, obesity, cancer, and cardiovascular diseases, among others, are associated with the emergence of a low-grade inflammatory state. Though, anti-inflammatory steroidal, as well as non-steroidal drugs, are extensively used against different inflammatory conditions, they show undesirable side effects upon long-term exposure, at times, leading to life-threatening consequences. Thus, drugs targeting chronic inflammation need to be developed to achieve better therapeutic management without or with a fewer side effects. Plants have been well known for their medicinal use for thousands of years due to their pharmacologically active phytochemicals belonging to diverse chemical classes with a number of these demonstrating potent anti-inflammatory activity. Some typical examples include colchicine (alkaloid), escin (triterpenoid saponin), capsaicin (methoxy phenol), bicyclol (lignan), borneol (monoterpene), and quercetin (flavonoid). These phytochemicals often act via regulating molecular mechanisms that synergize the anti-inflammatory pathways such as increased production of anti-inflammatory cytokines or interfere with the inflammatory pathways such as to reduce the production of pro-inflammatory cytokines and other modulators to improve the underlying pathological condition. This review describes the anti-inflammatory properties of a number of biologically active compounds derived from medicinal plants, and their mechanisms of pharmacological intervention to alleviate inflammation-associated diseases. The emphasis is given to information on anti-inflammatory phytochemicals that have been evaluated at the preclinical and clinical levels. Recent trends and gaps in the development of phytochemical-based anti-inflammatory drugs have also been included.

Cyanidin-3-O-glucoside protects intestinal epithelial cells from palmitate-induced lipotoxicity

CONTEXT

Increased free fatty acids (FFAs) levels, typical in obesity condition, can contribute to systemic lipotoxicity and inflammation adversely influencing Inflammatory Bowel Disease development and progression. Anthocyanins possess health promoting properties mainly associated to the induction of Nrf2-regulated cytoprotective proteins.

OBJECTIVE

Using a novel experimental model, we evaluated the in vitro intracellular mechanisms involved in FFAs modulation of intestinal epithelial lipotoxicity and the protective effects of cyanidin-3-O-glucoside (C3G) in Caco-2 cells.

RESULTS

Caco-2 exposed to palmitic acid (PA) in the serosal (basolateral) side showed a combined state of epithelial inflammation, inducing NF-κB pathway and downstream cytokines, that was reverted by C3G apical pre-treatment. In addition, PA altered intracellular redox status and induced reactive oxygen species that were reduced by C3G via the redox-sensitive Nrf2 signalling.

DISCUSSION AND CONCLUSION

Results suggest that anti-inflammatory properties of anthocyanins, mediated by Nrf2, could represent an interesting tool for intestinal inflammatory disorders.

Evaluation of the Potential Anti-Inflammatory Activity of Black Rice in the Framework of Celiac Disease

Inflammation and oxidative stress are two mechanisms involved in the pathogenesis of celiac disease (CD). Since the direct effect of gliadin on the intestinal epithelia is less studied, the aims of this study were the development of a specific cellular model based on the use of gliadin as a pro-inflammatory stimulus and the evaluation of the potential antioxidant and anti-inflammatory properties of extracts from different black rice in the framework of CD. The rice extracts were in vitro digested, characterized in terms of phenolic compounds and antioxidant capacity, and tested on Caco-2 cells to investigate their inhibitory effect on Reactive Oxygen Species, the NF-κB transcription and the CXC chemokines (sICAM-1, IL-8, and CXCL-10). In addition, the role of the extracts in modulating the activation of epithelial cells in CD was confirmed by applying the K562(S) agglutination test. The black rice extracts showed inhibitory effects on the production of the oxidative and the inflammatory mediators considered, with particular reference to lymphocyte-attracting CXCL-10 both before and after digestion. The presence of anthocyanins and their digestion metabolites may account for the observed anti-inflammatory activity after in vitro digestion. This work provided preliminary data supporting the use of black rice as a healthy food or ingredient of food supplements for celiacs.

Elderberries as a potential supplement to improve vascular function in a SARS-CoV-2 environment

Coronavirus disease 2019 (COVID-19) pandemic has been triggered by the severe acute respiratory syndrome coronavirus (SARS-CoV-2). Although recent studies demonstrate that SARS-CoV-2 possibly does not directly infect endothelial cells (EC), the endothelium may be affected as a secondary response due to the damage of neighboring cells, circulating pro-inflammatory cytokines, and/or other mechanisms. Long-term COVID-19 symptoms specifically nonrespiratory symptoms are due to the persistence of endothelial dysfunction (ED). Based on the literature, anthocyanins a major subgroup of flavonoid polyphenols found in berries, have been well researched for their vascular protective properties as well as the prevention of cardiovascular disease (CVD)-related deaths. Elderberries have been previously used as a natural remedy for treating influenza, cold, and consequently cardiovascular health due to a high content of cyanidin-3-glucoside (C3G) a major anthocyanin found in the human diet. The literature reported many studies demonstrating that EE has both antiviral and vascular protective properties that should be further investigated as a nutritional component used against the (in)direct effect of SARS-CoV-2 in vascular function. PRACTICAL APPLICATIONS: While previous work among the literature looks promising and builds a suggestion for investigating elderberry extract (EE) against COVID-19, further in vitro and in vivo research is required to fully evaluate EE mechanisms of action and its use as a supplement to aid current therapies.

Cyanidin-3-O-glucoside extracted from the Chinese bayberry (Myrica rubra Sieb. et Zucc.) alleviates antibiotic-associated diarrhea by regulating gut microbiota and down-regulating inflammatory factors in NF-κB pathway

Chinese bayberry has been used to treat diarrhea in China for more than 2,000 years, but the mechanism is not clear. Due to the extensive use of antibiotics, antibiotic-associated diarrhea (AAD) is becoming more and more common in clinic, but there is no effective drug for the treatment. The present study aimed to explore the therapeutic effect of Chinese bayberry on AAD for the first time, and explained the underlying mechanism from different aspects. The BALB/c mice model was established by intragastric administration of lincomycin (3 g/kg). Successfully modeled mice were treated with purified water, dried bayberry powder suspension (100 mg/kg), C3G suspension (40 mg/kg) and montmorillonite powder suspension (40 mg/kg), respectively. The changes of body weight, diarrhea index, diarrhea status score were recorded and calculated regularly. 16S rRNA gene sequencing, intestinal immunofluorescence and inflammatory factor detection were further performed. The treatment with dried bayberry powder suspension and C3G suspension could rapidly reduce the diarrhea score and diarrhea index, increase food intake and restore body weight gain. The gut microbiota richness and diversity were significantly increased after dried bayberry powder suspension and C3G suspension treatments, typically decreased bacterial genera Enterococcus and Clostridium senus stricto 1. In addition, intake of Chinese bayberry powder and C3G significantly decreased the level of p65 phosphorylation, and up-regulated the expression of intestinal tight junction protein claudin-1 and ZO-1. Chinese bayberry fruit had the effect of alleviating AAD, and C3G was supposed to play the predominant role. The mechanism was indicated to be related with restoring the homeostasis of gut microbiota, inhibiting the level of harmful bacteria and increasing the abundance of beneficial bacteria, down-regulating TNF-α, IL-6, and IL-12 factors to reduce inflammation, restoring intestinal tight junction proteins and reducing intestinal permeability.

Anti-Inflammatory Activity of an In Vitro Digested Anthocyanin-Rich Extract on Intestinal Epithelial Cells Exposed to TNF-α

Background: The consumption of foods rich in anthocyanins (ACN) have been associated with beneficial properties in chronic inflammatory disorders such as intestinal bowel diseases (IBD). These effects were attributed not only to a direct antioxidant mechanism but also to the modulation of cell redox-dependent signaling. However, ACN bioavailability is low for their poor stability in the digestive tract, so ACN gastrointestinal digestion should be considered. Methods: To have a more realistic knowledge of the effects of ACN, we performed an in vitro simulated gastrointestinal digestion of an ACN-rich purified and standardized bilberry and blackcurrant extract (BBE), followed by an evaluation of ACN composition modification (HPLC-DAD and pH differential method) and antioxidant activity (FRAP assay). Then, we studied the effects of BBE gastrointestinal extract on Caco-2 exposed to TNF-α. Results: The results confirmed the high instability of ACN in the mild alkaline environment of the small intestine (17% recovery index). However, the digested BBE maintained part of its bioactivity. Additionally, BBE gastrointestinal extract inhibited the TNF-α-induced NF-κB pathway in Caco-2 and activated the Nrf2 pathway. Conclusions: Although ACN stability is affected by gastrointestinal digestion, the anti-inflammatory and antioxidant activity of digested extracts were confirmed; thus, the loss of ACN can probably be counterweighed by their metabolites. Then, ACN introduced by diet or food supplements could represent an approach for IBD prevention.

Non-Celiac Gluten Sensitivity and Protective Role of Dietary Polyphenols

Pathogenetically characterized by the absence of celiac disease and wheat allergy, non-celiac gluten sensitivity (NCGS) is a clinical entity triggered by the consumption of gluten-containing foods that relieved by a gluten-free diet. Since it is very difficult to maintain a complete gluten-free diet, there is a high interest in discovering alternative strategies aimed at reducing gluten concentration or mitigating its toxic effects. Plant-based dietary models are usually rich in bioactive compounds, such as polyphenols, recognized to prevent, delay, or even reverse chronic diseases, including intestinal disorders. However, research on the role of polyphenols in mitigating the toxicity of gluten-containing foods is currently limited. We address the metabolic fate of dietary polyphenols, both as free and bound macromolecule-linked forms, with particular reference to the gastrointestinal compartment, where the concentration of polyphenols can reach high levels. We analyze the potential targets of polyphenols including the gluten peptide bioavailability, the dysfunction of the intestinal epithelial barrier, intestinal immune response, oxidative stress and inflammation, and dysbiosis. Overall, this review provides an updated overview of the effects of polyphenols as possible dietary strategies to counteract the toxic effects of gluten, potentially resulting in the improved quality of life of patients with gluten-related disorders.

Pharmacological Effects of Polyphenol Phytochemicals on the Intestinal Inflammation via Targeting TLR4/NF-κB Signaling Pathway

TLR4/NF-κB is a key inflammatory signaling transduction pathway, closely involved in cell differentiation, proliferation, apoptosis, and pro-inflammatory response. Toll like receptor 4 (TLR4), the first mammalian TLR to be characterized, is the innate immune receptor that plays a key role in inflammatory signal transductions. Nuclear factor kappa B (NF-κB), the TLR4 downstream, is the key to accounting for the expression of multiple genes involved in inflammatory responses, such as pro-inflammatory cytokines. Inflammatory bowel disease (IBD) in humans is a chronic inflammatory disease with high incidence and prevalence worldwide. Targeting the TLR4/NF-κB signaling pathway might be an effective strategy to alleviate intestinal inflammation. Polyphenol phytochemicals have shown noticeable alleviative effects by acting on the TLR4/NF-κB signaling pathway in intestinal inflammation. This review summarizes the pharmacological effects of more than 20 kinds of polyphenols on intestinal inflammation via targeting the TLR4/NF-κB signaling pathway. We expected that polyphenol phytochemicals targeting the TLR4/NF-κB signaling pathway might be an effective approach to treat IBD in future clinical research applications.

Nano-Hybrid Au@LCCs Systems Displaying Anti-Inflammatory Activity

Gold nanoparticles (Au NPs) have received great attention owing to their biocompatible nature, environmental, and widespread biomedical applications. Au NPs are known as capable to regulate inflammatory responses in several tissues and organs; interestingly, lower toxicity in conjunction with anti-inflammatory effects was reported to occur with Au NPs treatment. Several variables drive this benefit-risk balance, including Au NPs physicochemical properties such as their morphology, surface chemistry, and charge. In our research we prepared hybrid Au@LCC nanocolloids by the Pulsed Laser Ablation, which emerged as a suitable chemically clean technique to produce ligand-free or functionalized nanomaterials, with tight control on their properties (product purity, crystal structure selectivity, particle size distribution). Here, for the first time to our knowledge, we have investigated the bioproperties of Au@LCCs. When tested in vitro on intestinal epithelial cells exposed to TNF-α, Au@LCCs sample at the ratio of 2.6:1 showed a significantly reduced TNF gene expression and induced antioxidant heme oxygenase-1 gene expression better than the 1:1 dispersion. Although deeper investigations are needed, these findings indicate that the functionalization with LCCs allows a better interaction of Au NPs with targets involved in the cell redox status and inflammatory signaling.

Grape Pomace Extract Attenuates Inflammatory Response in Intestinal Epithelial and Endothelial Cells: Potential Health-Promoting Properties in Bowel Inflammation

Inflammatory bowel disease (IBD) implies the chronic inflammation of the gastrointestinal tract, combined with systemic vascular manifestations. In IBD, the incidence of cardiovascular disease appears to be related to an increase of oxidative stress and endothelial dysfunction. Grape pomace contains high levels of anti-oxidant polyphenols that are able to counteract chronic inflammatory symptoms. The aim of this study was to determine whether grape pomace polyphenolic extract (GPE) was able to mitigate the overwhelming inflammatory response in enterocyte-like cells and to improve vascular function. Intestinal epithelial Caco-2 cells, grown in monolayers or in co-culture with endothelial cells (Caco-2/HMEC-1), were treated with different concentrations of GPE (1, 5, 10 µg/mL gallic acid equivalents) for 2 h and then stimulated with lipopolysaccharide (LPS) and tumor necrosis factor (TNF)-α for 16 h. Through multiple assays, the expression of intestinal and endothelial inflammatory mediators, intracellular reactive oxygen species (ROS) levels and NF-κB activation, as well as endothelial-leukocyte adhesion, were evaluated. The results showed that GPE supplementation prevented, in a concentration-dependent manner, the intestinal expression and release of interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, and matrix metalloproteinases (MMP)-9 and MMP-2. In Caco-2 cells, GPE also suppressed the gene expression of several pro-inflammatory markers, such as IL-1β, TNF-α, macrophage colony-stimulating factor (M-CSF), C-X-C motif ligand (CXCL)-10, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and cyclooxygenase (COX)-2. The GPE anti-inflammatory effect was mediated by the inhibition of NF-κB activity and reduced intracellular ROS levels. Furthermore, transepithelial GPE suppressed the endothelial expression of IL-6, MCP-1, VCAM-1, and ICAM-1 and the subsequent adhesion of leukocytes to the endothelial cells under pro-inflammatory conditions. In conclusion, our findings suggest grape pomace as a natural source of polyphenols with multiple health-promoting properties that could contribute to the mitigation of gut chronic inflammatory diseases and improve vascular endothelial function.

In Vitro Protective Effects of a Standardized Extract From Cynara Cardunculus L. Leaves Against TNF-α-Induced Intestinal Inflammation

Inflammatory bowel disease (IBD) represents a group of progressive disorders characterized by recurrent chronic inflammation of the gut. New unconventional therapies based on plant derived compounds capable of preventing and/or reducing acute or chronic inflammation could represent a valid alternative for the treatment or prevention of IBDs. Cynara cardunculus L. leaves, considered a food-waste suitable as a rich source of bioactive polyphenols including luteolin and chlorogenic acid, has been reported for its positive effects in digestive tract. The aim of the present work was to evaluate the in vitro molecular mechanisms of beneficial effects of a standardized polyphenol-rich extract obtained from the leaves of Cynara cardunculus L (CCLE) against acute intestinal inflammation induced by TNF-α on intestinal epithelial Caco-2 cells. CCLE prevented TNF-α-induced NF-κB inflammatory pathway and the overexpression of IL-8 and COX-2. In addition, CCLE was able to improve basal intracellular antioxidant power in both TNF-α-unexposed or -exposed Caco-2 cells and this effect was associated to the activation of Nrf2 pathway, a master regulator of redox homeostasis affecting antioxidant and phase II detoxifying genes, stimulating an adaptive cellular response. In conclusion, our data clearly evidenced that, although considered a waste, Cynara cardunculus leaves may be used to obtain extracts rich in bioactive polyphenols potentially useful for prevention and treatment of inflammatory intestinal diseases.

Impact of Food-Derived Bioactive Compounds on Intestinal Immunity

The gastrointestinal system is responsible for the digestion and the absorption of nutrients. At the same time, it is essentially involved in the maintenance of immune homeostasis. The strongest antigen contact in an organism takes place in the digestive system showing the importance of a host to develop mechanisms allowing to discriminate between harmful and harmless antigens. An efficient intestinal barrier and the presence of a large and complex part of the immune system in the gut support the host to implement this task. The continuous ingestion of harmless antigens via the diet requires an efficient immune response to reliably identify them as safe. However, in some cases the immune system accidentally identifies harmless antigens as dangerous leading to various diseases such as celiac disease, inflammatory bowel diseases and allergies. It has been shown that the intestinal immune function can be affected by bioactive compounds derived from the diet. The present review provides an overview on the mucosal immune reactions in the gut and how bioactive food ingredients including secondary plant metabolites and probiotics mediate its health promoting effects with regard to the intestinal immune homeostasis.

Advances in Research on Chemical Constituents and Their Biological Activities of the Genus Actinidia

Kiwi, a fruit from plants of the genus Actinidia, is one of the famous fruits with thousand years of edible history. In the past twenty years, a great deal of research has been done on the chemical constituents of the Actinidia species. A large number of secondary metabolites including triterpenoids, flavonoids, phenols, etc. have been identified from differents parts of Actinidia plants, which exhibited significant in vitro and in vivo pharmacological activities including anticancer, anti-inflammatory, neuroprotective, anti-oxidative, anti-bacterial, and anti-diabetic activities. In order to fully understand the chemical components and biological activities of Actinidia plants, and to improve their further research, development and utilization, this review summarizes the compounds extracted from different parts of Actinidia plants since 1959 to 2020, classifies the types of constituents, reports on the pharmacological activities of relative compounds and medicinal potentials.

Responses of increasingly complex intestinal epithelium in vitro models to bacterial toll-like receptor agonists

The intestine fulfills roles in the uptake of nutrients and water regulation and acts as a gatekeeper for the intestinal microbiome. For the latter, the intestinal gut barrier system is able to respond to a broad range of bacterial antigens, generally through Toll-like receptor (TLR) signaling pathways. To test the capacity of various in vitro intestinal models, we studied IL-8 secretion, as a marker of pro-inflammatory response through the TLR pathway, in a Caco-2 monoculture, Caco-2/HT29-MTX di-culture, Caco-2/HT29-MTX/HMVEC-d tri-culture and in a HT29-p monoculture in response to exposure to various TLR agonists. Twenty-one-day-old differentiated cells in Transwells were exposed to Pam3CSK4 (TLR1/2), lipopolysaccharide (TLR4), single-stranded RNA (TLR7/8), Poly(i:C) (TLR3) and flagellin (TLR5) for 24 h. In all systems IL-8 secretion was increased in response to flagellin exposure, with HT29-p cells also responding to Poly(I:C) exposure. All other agonists did not induce an IL-8 response in the tested in vitro models, indicating that the specific TLRs are either not present or not functional in these models. This highlights the need for careful selection of in vitro models when studying intestinal immune responses and the need for improved in vitro models that better recapitulate intestinal immune responses.

Comparative Transcriptome Analysis of the Expression of Antioxidant and Immunity Genes in the Spleen of a Cyanidin 3-O-Glucoside-Treated Alzheimer's Mouse Model

Cyanidin 3-O-glucoside (C3G) is a well-known antioxidant found as a dietary anthocyanin in different fruits and vegetables. It has protective and therapeutic effects on various diseases. It can reduce neuronal death from amyloid-beta (Aβ)-induced toxicity and promote the inhibition of Aβ fibrillization. Antioxidant and immune modulation might play a critical role in the properties of C3G against Alzheimer's disease (AD) and other diseases. However, limited studies have been performed on the mechanism involved in the effect of C3G through transcriptome analysis. Thus, the objective of this study was to perform comparative transcriptome analysis of the spleen to determine gene expression profiles of wild-type mice (C57BL/6J Jms), an Alzheimer's mouse model (APPswe/PS1dE9 mice), and a C3G-treated Alzheimer's mouse model. Differentially expressed antioxidant, immune-related, and AD pathways genes were identified in the treated group. The validation of gene expression data via RT-PCR studies further supported the current findings. Six important antioxidant genes (S100a8, S100a9, Prdx2, Hp, Mpst, and Prxl2a) and a high number of immune-related genes were found to be upregulated in the treatment groups, suggesting the possible antioxidant and immunomodulatory mechanisms of C3G, respectively. Further studies are strongly recommended to elucidate the precise role of these essential genes and optimize the therapeutic function of C3G in AD and other disease conditions.

Cyanidin-3-O-glucoside and its phenolic metabolites ameliorate intestinal diseases via modulating intestinal mucosal immune system: potential mechanisms and therapeutic strategies

The incidence of the intestinal disease is globally increasing, and the intestinal mucosa immune system is an important defense line. A potential environmental cause to regulate gut health is diet. Cyanidin-3-O-glucoside is a natural plant bioactive substance that has shown rising evidence of improving intestinal disease and keeping gut homeostasis. This review summarized the intestinal protective effect of Cyanidin-3-O-glucoside in vivo and in vitro and discussed the potential mechanisms by regulating the intestinal mucosal immune system. Cyanidin-3-O-glucoside and phenolic metabolites inhibited the presence and progression of intestinal diseases and explained from the aspects of repairing the intestinal wall, inhibiting inflammatory reaction, and regulating the gut microbiota. Although the animal and clinical studies are inadequate, based on the accumulated evidence, we propose that the interaction of Cyanidin-3-O-glucoside with the intestinal mucosal immune system is at the core of most mechanisms by which affect host gut diseases. This review puts forward the potential mechanism of action and targeted treatment strategies.

Angiocrine Regulation of Epithelial Barrier Integrity in Inflammatory Bowel Disease

Inflammatory bowel disease describes chronic inflammatory disorders. The incidence of the disease is rising. A major step in disease development is the breakdown of the epithelial cell barrier. Numerous blood vessels are directly located underneath this barrier. Diseased tissues are heavily vascularized and blood vessels significantly contribute to disease progression. The gut-vascular barrier (GVB) is an additional barrier controlling the entry of substances into the portal circulation and to the liver after passing the first epithelial barrier. The presence of the GVB rises the question, whether the vascular and endothelial barriers may communicate bi-directionally in the regulation of selective barrier permeability. Communication from epithelial to endothelial cells is well-accepted. In contrast, little is known on the respective backwards communication. Only recently, perfusion-independent angiocrine functions of endothelial cells were recognized in a way that endothelial cells release specific soluble factors that may directly act on the epithelial barrier. This review discusses the putative involvement of angiocrine inter-barrier communication in the pathogenesis of IBD.

Bioaccessibility and Bioactivity of Cereal Polyphenols: A Review

Cereal bioactive compounds, especially polyphenols, are known to possess a wide range of disease preventive properties that are attributed to their antioxidant and anti-inflammatory activity. However, due to their low plasma concentrations after oral intake, there is controversy regarding their therapeutic benefits in vivo. Within the gastrointestinal tract, some cereal polyphenols are absorbed in the small intestine, with the majority accumulating and metabolised by the colonic microbiota. Chemical and enzymatic processes occurring during gastrointestinal digestion modulate the bioactivity and bioaccessibility of phenolic compounds. The interactions between the cereal polyphenols and the intestinal epithelium allow the modulation of intestinal barrier function through antioxidant, anti-inflammatory activity and mucin production thereby improving intestinal health. The intestinal microbiota is believed to have a reciprocal interaction with polyphenols, wherein the microbiome produces bioactive and bioaccessible phenolic metabolites and the phenolic compound, in turn, modifies the microbiome composition favourably. Thus, the microbiome presents a key link between polyphenol consumption and the health benefits observed in metabolic conditions in numerous studies. This review will explore the therapeutic value of cereal polyphenols in conjunction with their bioaccessibility, impact on intestinal barrier function and interaction with the microbiome coupled with plasma anti-inflammatory effects.

Evaluation of Antioxidant, Anti-Inflammatory and Antityrosinase Potential of Extracts from Different Aerial Parts of Rhanterium suaveolens from Tunisia

The genus Rhanterium (Asteraceae) is a widely distributed medicinal plant throughout western North Africa and some Rhanterium species are used in folk medicine. The aim of research was to investigate methanolic extracts from different parts (flowers, leaves, and stems) of Tunisian Rhanterium suaveolens as potential sources of bioactive products useful for healthy purposes. In particular, were analyzed the phenolic composition of these extracts and their antioxidant, anti-inflammatory, and anti-tyrosinase properties. The phytochemical analyses were performed using standard colorimetric procedures, HPLC-DAD and HPLC-DAD-ESI-MS. Then, several in vitro cell-free assays have been used to estimate the antioxidant/free radical scavenging capability of the extracts. Moreover, in vitro, and in vivo anti-melanogenesis activities of these extracts were tested, respectively, with the tyrosinase inhibition assay and the Zebrafish embryo model. Finally, the anti-inflammatory potential of these extracts in an in vitro model of acute intestinal inflammation in differentiated Caco-2 cells was evaluated. The R. suaveolens extracts under study appeared particularly rich in flavonols and hydroxycinnamic acids and all extracts appeared endowed with good antioxidant/free radical scavenging properties, being the flower extracts slightly more active than the others. Moreover, R. suaveolens flowers extract was able to inhibit in vitro tyrosinase activity and exhibited bleaching effects on the pigmentation of zebrafish embryos. Furthermore, all extracts showed good anti-inflammatory activity in intestinal epithelial cells as demonstrated by the inhibition of TNF-α-induced gene expression of IL-6 and IL-8. R. suaveolens aerial parts may be considered as a potential source of whitening agents, as well as of agents for the treatment of disorders related to oxidative stress and inflammation.

Flavonoids and cellular stress: a complex interplay affecting human health

Flavonoid consumption has beneficial effects on human health, however, clinical evidence remains often inconclusive due to high interindividual variability. Although this high interindividual variability has been consistently observed in flavonoid research, the potential underlying reasons are still poorly studied. Especially the knowledge on the impact of health status on flavonoid responsiveness is limited and merits more investigation. Here, we aim to highlight the bidirectional interplay between flavonoids and cellular stress. First, the state-of-the-art concerning inflammatory stress and mitochondrial dysfunction is reviewed and a comprehensive overview of recent in vitro studies investigating the impact of flavonoids on cellular stress, induced by tumor necrosis factor α, lipopolysaccharide and mitochondrial stressors, is given. Second, we critically discuss the influence of cellular stress on flavonoid uptake, accumulation, metabolism and cell responses, which has, to our knowledge, never been extensively reviewed before. Next, we advocate the innovative insight that stratification of the general population based on health status can reveal subpopulations that benefit more from flavonoid consumption. Finally, suggestions are given for the development of future cell models that simulate the physiological micro-environment, including interindividual variability, since more mechanistic research is needed to establish scientific-based personalized food recommendations for specific subpopulations.

Evaluation of Antioxidant and Anti-Inflammatory Activity of Anthocyanin-Rich Water-Soluble Aronia Dry Extracts

Aronia fruits contain many valuable components that are beneficial to human health. However, fruits are characterized by significant variations in chemical composition dependent on the growing conditions and harvesting period. Therefore, there is a need to formulate the extracts with a precisely defined content of health-promoting substances. Aronia dry extracts (ADE) were prepared from frozen pomace applying water extraction, followed by purification and spray-drying. Subsequently, the content of anthocyanins, phenolic acids, and polyphenols was determined. The high-quality chokeberry pomace enabled obtaining extracts with anthocyanin content much higher than the typical market standards. Moreover, it was found that the antioxidant capacity of aronia extracts exceeded those found in other fruit preparations. Antioxidant and free-radical scavenging properties were evaluated using a 2,2'-diphenyl-1-picrylhydrazyl using Electron Paramagnetic Resonance (EPR) spectroscopy (DPPH-EPR) test and Oxygen Radical Absorbance Capacity (ORAC) assay. The inhibition of lipid peroxidation and the level of inflammatory markers have been also investigated using lipopolysaccharide (LPS)-stimulated RAW 264 cells. It was revealed that ADE standardized to 25% of anthocyanins depresses the level of markers of inflammation and lipid peroxidation (Interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and malondialdehyde (MDA)) in in vitro conditions. Additionally, it was confirmed that ADE at all analyzed concentrations did not show any cytotoxic effect as demonstrated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

Anthocyanins As Modulators of Cell Redox-Dependent Pathways in Non-Communicable Diseases

Chronic Noncommunicable Diseases (NCDs), mostly represented by cardiovascular diseases, diabetes, chronic pulmonary diseases, cancers, and several chronic pathologies, are one of the main causes of morbidity and mortality, and are mainly related to the occurrence of metabolic risk factors. Anthocyanins (ACNs) possess a wide spectrum of biological activities, such as anti-inflammatory, antioxidant, cardioprotective and chemopreventive properties, which are able to promote human health. Although ACNs present an apparent low bioavailability, their metabolites may play an important role in the in vivo protective effects observed. This article directly addresses the scientific evidences supporting that ACNs could be useful to protect human population against several NCDs not only acting as antioxidant but through their capability to modulate cell redox-dependent signaling. In particular, ACNs interact with the NF-κB and AP-1 signal transduction pathways, which respond to oxidative signals and mediate a proinflammatory effect, and the Nrf2/ARE pathway and its regulated cytoprotective proteins (GST, NQO, HO-1, etc.), involved in both cellular antioxidant defenses and elimination/inactivation of toxic compounds, so countering the alterations caused by conditions of chemical/oxidative stress. In addition, supposed crosstalks could contribute to explain the protective effects of ACNs in different pathological conditions characterized by an altered balance among these pathways. Thus, this review underlines the importance of specific nutritional molecules for human health and focuses on the molecular targets and the underlying mechanisms of ACNs against various diseases.

Modulation of Adhesion Process, E-Selectin and VEGF Production by Anthocyanins and Their Metabolites in an in vitro Model of Atherosclerosis

The present study aims to evaluate the ability of peonidin and petunidin-3-glucoside (Peo-3-glc and Pet-3-glc) and their metabolites (vanillic acid; VA and methyl-gallic acid; MetGA), to prevent monocyte (THP-1) adhesion to endothelial cells (HUVECs), and to reduce the production of vascular cell adhesion molecule (VCAM)-1, E-selectin and vascular endothelial growth factor (VEGF) in a stimulated pro-inflammatory environment, a pivotal step of atherogenesis. Tumor necrosis factor-α (TNF-α; 100 ng mL-1) was used to stimulate the adhesion of labelled monocytes (THP-1) to endothelial cells (HUVECs). Successively, different concentrations of Peo-3-glc and Pet-3-glc (0.02 µM, 0.2 µM, 2 µM and 20 µM), VA and MetGA (0.05 µM, 0.5 µM, 5 µM and 50 µM) were tested. After 24 h, VCAM-1, E-selectin and VEGF were quantified by ELISA, while the adhesion process was measured spectrophotometrically. Peo-3-glc and Pet-3-glc (from 0.02 µM to 20 µM) significantly (p < 0.0001) decreased THP-1 adhesion to HUVECs at all concentrations (-37%, -24%, -30% and -47% for Peo-3-glc; -37%, -33%, -33% and -45% for Pet-3-glc). VA, but not MetGA, reduced the adhesion process at 50 µM (-21%; p < 0.001). At the same concentrations, a significant (p < 0.0001) reduction of E-selectin, but not VCAM-1, was documented. In addition, anthocyanins and their metabolites significantly decreased (p < 0.001) VEGF production. The present findings suggest that while Peo-3-glc and Pet-3-glc (but not their metabolites) reduced monocyte adhesion to endothelial cells through suppression of E-selectin production, VEGF production was reduced by both anthocyanins and their metabolites, suggesting a role in the regulation of angiogenesis.

Accumulation of Anthocyanins through Overexpression of AtPAP1 in Solanum nigrum Lin. (Black Nightshade)

Black nightshade (Solanum nigrum) belongs to the Solanaceae family and is used as a medicinal herb with health benefits. It has been reported that the black nightshade plant contains various phytochemicals that are associated with antitumor activities. Here we employed a genetic approach to study the effects of overexpression of Arabidopsis thaliana production of anthocyanin pigment 1 (AtPAP1) in black nightshade. Ectopic expression of AtPAP1 resulted in enhanced accumulation of anthocyanin pigments in vegetative and reproductive tissues of the transgenic plants. Analysis of anthocyanin revealed that delphinidin 3-O-rutinoside-5-O-glucoside, delphinidin 3,5-O-diglucoside, delphinidin 3-O-rutinoside, petunidin 3-O-rutinoside (cis-p-coumaroyl)-5-O-glucoside, petunidin 3-(feruloyl)-rutinoside-5-glucoside, and malvidin 3-(feruloyl)-rutinoside-5-glucoside are highly induced in the leaves of AtPAP1 overexpression lines. Furthermore, ectopic expression of AtPAP1 evoked expression of early and late biosynthetic genes of the general phenylpropanoid and flavonoid pathways that include phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate CoA ligase (4CL), chalcone isomerase (CHI), and quinate hydroxycinnamoyl transferase (HCT), which suggests these genes might be transcriptional targets of AtPAP1 in black nightshade. Concomitantly, the total content of anthocyanin in the transgenic black nightshade plants was higher compared to the control plants, which supports phenotypic changes in color. Our data demonstrate that a major anthocyanin biosynthetic regulator, AtPAP1, can induce accumulation of anthocyanins in the heterologous system of black nightshade through the conserved flavonoid biosynthesis pathway in plants.

Cyanidin-3-glucoside binds to talin and modulates colon cancer cell adhesions and 3D growth

Cyanidin-3-glucoside (C3G) is a natural pigment, found in many colorful fruits and vegetables. It has many health benefits, including anti-inflammation, cancer prevention, and anti-diabetes. Although C3G is assumed to be an antioxidant, it has been reported to affect cell-matrix adhesions. However, the underlying molecular mechanism is unknown. Here, we show that the expression of talin1, a key regulator of integrins and cell adhesions, negatively correlated with the survival rate of colon cancer patients and that depletion of talin1 inhibited 3D spheroid growth in colon cancer cells. Interestingly, C3G bound to talin and promoted the interaction of talin with β1A-integrin. Molecular docking analysis shows that C3G binds to the interface of the talin-β-integrin complex, acting as an allosteric regulator and altering the interaction between talin and integrin. Moreover, C3G promoted colon cancer cell attachment to fibronectin. While C3G had no significant effect on colon cancer cell proliferation, it significantly inhibited 3D spheroid growth in fibrin gel assays. Since C3G has no or very low toxicity, it could be potentially used for colon cancer prevention or therapy.

Protective Effect of Kaempferol on LPS-Induced Inflammation and Barrier Dysfunction in a Coculture Model of Intestinal Epithelial Cells and Intestinal Microvascular Endothelial Cells

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of intestinal mucosa and submucosa, characterized by the disruption of the intestinal epithelial barrier, increased production of inflammatory mediators, and excessive tissue injury. Intestinal epithelial cells, as well as microvascular endothelial cells, play important roles in IBD. To study the potential effects of kaempferol in IBD progress, we established a novel epithelial-endothelial cells coculture model to investigate the intestinal inflammation and barrier function. Data demonstrated an obvious increased transepithelial electrical resistance (TEER) (1222 ± 60.40 Ω cm² vs 1371 ± 38.77 Ω cm²), decreased flux of FITC (180.8 ± 20.06 μg/mL vs 136.7 ± 14.78 μg/mL), and up-regulated occludin and claudin-2 expression in Caco-2 that was specifically cocultured with endothelial cells. Meanwhile, 80 μM kaempferol alleviated the drop of TEER, the increase of FITC flux, and the overexpression of interleukin-8 (IL-8) induced by 1 μg/mL lipopolysaccharide (LPS). Additionally, kaempferol also ameliorated the LPS-induced decrease of protein expression of zonula occludens-1 (ZO-1), occludin, and claudin-2, together with the inhibited protein expressions of the phosphorylation level of NF-κB and I-κB induced by LPS. Our results suggest that kaempferol alleviates the IL-8 secretion and barrier dysfunction of the Caco-2 monolayer in the LPS-induced epithelial-endothelial coculture model via inhibiting the NF-κB signaling pathway activation.

The Effects and Mechanisms of Cyanidin-3-Glucoside and Its Phenolic Metabolites in Maintaining Intestinal Integrity

Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin and possesses antioxidant and anti-inflammatory properties. The catabolism of C3G in the gastrointestinal tract could produce bioactive phenolic metabolites, such as protocatechuic acid, phloroglucinaldehyde, vanillic acid, and ferulic acid, which enhance C3G bioavailability and contribute to both mucosal barrier and microbiota. To get an overview of the function and mechanisms of C3G and its phenolic metabolites, we review the accumulated data of the absorption and catabolism of C3G in the gastrointestine, and attempt to give crosstalk between the phenolic metabolites, gut microbiota, and mucosal innate immune signaling pathways.

The Alternaria Mycotoxin Alternariol Triggers the Immune Response of IL-1β-stimulated, Differentiated Caco-2 Cells

SCOPE

Alternariol (AOH), a toxic secondary metabolite of Alternaria spp., may contaminate a broad spectrum of food and feed. Besides its cytotoxic, genotoxic, and estrogenic properties, several studies report the potential of AOH to suppress the rich network of immune responses. The specific effect of AOH on inflammation-related signaling in non-immune cells of the intestinal epithelial layer has, however, not been investigated yet. Since intestinal epithelial cells (IECs) are, compared to underlying cells, exposed to higher concentrations of the ingested mycotoxin, the question is addressed whether immunomodulation by AOH at the gastrointestinal barrier must be considered.

METHODS AND RESULTS

The impact of AOH (0.02-40 µm) on inflammatory signaling in either IL-1β-stimulated or non-stimulated differentiated Caco-2 cells is determined. AOH significantly reduces IL-1β transcription after 5 h but shows an increasing tendency on IL-8 transcript levels after long-term exposure (20 h). In IL-1β-stimulated cells, AOH (20-40 µm) augments TNF-α transcripts while repressing IL-8, IL-6, and IL-1β transcription as well as IL-8 secretion. Furthermore, inflammation-related microRNAs miR-16, miR-146a, miR-125b, and miR-155 are altered in response to AOH.

CONCLUSION

The obtained data indicate that AOH represses immune responses in an inflamed environment, possibly leading to higher susceptibility to diseases.

Impact of Saskatoon berry powder on insulin resistance and relationship with intestinal microbiota in high fat-high sucrose diet-induced obese mice

The present study examined the impact of Saskatoon berry powder (SBp) on insulin resistance, inflammation and intestinal microbiota in diet-induced obese mice. Male C57 BL/6 J mice were fed control diet, high fat-high sucrose (HFHS) diet or HFHS+5% SBp (HFHS+B) diet for 15 weeks. The composition of fecal bacterial community was characterized using the Illumina sequencing of V4 region of 16S rRNA gene. HFHS diet increased body weight, fasting plasma glucose, cholesterol, triglycerides, insulin, homeostatic model assessment-insulin resistance, monocyte adhesion, tumor necrosis factor-α, plasminogen activator inhibitor-1, monocyte chemotactic protein-1, intracellular cell adhesion molecule-1, urokinase plasminogen activator and its receptor in plasma or aortae compared to the control diet. HFHS+B diet postponed the increase in body weight, suppressed HFHS diet-induced disorders in the metabolic and inflammatory variables. The ratio of Firmicutes/Bacteroidetes in the HFHS group was higher than that in the control group (P<.01), and that in the HFHS+B group was lower than that in the HFHS group (P<.05). The abundances of S24-7 family negatively correlated with body weight and tested metabolic or inflammatory variables. The results suggest that SBp attenuated HFHS diet-induced metabolic disorders and vascular inflammation in gut microbiota in mice.

Anthocyanins: From Sources and Bioavailability to Cardiovascular-Health Benefits and Molecular Mechanisms of Action

Anthocyanins are phytochemicals widely found in plant foods, with berries and fruit-derived beverages as the main dietary sources. Accumulating evidence suggests the positive role of anthocyanins in preserving cardiovascular health. Epidemiological data show an association between anthocyanin intake and lower risk of myocardial infarction and cardiovascular-disease-related mortality. Clinical studies report the beneficial effects of the consumption of different anthocyanin-rich sources on surrogate markers of cardiovascular risk. Animal and in vitro evidence suggest the protective role of anthocyanins in dysfunctions related to the development of cardiovascular diseases. Still, the underlying molecular mechanisms of anthocyanin action seem complex and are not entirely clear. This review aims to give a comprehensive update on anthocyanins and their cardioprotective properties. It provides information on their sources; quantities consumed through diet; absorption; bioavailability; cardiovascular properties; and underlying mechanisms of action, including their effects on gene and protein expression and their interactions with cell-signaling pathways and miRNAs.

Anthocyanins and metabolites resolve TNF-α-mediated production of E-selectin and adhesion of monocytes to endothelial cells

This study investigated the capacity of an anthocyanin-rich fraction (ACN-RF) from blueberry, single anthocyanins (cyanidin, delphinidin and malvidin-3-glucoside; Cy, Dp and Mv-3-glc) and related metabolites (protocatechuic, gallic and syringic acid; PrA, GA and SA) to resolve an inflammation-driven adhesion of monocytes (THP-1) on endothelial cell (HUVECs) and secretion of cell adhesion molecules E-selectin and vascular cell adhesion molecule 1 (VCAM-1). The adhesion of THP-1 to HUVECs was induced by tumour necrosis factor α (TNF-α, 100 ng mL^-1). Subsequently, ACN-RF, single ACNs and metabolites (from 0.01 to 10 μg mL^-1) were incubated for 24 h. The adhesion was measured in a fluorescence spectrophotometer. E-selectin and VCAM-1 were quantified by ELISA. No toxicological effects were observed for the compounds and the doses tested. ACN-RF and Mv-3-glc reducedTHP-1 adhesion at all the concentrations with the maximum effect at 10 μg/ml (-60.2% for ACNs and-33.9% for Mv-3-glc). Cy-3-glc decreased the adhesion by about 41.8% at 10 μg mL^-1, while PrA and GA reduced the adhesion of THP-1 to HUVECs both at 1 and at 10 μg mL^-1 (-29.5% and -44.3% for PrA, respectively, and -18.0%and -59.3% for GA, respectively). At the same concentrations a significant reduction of E-selectin, but notVCAM-1 levels, was documented. No effect was observed following Dp-3-glc and SA supplementation. Overall, ACNs and metabolites seem to resolve, in a dose-dependent manner, the inflammation-driven adhesion of THP-1 to HUVECs by decreasing E-selectin concentrations. Interestingly, Mv-3-glc was active at physiologically relevant concentrations.

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.

Cytokine Tuning of Intestinal Epithelial Function

The intestine serves as both our largest single barrier to the external environment and the host of more immune cells than any other location in our bodies. Separating these potential combatants is a single layer of dynamic epithelium composed of heterogeneous epithelial subtypes, each uniquely adapted to carry out a subset of the intestine’s diverse functions. In addition to its obvious role in digestion, the intestinal epithelium is responsible for a wide array of critical tasks, including maintaining barrier integrity, preventing invasion by microbial commensals and pathogens, and modulating the intestinal immune system. Communication between these epithelial cells and resident immune cells is crucial for maintaining homeostasis and coordinating appropriate responses to disease and can occur through cell-to-cell contact or by the release or recognition of soluble mediators. The objective of this review is to highlight recent literature illuminating how cytokines and chemokines, both those made by and acting on the intestinal epithelium, orchestrate many of the diverse functions of the intestinal epithelium and its interactions with immune cells in health and disease. Areas of focus include cytokine control of intestinal epithelial proliferation, cell death, and barrier permeability. In addition, the modulation of epithelial-derived cytokines and chemokines by factors such as interactions with stromal and immune cells, pathogen and commensal exposure, and diet will be discussed.

Comparison of anticancer activity and antioxidant activity between cyanidin-3-O-glucoside liposomes and cyanidin-3-O-glucoside in Caco-2 cells in vitro

In this study, we compared the antioxidant activities of cyanidin-3-O-glucoside (C3G) and C3G liposomes.