Biotransformation and metabolism of three mulberry anthocyanin monomers by rat gut microflora

Novel insights into bound Phenolics: Conversion and release of phenolic compounds in lychee pulp by heat pump drying and lactic acid bacterial fermentation

The bioactivities of lychee pulp (LP) phenolics have been extensively documented. However, the impact of processing techniques on the phenolics remains unclear. The objective of this study was to investigate the conversion and metabolism of phenolics in LP that was first heat pump-dried and then fermented by lactic acid bacteria. HPLC-DAD analysis revealed that a portion of the free phenolics were converted to bound phenolics during the drying process. It is noteworthy that 4-hydroxybenzoic acid, procyanidin B2, and syringic acid were identified as novel compounds. The HPLC-MS/MS analysis demonstrated that Lactobacillus fermentation facilitated the additional release of polyphenols from dried LP. Seven previously unidentified phenolic compounds, including protocatechuic acid, 4-hydroxyphenylpropionic acid, dihydrocaffeic acid, 3-phenylpropionic acid, 4-hydroxyphenylacetic acid, isorhamnetin-3-O-rutinoside, and isoferulic acid, were discovered in samples of mixed strain Lactobacillus fermentation. These findings provide a theoretical foundation for the lychee processing industry.

The interaction between various food components and intestinal microbiota improves human health through the gut-X axis: independently or synergistically

Food contains various components that improve health by affecting the gut microbiota, primarily by modulating its abundance or altering its diversity. Active substances in food have different effects on the gut microbiota when they act alone or in synergy, resulting in varying impacts on health. The bioactive compounds in food exert different effects on various gut microbiota through multiple pathways, thereby delaying or preventing different kinds of disease. The combination of two or more active compounds may have a synergistic effect, which can more effectively alter the gut microbiota and alleviate diseases through the microbiota-gut-organ axis. According to reports, multiple different food components have similar effects, some of which have been shown to have a synergistic effect on the gut microbiota to promote health. However, there is currently no systematic review of its synergistic effects and mechanisms. There may be more compounds with synergistic effects that have not yet been discovered, while their mechanisms of synergy and ways of impacting host health through the gut microbiota deserve further investigation. The purpose of this review is to systematically summarize the effects of different food components on intestinal flora and health, and further analyze the potential synergies between different food components. PubMed and Google Scholar databases were searched in this review.

Unraveling the color evolution and metabolic pathways of pelargonidin-3-O-glucoside during lactic acid fermentation of the strawberry juice color simulation system: A novel perspective through untargeted metabolomics

This study aimed to unraveling the color evolution and metabolic pathways of pelargonidin-3-O-glucoside (P3G) during lactic acid fermentation of the strawberry juice color simulation system. The results revealed that fermentation with both Lactobacillus plantarum and Lactobacillus acidophilus caused a decline in pH of the strawberry juice color simulation system and significantly accelerated the decrease in P3G content. The CIELAB space model pointed out that parameters a⁎ and b⁎ of the group treated with both lactic acid bacteria and P3G initially increased to a peak level and then gradually decreased, shifting the overall color towards orange and then gradually fading. Furthermore, untargeted metabolomics results revealed that P3G was progressively degraded and converted to pyruvate, methylparaben, 3,4-dihydroxybenzoic acid, p-anisic acid, and terephthalic acid, affecting the metabolic pathways of glycolysis, d-amino acids, benzoate degradation, aromatic compounds degradation, and aminobenzoate degradation in lactic acid bacteria.

Peonidin-3-O-(3,6-O-dimalonyl-β-D-glucoside), a polyacylated anthocyanin isolated from the black corncobs, alleviates colitis by modulating gut microbiota in DSS-induced mice

Polyacylated anthocyanins are known for their enhanced stability and immunosuppressive properties. Although peonidin-3-O-(3,6-O-dimalonyl-β-D-glucoside) (P3GdM) from black corncobs has demonstrated notable antibacterial and stress-resistance effects in plants, its regulatory role in inflammatory bowel disease (IBD) remains unexplored. In this study, P3GdM was isolated from black corncobs, and its potential as a treatment for dextran sulfate sodium (DSS)-induced colitis in mice was evaluated. The findings revealed that P3GdM significantly mitigated clinical symptoms, reduced the disease activity index (DAI), suppressed the production of pro-inflammatory cytokines and endotoxins, and repaired the intestinal barrier. Furthermore, P3GdM markedly improved DSS-induced gut microbiota dysbiosis, significantly increasing microbial diversity and enhancing the relative abundance of critical bacterial species such as Akkermansia muciniphila and Lactobacillus reuteri, while also stimulating the production of short-chain fatty acids (SCFAs) and lactic acid. Correlation analyses further revealed strong associations between key microbial taxa, pro-inflammatory factors, clinical symptoms, tight junction proteins, and SCFAs. These findings provide support for the potential of P3GdM as an adjunct therapy for intestinal disorders, particularly colitis.

Precision Dietary Intervention: Gut Microbiome and Meta-metabolome as Functional Readouts

Gut microbiome, the group of commensals residing within the intestinal tract, is closely associated with dietary patterns by interacting with food components. The gut microbiome is modifiable by the diet, and in turn, it utilizes the undigested food components as substrates and generates a group of small molecule-metabolites that addressed as "meta-metabolome" in this review. Profiling and mapping of meta-metabolome could yield insightful information at higher resolution and serve as functional readouts for precision nutrition and formation of personalized dietary strategies. For assessing the meta-metabolome, sample preparation is important, and it should aim for retrieval of gut microbial metabolites as intact as possible. The meta-metabolome can be investigated via untargeted and targeted meta-metabolomics with analytical platforms such as nuclear magnetic resonance spectroscopy and mass spectrometry. Employing flux analysis with meta-metabolomics using available database could further elucidate metabolic pathways that lead to biomarker discovery. In conclusion, integration of gut microbiome and meta-metabolomics is a promising supplementary approach to tailor precision dietary intervention. In this review, relationships among diet, gut microbiome, and meta-metabolome are elucidated, with an emphasis on recent advances in alternative analysis techniques proposed for nutritional research. We hope that this review will provide information for establishing pipelines complementary to traditional approaches for achieving precision dietary intervention.

Advances in 3D and 4D Printing of Gel-Based Foods: Mechanisms, Applications, and Future Directions

This review examines recent advancements in gel-based 3D and 4D food-printing technologies, with a focus on their applications in personalized nutrition and functional foods. It emphasizes the critical role of tunable rheological and mechanical properties in gels such as starch, protein, and Pickering emulsions, which are essential for successful printing. The review further explores 4D food printing, highlighting stimuli-responsive mechanisms, including color changes and deformation induced by external factors like temperature and pH. These innovations enhance both the sensory and functional properties of printed foods, advancing opportunities for personalization. Key findings from recent studies are presented, demonstrating the potential of various gels to address dietary challenges, such as dysphagia, and to enable precise nutritional customization. The review integrates cutting-edge research, identifies emerging trends and challenges, and underscores the pivotal role of gel-based materials in producing high-quality 3D-printed foods. Additionally, it highlights the potential of Pickering emulsions and lipid gels for expanding functionality and structural diversity. Overall, this work provides a comprehensive foundation for advancing future research and practical applications in gel-based 3D and 4D food printing.

Natural pigments: innovative extraction technologies and their potential application in health and food industries

Natural pigments, or natural colorants, are frequently utilized in the food industry due to their diverse functional and nutritional attributes. Beyond their color properties, these pigments possess several biological activities, including antioxidant, anti-inflammatory, anticancer, antibacterial, and neuroprotective effects, as well as benefits for eye health. This review aims to provide a timely overview of the potential of natural pigments in the pharmaceutical, medical, and food industries. Special emphasis is placed on emerging technologies for natural pigment extraction (thermal technologies, non-thermal technologies, and supercritical fluid extraction), their pharmacological effects, and their potential application in intelligent food packaging and as food colorants. Natural pigments show several pharmaceutical prospects. For example, delphinidin (30 µM) significantly inhibited the growth of three cancer cell lines (B16-F10, EO771, and RM1) by at least 90% after 48 h. Furthermore, as an antioxidant agent, fucoxanthin at the highest concentration (50 μg/mL) significantly increased the ratio of glutathione to glutathione disulfide (p < 0.05). In the food industry, natural pigments have been used to improve the nutritional value of food without significantly altering the sensory experience. Moreover, the use of natural pH-sensitive pigments as food freshness indicators in intelligent food packaging is a cutting-edge technological advancement. This innovation could provide useful information to consumers, increase shelf life, and assist in evaluating the quality of packaged food by observing color variations over time. However, the use of natural pigments presents certain challenges, particularly regarding their stability and higher production costs compared to synthetic pigments. This situation underscores the need for further investigation into alternative pigment sources and improved stabilization methods. The instability of these natural pigments emphasizes their tendency to degrade and change color when exposed to various external conditions, including light, oxygen, temperature fluctuations, pH levels, and interactions with other substances in the food matrix.

Effect of anthocyanins on metabolic syndrome through interacting with gut microbiota

Metabolic syndrome, as a complex pathological condition, is caused by a series of pathogenic factors and has become a global public health challenge. Anthocyanins, a natural water-soluble flavonoid pigment, have attracted much attention due to their antioxidant, anti-inflammatory, and anticancer biological activities. After ingestion, a majority of anthocyanins is not directly absorbed but rather reaches the colon. Hence, the exertion of their biological benefits is closely intertwined with the role played by gut microbiota. In this review, we introduce the pathogenesis and intervention methods of metabolic syndrome, as well as the interaction between anthocyanins and gut microbiota. We also discuss the therapeutic potential of anthocyanins through gut microbiota in addressing a range of metabolic syndrome conditions, including obesity, type 2 diabetes mellitus, cardiovascular diseases, non-alcoholic fatty liver disease, inflammatory bowel disease, polycystic ovary syndrome, osteoporosis, and cancer.

Aronia-derived anthocyanins and metabolites ameliorate TNFα-induced disruption of myogenic differentiation in satellite cells

This study investigates the effects of Aronia berries, their primary anthocyanins and other second metabolites-mimicking dietary anthocyanin consumption-on enhancing muscular myogenesis under chronic inflammation. Murine muscle satellite cells (MuSCs) were cultured ex vivo, allowing for expansion and differentiation into myotubes. Myogenic differentiation was disrupted by TNFα at both early and terminal stages, with treatment using Aronia berries applied at physiologically relevant concentrations alongside TNFα. The results demonstrated that Aronia berries treatments, particularly phenolic metabolites, significantly stimulated the proliferative capacity of MuSCs. Furthermore, Aronia berries treatment enhanced early-stage myogenesis, marked by increased MymX and MyoG expression and nascent myotube formation, with metabolites showing the most pronounced effects. Aronia berry powder and individual anthocyanins exerted milder regulatory effects. Similar trends were observed during terminal differentiation, where Aronia berries treatment promoted myotube growth and inhibited TNFα-induced inflammatory atrophic ubiquitin-conjugating activity. Additionally, the secondary metabolites of Aronia berries significantly prevented muscle-specific ubiquitination in the dexamethasone-induced atrophy model. Overall, the treatment with Aronia berries enhanced myogenesis in a cellular model of chronic muscular inflammation, with Aronia-derived metabolites showing the strongest response, likely through TLR4/NF-κB modulation. In this case, enhanced regeneration capacity and anti-atrophy potential were associated with TLR4/NF-κB modulation.

Antioxidant Activity of Anthocyanins and Anthocyanidins: A Critical Review

Anthocyanins are the main plant pigments responsible for the color of flowers, fruits, and vegetative organs of many plants, and are applied also as safe food colorants. They are efficient antioxidants. In this review, the reactivity of anthocyanins and their aglycones, anthocyanidins, in the main antioxidant assays, and their reactions with reactive oxygen and nitrogen species, effects of interactions with other compounds and metal ions on the antioxidant activity of anthocyanins and the electrochemical properties of anthocyanins are presented. Numerous cases of attenuation of oxidative stress at the cellular and organismal levels by anthocyanins are cited. The direct and indirect antioxidant action of anthocyanins, the question of the specificity of anthocyanin action in complex extracts, as well as limitations of cellular in vitro assays and biomarkers used for the detection of antioxidant effects of anthocyanins, are critically discussed.

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.

Microbiota alterations associated with vascular diseases: postbiotics as a next-generation magic bullet for gut-vascular axis

The intestinal microbiota represents a key element in maintaining the homeostasis and health conditions of the host. Vascular pathologies and other risk factors such as aging have been recently associated with dysbiosis. The qualitative and quantitative alteration of the intestinal microbiota hinders correct metabolic homeostasis, causing structural and functional changes of the intestinal wall itself. Impairment of the intestinal microbiota, combined with the reduction of the barrier function, worsen the pathological scenarios of peripheral tissues over time, including the vascular one. Several experimental evidence, collected in this review, describes in detail the changes of the intestinal microbiota in dysbiosis associated with vascular alterations, such as atherosclerosis, hypertension, and endothelial dysfunction, the resulting metabolic disorders and how these can impact on vascular health. In this context, the gut-vascular axis is considered, for the first time, as a merged unit involved in the development and progression of vascular pathologies and as a promising target. Current approaches for the management of dysbiosis such as probiotics, prebiotics and dietary modifications act mainly on the intestinal district. Postbiotics, described as preparation of inanimate microorganisms and/or their components that confers health benefits on the host, represent an innovative strategy for a dual management of intestinal dysbiosis and vascular pathologies. In this context, this review has the further purpose of defining the positive effects of the supplementation of bacterial strains metabolites (short‑chain fatty acids, exopolysaccharides, lipoteichoic acids, gallic acid, and protocatechuic acid) restoring intestinal homeostasis and acting directly on the vascular district through the gut-vascular axis.

Anthocyanins-gut microbiota-health axis: A review

Anthocyanins are a subclass of flavonoids responsible for color in some fruits and vegetables with potent antioxidative capacity. During digestion, a larger proportion of dietary anthocyanins remains unabsorbed and reach the large intestine where they interact with the gut microbiota. Anthocyanins can modulate gut microbial populations to improve diversity and the proportion of beneficial populations, leading to alterations in short chain fatty acid and bile acid production. Some anthocyanins can be degraded into colonic metabolites, such as phenolic acids, which accumulate in the body and regulate a range of biological activities. Here we provide an overview of the effects of dietary anthocyanin consumption on gut microbial interactions, metabolism, and composition. Progression of chronic diseases has been strongly associated with imbalances in gut microbial populations. We therefore focus on the role of the gut microbiota as the 'mediator' that facilitates the therapeutic potential of anthocyanins against various chronic diseases, including obesity, type II diabetes, cardiovascular disease, neurodegenerative disease, inflammatory bowel disease, cancer, fatty liver disease, chronic kidney disease and osteoarthritis.

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.

Carboxymethyl Chitosan-Coated Cyanidin-3-O-Glucoside-Beared Nanonutriosomes Suppress Palmitic Acid-Induced Hepatocytes Injury

Cyanidin-3-O-glucoside (C3G) is classified as an anthocyanin (ACN) and is recognized for its remarkable antioxidant properties. Yet, the inadequate physicochemical stability of C3G restricts its potential for various biological applications. Thus, in this study, carboxymethyl chitosan (CMC)-coated nanonutriosomes (NS) were synthesized as a novel carrier for encapsulating C3G (CMC-C3G-NS) to improve C3G stability. CMC-C3G-NS exhibited a diameter of less than 200 nm along with an encouraging encapsulation efficiency exceeding 90%. Notably, the formulated CMC-C3G-NS possessed better stability under various pH, ionic, and oxygen conditions, improved controlled release properties, and higher hepatocellular uptake than uncoated particles (C3G-NS), indicating a longer retention time of C3G in a physiological environment. Of utmost significance, CMC-C3G-NS demonstrated superior alleviating effects against palmitic acid (PA)-induced oxidative hepatic damage compared to C3G-NS. Our study provided promising nanocarriers with the potential to deliver hydrophilic ACNs and controlled release properties for PA-induced hepatotoxicity alleviation.

Unlocking the health potential of anthocyanins: a structural insight into their varied biological effects

Anthocyanins have become increasingly important to the food industry due to their colorant features and many health-promoting activities. Numerous studies have linked anthocyanins to antioxidant, anti-inflammatory, anticarcinogenic properties, as well as protection against heart disease, certain types of cancer, and a reduced risk of diabetes and cognitive disorders. Anthocyanins from various foods may exhibit distinct biological and health-promoting activities owing to their structural diversity. In this review, we have collected and tabulated the key information from various recent published studies focusing on investigating the chemical structure effect of anthocyanins on their stability, antioxidant activities, in vivo fate, and changes in the gut microbiome. This information should be valuable in comprehending the connection between the molecular structure and biological function of anthocyanins, with the potential to enhance their application as both colorants and functional compounds in the food industry.

Effects of in vitro fecal fermentation on the metabolism and antioxidant properties of cyanidin-3-O-glucoside

Anthocyanins' potential health benefits have garnered significant interest. However, due to low bioavailability, the gut microbiota-associated metabolites are suspected to mediate their bioactivity. In this study, cyanidin-3-glucoside (C3G) was fermented with fecal inoculum to simulate colonic microbiota interaction in vitro. The metabolites and antioxidant properties of pre- (P-C3G) and post-fermentation (F-C3G) were determined. Fermentation significantly increased contents of five metabolites (cyanidin, protocatechuic acid, phloroglucinaldehyde, 4-hydroxybenzoic acid and 4-hydroxyphenylacetic acid). Additionally, F-C3G demonstrated superior radicals scavenging than P-C3G, as well as to alleviate H2O2-induced damage in HepG2 cell via increasing superoxide dismutase by 43.26% and catalase by 39.83%, reducing malonaldehyde by 16.40% and cellular ROS production, and activating Nrf2 pathway. Moreover, F-C3G significantly extended the survival rate by 20.67% of Caenorhabditis elegans under heat stress by antioxidation in vivo. This study suggested that anthocyanins metabolism by gut microbiota produce specific metabolites, which potentially exerts protection.

Identification of Phytochemicals and Assessment of Hypoglycemic and Haematological Potentials of Terminalia catappa Linn leaf Extract in Alloxan-induced Diabetic Wistar Rats

INTRODUCTION

Hypoglycemia and anemia are associated with diabetes mellitus. Medicinal plants and orthodox drugs have been used for the management of this disease. This study aimed to validate the ethnomedical claims of Terminalia catappa Linn. leaf extract in reducing hyperglycemia and hematological potentials in alloxan-induced diabetic rats and to identify likely antidiabetic compounds.

MATERIALS AND METHODS

Ultra-high-performance liquid chromatography was used to identify the various phytochemical constituents. Male Wistar rats were randomly divided into five groups containing 6 rats per group. Group 1 (control) received 0.2 ml/kg of distilled water, group 2 received 130 mg/kg of T. catappa aqueous extract, groups 3-5 were diabetic and received 0.2 ml/g distilled water, 130 mg/kg T. catappa extract and 0.75 IU/kg insulin respectively for 14 days. Hematological parameters were measured and an oral glucose tolerance test was carried out using 2 g/kg body weight glucose. A histological analysis of the pancreas was done.

RESULTS

Twenty-five compounds identified as flavonoids, phenolic acids, tannins, and triterpenoids were detected. The blood glucose levels were significantly (p <0.05) elevated in DM groups but were significantly (p <0.05) reduced following Terminalia catappa leaves extract to DM groups. There was s significant (p <0.05) increase in insulin levels improved hematological parameters (RBC, WBC, and platelets), and increased islet population.

CONCLUSION

These results suggest that T. catappa extract has hypoglycemic, insulinogenic, and hematopoietic potentials in diabetic condition and offer protection to the pancreas which could be attributed to the phytochemical constituents thereby justifying its use in traditional therapy.

Fructo-oligosaccharide enhanced bioavailability of polyglycosylated anthocyanins from red radish via regulating gut microbiota in mice

The anthocyanins from red radish (ARR) rich in polyglycosylated pelargonidin glucosides were used as pigment. However, bioavailability of anthocyanins was considered at low level. This work examined the intensive effects of fructo-oligosaccharide (FOS) on ARR bioavailability. Pelargonidin, cyanidin and pelargonidin-3-glucoside showed higher level in serum of mice fed with FOS together with ARR for 8 weeks than that fed with only ARR. Co-ingestion of FOS and ARR more effectively elevated the hepatic antioxidant activity by increase in total antioxidant capacity and activities of superoxide dismutase and glutathione peroxidase when compared with intake of ARR. FOS also markedly increased pelargonidin level in cecum of mice. 16S RNA sequencing found that Bacteroides genus play an important role in FOS elevating bioavailability of ARR. Fecal bacteria transplantation verified the positive effects of FOS on ARR bioavailability. These results suggested that combined ingestion of FOS and ARR is effective strategy for bioactivity of ARR.

Spontaneous and Microbiota-Driven Degradation of Anthocyanins in an In Vitro Human Colon Model

SCOPE

The consumption of dietary anthocyanins is associated with various health benefits. However, anthocyanins are poorly bioavailable, and most ingested anthocyanins will enter the colon where they are degraded to small phenolic metabolites that are the main absorbed forms. Little is known about the processes of anthocyanin degradation in the gut and the role of the human gut microbiota. This study aims to determine the contribution of spontaneous and microbiota-dependent degradation of anthocyanins in the human colon.

METHODS AND RESULTS

Purified anthocyanin extracts from black rice and bilberry were incubated in an in vitro human fecal-inoculated pH-controlled colon model over 24 h and anthocyanins were analyzed using HPLC-DAD. The study shows that the loss of anthocyanins occurs both spontaneously and as a consequence of metabolism by the gut microbiota. The study observes that there is high variability in spontaneous degradation but only modest variation in total degradation, which included the microbiota-dependent component. The degradation rate of anthocyanins is also shown to be dependent on the B-ring substitution pattern and the type of sugar moiety, both for spontaneous and microbiota-dependent degradation.

CONCLUSION

Anthocyanins are completely degraded in a model of the human colon by a combination of spontaneous and microbiota-dependent processes.

Ameliorative Effects of Anthocyanin Metabolites on Western Diet-Induced NAFLD by Modulating Co-Occurrence Networks of Gut Microbiome

Anthocyanins (Acn) have been reported to have preventive effects on Western diet (WD)-induced non-alcoholic fatty liver disease (NAFLD). However, the amount of Acn that reached the bloodstream were less than 1%, suggesting that anthocyanin metabolites (Acn-M) in the gut may contribute to their in vivo effects. This study is focused on a gut microbiota investigation to elucidate the effect of two major Acn-M, protocatechuic acid (PC) and phloroglucinol carboxaldehyde (PG), on NAFLD prevention. C57BL/6N male mice were divided into five groups and fed with a normal diet (ND), WD, WD + 0.5% PC, WD + 0.5% PG and WD + a mixture of 0.25% PC + 0.25% PG (CG) for 12 weeks. The results revealed that WD-fed mice showed a significant increase in final body weight, epididymis fat weight, liver weight and fat accumulation rate, serum total cholesterol, alanine aminotransferase, monocyte chemoattractant protein 1, and 2-thiobarbituric acid reactive substances. At the same time, these indices were significantly decreased by Acn-M in the order of PG, CG > PC. In particular, PG significantly decreased serum glucose and insulin resistance. Gut microbiome analysis revealed that PG significantly increased the relative abundance of Parabacteroides, Prevotella, Prevotella/Bacteroides ratio, and upregulated glucose degradation pathway. Interestingly, the co-occurrence networks of Lachnospiraceae and Desulfovibrionaceae in the PC and PG groups were similar to the ND group and different to WD group. These data suggest that PC and PG were able to recover the gut microbiome networks and functions from dysbiosis caused by WD. Therefore, PG might act as a master metabolite for anthocyanins and prevent WD-induced NAFLD and gut dysbiosis.

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.

Lychee pulp phenolics fermented by mixed lactic acid bacteria strains promote the metabolism of human gut microbiota fermentation in vitro

Lychee pulp phenolics possess excellent biological activities, however, changes in phenolic substances after microbial treatments are unknown. Herein, lychee pulp was fermented by Lactobacillus plantarum, Lactobacillus rhamnosus, and a mixed strain of the two, followed by an investigation of the products' colonic fermentation. In comparison to single-strain fermentation, mixed-strain fermentation significantly increased catechin and quercetin. In addition, lychee phenolics fermented by mixed strains were more conducive to the growth of gut microbiota. The results of HPLC-DAD showed that colonic fermentation further promoted the release of lychee phenolics. There was a notable increase in the content of gallic acid and quercetin, while multiple phenolics were degraded. Quercetin-3-O-rutinose-7-O-α-L-rhamnoside (QRR) and rutin were catabolized into quercetin by gut microbiota, and 4-hydroxybenzoic acid was produced from the metabolism of QRR and procyanidin B2. Lychee phenolics fermented by mixed lactic acid bacteria were easily metabolized and transformed by gut microbiota. These findings indicate that lychee pulp fermented by mixed lactic acid bacteria possesses probiotic potential, which is of great significance for the development of functional probiotic products.

Effects of α-casein on the excretion of blueberry anthocyanins via urine and feces: Analysis of their bioavailability

Anthocyanins are bioactive compounds found in blueberries. However, their poor bioavailability restricts their functional activities in vivo, which is a challenging issue in the application of blueberry anthocyanins. Our current study utilized α-casein as a carrier and analyzed its influence on the excretion of blueberry anthocyanins in urine and feces in a rat model to reflect the enhanced bioavailability of blueberry anthocyanins by α-casein in vivo. The results showed that α-casein suppressed the excretive content of blueberry anthocyanins (malvidin-3-O-galacoside (M3G), cyanidin-3-O-glucoside (C3G), and delphinidin-3-O-glucoside (D3G)), increased the content of metabolites in urine (syringic acid, ferulic acid, 4-hydroxybenzoic acid, and vanillic acid), and reduced metabolite content in feces (syringic acid, ferulic acid, and gallic acid), indicating that α-casein was effective in controlling the excretion of blueberry anthocyanins and their metabolites. In summary, these results provided sufficient evidence for the positive effects of α-casein on the bioavailability of blueberry anthocyanins.

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.

Pectin-based nanoencapsulation strategy to improve the bioavailability of bioactive compounds

Pectin is one of the polysaccharides to be used as a coating nanomaterial. The characteristics of pectin are suitable to form nanostructures for protection, increased absorption, and bioavailability of different active compounds. This review aims to point out the structural features of pectins and their use as nanocarriers. It also indicates the principal methodologies for the elaboration and application of foods. The research carried out shows that pectin is easily extracted from natural sources, biodegradable, biocompatible, and non-toxic. The mechanical resistance and stability in different pH ranges and the action of digestive enzymes allow the nanostructures to pass intact through the gastrointestinal system and be effectively absorbed. Pectin can bind to macromolecules, especially proteins, to form stable nanostructures, which can be formed by different methods; polyelectrolyte complexes are the most frequent ones. The pectin-derived nanoparticles could be added to foods and dietary supplements, demonstrating a promising nanocarrier with a broad technological application.

Protective Effect of Anthocyanins against Neurodegenerative Diseases through the Microbial-Intestinal-Brain Axis: A Critical Review

With the increase in human mean age, the prevalence of neurodegenerative diseases (NDs) also rises. This negatively affects mental and physiological health. In recent years, evidence has revealed that anthocyanins could regulate the functioning of the central nervous system (CNS) through the microbiome-gut-brain axis, which provides a new perspective for treating NDs. In this review, the protective effects and mechanisms of anthocyanins against NDs are summarized, especially the interaction between anthocyanins and the intestinal microbiota, and the microbial-intestinal-brain axis system is comprehensively discussed. Moreover, anthocyanins achieve the therapeutic purpose of NDs by regulating intestinal microflora and certain metabolites (protocateic acid, vanillic acid, etc.). In particular, the inhibitory effect of tryptophan metabolism on some neurotransmitters and the induction of blood-brain barrier permeability by butyrate production has a preventive effect on NDs. Overall, it is suggested that microbial-intestinal-brain axis may be a novel mechanism for the protective effect of anthocyanins against NDs.

Improved Stabilization and In Vitro Digestibility of Mulberry Anthocyanins by Double Emulsion with Pea Protein Isolate and Xanthan Gum

There is significant evidence that double emulsion has great potential for successfully encapsulating anthocyanins. However, few research studies are currently using a protein-polysaccharide mixture as a stable emulsifier for double emulsion. This study aimed to improve the stability and in vitro digestibility of mulberry anthocyanins (MAs) by employing a double emulsion composed of pea protein isolate (PPI) and xanthan gum (XG). The influence of various XG concentrations (0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%) and different temperatures (5 °C, 25 °C, 45 °C, 65 °C) on the physical stability and the thermal degradation of MAs from double emulsions were investigated. In addition, the physicochemical properties of double emulsions and the release performance of MAs during in vitro simulated digestion were evaluated. It was determined that the double emulsion possessed the most stable physical characteristics with the 1% XG addition. The PPI-1% XG double emulsion, when compared to the PPI-only double emulsion, expressed higher thermal stability with a retention rate of 83.19 ± 0.67% and a half-life of 78.07 ± 4.72 days. Furthermore, the results of in vitro simulated digestion demonstrated that the MAs in the PPI-1% XG double emulsion were well-protected at oral and gastric with ample release found in the intestine, which was dissimilar to findings for the PPI-only double emulsion. Ultimately, it was concluded that the double emulsion constructed by the protein-polysaccharide system is a quality alternative for improving stability and absorption with applicability to a variety of food and beverage systems.

Mulberry plant as a source of functional food with therapeutic and nutritional applications: A review

Medicinal plants from the family Moraceae have diverse applications in agriculture, cosmetics, food, and the pharmaceutical industry. Their extensive spectrum of pharmacological activity for treating numerous inflammatory illnesses, cancer, cardiovascular diseases, and gastrointestinal problems reflects their biological and therapeutic value. This article summarizes the molecular mechanisms related to the biological implications of mulberry extracts, fractions, and isolated bioactive compounds from different parts in various health-related ailments. Additionally, the food industry and animal nutrition applications are summarized. Phytochemicals such as steroids, saponins, alkaloids, glycosides, polysaccharides, and phenolic compounds including terpenoids, flavonoids, anthocyanins, and tannins are found in this medicinal plant. The aqueous, ethanolic, and methanolic extracts, as well as bioactive compounds, have anti-oxidative, hypoglycemic, nephroprotective, antimicrobial, neuroprotective, anti-mutagenic, hepatoprotective, anthelmintic, immune-modulatory, cardioprotective, and skin protecting activities. Mulberry supplementation in food products improves the stability of phenolics, sensory properties, antioxidant activity, and antimicrobial properties. Mulberry leaves in animal feed increase the nutrient digestibility, growth parameters, antimicrobial, and antioxidant properties. PRACTICAL APPLICATIONS: This review summarized the in vivo and in vitro biological activities of the mulberry and isolated constituents in various health conditions. In addition, the food uses such as antioxidant potential, antimicrobial, and physicochemical properties were discussed. Furthermore, in vivo studies revealed mulberry as a significant protein source and its flavonoids as potential animal foliage.

Anti-aging effects and mechanisms of anthocyanins and their intestinal microflora metabolites

Aging, a natural and inevitable physiological process, is the primary risk factor for all age-related diseases; it severely threatens the health of individuals and places a heavy burden on the public health-care system. Thus, strategies to extend the lifespan and prevent and treat age-related diseases have been gaining increasing scientific interest. Anthocyanins (ACNs) are a subclass of flavonoids widely distributed in fruits and vegetables. Growing evidence suggests that ACNs delay aging and relieve age-related diseases. However, owing to the low bioavailability of ACNs, their gut metabolites have been proposed to play a critical role in mediating health benefits. In this review, we introduce the biological fate of ACNs after consumption and highlight ACNs metabolites (phenolic acids) from intestinal microorganisms. Additionally, ACNs and gut metabolites exhibit outstanding anti-aging ability in Caenorhabditis elegans, Drosophila melanogaster, and mouse models, probably associated with increasing antioxidation, anti-inflammation, protein homeostasis, antiglycation, mitochondrial function, and inhibition of insulin/IGF-1 signaling (IIS). ACNs and gut metabolites have great application prospects as functional foods and drugs to delay aging and manage age-related diseases. Further investigation should focus on the interaction between ACNs and gut microbiota, including clarifying the complex metabolic pathway and maximizing the health effects of ACNs.

Dietary Polyphenol, Gut Microbiota, and Health Benefits

Polyphenols, which are probably the most important secondary metabolites produced by plants, have attracted tremendous attention due to their health-promoting effects, including their antioxidant, anti-inflammatory, antibacterial, anti-adipogenic, and neuro-protective activities, as well as health properties. However, due to their complicated structures and high molecular weights, a large proportion of dietary polyphenols remain unabsorbed along the gastrointestinal tract, while in the large intestine they are biotransformed into bioactive, low-molecular-weight phenolic metabolites through the residing gut microbiota. Dietary polyphenols can modulate the composition of intestinal microbes, and in turn, gut microbes catabolize polyphenols to release bioactive metabolites. To better investigate the health benefits of dietary polyphenols, this review provides a summary of their modulation through in vitro and in vivo evidence (animal models and humans), as well as their possible actions through intestinal barrier function and gut microbes. This review aims to provide a basis for better understanding the relationship between dietary polyphenols, gut microbiota, and host health.

Antioxidant, Anti-Inflammatory and Cytotoxic Activity of Phenolic Compound Family Extracted from Raspberries (Rubus idaeus): A General Review

Raspberries (Rubus idaeus) possess a wide phenolic family profile; this serves the role of self-protection for the plant. Interest in these compounds have significantly increased, since they have been classified as nutraceuticals due to the positive health effects provided to consumers. Extensive chemical, in vitro and in vivo studies have been performed to prove and validate these benefits and their possible applications as an aid when treating several chronic degenerative diseases, characterized by oxidative stress and an inflammatory response. While many diseases could be co-adjuvanted by the intake of these phenolic compounds, this review will mainly discuss their effects on cancer. Anthocyanins and ellagitannins are known to provide a major antioxidant capacity in raspberries. The aim of this review is to summarize the current knowledge concerning the phenolic compound family of raspberries, and topics discussed include their characterization, biosynthesis, bioavailability, cytotoxicity, antioxidant and anti-inflammatory activities.

Cyanidin-3-O-glucoside, cyanidin, and oxidation products of cyanidin protect neuronal function through alleviating inflammation and oxidative damage

Neurotoxicity seriously affects the normal function of the nervous system. Cyanidin-3-O-glucoside (C3G) is the most abundant anthocyanin widely distributed in plants. Using β-amyloid (Aβ) transgenic Caenorhabditis elegans and cell models, the neuroprotective effect of C3G was examined. The results showed that C3G remarkably suppressed Aβ aggregation, enhanced antioxidant capacity, improved the sensitive capacity towards chemical compounds, and boosted the memory ability of C. elegans. There was no significant difference between preventive and long-term treatment groups at the same dosage of C3G. Given the rapid metabolism and oxidation of C3G in vivo, the antioxidative and anti-inflammatory activities of C3G, the metabolite cyanidin (Cy), oxidation products of Cy (OP), as well as protocatechuic acid (PCA) at the corresponding level in OP were compared by using lipopolysaccharide (LPS)-stimulated BV2 microglia cell model. The results indicated that C3G, Cy, and OP could prevent BV2 cells against LPS-induced inflammation and oxidative damage. There was no significant difference on antioxidative and anti-inflammatory activities among C3G, Cy, and OP at the same level. Notably, PCA at the corresponding concentration in OP exhibited limited antioxidative and anti-inflammatory activities. The results suggested that C3G could exert neuroprotective function through the metabolite Cy and its oxidation products by inhibiting inflammation and oxidative damage, and PCA was not the primary bioactive species in OP. PRACTICAL APPLICATION: This study confirmed the neuroprotection of cyanidin-3-O-glucoside (C3G) in transgenic Caenorhabditis elegans. C3G, its metabolite cyanidin (Cy), and oxidation products of Cy (OP) alleviated both neuroinflammation and oxidative damage. It highlighted that C3G-rich foods could exert neuroprotective potential through their oxidation products, the constitution, and existence of OP in vivo need further study.

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.

Functional implications of bound phenolic compounds and phenolics-food interaction: A review

Sizeable scientific evidence indicates the health benefits related to phenolic compounds and dietary fiber. Various phenolic compounds-rich foods or ingredients are also rich in dietary fiber, and these two health components may interrelate via noncovalent (reversible) and covalent (mostly irreversible) interactions. Notwithstanding, these interactions are responsible for the carrier effect ascribed to fiber toward the digestive system and can modulate the bioaccessibility of phenolics, thus shaping health-promoting effects in vivo. On this basis, the present review focuses on the nature, occurrence, and implications of the interactions between phenolics and food components. Covalent and noncovalent interactions are presented, their occurrence discussed, and the effect of food processing introduced. Once reaching the large intestine, fiber-bound phenolics undergo an intense transformation by the microbial community therein, encompassing reactions such as deglycosylation, dehydroxylation, α- and β-oxidation, dehydrogenation, demethylation, decarboxylation, C-ring fission, and cleavage to lower molecular weight phenolics. Comparatively less information is still available on the consequences on gut microbiota. So far, the very most of the information on the ability of bound phenolics to modulate gut microbiota relates to in vitro models and single strains in culture medium. Despite offering promising information, such models provide limited information about the effect on gut microbes, and future research is deemed in this field.

Current knowledge of anthocyanin metabolism in the digestive tract: absorption, distribution, degradation, and interconversion

Potential roles for anthocyanins in preventing various chronic diseases have been reported. These compounds are highly sensitive to external conditions and are susceptible to degradation, which increases the complexity of their metabolism in vivo. This review discusses anthocyanin metabolism in the digestive tract, phase I and II metabolism, and enterohepatic circulation (EHC), as well as their distribution of anthocyanins in blood, urine, and several organs. In the oral cavity, anthocyanins are partly hydrolyzed by microbiota into aglycones which are then conjugated by glucuronidase. In stomach, anthocyanins are absorbed without deglycosylation via specific transporters, such as sodium-dependent glucose co-transporter 1 and facilitative glucose transporters 1, while in small intestine, they are mainly absorbed as aglycones. High polymeric anthocyanins are easily degraded into low-polymeric forms or smaller phenolic acids by colonic microbiota, which improves their absorption. Anthocyanins and their derivatives are modified by phase I and II metabolic enzymes in cells and are released into the blood via the gastrovascular cavity into EHC. Notably, interconversion can be occurred under the action of enzymes such as catechol-O-methyltransferase. Taking together, differences in anthocyanin absorption, distribution, metabolism, and excretion largely depend on their glycoside and aglycone structures.

Evaluation of Blood-Brain Barrier Permeability of Polyphenols, Anthocyanins, and Their Metabolites

Anthocyanins (ACs) are able to protect neurons against β-amyloid-induced neurotoxicity. In this study, we evaluated blood-brain barrier (BBB) permeability of these compounds using a model kit to clarify the mechanism of AC on the brain. Black currant or strawberry AC extract was orally administrated to male Wistar rats. The urine and extirpated brain were collected before and after administration and analyzed quantitatively by liquid chromatography-tandem mass spectrometry. After administration of AC, several phenolic acids were detected in the urine samples. Further, AC and some AC metabolites were found in the brain tissue. BBB permeabilities of these compounds were much lower than the positive control. Epigallocatechin, daidzein, genistein, equol, and nobiletin presented high BBB permeability, whereas apigenin, luteolin, quercetin, and kaempferol showed medium permeability, and epicatechin, rutin, fisetin, resveratrol, and curcumin BBB permeation was neglected. These results suggested that ACs were difficult to cross BBB into the brain and ACs were not directly associated with the prevention of β-amyloid-induced neurotoxicity.

Extensive metabolism of flavonoids relevant to their potential efficacy on Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder, the incidence of which is climbing with ever-growing aged population, but no cure is hitherto available. The epidemiological studies unveiled that chronic intake of flavonoids was negatively associated with AD risk. Flavonoids, a family of natural polyphenols widely distributed in human daily diets, were readily conjugated by phase II drug metabolizing enzymes after absorption in vivo, and glucuronidation could occur in 1 min following intravenous administration. Recently, as many as 191 metabolites were obtained after intragastric administration of a single flavonoid, indicating that other bioactive metabolites, besides conjugates, might be formed and account for the contradiction between efficacy of flavonoids in human or animal models and low systematic exposure of flavonoid glycosides or aglycones. In this review, metabolism of complete 68 flavonoid monomers potential for AD treatment, grouped in flavonoid O-glycosides, flavonoid aglycones, flavonoid C-glycosides, flavonoid dimers, flavonolignans and prenylated flavonoids according to their common structural elements, respectively, has been systematically retrospected, summarized and discussed, including their unequivocally identified metabolites, metabolic interconversions, metabolic locations, metabolic sites (regio- or stereo-selectivity), primarily involved metabolic enzymes or intestinal bacteria, and interspecies correlations or differences in metabolism, and their bioactive metabolites and the underlying mechanism to reverse AD pathology were also reviewed, providing whole perspective about advances on extensive metabolism of diverse potent flavonoids in vivo and in vitro up to date and aiming at elucidation of mechanism of actions of flavonoids on AD or other central nervous system (CNS) disorders.

Effects of α-Casein on the Absorption of Blueberry Anthocyanins and Metabolites in Rat Plasma Based on Pharmacokinetic Analysis

Blueberry anthocyanins are well known for their beneficial biological activities. However, the poor bioavailability of anthocyanins limits their functional capacity in vivo. Our current study aimed to detect the effects of α-casein on the absorption of blueberry anthocyanins and their metabolites in rats. Blueberry anthocyanins with and without α-casein were intragastrically administered to two groups of rats and their blood samples were collected within 24 h. Results illustrated that rapid absorption of anthocyanins was observed in the rat plasma, but their concentration was relatively low. With the complexation of α-casein, the maximum concentration (C_max) of bioavailable anthocyanins and metabolites could increase by 1.5-10.1 times (P < 0.05 or P < 0.01). The promotional effect on the plasma absorption of malvidin-3-O-galactoside and vanillic acid was outstanding with the C_max increasing from 0.032 to 0.323 and from 0.360 to 1.902 μg/mL, respectively (P < 0.01). Besides, the molecular docking models presented that anthocyanins could enter the structural cavity and interact with amino acid residues of α-casein, which was in accordance with the improved bioavailability of anthocyanins. Therefore, α-casein could assist more blueberry anthocyanins and their metabolites to enter blood circulation.

Beneficial Effects of Phenolic Compounds on Gut Microbiota and Metabolic Syndrome

The human intestine contains an intricate community of microorganisms, referred to as the gut microbiota (GM), which plays a pivotal role in host homeostasis. Multiple factors could interfere with this delicate balance, including genetics, age, medicines and environmental factors, particularly diet. Growing evidence supports the involvement of GM dysbiosis in gastrointestinal (GI) and extraintestinal metabolic diseases. The beneficial effects of dietary polyphenols in preventing metabolic diseases have been subjected to intense investigation over the last twenty years. As our understanding of the role of the gut microbiota advances and our knowledge of the antioxidant and anti-inflammatory functions of polyphenols accumulates, there emerges a need to examine the prebiotic role of dietary polyphenols. This review firstly overviews the importance of the GM in health and disease and then reviews the role of dietary polyphenols on the modulation of the gut microbiota, their metabolites and how they impact on host health benefits. Inter-dependence between the gut microbiota and polyphenol metabolites and the vital balance between the two in maintaining the host gut homeostasis are also discussed.

Recognizing the Benefits of Pre-/Probiotics in Metabolic Syndrome and Type 2 Diabetes Mellitus Considering the Influence of Akkermansia muciniphila as a Key Gut Bacterium

Metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) are diseases that can be influenced by the structure of gut microbiota, whose improvement is often neglected in metabolic pathology. This review highlights the following main aspects: the relationship between probiotics/gut microbes with the pathogenesis of MetS, the particular positive roles of Akkermansia muciniphila supplementation in the onset of MetS, and the interaction between dietary polyphenols (prebiotics) with gut microbiota. Therefore, an extensive and in-depth analysis of the often-neglected correlation between gut microbiota and chronic metabolic diseases was conducted, considering that this topic continues to fascinate and stimulate researchers through the discovery of novel strains and their beneficial properties.

The Interactions between Polyphenols and Microorganisms, Especially Gut Microbiota

This review presents the comprehensive knowledge about the bidirectional relationship between polyphenols and the gut microbiome. The first part is related to polyphenols' impacts on various microorganisms, especially bacteria, and their influence on intestinal pathogens. The research data on the mechanisms of polyphenol action were collected together and organized. The impact of various polyphenols groups on intestinal bacteria both on the whole "microbiota" and on particular species, including probiotics, are presented. Moreover, the impact of polyphenols present in food (bound to the matrix) was compared with the purified polyphenols (such as in dietary supplements) as well as polyphenols in the form of derivatives (such as glycosides) with those in the form of aglycones. The second part of the paper discusses in detail the mechanisms (pathways) and the role of bacterial biotransformation of the most important groups of polyphenols, including the production of bioactive metabolites with a significant impact on the human organism (both positive and negative).

Anthocyanins Are Converted into Anthocyanidins and Phenolic Acids and Effectively Absorbed in the Jejunum and Ileum

Anthocyanins have been known for their health benefits. However, the in vivo digestion and absorption of anthocyanins through the gastrointestinal tract have not been fully clarified, creating challenges for understanding why anthocyanins have high biological activities and purported low bioavailability in vivo. Twenty-seven male rats were intubated with a 500 mg/kg dose of cyanidin-3-glucoside (C3G). Samples from rats' stomach, duodenum, jejunum, ileum, colon, and serum were collected at 0.5, 1, 2, 3, 4, 5, 6, 12, and 24 h after intubation. Three rats without C3G were used as the control with samples collected at 0 h. C3G and its metabolites in each sample were analyzed using high-performance liquid chromatography-PDA-electrospray ionization-MS/MS. These in vivo studies' results unequivocally demonstrated that cyanidin and phenolic acids were the primary C3G metabolites absorbed, mainly in the jejunum and ileum, between 1 and 5 h post-ingestion. We speculate that C3G uses phloroglucinaldehyde and protocatechuic acid metabolic pathways in its metabolism in vivo.

Berry polyphenols metabolism and impact on human gut microbiota and health

Berries are rich in phenolic compounds such as phenolic acids, flavonols and anthocyanins. These molecules are often reported as being responsible for the health effects attributed to berries. However, their poor bioavailability, mostly influenced by their complex chemical structures, raises the question of their actual direct impact on health. The products of their metabolization, however, may be the most bioactive compounds due to their ability to enter the blood circulation and reach the organs. The main site of metabolization of the complex polyphenols to smaller phenolic compounds is the gut through the action of microorganisms, and reciprocally polyphenols and their metabolites can also modulate the microbial populations. In healthy subjects, these modulations generally lead to an increase in Bifidobacterium, Lactobacillus and Akkermansia, therefore suggesting a prebiotic-like effect of the berries or their compounds. Finally, berries have been demonstrated to alleviate symptoms of gut inflammation through the modulation of pro-inflammatory cytokines and have chemopreventive effects towards colon cancer through the regulation of apoptosis, cell proliferation and angiogenesis. This review recapitulates the knowledge available on the interactions between berries polyphenols, gut microbiota and gut health and identifies knowledge gaps for future research.

Chemopreventive Effect of Dietary Anthocyanins against Gastrointestinal Cancers: A Review of Recent Advances and Perspectives

Anthocyanins are a group of dietary polyphenols, abundant mainly in fruits and their products. Dietary interventions of anthocyanins are being studied extensively related to the prevention of gastrointestinal (GI) cancer, among many other chronic disorders. This review summarizes the hereditary and non-hereditary characteristics of GI cancers, chemistry, and bioavailability of anthocyanins, and the most recent findings of anthocyanin in GI cancer prevention through modulating cellular signaling pathways. GI cancer-preventive attributes of anthocyanins are primarily due to their antioxidative, anti-inflammatory, and anti-proliferative properties, and their ability to regulate gene expression and metabolic pathways, as well as induce the apoptosis of cancer cells.

Impact of Cyanidin-3-Glucoside on Gut Microbiota and Relationship with Metabolism and Inflammation in High Fat-High Sucrose Diet-Induced Insulin Resistant Mice

The present study assessed the effects of freeze-dried cyanidin-3-glucoside (C3G), an anthocyanin enriched in dark-red berries, compared to Saskatoon berry powder (SBp) on metabolism, inflammatory markers and gut microbiota in high fat-high sucrose (HFHS) diet-induced insulin-resistant mice. Male C57 BL/6J mice received control, HFHS, HFHS + SBp (8.0 g/kg/day) or HFHS + C3G (7.2 mg/kg/day, equivalent C3G in SBp) diet for 11 weeks. The HFHS diet significantly increased plasma levels of glucose, cholesterol, triglycerides, insulin resistance and inflammatory markers. The HFHS + SBp diet increased the Bacteroidetes/Firmicutes (B/F) ratio and relative abundance of Muriculaceae family bacteria in mouse feces detected using 16S rRNA gene sequencing. The HFHS + SBp or HFHS + C3G diet attenuated glucose, lipids, insulin resistance and inflammatory markers, and increased the B/F ratio and Muriculaceae relative abundance compared to the HFHS diet alone. The relative abundances of Muriculaceae negatively correlated with body weight, glucose, lipids, insulin resistance and inflammatory mediators. Functional predication analysis suggested that the HFHS diet upregulated gut bacteria genes involved in inflammation, and downregulated bacteria involved in metabolism. C3G and SBp partially neutralized HFHS diet-induced alterations of gut bacteria. The results suggest that C3G is a potential prebiotic, mitigating HFHS diet-induced disorders in metabolism, inflammation and gut dysbiosis, and that C3G contributes to the metabolic beneficial effects of SBp.