Non-digestible Polysaccharides Research Articles

The Degree of Inulin Polymerization Is Important for Short-Term Amelioration of High-Fat Diet (HFD)-Induced Metabolic Dysfunction and Gut Microbiota Dysbiosis in Rats.

Inulin, a non-digestible polysaccharide, has gained attention for its prebiotic properties, particularly in the context of obesity, a condition increasingly understood as a systemic inflammatory state linked to gut microbiota composition. This study investigates the short-term protective effects of inulin with different degrees of polymerization (DPn) against metabolic health deterioration and gut microbiota alterations induced by a high-fat diet (HFD) in Sprague Dawley rats. Inulin treatments with an average DPn of 7, 14, and 27 were administered at 1 g/kg of bodyweight to HFD-fed rats over 21 days. Body weight, systemic glucose levels, and proinflammatory markers were measured to assess metabolic health. Gut microbiota composition was analyzed through 16S rRNA gene sequencing. The results showed that inulin27 significantly reduced total weight gain and systemic glucose levels, suggesting a DPn-specific effect on metabolic health. The study also observed shifts in gut microbial populations, with inulin7 promoting several beneficial taxa from the Bifidobacterium genera, whilst inducing a unique microbial composition compared to medium-chain (DPn 14) and long-chain inulin (DPn: 27). However, the impact of inulin on proinflammatory markers and lipid metabolism parameters was not statistically significant, possibly due to the short study duration. Inulin with a higher DPn has a more pronounced effect on mitigating HFD-induced metabolic health deterioration, whilst inulin7 is particularly effective at inducing healthy microbial shifts. These findings highlight the benefits of inulin as a dietary adjuvant in obesity management and the importance of DPn in optimizing performance.

Auricularia auricula polysaccharides attenuate obesity in mice through gut commensal Papillibacter cinnamivorans

IntroductionAuricularia auricula is a well-known traditional edible and medical fungus with high nutritional and pharmacological values, as well as metabolic and immunoregulatory properties. Nondigestible fermentable polysaccharides are identified as primary bioactive constituents of Auricularia auricula extracts. However, the exact mechanisms underlying the effects of Auricularia auricula polysaccharides (AAP) on obesity and related metabolic endpoints, including the role of the gut microbiota, remain insufficiently understood. MethodsThe effects of AAP on obesity were assessed within high-fat diet (HFD)-based mice through obesity trait analysis and metabolomic profiling. To determine the mechanistic role of the gut microbiota in observed anti-obesogenic effects AAP, faecal microbiota transplantation (FMT) and pseudo-germ-free mice model treated with antibiotics were also applied, together with 16S rRNA genomic-derived taxonomic profiling. ResultsHigh-fat diet (HFD) murine exposure to AAP thwarted weight gains, reduced fat depositing and enhanced glucose tolerance, together with upregulating thermogenesis proteomic biomarkers within adipose tissue. Serum metabolome indicated these effects were associated with changes in fatty acid metabolism. Intestine-dwelling microbial population assessments discovered that AAP selectively enhanced Papillibacter cinnamivorans, a commensal bacterium with reduced presence in HFD mice. Notably, HFD mice treated with oral formulations of P. cinnamivorans attenuated obesity, which was linked to decreased intestinal lipid transportation and hepatic thermogenesis. Mechanistically, it was demonstrated that P. cinnamivorans regulated intestinal lipids metabolism and liver thermogenesis by reducing the proinflammatory response and gut permeability in a JAK-STAT signaling-related manner. ConclusionDatasets from the present study show that AAP thwarted dietary-driven obesity and metabolism-based disorders by regulating intestinal lipid transportation, a mechanism that is dependent on the gut commensal P. cinnamivorans. These results indicated AAP and P. cinnamivorans as newly identified pre- and probiotics that could serve as novel therapeutics against obesity.

Development and validation of derivatization-based LC-MS/MS method for quantification of short-chain fatty acids in human, rat, and mouse plasma

Short-chain fatty acids (SCFAs), the end products of gut microbial fermentation of dietary fibers and non-digestible polysaccharides, act as a link between the microbiome, immune system, and inflammatory processes. The importance of accurately quantifying SCFAs in plasma has recently emerged to understand their biological role. In this work, a sensitive and reproducible LC-MS/MS method is reported for SCFAs quantification in three different matrices such as human, rat and mouse plasma via derivatization, using as derivatizing agent O-benzylhydroxylamine (O-BHA), coupled with liquid-liquid extraction. First, the instrumental parameters of the mass spectrometer and then the chromatographic conditions were optimized using previously SCFAs derivatives synthetized and used as standards. After that, the best conditions for derivatization and extraction from plasma were studied and a series of determinations were performed on human, rat, and mouse plasma aliquots to validate the overall method (derivatization, extraction, and LC-MS/MS determination). The method showed good performance in terms of recovery (> 80%), precision (RSD <14%), accuracy (RE < ± 10%) and sensitivity (LOQ of 0.01 µM for acetic, butyric, propionic and isobutyric acid) in all plasma samples. The method thus developed and validated was applied to the quantification of major SCFAs in adult and aged mice, germ-free mice and in germ-free recipient mice subjected to fecal transplant from adult and aged donors. Results highlighted how plasma concentrations of SCFAs are correlated with age further highlighting the importance of developing a method that is reliable for the quantification of SCFAs to study their biological role.

Obtaining non-digestible polysaccharides from distillers' grains of Chinese baijiu after extrusion with enhanced antioxidation capability

Distillers' grains of Chinese Baijiu (DGS) presents a significant challenge to the environmentally-friendly production of the brewing industry. This study utilized screw extrusion to modify the morphological and crystalline characteristics of DGS, resulting in a 316 % increase in the yield of non-digestible polysaccharides extraction. Physiochemical characteristics of extracted polysaccharides were variated, including infrared spectrum, monosaccharide composition, and molecular weight. Polysaccharides extracted from extruded DGS exhibited enhanced inhibitory capacity on α-amylase activity and starch hydrolyzation, as compared to those extracted from unextruded DGS. Additionally, the ABTS, DPPH, and OH radical scavenging efficiencies took a maximum increase of 1.20, 1.38, and 1.02-fold, correspondingly. Extrusion is a novel approach for the recycling non-digestible polysaccharides from DGS, augmenting the bioactivity of extracts and their potential application in functional food.

Depolymerized non-digestible sulfated algal polysaccharides produced by hydrothermal treatment with enhanced bacterial fermentation characteristics

Hydrothermal treatment was used to depolymerize sulfated polysaccharide extracted from Gracilaria chouae (GCP1) with an average molecular weight (Mw) of 1.79 × 10 3 kDa to produce three fractions GCP2, GCP3, and GCP4 with a Mw of 20.84, 8.25, and <5 kDa, respectively. While the chemical composition and monosaccharide profile of the three depolymerized GCPs were not significantly affected by the hydrothermal treatment. However, they exhibited lower apparent viscosity, storage modulus, and loss modulus. All four GCPs were shown to be nondigestible during simulated gastrointestinal digestion. During a 24-h in vitro fermentation using human fecal bacteria as inoculum, GCPs with lower Mw produced more short chain fatty acids (SCFAs), and lower branched chain fatty acids. Having the lowest Mw, GCP4 exhibited the best fermentation characteristics by inhibiting the growth of protein-fermentative bacteria including Bacteroides , Parabacteroides , Lachnoclostridium , and Phascolarctobacterium which have harmful effect and increased the relative abundance of butyrate-producing bacteria including Anaerostipes , Eubacterium , Roseburia , Ruminococcus and Lachnospira which are beneficial to gut health. The present study suggested that hydrothermal treatment could be used to prepare low Mw non-digestible polysaccharides that enhance the growth of beneficial bacteria for human gut health. • Polysaccharide from Gracilaria chouae was depolymerized using hydrothermal treatment. • Polysaccharides with lower Mw exhibited lower apparent viscosity, storage and loss modulus. • G. chouae polysaccharides with lower Mw showed better fermentation properties. • Hydrothermal treatment can be used to obtain polysaccharides with enhanced prebiotic activities.

Fiber-enriched botanicals: A therapeutic tool against certain metabolic ailments.

Plant‐based foods are natural sources including vegetables, fruits, cereals and legumes. These foods consist of various types of nutrients in which carbohydrate is the basic component. However, some plant‐based diets contain carbohydrates in the form of fiber. The fiber is usually a nondigestible polysaccharide that is not digested in the human body. It is present in the form of soluble or insoluble in different part of foods like peel, bran, pulp and grain. Pectin, beta‐glucan, mucilage, psyllium, resistant starch and inulin are soluble fiber, and cellulose, hemicellulose and lignin are insoluble fiber attained from plant foods. The major function enhances immunity by creating gastrointestinal barrier, mucus production, immune cell activity and IgA level. Previous evidences showed that peoples with strong immunity have fewer chances of viral disease. A recent viral disease named COVID‐19 spread in the world and millions of peoples died due to this viral disease. Coronavirus mostly attacks humans that suffer with weak immune system. It is due chronic diseases like diabetes and CVD (cardiovascular disease). The current review shows that fiber‐containing plant‐based foods boost immunity and aid human against COVID‐19. The therapeutic role of fiber in the human body is to control the risk of hypertension and diabetes because a high‐fiber diet has the ability to lower cholesterol, blood pressure and blood sugar. Fibers aid in GIT (gastrointestinal tract) and prevent constipation because it absorbs water and adds bulk to stool.

Structural characterization of mushroom polysaccharides by cyclic ion mobility-mass spectrometry

Polysaccharides are biopolymers known to possess various bioactivities. Because of their molecular complexity, the structural characterization of polysaccharides remains challenging, and difficult to be completed with a single analytical method. In this study, a novel approach for the characterization of linkages and anomeric configuration of polysaccharides was proposed. Based on ion mobility-mass spectrometry (IM-MS), a database containing 5 glucotriose standards was set up. Information about the arrival time distribution and fragmentation patterns of these standards were included. The method was validated by three commercially available purified polysaccharides, namely laminarin, dextrin, and dextran, each having distinct connectivity and configuration of the glycosidic bonds. Lastly, the method was successfully applied to analyze polysaccharides prepared from three medicinal mushrooms, namely Xylaria nigripes, Grifola frondosa, and Laetiporus sulphureus. The results showed that water-soluble non-digestible polysaccharides of X. nigripes and G. frondosa were mainly composed of (1→3)-β-glucan, while that of L.sulphureus was composed of (1→3)-ɑ-glucan. The present method has the advantages of being simple in sample preparation and short analysis time.

Prebiotics and the Human Gut Microbiota: From Breakdown Mechanisms to the Impact on Metabolic Health.

The colon harbours a dynamic and complex community of microorganisms, collectively known as the gut microbiota, which constitutes the densest microbial ecosystem in the human body. These commensal gut microbes play a key role in human health and diseases, revealing the strong potential of fine-tuning the gut microbiota to confer health benefits. In this context, dietary strategies targeting gut microbes to modulate the composition and metabolic function of microbial communities are of increasing interest. One such dietary strategy is the use of prebiotics, which are defined as substrates that are selectively utilised by host microorganisms to confer a health benefit. A better understanding of the metabolic pathways involved in the breakdown of prebiotics is essential to improve these nutritional strategies. In this review, we will present the concept of prebiotics, and focus on the main sources and nature of these components, which are mainly non-digestible polysaccharides. We will review the breakdown mechanisms of complex carbohydrates by the intestinal microbiota and present short-chain fatty acids (SCFAs) as key molecules mediating the dialogue between the intestinal microbiota and the host. Finally, we will review human studies exploring the potential of prebiotics in metabolic diseases, revealing the personalised responses to prebiotic ingestion. In conclusion, we hope that this review will be of interest to identify mechanistic factors for the optimization of prebiotic-based strategies.

Intestinal Microbiota-Derived Short Chain Fatty Acids in Host Health and Disease

Intestinal microbiota has its role as an important component of human physiology. It produces metabolites that module key functions to establish a symbiotic crosstalk with their host. Among them, short chain fatty acids (SCFAs), produced by intestinal bacteria during the fermentation of partially and non-digestible polysaccharides, play key roles in regulating colon physiology and changing intestinal environment. Recent research has found that SCFAs not only influence the signal transduction pathway in the gut, but they also reach tissues and organs outside of the gut, through their circulation in the blood. Growing evidence highlights the importance of SCFAs level in influencing health maintenance and disease development. SCFAs are probably involved in the management of host health in a complicated (positive or negative) way. Here, we review the current understanding of SCFAs effects on host physiology and discuss the potential prevention and therapeutics of SCFAs in a variety of disorders. It provides a systematic theoretical basis for the study of mechanisms and precise intake level of SCFAs to promote human health.

Real-Time Non-Invasive Monitoring of Short-Chain Fatty Acids in Exhaled Breath.

Short-chain fatty acids (SCFAs) are important metabolites produced by the gut microbiome as a result of the fermentation of non-digestible polysaccharides. The most abundant SCFAs are acetic acid, propionic acid, and butyric acid which make up 95% of this group of metabolites in the gut. Whilst conventional analysis SCFAs is done using either blood or fecal samples, SCFAs can also be detected in exhaled breath using proton transfer reaction-time-of-flight- mass spectrometry (PTR-ToF-MS) using H3O+ for ionization. However, no investigation has been performed to characterize the reactions of SCFAs with H3O+ and with other reagent ions, such as O2 + and NO+. Gas-phase samples of acetic acid, propionic acid, and butyric acid were analyzed with SRI/PTR-ToF-MS under dry and humid conditions. The ions generated and their distribution was determined for each reagent ion. It was found the humidity did not influence the product ion distribution for each SCFA. Using H3O+ as a reagent ion, SRI/PTR-ToF-MS analysis of an exhaled breath sample was performed in real-time to demonstrate the methodology. The presence of SCFAs in exhaled breath was confirmed by thermal desorption—gas chromatography—mass spectrometry (TD-GC-MS). Breath sampling repeatability was within acceptable limits (<15%) for an analytical methodology for each investigated SCFA. Nutritional intervention studies could potentially benefit from real-time monitoring of exhaled SCFAs as an alternative to measuring SCFAs invasively in blood or fecal samples since it is non-invasive, and requires minimal time investment from participants.

Enhanced Growth Inhibition and Apoptosis Induction in Human Colon Carcinoma HT-29 Cells of Soluble Longan Polysaccharides with a Covalent Chemical Selenylation.

The selenylated polysaccharides chemically belong to the organic Se-conjugated macromolecules and have recently been attracting more and more attention due to their potential to promote body health or prevent cancers. Longan (Dimocarpus longan L.), as a subtropical fruit, contains soluble and non-digestible polysaccharides that are regarded with health care functions in the body. In this study, the longan polysaccharides (LP) were obtained via enzyme-assisted water extraction, and then chemically selenylated using a reaction system composed of HNO3–Na2SeO3 to yield two selenylated products, namely, SeLP1 and SeLP2, with Se contents of 1.46 and 4.79 g/kg, respectively. The anti-cancer effects of the three polysaccharide samples (LP, SeLP1, and SeLP2) were thus investigated using the human colon cancer HT-29 cells as the cell model. The results showed that SeLP1 and SeLP2 were more able than LP to inhibit cell growth, alter cell morphology, cause mitochondrial membrane potential loss, increase intracellular reactive oxygen and [Ca2+]i levels, and induce apoptosis via regulating the eight apoptosis-related genes and proteins including Bax, caspases-3/-8/-9, CHOP, cytochrome c, DR5, and Bcl-2. It was thereby proven that the selenylated polysaccharides could induce cell apoptosis via activating the death receptor, mitochondrial-dependent, and ER stress pathways. Collectively, both SeLP1 and SeLP2 showed higher activities than LP in HT-29 cells, while SeLP2 was consistently more active than SeLP1 in exerting these assessed anti-cancer effects on the cells. In conclusion, this chemical selenylation covalently introduced Se into the polysaccharide molecules and caused an enhancement in their anti-cancer functions in the cells, while higher selenylation extent was beneficial to the activity enhancement of the selenylated products.

Plant-sourced intrinsic dietary fiber: Physical structure and health function

Plant-sourced intrinsic dietary fiber (PIDF), mainly composed of nondigestible polysaccharides in a cell wall form, is often existed in plant tissue particles in which the physical structure of the particle size, density and spatial organization of food component as well as the intactness and porosity of cell wall are critical to its physicochemical properties and health functions. However, there is limited information of PIDF compared to isolated and purified DF that is a chemical entity without association with the food context. The health benefit and physical structures of PIDF are emerging as a new research area in the field of DF although there is still limited information in the literature reports. In the current article, available information on the relationship between the physical structure and the physiological function as well as resulted health benefits of PIDF in a whole food context were reviewed in conjunction with food processing. The physical structure of PIDF is a critical factor modulating the intestinal digestion and bioavailability of intracellular nutrients. PIDF can exert its health function through a physical structure-specific microbial fermentation and/or microbiota-independent pathways. A holistic approach to reveal the relationship between the physical structure and health function of PIDF will shed novel insight into the designing of PIDF enriched functional foods. • Plant-sourced intrinsic dietary fiber (PIDF) is an physical entity presented as plant tissue particles • The physical structure is crucial for the functions of plant-sourced intrinsic dietary fiber (PIDF) • Encapsulation mechanism is involved in PIDF's impact on the metabolic fate of intracellular nutrients • The colonic fermentation-dependent and independent pathways are the basis for PIDF's health function

Chronic in vitro fermentation and in vivo metabolism: Extracellular polysaccharides from Sporidiobolus pararoseus regulate the intestinal microbiome of humans and mice

The fungus Sporidiobolus pararoseus not only produces carotenoids, but also produces bioactive extracellular polysaccharides (SPP). However, the relationship between SPP and the metabolism of gut microbiome is unclear. The aim of this study was to investigate the mechanism of SPP regulating intestinal health in vivo and in vitro. Results showed that SPP are nondigestible polysaccharides after the digestion with simulated stomach and small intestinal juice in vitro. After SPP was cultured in an in vitro intestinal simulation system for seven days, the concentration of short-chain fatty acids (SCFAs) increased; the microbial diversity changed; the relative abundance of Bifidobacterium and Streptococcus increased; and that of Escherichia Shigella and Lachnospiraceae NK4A136 decreased. In addition, metabolism of SPP by the mice colonic microbiome showed SPP decreased the relative abundance of Firmicutes and Bacteroidota, while the relative abundance of Verrucomicrobiota, Desulfobacterota, and Actinobacteriota increased. Finally, predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolism results also showed that SPP can enhance the metabolism of cofactors, vitamins, amino acids, starch, and sucrose. In conclusion, SPP can multiply the intestinal beneficial bacteria of humans and mice, promote the production of SCFAs and metabolism of amino acids, and promote intestinal health.

Adjuvant Effect of Orally Applied Preparations Containing Non-Digestible Polysaccharides on Influenza Vaccination in Healthy Seniors: A Double-Blind, Randomised, Controlled Pilot Trial.

Senior individuals can suffer from immunosenescence and novel strategies to bolster the immune response could contribute to healthy ageing. In this double-blind, randomised, controlled pilot trial, we investigated the ability of non-digestible polysaccharide (NPS) preparations to enhance the immune response in a human vaccination model. In total, 239 subjects (aged 50–79 years) were randomised to consume one of five different NPS (yeast β-glucan (YBG), shiitake β-glucan (SBG), oat β-glucan (OBG), arabinoxylan (AX), bacterial exopolysaccharide (EPS)) or control (CTRL) product daily for five weeks. After two weeks of intervention, subjects were vaccinated with seasonal influenza vaccine. The post-vaccination increases in haemagglutination inhibition antibody titres and seroprotection rate against the influenza strains were non-significantly enhanced in the NPS intervention groups compared to CTRL. Specifically, a trend towards a higher mean log2 fold increase was observed in the AX group (uncorrected p = 0.074) combined with a trend for an increased seroprotection rate, AX group (48.7%) compared to CTRL (25.6%) (uncorrected p = 0.057), for the influenza A H1N1 strain. Subjects consuming AX also had a reduced incidence of common colds compared to CTRL (1 vs. 8; p = 0.029 in Fisher exact test). No adverse effects of NPS consumption were reported. The findings of this pilot study warrant further research to study AX as an oral adjuvant to support vaccine efficacy.

Continuous Exposure to Non-Soluble β-Glucans Induces Trained Immunity in M-CSF-Differentiated Macrophages.

Beta-glucans enable functional reprogramming of innate immune cells, a process defined as “trained immunity”, which results in enhanced host responsiveness against primary (training) and/or secondary infections (resilience). Trained immunity holds great promise for promoting immune responses in groups that are at risk (e.g. elderly and patients). In this study, we modified an existing in vitro model for trained immunity by actively inducing monocyte-to-macrophage differentiation using M-CSF and applying continuous exposure. This model reflects mucosal exposure to β-glucans and was used to study the training effects of a variety of soluble or non-soluble β-glucans derived from different sources including oat, mushrooms and yeast. In addition, trained immunity effects were related to pattern recognition receptor usage, to which end, we analyzed β-glucan-mediated Dectin-1 activation. We demonstrated that β-glucans, with different sources and solubilities, induced training and/or resilience effects. Notably, trained immunity significantly correlated with Dectin-1 receptor activation, yet Dectin-1 receptor activation did not perform as a sole predictor for β-glucan-mediated trained immunity. The model, as validated in this study, adds on to the existing in vitro model by specifically investigating macrophage responses and can be applied to select non-digestible dietary polysaccharides and other components for their potential to induce trained immunity.

In Vitro Fermentation Characteristics and Fiber-Degrading Enzyme Kinetics of Cellulose, Arabinoxylan, β-Glucan and Glucomannan by Pig Fecal Microbiota.

Non-digestible polysaccharides are of great significance to human and animal intestinal health. Cellulose, arabinoxylan, β−glucan and glucomannan were selected in the present study to investigate the fermentation characteristics and fiber-degrading enzyme kinetics by inoculating pig fecal microbiota in vitro. Our results showed that fermentation of arabinoxylan and β-glucan produced the highest amount of acetate and lactate, respectively. The abundance of Prevotella_9 was the highest in β-glucan group and positively correlated with lactate and acetate. Glucomannan fermentation produced the highest amount of butyrate, and the abundance of Lachnospiraceae_XPB_1014_group and Bacteroides were the lowest. A significant negative correlation was found between Lachnospiraceae_XPB_1014_group, Bacteroides and butyrate. Exo-β-1,4-xylanase had the highest activity at 24 h during arabinoxylan fermentation. The activity of β-glucosidase and β-mannosidase at 36 h were higher than those at 15 h in the glucomannan group. The abundance of Prevotella_9 was positively correlated with β-glucosidase while Lachnospiraceae_XPB_1014_group and Bacteroides were negatively correlated with β-xylosidase. Our findings demonstrated the β-glucan and arabinoxylan promote proliferation of Prevotella_9, with the preference to secret β-glucosidase, β-mannosidase and the potential to produce lactate and acetate. Butyrate production can be improved by inhibiting the proliferation of Lachnospiraceae_XPB_1014_group and Bacteroides, which have the lack of potential to secret β-xylosidase.

Behavior of Non-Digestible Polysaccharides in Gastrointestinal Tract: A Mechanistic Review of its Anti-Obesity Effect

Nowadays, obesity in humans is a huge challenge requiring effective, readily available, and low-risk alternative treatments. Intake of edible Non-Digestible Polysaccharides (NDPs) is regarded as a promising strategy to combat obesity. Herein, an overview of the behavior of NDPs in the Gastrointestinal (GI) tract and its association with anti-obesity effect is summarized. Both the in vitro and in vivo of such investigations are discussed. Results show that NDPs can reach the large intestine to mediate the gut microbiota with the extent of regulation varies among NDPs with different chemical structures. The possible anti-obesity mechanisms associated with behavior of NDPs in the GI tract include: (i) inhibition of fat absorption, (ii) modification of gut microbiota and their metabolites such as short-chain fatty acids, (iii) regulation of bile acid profiles, (iv) modulation on appetite and satiety effect, and (v) protection of intestinal barrier. However, more efforts are required to clarify the exact behavior and their beneficial effects of NDPs within GI tract. This paper will provide an overlook of recent advances for better understanding anti-obesity activity of NDPs.

Synergistic anti-inflammatory effects of different polysaccharide components from Xylaria nigripes.

Nondigestible polysaccharides are essential nutrients, which are also important bioactive constituents of mushrooms. This study aimed to investigate the physicochemical properties and anti-inflammatory effects of different polysaccharide components of Xylaria nigripes in lipopolysaccharides (LPS)-induced RAW264.7 macrophages. Results showed that X. nigripes nondigestible polysaccharide (XN) possessed a molecular weight of 910.7kDa and mainly composed of glucose; it effectively suppressed NO, TNF-α, and IL-6 production. Based on molecular weight, two bioactive polysaccharide components (F1 and F2) were isolated from XN. F1 was a glucan with high molecular weight (885.2kDa), whereas F2 was a low molecular weight heteropolysaccharide (24.5kDa) composing of glucose, mannose, and galactose. F1 showed stronger inhibitory effects on NO, TNF-α, and IL-6 production than F2, however, its inhibitory effects were weaker than XN. Further analysis demonstrated that the combined treatment of F1 and F2 exhibited anti-inflammatory activity as good as XN, and they possessed synergistic effects on inhibiting pro-inflammatory mediator production. PRACTICAL APPLICATIONS: Polysaccharides are essential nutrients, and are major bioactive constituents of mushrooms. This study isolated two bioactive polysaccharide components from Xylaria nigripes, namely F1 and F2. F1 was a high molecular weight glucan, whereas F2 was a low molecular weight heteropolysaccharide. F1 showed stronger anti-inflammatory activity than F2, but was weaker than their combined treatment (F1+F2). Different polysaccharide components were shown to possess synergistic anti-inflammatory effects, suggesting their importance in the formulation of polysaccharide-based products.

Differences in anti-inflammatory properties of water soluble and insoluble bioactive polysaccharides in lipopolysaccharide-stimulated RAW264.7 macrophages.

β-Linked polysaccharides including β-glucans are well known to be important functional ingredients, and are known to possess immunomodulatory and anti-tumor activities. This study aimed to investigate the anti-inflammatory properties and participating receptor of water soluble and insoluble bioactive polysaccharides from Grifola frondosa (GFP, non-digestible water soluble polysaccharides), Laminaria digitata (laminarin, a water soluble β-glucan) and Saccharomyces cerevisiae (zymosan, a water insoluble β-glucan) in lipopolysaccharide (LPS)-stimulated parental and Dectin-1 highly expressing RAW264.7 macrophages. Results showed that GFP and laminarin significantly inhibited nitric oxide and prostaglandin E2 production, but only the GFP with high molecular weight exhibited strong inhibition on pro-inflammatory cytokine (TNF-α and IL-6) secretion in a concentration-dependent manner. The activation of NF-κB was also significantly down-regulated by GFP treatment as compared with cells treated with LPS alone. Although GFP and laminarin were able to bind to β-glucan receptor Dectin-1, there was no relationship between the inhibitory potency and the content of β-glucans in GFP, and these inhibitory effects were not affected by the expression level of Dectin-1 in macrophage cells. In contrast, zymosan significantly intensified LPS-induced inflammatory responses through Dectin-1. In conclusion, these results suggest that the inhibitory effects of water soluble polysaccharides on LPS-induced pro-inflammatory mediator production in murine macrophages may not involve β-glucan receptor Dectin-1.

PH-sensitive PEG-coated hyper-branched β-d-glucan derivative as carrier for CpG oligodeoxynucleotide delivery

β-d-glucan is a natural non-digestible polysaccharide that can be selectively recognized by recognition receptors such as Dectin-1 receptors, resulting in an emerging interest on exploring its capacity for carrying biological information to desired organs or cells. CpG oligodeoxynucleotide (ODN) has the potentiality to initiate an immune-stimulatory cascade via activating B cells inducing proinflammatory cytokines, which is conducive to immunotherapy and nucleic acid vaccine. Herein, we developed a pH-sensitive delivery system loading with CpG ODN by introducing poly-ethylenimine (PEI) to a hyperbranched β-d-glucan (HBB) and coating with poly-ethylene glycol (PEG) shell via acidic liable Schiff bond. This delivery system exhibited a favorable biocompatibility and facilitated the cellular uptake of CpG ODN at pH 6.8 with the possibility of having higher accumulation in acidic cancer microenvironment. Furthermore, this carrier together with class B CpG ODN could enhance the secretion of cytokines including interleukin-6 and interferon-α as well as capable of interferon-α induction.