A new polysaccharide from Hawk tea: Structural characterization and immunomodulatory activity associated with regulating gut microbiota

Structural characteristics of a polysaccharide from Armillariella tabescens and its protective effect on colitis mice via regulating gut microbiota and intestinal barrier function

A new polysaccharide fraction (ATP) was obtained from Armillariella tabescens mycelium. Structural analysis suggested that the backbone of ATP was →4)-α-D-Glcp(1 → 2)-α-D-Galp(1 → 2)-α-D-Glcp(1 → 4)-α-D-Glcp(1→, which branched at O-3 of →2)-α-D-Glcp(1 → and terminated with T-α-D-Glcp or T-α-D-Manp. Besides, ATP significantly alleviated ulcerative colitis (UC) symptoms and inhibited the production of pro-inflammation cytokines (IL-1β, IL-6). Meanwhile, ATP could improve colon tissue damage by elevating the expression of MUC2 and tight junction proteins (ZO-1, occludin and claudin-1) levels and enhance intestinal barrier function through inhibiting the activation of MMP12/MLCK/p-MLC2 signaling pathway. Further studies exhibited that ATP could increase the relative abundance of beneficial bacteria such as f. Muribaculacese, g. Muribaculaceae, and g. Alistips, and decrease the relative abundance of g. Desulfovibrio, g. Colidextribacter, g. Ruminococcaceae and g.Oscillibacter, and regulate the level of short-chain fatty acids. Importantly, FMT intervention with ATP-derived microbiome certified that gut microbiota was involved in the protective effects of ATP on UC. The results indicated that ATP was potential to be further developed into promising therapeutic agent for UC.

Extraction methods, chemical compositions, molecular structure, health functions, and potential applications of tea polysaccharides as a promising biomaterial: a review

Tea polysaccharides (TPS) have attracted much attention due to their multiple biological activities, excellent biocompatibility and good biodegradability, creating a wide range of potential applications in the food and pharmaceutical industries. However, the high molecular weight and complexity of TPS components have restricted its purification and bioactivity, limiting its potential applications. In this review, the effects of various extraction methods, tea processing, and degree of fermentation on the composition and structure of TPS were thoroughly investigated to overcome this dilemma. Through a comprehensive analysis of in vivo and in vitro studies, the health benefits of TPS are discussed in detail, including antioxidant, anti-obesity, modulation of gut microbial communities, and anticancer bioactivities. Typical structural characterization techniques of TPS are also summarized, and interactions with common food components are discussed in depth, providing a deeper perspective on the overall knowledge of TPS. Finally, this review offers an extensive overview of the wide range of applications of TPS, including its strong emulsifying properties and bio-accessibility, in various fields such as food nutrition, drug delivery, encapsulation films, and emulsifiers. This review aims to provide a theoretical basis for the profound development of TPS for productive utilization.

Hyperuricemia drives intestinal barrier dysfunction by regulating gut microbiota

Background

Hyperuricemia elevates gut permeability; however, the risk of its influence on the compromised intestinal barrier is poorly understood.

Aims

This study was carried out, aiming to elucidate the orchestrators and disruptors of intestinal barrier in hyperuricemia.

Methods

A mouse model of hyperuricemia was induced by administering adenine and oteracil potassium to mice. Allopurinol was used to decrease uric acid level, and antibiotics were administered to mice to deplete gut microbiota. Intestinal permeability was assessed using FITC-labeled dextran. Changes in gut microbial community were analyzed through 16S rRNA sequencing. IL-1β and TNF-α levels were quantified using ELISA. The expression of tight junction protein genes, TLR4, p65 and IL-1β, was determined with Q-PCR and Western blotting.

Results

Allopurinol treatment effectively reduced intestinal permeability and serum TNF-α levels. Antibiotic treatment alleviated but not abolished intestinal permeability. Uric acid alone was insufficient to increase Coca2 monolayer permeability. Allopurinol treatment altered microbial composition and suppressed opportunistic infections. Re-establishing hyperuricemia in a germfree mouse model protected mice from intestinal injury. Allopurinol and antibiotic treatments reduced TLR4 and IL-1β expressions, increased occludin and claudin-1 expressions but suppressed NF-ĸB p65 signaling. However, removing gut microbiota aggravated lipid metabolic dysfunction.

Conclusion

Gut microbiota is a direct and specific cause for intestinal barrier dysfunction.

Isolation and characterization of a hepatoprotective polysaccharide from Lonicera caerulea L. var. edulis Turcz. ex Herd. fruit against APAP-induced acute liver injury mice

The structure and bioactivities of a novel polysaccharide from Lonicera caerulea L. var. edulis Turcz. ex Herd. fruit (THP-3) were investigated. The crude polysaccharides of Turcz. ex Herd. (THP) were extracted by hot water extraction. After purification, the chemical structure of polysaccharides was identified. Then, a mouse model of acute drug-induced liver injury was constructed using 4-acetamidophenol (APAP) and pretreated with THP. The number-average molecular weight of THP-3 was 48.89 kDa and the mass average molar mass was 97.87 kDa. THP-3 was mainly composed of arabinose (42.54 %), glucose (27.62 %), galacturonic acid and galactose (29.84 %). The main linkage types of THP-3 were 1-linked Araf, 1,4-linked Glcp, and 1,3,6-linked Galp. In addition, after THP treatment, serum Alanine aminotransferase (ALT), Aspartate aminotransferase (AST) and γ-glutamyl transpeptidase (γGT) in AILI mice were successfully down-regulated. The results showed that THP could prevent the characteristic morphological changes of hepatic lobular injury and lipid depletion caused by APAP, reduced the level of oxidative damage in mice, increased the expression of APAP-induced hypolipidemia and related inflammatory indicators, and improved the detoxification function of liver. In general, the newly extracted THP polysaccharide has a good liver protection effect and is an ideal natural medicine for the treatment of liver diseases.

Positive effects of extracellular polysaccharides from Paecilomyces hepiali on immune-enhancing properties by regulating gut microbiota in cyclophosphamide-induced mice

Paecilomyces hepiali is a precious health-care edible medicinal fungus with rich polysaccharides and exhibits various biological activities. Polysaccharides from P. hepiali fermentation broth (PHP) exhibits good immunomodulatory activity; however, the mechanism underlying PHP-mediated regulation of immunity and gut microbiota remains unclear. To reveal the mechanisms, PHP of different doses were used to intervene cyclophosphamide (CTX)-induced immunosuppressive model mice. The results revealed that PHP facilitated the secretion of serum cytokines, increased the mRNA and protein expression of TLR4/NF-κB signaling pathway. Furthermore, it improved the physical barrier function of the intestine by upregulating the expression of tight junction proteins. PHP increased the proliferation of beneficial bacteria, including, Actinobacteriota, Alistipes, Candidatus_Saccharimonas and unclassified_Clostridia_vadinBB60_group, and reduced the abundance of Proteobacteria, Deferribacterota, Mucispirillum and Escherichia_Shigella, promoted the production of short-chain fatty acids, which were positively associated with immune traits. Thus, as an immune enhancer, PHP has the potential to regulate the intestinal immune response in immunosuppressed mice through modulating gut microbiota.

Progress of plant-derived non-starch polysaccharides and their challenges and applications in future foods

The development of future food is devoted not only to obtaining a sustainable food supply but also to providing high-quality foods for humans. Plant-derived non-starch polysaccharides (PNPs) are widely available, biocompatible, and nontoxic and have been largely applied to the food industry owing to their mechanical properties and biological activities. PNPs are considered excellent biomaterials and food ingredients contributing to future food development. However, a comprehensive review of the potential applications of PNPs in future food has not been reported. This review summarized the physicochemical and biological activities of PNPs and then discussed the structure-activity relationships of PNPs. Latest studies of PNPs on future foods including cell-cultured meat, food for special medical purposes (FSMPs), and three-dimensional-printed foods were reviewed. The challenges and prospects of PNPs applied to future food were critically proposed. PNPs with strong thermal stability are considered good thickeners, emulsifiers, and gelatinizers that greatly improve the processing adaptability of foods. The mechanical properties of PNPs and decellularized plant-based PNPs make them desirable scaffolds for cultured meat manufacturing. In addition, the biological activities of PNPs exhibit multiple health-promoting effects; therefore, PNPs can act as food ingredients producing FSMP to promote human health. Three-dimensional printing technology enhances food structures and biological activities of functional foods, which is in favor of expanding the application scopes of PNPs in future food. PNPs are promising in future food manufacturing, and more efforts need to be made to realize their commercial applications.

Isolation, structural characterization and immunomodulatory activity on RAW264.7 cells of a novel exopolysaccharide of Dictyophora rubrovalvata

Fungal polysaccharides have been explored by many for both structural studies and biological activities, but few studies have been done on the extracellular polysaccharides of Dictyophora rubrovalvata, so a new exopolysaccharide was isolated from Dictyophora rubrovalvata and its structure and its immunological activity were investigated. The crude exopolysaccharide (EPS) was purified by DEAE52 cellulose and Sephadex G-200 to obtain a new acidic polysaccharide (DR-EPS). DR-EPS (2.66 × 103 kDa) was consisted mainly of mannose, glucose, galactose and glucuronic acid with a molar ratio of 1: 0.86: 0.20: 0.01. In addition, DR-EPS increased the phagocytic activity of RAW264.7 cells up to 2.67 times of the blank control group. DR-EPS improved intracellular nucleic acid and glycogen metabolism as observed by AO and PAS staining. DR-EPS(40 μg/mL) promoted NO production up to 30.66 μmol, enhanced acid phosphatase (ACP) and superoxide dismutase (SOD) activities, with activity maxima of 660 U/gprot and 96.27 U/mgprot, respectively, and DR-EPS (160 μg / mL) significantly increased the lysozyme content as 2.73 times of the control group. The good immunological activity of extracellular polysaccharides of Dictyophora rubrovalvata provides directions for the use of fermentation broths.

Attenuation effect of a polysaccharide from large leaf yellow tea by activating autophagy

Chemotherapy, the most common class of anticancer drugs, is considerably limited owing to its adverse side effects. In this study, we aimed to evaluate the protective effect and mechanism of action of large-leaf yellow tea polysaccharides (ULYTP-1, 1.29 × 104 Da) against chemotherapeutic 5-fluorouracil (5-Fu). Structural characterisation revealed that ULYTP-1 was a β-galactopyranouronic acid. Furthermore, ULYTP-1 promoted autolysosome formation, activating autophagy and reducing the oxidative stress and inflammation caused by 5-Fu. Our in vivo study of 4 T1 tumour-bearing mice revealed that ULYTP-1 also attenuated 5-Fu toxicity through modulation of the gut microbiota. Moreover, ULYTP-1 effectively protected immune organs and the liver from 5-Fu toxicity, while promoting its tumour-inhibitory properties. The current findings provide a new strategy for optimising chemotherapy regimens in the clinic.

Structural Characterization and Antidepressant-like Effects of Polygonum sibiricum Polysaccharides on Regulating Microglial Polarization in Chronic Unpredictable Mild Stress-Induced Zebrafish

Polysaccharides are one of the main active ingredients of Polygonum sibiricum (PS), which is a food and medicine homolog used throughout Chinese history. The antidepressant-like effects of PSP and its underlying mechanisms remain elusive, especially the regulation of microglial polarization. The current study determined the chemical composition and structural characteristics of PSP. Then, the chronic unpredictable mild stress (CUMS) procedure was carried out on the zebrafish for 5 weeks, and PSP was immersed for 9 days (1 h/d). The body weight of zebrafish was monitored, and behavioral tests, including the novel tank test and light and dark tank test, were performed to evaluate the antidepressant-like effects of PSP. Then, the function of the hypothalamic-pituitary-interrenal (HPI) axis, the levels of peripheral inflammation, neuronal and blood-brain barrier damage in the mesencephalon and telencephalon, and the mRNA expression of M1/M2 phenotype genes in the brain were examined. PSP samples had the typical structural characteristics of polysaccharides, consisting of glucose, mannose, and galactose, with an average Mw of 20.48 kDa, which presented porous and agglomerated morphologies. Compared with untreated zebrafish, the depression-like behaviors of CUMS-induced zebrafish were significantly attenuated. PSP significantly decreased the levels of cortisol and pro-inflammatory cytokines and increased the levels of the anti-inflammatory cytokines in the body of CUMS-induced depressive zebrafish. Furthermore, PSP remarkably reversed the neuronal and blood-brain barrier damage in the mesencephalon and telencephalon and the mRNA expression of M1/M2 phenotype genes in the brain. These findings indicated that the antidepressant-like effects of PSP were related to altering the HPI axis hyperactivation, suppressing peripheral inflammation, inhibiting neuroinflammation induced by microglia hyperactivation, and modulating microglial M1/M2 polarization. The current study provides the foundations for future examinations of PSP in the functional foods of emotional regulation.

A dynamics association study of gut barrier and microbiota in hyperuricemia

Introduction

The intricate interplay between gut microbiota and hyperuricemia remains a subject of growing interest. However, existing studies only provided snapshots of the gut microbiome at single time points, the temporal dynamics of gut microbiota alterations during hyperuricemia progression and the intricate interplay between the gut barrier and microbiota remain underexplored. Our investigation revealed compelling insights into the dynamic changes in both gut microbiota and intestinal barrier function throughout the course of hyperuricemia.

Methods

The hyperuricemia mice (HY) were given intragastric administration of adenine and potassium oxalate. Gut microbiota was analyzed by 16S rRNA sequencing at 3, 7, 14, and 21 days after the start of the modeling process. Intestinal permeability as well as LPS, TNF-α, and IL-1β levels were measured at 3, 7, 14, and 21 days.

Results

We discovered that shifts in microbial community composition occur prior to the onset of hyperuricemia, key bacterial Bacteroidaceae, Bacteroides, and Blautia exhibited reduced levels, potentially fueling microbial dysbiosis as the disease progresses. During the course of hyperuricemia, the dynamic fluctuations in both uric acid levels and intestinal barrier function was accompanied with the depletion of key beneficial bacteria, including Prevotellaceae, Muribaculum, Parabacteroides, Akkermansia, and Bacteroides, and coincided with an increase in pathogenic bacteria such as Oscillibacter and Ruminiclostridium. This microbial community shift likely contributed to elevated lipopolysaccharide (LPS) and pro-inflammatory cytokine levels, ultimately promoting metabolic inflammation. The decline of Burkholderiaceae and Parasutterella was inversely related to uric acid levels, Conversely, key families Ruminococcaceae, Family_XIII, genera Anaeroplasma exhibited positive correlations with uric acid levels. Akkermansiaceae and Bacteroidaceae demonstrating negative correlations, while LPS-containing microbiota such as Desulfovibrio and Enterorhabdus exhibited positive correlations with intestinal permeability.

Conclusion

In summary, this study offers a dynamic perspective on the complex interplay between gut microbiota, uric acid levels, and intestinal barrier function during hyperuricemia progression. Our study suggested that Ruminiclostridium, Bacteroides, Akkermansiaceae, Bilophila, Burkholderiaceae and Parasutterella were the key bacteria that play vital rols in the progress of hyperuricemia and compromised intestinal barrier, which provide a potential avenue for therapeutic interventions in hyperuricemia.

Exopolysaccharides from Genistein-Stimulated Monascus purpureus Ameliorate Cyclophosphamide-Induced Intestinal Injury via PI3K/AKT-MAPKs/NF-κB Pathways and Regulation of Gut Microbiota

Exopolysaccharides from genistein-stimulated Monascus purpureus (G-EMP) exhibited immunomodulatory potential in vitro, but whether it had immune-enhancing effects in vivo and its potential mechanism are not yet known. Here, the immunomodulatory effects of G-EMP were investigated by establishing an immunosuppressed mouse model treated with cyclophosphamide (Cy). The results suggested that G-EMP effectively alleviated the signs of weight reduction and diet reduction caused by Cy, increased fecal water content and splenic index, and decreased the oxidative stress of the liver. Simultaneously, G-EMP improved Cy-induced intestinal injury by restoring villus length, increasing the number of cupped cells, upregulating the expression of mucin and tight junction proteins, and downregulating the ratio of apoptotic proteins (Bax/Bcl-2). It also boosted the levels of mouse colonic cytokines, CD4+ and CD8+ T cells. Additionally, G-EMP markedly enhanced immunomodulation via the activation of PI3K/AKT-MAPKs/NF-κB signal pathways. Furthermore, G-EMP intervention displayed a positive association with most immunological indexes by elevating the levels of short-chain fatty acids, varying gut microbiota composition, and enhancing beneficial bacteria (Lactobacillaceae, Prevotellaceae, and S24-7). These findings demonstrated that G-EMP can strengthen immunity, repair intestinal mucosal damage, regulate gut microbiota, and be a potential source of prebiotics.