Characterization of polysaccharide from Pleurotus eryngii during simulated gastrointestinal digestion and fermentation

Structural and physicochemical properties and changes in vitro digestion and fermentation of soluble dietary fiber from tea residues modified by fermentation

The aim of this study was to investigate the structure, physicochemical properties, and changes in vitro digestion and fermentation between unfermented tea residue dietary fiber (UDF) and fermented tea residue soluble dietary fiber (FSDF). The results showed that soluble dietary fiber in FSDF was increased from 2.54 % to 15.65 % after fermentation modification. Monosaccharide composition analysis showed that xylose and glucose accounted for a higher proportion in FSDF. FSDF had smaller particle size, lower crystallinity and higher thermal stability. The water holding capacity, oil holding capacity and water swelling capacity of FSDF were significantly increased. Rheological properties showed that FSDF exhibited higher viscosity and better elastic than UDF. Furthermore, FSDF generated more short-chain fatty acids, and the structure was looser than UDF, which was easier to be utilized by intestinal flora. These findings provided higher value of dietary fiber in tea residue by fermentation modification as functional products.

Digestive characteristics of Tibetan tea polyphenols and polysaccharides in vitro and their effects on gut microbiota

Tibetan tea contains highly valuable bioactive components like polyphenols and polysaccharides, which can regulate gut microbiota and promote bodily health. This study systematically investigated the gastrointestinal digestion and colonic fermentation behavior of Tibetan tea polyphenols (TPP), polysaccharides (TPS), and their polyphenol-polysaccharide complex (TC). TPP, TPS, and TC demonstrated minimal changes in physicochemical and structural characteristics after gastrointestinal digestion. Following 24 h of fecal fermentation, all components significantly degraded and altered microbial composition (pH decreased to 6.44, 5.76, and 6.14, respectively), promoting dominant flora such as Phascolarctobacterium and Lachnoclostridium. Differentially, TPS and TC demonstrated stronger promotion of dominant Bifidobacterium, Faecalibacterium, and Collinsella, whereas TPP preferentially enriched Megasphaera and Butyricicoccus. Additionally, fermentation markedly increased the concentration of short-chain fatty acids (SCFAs), with TPS yielding the highest total SCFAs (17.29 ± 0.50 mM), particularly acetic and propionic acids. Overall, Tibetan tea polyphenols and polysaccharides may serve as potential prebiotics to improve intestinal health.

Recent developments in Artocarpus heterophyllus Lam. (jackfruit) polysaccharides: Nutritional values, structural characteristics and health benefits

Artocarpus heterophyllus Lam. (Jackfruit) is a common plant in the genus Artocarpus of Moraceae family, and its fruit has a variety of nutritional values. Jackfruit polysaccharides are considered to be one of the main bioactive compounds in jackfruit, which have immunomodulatory, anticancer, antioxidant, hepatoprotective, hypoglycemic, antibacterial and other health benefits. This article reviews the research progress in the extraction, purification, structural characteristics and health benefits of jackfruit polysaccharides. Mechanisms of action based on in vivo and in vitro experiments are also elucidated. The structural-activity relationships of jackfruit polysaccharides are discussed in depth, and their potential application values are revealed by combining the relationships between molecular structures and health benefits. This article aims to address the key issue of how to obtain jackfruit polysaccharides that feature both high yield and significant health benefits, and to conduct an in-depth exploration of the development pathways for their transformation into new health products, as well as their practical applications in the sustainable utilization of plant resources. Through a comprehensive analysis of the current research status and development trend, this article puts forward a new prospect for jackfruit polysaccharides research, hoping to provide innovative ideas and practical guidance for follow-up related work.

Effects and Mechanisms of Pleurotus eryngii Polysaccharide on Intestinal Barrier Damage: Based on the Perspective of Its Interaction with Intestinal Mucus during Gut Digestion

In this study, pathways and mechanisms of action of a new type of Pleurotus eryngii polysaccharide (PEP) with known structural characteristics and probiotic properties in the intestine were investigated. An in vitro cell model was used to investigate the protective effects of complexes formed between PEPs and their related products with mucin against gut barrier damage. Dextran sulfate sodium salt-induced colitis was used to determine the characteristics of the interaction between PEPs and intestinal mucus (IMs) at different consumption times. Finally, the protective effect of PEPs against intestinal barrier damage was investigated, as mediated by IMs. The result showed that complexes of PEP-related products and mucin improved damage to the intestinal barrier. PEPs exhibited differential functional activities at different stages. In normal and colitis mice, the interactions between IMs and PEPs showed different characteristics. From the transport and absorption standpoint, the role of PEPs in driving intestinal health was also clarified in this study.

Blending polysaccharides from three edible mushrooms represents a promising approach for augmenting their anti-oxidant and anti-fatigue activities

It has been well documented that a number of polysaccharides with potent free-radical scavenging capability possess notable anti-fatigue activity. Interestingly, recent evidence also suggested mixed polysaccharides derived from multiple sources may yield augmented bioactivities compared to the polysaccharides from a single source. Therefore, in the current study, we investigated the anti-oxidant and anti-fatigue activities of a blend of polysaccharides isolated from three mushrooms. The optimal ratio of Pleurotus eryngii polysaccharide, Agrocybe aegerita polysaccharide, and Agaricus bisporus polysaccharide was firstly screened out by in vitro antioxidant assays with a Z-score comprehensive evaluation method. Then, the fatigue-reducing effects of the polysaccharide mixture at optimal ratio (1:2:2) were studied in mice. The results showed that the polysaccharide mixture exerted desirable fatigue-reducing effect evidence by significantly extended exhaustion time in the weight-loaded swimming assay (from 9.45 ± 3.06 min to 27.65 ± 19.84 min). Moreover, the observed fatigue-reducing effect may be attributed to its capacity to decrease fatigue-related metabolites, increase muscle glycogen reserves, and regulate energy metabolism-related transcripts in muscle tissue. Taken together, these findings highlighted the potential application of blending polysaccharides from multiple mushroom sources in mitigating fatigue.

In vitro simulated digestion of and microbial characteristics in colonic fermentation of polysaccharides from Lentinus edodes

Lentinus edodes is widely cultivated and utilized globally, and Lentinus edodes polysaccharides (LEPs) are recognized as its primary bioactive components. However, the influence of regional variations LEPs has not yet been elucidated. This study aimed to investigate the differences in the and activity of LEPs from various sources following simulated in vitro digestion, as well as their impact on gut microbes. Our work demonstrated that while the three LEPs were partially digested during digestion progress, yet their structural integrity remained largely unchanged. These LEPs exhibited variations in the monosaccharide molar ratios and molecular weights (Mw), which contributed to differences in their biological activities. Furthermore, the three LEPs were found to promote the growth of Megasphaera and Bacteroides and enhance the production of short-chain fatty acids (SCFAs). Finally, we investigated the correlations between monosaccharide composition, SCFAs, and the growth of gut microbes. Taken together, these results provide important insights into the regional characteristics of LEPs, supporting their personalized application in various contexts.

Advanced insights into mushroom polysaccharides: Extraction methods, structure-activity, prebiotic properties, and health-promoting effects

Mushroom-derived polysaccharides, especially β-glucans, have attracted considerable attention because of their various biological regulatory functions. Advanced extraction technologies, including ultrasonic-assisted, microwave-assisted, enzyme-assisted, ultrasonic-microwave synergistic, subcritical water, and aqueous two-phase extractions, are extensively utilized to optimize the efficient recovery of biologically active compounds from mushrooms, progressively supplanting conventional methods. In addition, mushroom polysaccharides are acknowledged as "important biological response modifiers." Beyond their diverse bioactivities, including anticancer, immunomodulatory, anti-inflammatory, antimicrobial, antiviral, antidiabetic, hypocholesterolemia, anti-lipidemic, and antioxidant effects, increasing interest has been directed towards their prebiotic potential, especially regarding their ability to influence gut microbiota. This review presents a comprehensive summary of the extraction and purification methods, biological properties, structure-function relationships, and mechanisms of mushroom polysaccharides, highlighting the latest advancements in the field from 2019 to 2024. Additionally, this review discusses the key findings and limitations associated with the structure-function correlation. While most studies focus on β-glucans or their extracts, α-glucans and chitin have gained increasing attention. The prebiotic potential is associated with α-glucans and chitin, with chitin recognized for its substantial antimicrobial and wound-healing properties. This review systematically identifies current research gaps and proposes avenues for future investigation into the therapeutic potential of mushroom polysaccharides. However, further research is required to comprehensively understand their full therapeutic potential.

Role of Mushroom Polysaccharides in Modulation of GI Homeostasis and Protection of GI Barrier

Edible and medicinal mushroom polysaccharides (EMMPs) have been widely studied for their various biological activities. It has been shown that EMMPs could modulate microbiota in the large intestine and improve intestinal health. However, the role of EMMPs in protecting the gastric barrier, regulating gastric microbiota, and improving gastric health cannot be ignored. Hence, this review will elucidate the effect of EMMPs on gastric and intestinal barriers, with emphasis on the interaction of EMMPs with microbiota in maintaining overall gastrointestinal health. Additionally, this review highlights the gastroprotective effects and underlying mechanisms of EMMPs against gastric mucosa injury, gastritis, gastric ulcer, and gastric cancer. Furthermore, the effects of EMMPs on intestinal diseases, including inflammatory bowel disease, colorectal cancer, and intestinal infection, are also summarized. This review will also discuss the future perspective and challenges in the use of EMMPs as a dietary supplement or a nutraceutical in preventing and treating gastrointestinal diseases.

Structural characteristics of a heteropolysaccharide from Ganoderma lucidum and its protective effect against Alzheimer's disease via modulating the microbiota-gut-metabolomics

Ganoderma lucidum is a traditional Chinese medicine used to treat Alzheimer's disease (AD), whose main active ingredient is polysaccharides. A heteropolysaccharide named GLPZ-1 was isolated from Ganoderma lucidum. GLPZ-1 (6.608 kDa) predominantly consisted of Glc and minor Gal. The results of GC-MS and NMR analyses indicated that the backbone of GLPZ-1 was mainly composed of 1,4-α-D-Glcp, 1,4,6-α-Glcp and a minor amount of 1,3,4-β-D-Glcp, which was substituted with complex side chains at C-6 of 1,4,6-α-D-Glcp and at C-3 of 1,3,4-β-D-Glcp. GLPZ-1 demonstrated a protective effect on AD rats by improving behavioral abnormalities, alleviating pathological damage and ameliorating levels of IL-6, IL-1β, TNF-α and Th17, which were associated with GLPZ-1 modulating the microbiota-gut-metabolomics of AD rats. GLPZ-1 regulated the gut microbiota in AD rats by increasing the abundance of Bacteroides, unclassified_Lachnospiraceae, Lactobacillus, Pediococcus, Oscillibacter, Lachnoclostridium and Bifidobacterium, while simultaneously reducing the abundance of Pseudomonas and Desulfovibrio. GLPZ-1 could regulate fecal metabolites in AD rats tending towards the normal levels. These regulated fecal metabolites belonged to fatty acid metabolism, cholesterol and bile acid metabolism, neurotransmitters and aromatic amino acid metabolism. These findings provide a preliminary research basis for the exploitation of GLPZ-1 as an effective drug to prevent and delay AD.

Simulated digestion and gut microbiota fermentation of polysaccharides from Lactarius hatsudake Tanaka mushroom

Lactarius hatsudake Tanaka is a popular edible mushroom known for its delicious flavor and health benefits. Its polysaccharides (LHP) exhibit significant bioactivity, but their application is limited due to uncertainties in digestion. This study used in vitro simulated models to explore the dynamic changes of LHP during the digestive and fermentation process and validated them through mouse models. Results revealed that LHP cannot be digested by the simulated digestive system, but is primarily degraded into fatty acids by gut microbes, accompanied by reductions in molecular weight, carbohydrate content, and pH. Additionally, LHP promotes the proliferation of beneficial bacteria (Faecalibacterium, Bifidobacterium, Lactobacillus, etc.), while inhibiting harmful bacteria (Escherichia and Shigella). Metabolite analysis in serum indicated that LHP can regulate amino acid and lipid metabolism, enhancing overall health. These findings provide a theoretical foundation for developing LHP as a potential prebiotic, highlighting its considerable promise for disease prevention through improved intestinal health.

Comparative evaluation of free radical scavenging activity and total metabolite profiles among 30 macrofungi species

The high antioxidant content of mushrooms such as polyphenols, polysaccharides, carotenoids, ergothioneine, glutathione, vitamins, and other compounds, has sparked interest in their potential use in preventive and therapeutic medicine. Therefore, this study aimed to evaluate the antioxidant potential of various macrofungi by measuring 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity and quantifying two classes of compounds: phenolics (TPC) and polysaccharides, both endo- (IPS) and exopolysaccharides (EPS). Species-specific abilities to produce mycelium, polysaccharides, and polyphenols were observed under submerged cultivation without agitation over 14 days. Mycelium productivity (PM) ranged significantly from 292 ± 11 to 1110 ± 37 mg·L⁻1·day⁻1, with the highest values observed in Ophiocordyceps sinensis (1110 ± 37 mg·L⁻1 ·day⁻1), Pleurotus djamor (1090 ± 14 mg·L⁻1·day⁻1), and Cordyceps militaris (1080 ± 90 mg· L⁻1·day⁻1). The DPPH inhibition values of the extracts varied from 4.30 ± 0.20 to 87.9 ± 0.80%, while TPC ranged from 0.35 ± 0.10 to 34.6 ± 0.80 mg GAE/g d.w. Lentinula edodes was the best source of produced IPS (10.3 ± 0.35 g·L-1), while Hypsizygus marmoreus exhibited the highest EPS content (2.24 ± 0.30 g·L-1). Overall, IPS levels across species were higher, ranging from 1.56 to 10.3 g·L-1. In half of the fungal species, the mycelium exhibited superior antioxidant activity compared to culture broth. However, in the majority (66.7%), TPC was higher in the culture broth than in the fungal mycelium. Distinct scavenging abilities and metabolite profiles were observed among different isolates. Notably, the mycelium of Fomitopsis pinicola and L. edodes showed the highest DPPH inhibition and TPC. The antioxidant activity and TPC varied depending on the culture medium, and solvents used. The highest DPPH inhibition (90%) and TPC (38.5 ± 0.40 mg GAE/g d.w.) were observed in the methanol (MeOH) extract of F. pinicola mycelium grown in Sabouraud dextrose medium. Similarly, MeOH and ethyl acetate (EtOAc) extracts demonstrated strong DPPH inhibition (over 87%), while the maximum TPC (40.0 ± 0.60 mg GAE/g d.w.) was detected in the water (H2O) extract of L. edodes mycelium cultivated in glucose-peptone-yeast medium. A positive correlation was found between TPC and antioxidant activity, with Pearson's coefficient of 0.6615 for fungal mycelium, 0.1192 for culture broth, and 0.8924 and 0.7143 for F. pinicola and L. edodes, respectively. Both fungal mycelium and culture broth exhibit significant potential as natural antioxidants. These can be applied in nutraceuticals, food products, and nutritional supplements, offering diverse health benefits. Additionally, this study is a pioneering exploration of Auriporia aurea, Hohenbuehelia myxotricha, Lepista luscina, Oxyporus obducens, and Pseudospongipellis litschaueri, highlighting their largely unexplored potential for antioxidant applications.

Metabolic outcomes of Cordyceps fungus and Goji plant polysaccharides during in vitro human fecal fermentation

This study was to assess the digestion and colonic fermentation of two bioactive polysaccharides, EPS-LM and LBPS, and the subsequent influences on human gut microbiota through simulated gastrointestinal systems. EPS-LM, an exopolysaccharide isolated from mycelial culture of a medicinal fungus Cordyceps sinensis Cs-HK1, was characterized as a heteropolysaccharide consisting of Man(108):Gal(52.7):Glc(29.2) (molar ratio) with an average molecular weight (MW) 5.513 × 106. LBPS was isolated from a well-known medicinal plant (Lycium barbarum L.) which was also characterized as a heteropolysaccharide (1.236 × 105 MW). Both polysaccharides were highly resistant to saliva, gastric and small-intestine digestion with negligible MW reduction and release of reducing sugars but were quickly degraded to lower MW during in vitro human fecal fermentation. They were consumed as a carbon source by the gut bacteria to produce short-chain fatty acids (SCFAs). In comparison, the carbohydrate content of EPS-LM was more completely consumed than LBPS and there were also notable differences in consumption of specific monosaccharides and production of specific SCFAs, propionic and butyric acid, and relative abundance of gut bacterial populations between EPS-LM and LBPS group. The results suggest that metabolic outcomes and modulating effects of EPS-LM and LBPS on the gut microbiota are highly dependent on their molecular composition.

In vitro fermentation characteristics of fucoidan and its regulatory effects on human gut microbiota and metabolites

Dietary polysaccharides affect the intestinal microorganisms and their metabolites in the host. Clarifying the relationship among polysaccharides, intestinal microflora, and their metabolites is helpful to formulate dietary nutrition intervention strategies. Thus, we explored the regulatory effects of fucoidan on the human gut microbiota and its metabolites. After 48 h of fermentation, fucoidan significantly reduced the pH value in the broth, accompanied by an increase in total short-chain fatty acids, acetic acid, and propanoic acid contents. Fucoidan significantly reduced the relative abundance of Escherichia_shigella and Blebsiella and increased the relative abundance of Bifidobacterium and Lactobacillus. Concurrently, fucoidan altered the composition of intestinal microbial metabolites. These results indicate that fucoidan can regulate the metabolism of the intestinal flora and host, which may contribute to the intestinal health of the host.

Optimization of Extraction Process, Structural Characterization, and Antioxidant and Hypoglycemic Activity Evaluation of Polysaccharides From the Medicinal and Edible Plant: Cistanche deserticola Ma

INTRODUCTION

Cistanche deserticola Ma (CD), an edible and medicinal plant native to Xinjiang, Inner Mongolia, and Gansu in China, is rich in bioactive polysaccharides known for their health-promoting properties. The polysaccharides of C. deserticola (CDPs) have been shown to possess a range of beneficial activities, including immunomodulatory, anti-aging, antioxidant, and anti-osteoporosis effects.

OBJECTIVE

This study seeks to identify the optimal conditions for extracting CDPs using hot water. Additionally, it aims to evaluate their chemical properties, antioxidant activity, hypoglycemic effects, and cytotoxicity. The findings will provide a theoretical foundation for the potential use of CDPs in functional foods and pharmaceuticals.

METHODOLOGY

The study employed response surface methodology to optimize the hot water extraction conditions for CDPs. The extracted CDPs were characterized using a range of chemical, spectroscopic, and instrumental analyses. Furthermore, their antioxidant activity, hypoglycemic effects, and cytotoxicity were evaluated through relevant assays to assess their potential health benefits.

RESULTS

Under optimal conditions, the yield of CDPs was 45.85% ± 1.91%. CDPs were identified as acidic heteropolysaccharides with a wide molecular weight distribution, ranging from 0.3 to 128.2 kDa. They were composed primarily of glucose (51.21%), arabinose (32.86%), galactose (17.88%), and smaller amounts of galacturonic acid (4.66%), rhamnose (1.85%), mannose (1.32%), glucosamine hydrochloride (1.08%), and xylose (0.56%). Antioxidant assays demonstrated that CDPs exhibited significant free radical scavenging activity, metal ion chelation, and reducing power. Additionally, CDPs inhibited α-glucosidase and α-amylase in vitro through a mixed-type mechanism, as well as static fluorescence quenching. Cytotoxicity assays showed that CDPs were nontoxic to L02 and AML12 cells.

CONCLUSION

This study offers a theoretical foundation for the potential use of CDPs in functional foods and pharmaceuticals and provides valuable insights for the development of new antioxidant and hypoglycemic agents from natural sources.

Impact of Enzymatic Degradation Treatment on Physicochemical Properties, Antioxidant Capacity, and Prebiotic Activity of Lilium Polysaccharides

In order to overcome the bioavailability limitation of Lilium polysaccharide (LPS) caused by its high molecular weight and complex structure, two low-molecular-weight degraded polysaccharides, namely G-LPS(8) and G-LPS(16), were prepared through enzymatic degradation. The molecular weight of LPS was significantly reduced by enzymolysis, leading to increased exposure of internal functional groups and altering the molar ratio of its constituent monosaccharides. The results of antioxidant experiments showed that enzymatic hydrolysis had the potential to enhance the antioxidant performance of LPS. In vitro fermentation experiments revealed that LPS and its derivatives exerted different prebiotic effects on intestinal microbial communities. Specifically, LPS mainly inhibited the growth of harmful bacteria such as Fusobacterium, while G-LPS(8) and G-LPS(16) tended to promote the growth of beneficial bacteria like Megamonas, Bacteroides, and Parabacteroides. Metabolomic analysis revealed that LPSs with varying molecular weights exerted comparable promoting effects on multiple amino acid and carbohydrate metabolic pathways. Importantly, with the reduction in molecular weight, G-LPS(16) also particularly stimulated sphingolipid metabolism, nucleotide metabolism, as well as ascorbic acid and uronic acid metabolism, leading to the significant increase in specific metabolites such as sphingosine. Therefore, this study suggests that properly degraded LPS components have greater potential as a prebiotic for improving gut health.

Effects of highland barley β-glucan on gut microbiota composition and metabolism in vitro fermentation

Highland barley β-glucan (HBG) has attracted increasing attention due to its excellent biological activities. However, the effects of HBG on gut flora and metabolites are unknown. Therefore, the effects of HBG on the gut microbiota during fermentation were analyzed by 16 s rRNA sequencing and untargeted metabolomics. The results showed that HBG could enrich microbial diversity, increase the abundance of beneficial bacteria, and inhibit the biology of pathogenic bacteria. In addition, HBG increased the content of short-chain fatty acids and decreased fermentation broth pH. Metabolomics analyses showed that HBG also increased the content of beneficial metabolites such as taurine and affected amino acid metabolism, among other pathways. This study lays the foundation for the application of HBG in functional foods.

Influence of enzymatic modification on the structure, antioxidant activity, and prebiotic activity of ginseng neutral polysaccharide

The abundant ginseng neutral polysaccharide (GPN) has been neglected due to its lower activity compared to acidic polysaccharide in ginseng. Herein, the composite enzymes were used to modify the GPN and obtained the enzymatic-degradation-GPN (EGPN). The structural changes were further characterized by GPC, FT-IR, Congo red, XRD, zeta potential, TG, cryo-SEM and AFM. The antioxidant activity of GPNs in vitro was investigated by in vitro chemical experiments and oxidative stress-related indicators on PC12 cells damaged by Aβ25-35, and EGPN showed favorable antioxidant activity. In addition, EGPN metabolized by intestinal microbiota also significantly increased the viability of injured PC12 cells. Furthermore, in vitro fermentation model was used to investigate the differences of physicochemical properties of GPNs and their regulatory effects on the microbiota. EGPN enhanced the diversity of the microbiota and increased the concentration of short-chain fatty acids (SCFAs). Importantly, EGPN demonstrated a significant reduction in the presence of detrimental bacteria such as Enterococcus and Allobaculum, while simultaneously promoting the growth of beneficial microorganisms including Lactobacillus, Prevotella, and Ruminococcu. This study highlights the potential use of EGPN prepared by composite enzymatic degradation in antioxidant, neuroprotection and restoration of intestinal homeostasis.

In vitro digestion and fecal fermentation behaviors of exopolysaccharide from Morchella esculenta and its impacts on hypoglycemic activity via PI3K/Akt signaling and gut microbiota modulation

This study aimed to evaluate the effects of gastrointestinal digestion on the physicochemical properties and hypoglycemic activity of extracellular polysaccharides from Morchella esculenta (MEPS). The results showed that the MEPS digestibility was 22.57 % after saliva-gastrointestinal digestion and only partial degradation had occurred. Contrarily, after 48 h of fecal fermentation, its molecular weight and molar ratios of the monosaccharide composition varied significantly due to being utilized by human gut microbiota, and the final fermentation rate was 76.89 %. Furthermore, the MEPS-I, the final product of saliva-gastrointestinal digestion still retained significant hypoglycemic activity, it alleviated insulin resistance and increased the IR cells glucose consumption by activating PI3K/AKT signaling pathway. MEPS-I treatment reduced the proportion of Firmicutes to Bacteroidetes, and the relative abundance of beneficial bacteria that enhanced insulin sensitivity and glucose uptake was promoted. This research can provide a theoretical basis for the further development of Morchella esculenta as a health functional food.

Evaluation of in vitro simulated digestion and fermentation characteristics of the crude exopolysaccharide from Levilactobacillus brevis M-14

The present study employed an in vitro static digestion model to simulate the saliva-gastrointestinal digestion and fecal fermentation of exopolysaccharides (EPSs) extracted from Levilactobacillus brevis M-14, aiming to understand the dynamic changes in physicochemical properties, biological potential of EPS, as well as their impact on the human enteric microorganism. EPS was mainly composed of polysaccharides. The molecular weight (Mw) showed that EPS comprised two parts with a high Mw and a low Mw fraction of 42.81 × 104 and 1.23 × 104 Da, respectively. EPSs mainly consisted of mannose, rhamnose, galacturonic acid, glucose, and galactose in a molar ratio of 0.42∶0.13∶0.21∶0.13∶0.11. In the simulated digestion process, EPS was relatively stable. Furthermore, simulated digestion increased the antioxidant and hypoglycemic capacities of EPS. During the fermentation stage, the total carbohydrate contents of EPS decreased by 20.19%. The Mw of the two components of EPS decreased by 16.37% and 61.67%, respectively, and accompanied by the production of free monosaccharides. EPS had the potential to modulate the composition of gut microbiota, increasing the relative abundance of Enterococcus and Parabacteroides, while decreasing the relative abundance of Bacteroides. The pH decreased and total short-chain fatty acids contents increased, especially acetic acid and propionic acid. This research provided valuable insights into the potential application of EPS as a prebiotic agent.

In vitro gastrointestinal digestion and fecal fermentation behaviors of pectin from feijoa (Acca sellowiana) peel and its impact on gut microbiota

This study investigated the digestion and fermentation characteristics of pectin from feijoa peel (FPP) and its effect on gut microbiota via in vitro simulated digestion and fecal fermentation. The gastrointestinal results showed that the molecular weight (Mw) of FPP kept stable with small production of reducing sugar and free monosaccharides, indicating that FPP was basically not degraded during digestion. However, during the fecal fermentation, the Mw of FPP significantly decreased with the release of free monosaccharides, which were further utilized by gut microbiota. The content of reducing sugar showed a trend of increasing at first and then decreasing. The production of gases and short-chain fatty acids (SCFAs) increased with the utilization of FPP, along with the pH decrease in fecal culture. Meanwhile, FPP regulated the composition of gut microbiota by suppressing enteropathogenic bacteria (genera Escherichia-Shigella and Fusobacterium) and promoting beneficial bacteria (genera Lactiplantibacillus and Bifidobacterium). Significantly positive correlation was found between SCFAs and bacteria including Lactiplantibacillus and Bifidobacterium. These results suggested that FPP had potential prebiotic functions to promote human intestinal health.

Structural characterization of oligosaccharide from Dendrobium officinale and its properties in vitro digestion and fecal fermentation

Oligosaccharides from Dendrobium officinale (DOO) is a kind of new potential prebiotic for health. In this study, structural characteristics, digestion properties and regulatory function on intestinal flora of DOO were investigated. An oligosaccharide, DOO 1-1, was purified by DEAE-Sepharose Fast Flow and Sephadex G-25, and its physicochemical properties were characterized as a glucomannan oligosaccharide with a molecular weight of 1560 Da (DP = 9). In vitro simulated digestion, it proved that the structure of DOO 1-1 was degraded hardly in the simulated gastric and small intestinal fluid. By evaluating the gas, short-chain fatty acids and intestinal microbiota in vitro fermentation, DOO has an excellent regulatory effect on intestinal microbiota, especially promoting the proliferation of Bacteroidetes and Actinobacteria. Therefore, DOO can be used as a potential prebiotic in functional foods.

Effects of steam explosion pretreatment on the digestive properties and gut microbiota of Laminaria japonica polysaccharide

BACKGROUND

Laminaria japonica polysaccharide, which is an important bioactive substance of Laminaria japonica with anti-inflammatory and antioxidant effects. In this study, the molecular weight, functional groups and surface morphology were investigated to evaluate the digestive properties of Laminaria japonica polysaccharide before and after steam explosion.

RESULTS

The results indicated that the Laminaria japonica polysaccharide entered the large intestine to be utilized by the gut microbiota after passing through the oral, gastric and small intestinal. Meanwhile, Laminaria japonica polysaccharide of steam explosion promoted the growth of beneficial bacteria Phascolarctobacterium and Intestinimonas, and increased the content of acetic, propionic and butyric acids, which was 2.29-folds, 2.60-folds and 1.63-folds higher than the control group after 48 h of fermentation.

CONCLUSION

This study reveals that the effect of steam explosion pretreatment on the digestion in vitro and gut microbiota of Laminaria japonica polysaccharide will provide a basic theoretical basis for the potential application of Laminaria japonica polysaccharide as a prebiotic in the food industry. © 2024 Society of Chemical Industry.

Almond polysaccharides inhibit DSS-induced inflammatory response in ulcerative colitis mice through NF-κB pathway

Ulcerative colitis (UC), a type of inflammatory bowel disease (IBD), is a chronic recurrent inflammatory disease of the colon. Our previous findings demonstrated that almond polysaccharide (AP-1) exhibits significant anti-inflammatory activity in vitro. Therefore, this study aimed to explore the ameliorative effect of AP-1 on dextrose sodium sulfate (DSS)-induced UC mice and to elucidate its possible mechanism of action. By observing changes in body weight, fecal viscosity, stool blood, disease activity index, and colon length, we found that AP-1 attenuated inflammation. It inhibited TNF-α, IL-1β, and IL-6 while boosting anti-inflammatory IL-10 levels. Histomorphologically, AP-1 protected against DSS-induced colonic tissue damage by reducing inflammatory cell infiltration and mucosal injury. It also lowered myeloperoxidase (MPO) and NO while increasing total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) in colonic tissues. Moreover, using the Western blot technique, AP-1 was shown to inhibit the phosphorylation of p65 and IκB-α proteins in the NF-κB/iNOS/COX2 signaling pathway and down-regulate the expression of inflammation-associated proteins COX2 and iNOS, thus slowing down and ameliorating inflammatory processes. Therefore, the safe and effective beneficial effects of AP-1 make it a promising therapeutic strategy for relieving IBD, especially UC.

Simulated human digestion and fermentation of a high-molecular weight polysaccharide from Lentinula edodes mushroom and protective effects on intestinal barrier

Lentinula edodes (Shiitake) is an important edible mushroom and polysaccharides are its major constituents with proven health benefits. The study was to investigate the gut bacterial fermentation and subsequent effects on gut barrier function of a glucan-rich polysaccharide, LePS40 precipitated from the mushroom water extract with 40 % (v/v) ethanol. LePS40 consisted of a β-(1→3)-glucan main chain with substitution in the C-6 position with side chains mainly composed of (1 → 6)-linked β-Glcp residues, (1 → 6)-linked α-Galp residues and terminal residues of β-Glcp. LePS40 was found highly resistant to digestive enzymes and gastric acid in simulated human gastrointestinal tract, but highly fermentable during in vitro human fecal fermentation. The fecal fermentation degradation of LePS40 appeared to selectively break the glucoside linkage in view of the dramatic decrease in the glucose molar ratio (12.68 to 1.07). Compared with the prebiotic reference FOS, LePS40 led to much higher levels of butyric, and propionic acid and a lower level of acetic acid. Moreover, LePS40 enhanced the abundance of some beneficial bacterial populations, but decreased the bacteria possibly linked with fatty-liver disease and colorectal cancer. Furthermore, the fecal fermentation products of LePS40 showed a potential protective effect on intestinal barrier function against inflammatory damage in Caco-2/Raw264.7 co-culture model. These findings suggest the potential of LePS40 for improvement of gut health through modulation of gut microbiota.

In vitro digestion and fecal fermentation of Tremella fuciformis exopolysaccharides from basidiospore-derived submerged fermentation

Tremella fuciformis polysaccharides (TFPS) belong to natural bioactive macromolecule with both edible and medicinal value, possessing much bioactivities such as anti-tumor, antioxidant, antidiabetics, and immunomodulatory. Currently, the production of TFPS through submerged fermentation (TFPS-1) is gradually replacing the polysaccharides extracted from the fruiting body due to improved fermentation efficiency and reduced separation costs. However, it is still unclear about the effect of TFPS-1 on gastrointestinal digestion and gut microbial fermentation, which is directly related to the function of its biological activity. This study aimed to illustrate the effect of TFPS-1 on digestive process through in vitro digestion and fecal fermentation. TFPS-1 was indigestible during the simulated gastrointestinal tract. But TFPS-1 can be digested by intestinal flora leading to alterations in the total polysaccharides content, molecular weight, and apparent viscosity. Moreover, TFPS-1 regulated the composition of gut microbial, lowering the proportion of Firmicutes to Bacteroidetes and enhancing the abundances of Parabacteroides and Bacteroides. The change of intestinal flora produced more short chain fatty acids and lowered the pH. The KEGG metabolic pathway analysis indicated that TFPS-1 enriched lipid metabolism, glycan biosynthesis and metabolism, and biosynthesis of other secondary metabolites. This study demonstrated that T. fuciformis fermented polysaccharide can be a potential prebiotic to optimize intestinal flora homeostasis and maintain host intestinal health.

Characterization, in vitro antioxidant activity and stability of cattle bone collagen peptides‑selenium chelate

In this study, cattle bone collagen peptides-selenium chelate (CCP-Se) was prepared and its structure, oxidation resistance and stability were characterized. The selenium binding capacity was 33.65 ± 0.13 mg/g by optimized preparation conditions. Structural analysis showed that selenium ions bound mainly to the amino nitrogen, carboxyl oxygen and hydroxyl oxygen atoms of the cattle bone collagen peptide (CCP). The microstructure and particle size analyses showed that the particle size of CCP-Se was increased and formed a regular and compact crystal structure compared with CCP. Additionally, CCP-Se exhibited excellent antioxidant activity. Stability analysis showed that CCP-Se was stable in thermal processing, simulated in vitro digestion and acid/alkali tolerance tests. The intestinal selenium permeability of CCP-Se was significantly better than sodium selenite (p < 0.05). This study provides reference for the high-value application of cattle bone and suggests the potential of CCP-Se as a new effective selenium supplement.

Effects of spent substrate of oyster mushroom (Pleurotus ostreatus) on ruminal fermentation, microbial community and growth performance in Hu sheep

Introduction

The study aimed to evaluate the effects of Pleurotus Spent Mushroom Substrate (P.SMS) on the rumen microbiota, encompassing bacteria and fungi, as well as their interactions in Hu sheep.

Methods

A total of forty-five 3-month-old Hu sheep were randomly assigned to five groups. Each group was fed diets in which whole-plant corn silage (WPCS) was substituted with P.SMS at varying levels: 0% (CON), 5% (PSMS5), 10% (PSMS10), 15% (PSMS15), or 20% (PSMS20).

Results

The results indicated that higher proportions of P.SMS during the experimental period might have a detrimental effect on feed utilization efficiency, kidney function, and blood oxygen-carrying capacity. Notably, moderate levels of P.SMS, specifically below 15%, were associated with improvements in rumen NH3-N levels and absorption capacity. The results indicated that (1) PSMS20 exhibited a significantly higher feed-to-gain ratio compared to CON (P < 0.05); (2) PSMS15 showed a significantly higher NH3-N content than CON, PSMS5, and PSMS20. Additionally, PSMS10 and PSMS20 had elevated concentrations of NH3-N compared to CON and PSMS5 (P < 0.05); (3) The length and width of rumen papillae were significantly greater in PSMS20 compared to CON and PSMS5 (P < 0.05); (4) Creatinine levels were significantly higher in PSMS20 than in CON, PSMS5, and PSMS10 (P < 0.05); (5) By the conclusion of the experiment, hemoglobin concentration in PSMS20 showed a significant increase compared to CON (P < 0.05). Furthermore, the addition of P.SMS influenced microorganisms at both the phylum and genus levels: (1) At the phylum level, the prevalence of Patescibacteria was significantly lower in PSMS20 compared to the other groups; (2) PSMS15 exhibited significantly higher relative abundances of Basidiomycota compared to CON and PSMS10, while PSMS20 also demonstrated significantly higher relative abundances compared to CON (P < 0.05); (3) At the genus level, the prevalence of Candidatus_Saccharimonas in PSMS20 was significantly lower than in PSMS5, PSMS10, and PSMS15. Conversely, the prevalence of Phanerochaete in PSMS15 was notably higher than in CON and PSMS10, and it was also significantly elevated in PSMS20 compared to CON (P < 0.05); (4) Correlation analysis indicated no significant correlation between changes in the structure of bacterial and fungal communities.

Discussion

Considering these findings, a high percentage of P.SMS negatively impacted feed utilization efficiency, blood oxygen carrying capacity, and kidney function, while a moderate percentage of P.SMS promotes rumen absorption capacity, indicating that feeding 10% P.SMS is optimal.

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.

In vitro simulated digestion and fermentation behaviors of polysaccharides from Pleurotus cornucopiae and their impact on the gut microbiota

This study investigated the physicochemical characteristics and fermentative behavior between original polysaccharides (PCPs) and polysaccharides extracted after microwave cooking (MPCPs) from Pleurotus cornucopiae during simulated digestion and fecal fermentation. The results revealed notable physicochemical differences between of PCPs and MPCPs. MPCPs exhibited a higher total carbohydrate content, with an increased proportion of glucose. Additionally, MPCPs showed a lower molecular weight (MW) and, a blue shift in Fourier transform infrared spectroscopy (FT-IR). Digestion has a minimal effect on the physicochemical and structural characteristics of PCPs and MPCPs. Within the first 6 h of fermentation, the gut microbiota showed significantly higher utilization of MPCPs. However, PCPs were consumed faster and surpassed MPCPs later. After 24 h, both PCPs and MPCPs were degraded and utilized by the gut microbiota, showing an increased abundance of Firmicutes and Bacteroidota. PCPs excelled in promoting beneficial gut microbiota, such as Phascolarctobacterium, Megamonas, and Bacteroides. Conversely, MPCPs demonstrated a stronger ability to inhibit the growth of harmful opportunistic pathogenic gut microbiota, such as Fusobacterium and Parasutterella. In addition, the content of acetic, propionic, and butyric acids increased significantly in both PCPs and MPCPs. These findings highlight the potential of Pleurotus cornucopiae polysaccharides as prebiotics for intestinal homeostasis.

A graminan type fructan from Achyranthes bidentata prevents the kidney injury in diabetic mice by regulating gut microbiota

Diabetic kidney disease (DKD) is the main cause of end-stage renal disease, and few therapeutic options are available. The root of Achyranthis bidentatae (AB) is commonly used for DKD treatment in Traditional Chinese medicine. However, its mechanisms are still unclear. Here, a graminan type fructan ABPW1 with molecular weight of 3998 Da was purified from AB. It was composed of β-1,2-linked Fruf, β-2,6-linked-Fruf and β-1,2,6-linked-Fruf backbone, and terminated with T-Glcp and 2-Fruf residues. ABPW1 protected against kidney injuries and intestinal barrier disruption in Streptozotocin (STZ)/High fat diet (HFD) mice. It could modulate gut microbiota composition, evidenced by a rise in the abundance of Bacteroide and decreases of Rikenella, Alistipes, Laedolimicola and Faecalibaculum. ABPW1 intervention promoted short chain fatty acids (SCFAs) production in STZ/HFD mice, especially propionate and isobutyric acid. Antibiotic treatment further demonstrated the key role of gut microbiota in the renal protective action of ABPW1. In addition, in vitro simulated digestion and fermentation together with in vivo fluorescent labeling studies demonstrated ABPW1 was indigestible in upper digestive tract but could reach the colon and be degraded into SCFAs by gut microbiota there. Overall, these data suggested ABPW1 has the potential application on DKD prevention.

Modulation of gut microbiota and metabolites by Flammulina velutipes polysaccharides during in vitro human fecal fermentation: Unveiling Bacteroides as a potential primary degrader

Flammulina velutipes, a widely cultivated species of edible fungus, exhibits diverse functional activities attributed to its polysaccharides. In this study, we employed an in vitro model to investigate the impact of F. velutipes polysaccharides (FVP) fermentation on gut microbiota, with a particular focus on Bacteroides. FVP fermentation resulted in the proliferation of microbiota associated with short-chain fatty acid (SCFA) metabolism and suppression of Escherichia-Shigella. Bacteroides emerged as potential primary degraders of FVP, with species-level analysis identifying the preference of B. thetaiotaomicron and B. intestinalis in FVP degradation. Metabolomics analysis revealed significant increases in hypoxanthine and 7-methyladenine contents, with histidine metabolism emerging as the most enriched pathway. B. nordii and B. xylanisolvens exhibited the most influence on amino acid and SCFA metabolism. Understanding the mechanisms by which gut microbiota metabolize FVP can provide valuable insights into the potential of FVP to promote intestinal health and disease prevention.

In vitro gastrointestinal digestion and fecal fermentation of Pleurotus eryngii proteins extracted using different methods: insights for the utilization of edible mushroom-based proteins as novel nutritional and functional components

Pleurotus eryngii (P. eryngii) protein is considered a high-quality protein because it is rich in essential amino acids and displays multiple significant functional characterizations that vary with its fabrication processes. We aimed to investigate the differences in P. eryngii protein extracted via alkaline extraction and acid precipitation (AA), cellulase complex alkaline extraction and acid precipitation (CAA), ultrasound-assisted alkaline extraction and acid precipitation (UAA), and salt dissolution (S) in terms of gastrointestinal digestion and fecal fermentation consequences. Protein hydrolysis and structural analysis were performed after in vitro gastrointestinal digestion, and it was found that AA showed the highest hydrolysis degree, whereas CAA showed the lowest. The results of fluorescence chromatography and infrared chromatography indicated that the reasons for the digestion difference might be the unfolding degrees of the protein tertiary structure and polysaccharide content, which is the major component of crude proteins and can prevent protein hydrolysis. Metagenomic analysis suggested that compared with other groups, AA had excellent biological functions, including regulating obesity and insulin-related microbiota. This study could provide a new theoretical basis for the P. eryngii protein as a novel type of nutritional and functional component and contributes to the development of a diversified emerging food protein supply system.

Evaluation of Physicochemical Properties and Prebiotics Function of a Bioactive Pleurotus eryngii Aqueous Extract Powder Obtained by Spray Drying

A bioactive Pleurotus eryngii aqueous extract powder (SPAE) was obtained by spray drying and its performance in terms of physicochemical properties, in vitro digestion, inflammatory factors, and modulation of the intestinal microbiota was explored. The results indicated that the SPAE exhibited a more uniform particle size distribution than P. eryngii polysaccharide (PEP). Meanwhile, a typical absorption peak observed at 843 cm-1 in the SPAE FTIR spectra indicated the existence of α-glycosidic bonds. SPAE exhibited higher antioxidant abilities and superior resistance to digestion in vitro. In addition, SPAE supplementation to mice significantly reduced the release of factors that promote inflammation, enhanced the secretion of anti-inflammatory factors, and sustained maximum production of short-chain fatty acids (SCFAs). Additionally, it significantly enhanced the relative abundance of SCFAs-producing Akkermansia and reduced the abundance of Ruminococcus and Clostridiides in intestines of mice. These results show the potential of SPAE as a novel material with prebiotic effects for the food and pharmaceutical industries.

In Vitro Characterization of Polysaccharides from Fresh Tea Leaves in Simulated Gastrointestinal Digestion and Gut Microbiome Fermentation

Tea plants have a long cultivation history in the world, but there are few studies on polysaccharides from fresh tea leaves. In this study, tea polysaccharides (TPSs) were isolated from fresh tea leaves. Then, we investigated the characteristics of TPSs during in vitro simulated digestion and fermentation; moreover, the effects of TPSs on gut microbiota were explored. The results revealed that saliva did not significantly affect TPSs' molecular weight, monosaccharide composition, and reducing sugar content, indicating that TPSs cannot be digested in the oral cavity. However, TPSs were partially decomposed in the gastrointestinal tract after gastric and intestinal digestion, resulting in the release of a small amount of free glucose monosaccharides. Our in vitro fermentation experiments demonstrated that TPSs are degraded by gut microbiota, leading to short-chain fatty acid (SCFA) production and pH reduction. Moreover, TPSs increased the abundance of Bacteroides, Lactobacillus, and Bifidobacterium but reduced that of Escherichia, Shigella, and Enterococcus, demonstrating that TPSs can regulate the gut microbiome. In conclusion, TPSs are partially decomposed by gut microbiota, resulting in the production of SCFAs and the regulation of gut microbiota composition and function. Therefore, TPSs may be used to develop a prebiotic supplement to regulate the gut microbiome and improve host health.

In vitro digestion and fermentation behaviors of polysaccharides from Choerospondias axillaris fruit and its effect on human gut microbiota

Choerospondias axillaris fruit has attracted more and more attention due to its various pharmacological activities, which are rich in polysaccharides. This study investigated the in vitro saliva-gastrointestinal digestion and fecal fermentation behaviors of polysaccharides from Choerospondias axillaris fruit (CAP), as well as its impact on human gut microbiota. The results showed that CAP could be partially degraded during the gastrointestinal digestion. The FT-IR spectra of the digested CAP didn't change significantly, however, the morphological feature of SEM changed to disordered flocculent and rod-like structures. 16S rRNA sequencing analysis found that after in vitro fermentation, CAP could increase the relative abundances of beneficial bacteria including Megasphaera, Megamonas and Bifidobacterium to produce short-chain fatty acids (SCFAs), while it can also reduce the abundances of harmful bacteria of Collinsella, Gemmiger, Klebsiella and Citrobacter, suggesting that CAP could modulate the composition and abundance of gut microbiota. These results implied that CAP can be developed as a potential prebiotic in the future.

In vivo absorption, in vitro simulated digestion and fecal fermentation properties of polysaccharides from Pinelliae Rhizoma Praeparatum Cum Alumine and their effects on human gut microbiota

Polysaccharides from Pinelliae Rhizoma Praeparatum Cum Alumine (PPA) have various biological activities, but their properties after oral administration are not clear. In this study, the absorption, digestion and fermentation properties of PPA were studied using in vivo fluorescence tracking, in vitro simulated digestion and fecal fermentation experiments. The absorption experiment showed that fluorescence was only observed in the gastrointestinal system, indicating that PPA could not be absorbed. Simulated digestion results showed that there were no significant changes in the molecular weight, Fourier transform infrared spectroscopy (FT-IR) spectrum, monosaccharides and reducing sugar of PPA during the digestion process, showing that the overall structure of PPA was not damaged. However, the carbohydrate gel electrophoresis bands of PPA enzymatic hydrolysates after simulated digestion were significantly changed, indicating that simulated digestion might impact the configuration of PPA. In vitro fermentation showed that PPA could be degraded by microorganisms to produce short chain fatty acids, leading to a decrease in pH value. PPA can promote the proliferation of Bacteroideaceae, Megasphaera, Bacteroideaceae, and Bifidobacteriaceae, and inhibit the growth of Desulfobacteriota and Enterobacteriaceae. The results indicated that PPA could treat diseases by regulating gut microbiota, providing a scientific basis for the application and development of PPA.

Changes in physicochemical and gut microbiota fermentation property induced by acetylation of polysaccharides from Cyperus esculentus

In this study, the impact of acetylation on physicochemical, digestive behavior and fermentation characteristics of Cyperus esculentus polysaccharides (CEP) was investigated. Results indicated that the acetylation led the molecules to be more likely aggregated, followed by a higher crystallinity, a lower apparent viscosity and a higher ratio of G" to G' (tan δ). Importantly, the acetylated polysaccharides (ACEP) had a lower digestibility, but its molecular weight was lower than that of original polysaccharides (CEP) following a simulated saliva-gastrointestinal digestion. Gut microbiota fermentation indicated that both polysaccharides generated outstanding short-chain fatty acids (SCFAs), in which the acetylated polysaccharides had a faster fermentation kinetics than the original one, followed by a quicker reduction of pH and a more accumulation of SCFAs, particularly butyrate. Fermentation of both polysaccharides promoted Akkermansia, followed by a reduced richness of Klebsiella. Importantly, the current study revealed that the fermentation of acetylated polysaccharides enriched Parabacteroides, while fermentation of original ones promoted Bifidobacterium, for indicating their individual fermentation characteristics and gut environmental benefits.

Structure and immunostimulatory activity studies on two novel Flammulina velutipes polysaccharides: revealing potential impacts of →6)-α-D-Glcp(1→ on the TLR-4/MyD88/NF-κB pathway

Two novel Flammulina velutipes (F. velutipes) polysaccharides, FVPH1 and FVPH2, were isolated and purified after hot water extraction. The structural characterization revealed that the backbone of FVPH1 consisted mainly of →6)-α-D-Glcp(1→, →3,4)-α-D-Galp(1→, →4)-α-L-Fucp(1→, and →4)-β-D-Manp(1→, while the backbone of FVPH2 consisted of →3)-α-D-Galp(1→, →3,4)-α-D-Manp(1→,→6)-α-D-Glcp(1→. The branches of FVPH1 contained →6)-α-D-Glcp(1→ and α-D-Glcp(1→ and the branches of FVPH2 consisted of →3)-α-D-Galp(1→, →6)-α-D-Glcp(1→, and β-L-Fucp(1→. FVPH2 exhibited significantly better immunostimulatory activity than FVPH1 (P < 0.05), as evidenced by the increased expression of NO, IL-1β, IL-6, and TNF-α and pinocytic activity of RAW264.7 cells. As the most abundant structure in the polysaccharides of F. velutipes, the content of →6)-α-D-Glcp(1→ might play a crucial role in influencing the immunostimulatory activity of F. velutipes polysaccharides. The F. velutipes polysaccharide with a lower content of →6)-α-D-Glcp(1→ and a higher branching degree could significantly enhance the immunostimulatory activity of F. velutipes polysaccharides via activating the TLR-4/MyD88/NF-κB pathway more effectively.

In vitro digestive properties of Dictyophora indusiata polysaccharide by steam explosion pretreatment methods

Dictyophora indusiata is medicinal and edible fungi containing various nutrients. The aim of this study was to investigate the efficient extraction and structural evolution of Dictyophora indusiata polysaccharide during the vitro digestion based on steam explosion pretreatment methods. In this study, the extraction rate of Dictyophora indusiata polysaccharide was optimized by steam explosion pretreatment methods, which was 2.46 folds that of the water extraction method. In addition, the digestion and fermentation properties of Dictyophora indusiata polysaccharide before and after steam explosion were evaluated in vitro by the changes of molecular weights, total and reducing sugars levels, surface morphology and functional groups, which showed that the structure of Dictyophora indusiata polysaccharide remained stable after salivary-gastric digestion, and partially entered the large intestine, where it could be utilized by gut microbiota. Dictyophora indusiata polysaccharide promoted the increase of beneficial bacteria Megamonas and increased the content of acetic acid, propionic acid and butyric acid, which was 2.17, 2.81, 2.43 folds that of the CON group after fermentation for 24 h, and 1.87, 2.77, 1.90 folds that of the CON group after fermentation for 48 h, respectively. This study will provide theoretical basis for the high value utilization of Dictyophora indusiata polysaccharide.

Sporisorium reilianum polysaccharides improve DSS-induced ulcerative colitis by regulating intestinal barrier function and metabolites

This study investigated the regulatory effects of Sporisorium reilianum polysaccharides (SRPS) on metabolism and the intestinal barrier in mice with colitis induced by dextran sulfate sodium (DSS). SRPS were resistant to the digestion of saliva, gastric juices, and intestinal fluid. SRPS significantly reduced the disease activity index and inhibited DSS-induced colon shortening. The expression of proinflammatory cytokines in the colon was normal (P < 0.05). Acetic acid, propionic acid, butyric acid, isobutyric acid, and isovaleric acid contents increased. Moreover, 64 biomarker metabolites were affected, including 42 abnormal decreases and 22 abnormal increases caused by DSS, which targeted amino acid biosynthesis; tryptophan metabolism; protein digestion and absorption; aminoacyl-tRNA biosynthesis; and glycine, serine, and threonine metabolism. In addition, SRPS reduced goblet cell loss and increased mucin secretion. The short-chain fatty acid receptor GPR41 was activated, and zonula occludens-1 and occludin expression levels were upregulated. Epithelial cell apoptosis was inhibited by increased Bcl-2 and decreased Bax expression NLRP3, ASC, and caspase-1 protein levels decreased. Intestinal barrier damage improved, and colon inflammation was reduced. Thus, our preliminary findings reveal that SRPS regulates metabolism and has the potential to protect the intestinal barrier in ulcerative colitis mice.

Anti-inflammatory activity of Boletus aereus polysaccharides: Involvement of digestion and gut microbiota fermentation

Boletus aereus, an edible mushroom, has gained popularity as a medicinal and functional food. This study aimed to investigate the digestive characteristics of B. aereus polysaccharide (BAP) and its effects on gut microbiota. In vitro digestion results indicated partial degradation of BAP. Furthermore, the digested BAP displayed significantly enhanced antioxidant ability. The 16S rRNA sequencing data revealed that BAP positively influenced the abundance of Phascolarctobacterium, Prevotella, and Bifidobacterium in the gut microbiota. Additionally, BAP promoted the production of short-chain fatty acids (SCFAs). Metabolites of BAP utilized by the gut microbiota effectively reduced the concentration of TNF-α, IL-1β, and NO in an LPS-stimulated RAW 264.7 cell inflammation model. Mantel tests demonstrated a strong correlation among fermentation indicators, gut microbiome composition, SCFAs, and inflammatory cytokines. Overall, this research revealed the underlying digestive and fermentation mechanisms of BAP and provided new insights into the usage of edible mushroom polysaccharides in functional food.

The function and application of edible fungal polysaccharides

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Anti-diabetic effect of red quinoa polysaccharide on type 2 diabetic mellitus mice induced by streptozotocin and high-fat diet

The purpose of this study was to explore the mechanism of red quinoa polysaccharide (RQP) in alleviating type 2 diabetes (T2D) through in vivo and in vitro experiments. Results of HPLC and FITR showed that RQP was a complex polysaccharide and contained more glucose, galactose and acarbose. In vitro experiments, RQP showed strong antioxidant capacity and inhibition on α-amylase and α-glucosidase. In vivo experiments, RQP was proved to induce a significant improvement of diabetes after 4 weeks of ingestion, including the abilities of lowering blood glucose, regulating lipid metabolism, anti-oxidation and promoting secretion of SCFAs. Furthermore, 16S rRNA study demonstrated that RQP transformed the intestinal microbiota composition in diabetic mice, decreased the abundance of norank_f_Muribaculaceae and Lachnospiraceae_NK4A136_group, and increased the relative abundance of Akkermansia, unclassified_f_Lachnospiraceae, norank_f_Eubacterium_coprostanoligenes_group, unclassified_f_Atopobiaceae and norank_f_Lachnospiraceae. The biosynthetic pathways, metabolic pathways and intestinal microbiome phenotypes in mice also changed accordingly. In conclusion, this study suggests that RQP can inhibit the development of diabetes by correcting the imbalance of intestinal flora.

Interactions between intestinal microbial fermentation products of Pleurotus eryngii polysaccharide with gut mucus

Recently, Pleurotus eryngii (P. eryngii) polysaccharide (PEP) has received a lot of attention from many researchers as the primary active substance. The PEP influences the gut microbiota in several ways, including the interaction of fermentation products with the intestinal mucus layer (IML) and intestinal epithelial cells. Herein, we characterized interactions between the IML and PEP after degradation by the gut microbes. Our results showed that fermented P. eryngii polysaccharide (FPEP) can interact with intestinal mucus (IM), and this interaction can reduce the degree of molecular aggregation of polysaccharides. At the same time, the fermentation time of FPEP also affects the interaction between the two. SEM showed that the FPEP solution tended to aggregate into larger particles, while with the addition of IM, the FPEP molecules were dispersed. Particle size measurements unveil substantial differences in the fermented polysaccharides' particle size between the group with supplementary IM (0 hours of fermentation: 485.1 ± 11.3 nm) and the group without IM (0 hours of fermentation: 989.33 ± 21.3 nm). Remarkably, within the group with added IM, the particle size reached its maximum at 24 hours of fermentation (585.87 ± 42.83 nm). Additionally, turbidity assessments demonstrate that, during the 12-hour interaction period, the 24-hour fermented polysaccharides consistently exhibit the highest OD values, ranging between 0.57 and 0.61. This work investigates the interaction between FPEP and IM, predicting the adhesion of polysaccharides to IM. Meanwhile, this provides a theoretical basis for further studies on the absorption and transport pathways of PEP and provides a novel research viewpoint on intestinal digestion and absorption.

The effect of in vitro digestion on the interaction between polysaccharides derived from Pleurotus eryngii and intestinal mucus

Pleurotus eryngii polysaccharides (PEPs) have been proven to display multiple activities through digestive system action, from which the digestion products should first interact with intestinal mucus (MUC), followed by the function of intestinal cells. Hence, possible interacting characterizations between MUC and in vitro simulated digestion products of P. eryngii polysaccharides (DPEPs) and PEP were carried out in the present study. Results showed that both PEP and DPEP could significantly interact with MUC. Moreover, digestion can modify the interaction between polysaccharides and MUC; the degree of interaction also changes with time incrementing. Viscosity could be decreased after digesting. According to the zeta potential and stability analysis result, the digestive behavior could be regular and stable between polysaccharides and MUC interactions. Following fluorescence and infrared spectra, the structure of polysaccharides and mucin might be changed by digestion between polysaccharides and MUC. The study indicates that the interaction formed between DPEP and MUC might indirectly impact the exercise and immune activities of polysaccharides and influence the transportation of other nutrients. Overall, our results, the absorption and transport pathways of PEP, can be initially revealed and may provide a novel research viewpoint on the active mechanism of PEP in the intestinal tract.

Gut microbiome-based thiamine metabolism contributes to the protective effect of one acidic polysaccharide from Selaginella uncinata (Desv.) Spring against inflammatory bowel disease

Inflammatory bowel disease (IBD) is a serious disorder, and exploration of active compounds to treat it is necessary. An acidic polysaccharide named SUSP-4 was purified from Selaginella uncinata (Desv.) Spring, which contained galacturonic acid, galactose, xylose, arabinose, and rhamnose with the main chain structure of →4)-α-d-GalAp-(1→ and →6)-β-d-Galp-(1→ and the branched structure of →5)-α-l-Araf-(1→ . Animal experiments showed that compared with Model group, SUSP-4 significantly improved body weight status, disease activity index (DAI), colonic shortening, and histopathological damage, and elevated occludin and zonula occludens protein 1 (ZO-1) expression in mice induced by dextran sulfate sodium salt (DSS). 16S ribosomal RNA (rRNA) sequencing indicated that SUSP-4 markedly downregulated the level of Akkermansia and Alistipes. Metabolomics results confirmed that SUSP-4 obviously elevated thiamine levels compared with Model mice by adjusting thiamine metabolism, which was further confirmed by a targeted metabolism study. Fecal transplantation experiments showed that SUSP-4 exerted an anti-IBD effect by altering the intestinal flora in mice. A mechanistic study showed that SUSP-4 markedly inhibited macrophage activation by decreasing the levels of phospho-nuclear factor kappa-B (p-NF-κB) and cyclooxygenase-2 (COX-2) and elevating NF-E2-related factor 2 (Nrf2) levels compared with Model group. In conclusion, SUSP-4 affected thiamine metabolism by regulating Akkermania and inhibited macrophage activation to adjust NF-κB/Nrf2/COX-2-mediated inflammation and oxidative stress against IBD. This is the first time that plant polysaccharides have been shown to affect thiamine metabolism against IBD, showing great potential for in-depth research and development applications.

Sustained release of chlorogenic acid by co-encapsulation of sodium alginate binding to the Northern pike (Esox Lucius) liver ferritin

Ferritin has a unique hollow spherical structure, which makes it a promising nanocarrier for food functional substances. In this study, a new ferritin was successfully extracted from the liver of Northern pike, purified, and identified. We used the reversible self-assembly characteristics of ferritin to fabricate chlorogenic acid (CA)-loaded apoferritin (Apo) complex (Apo-CA) and sodium alginate (SA)-apoferritin (Apo) co-encapsulate system. Apo-CA was encapsulated into the SA system to form SA-Apo-CA. The fabricated composites were analyzed using particle size, UV-Vis absorption spectroscopy, fluorescence spectroscopy, flourier transform infrared spectroscopy and transmission electron microscope. Physicochemical property of analysis confirmed th successful preparation of Apo-CA/SA-Apo-CA and improved thermal and UV radiation stability. The effect of sustained-release of CA were tested in vitro of simulated gastrointestinal tract digestion. SA-Apo-CA exhibited greater release ability than unencapsulated CA and Apo-CA. This study provides a new strategy for designing a multilayer delivery system with improved stability and sustained-release property.

Semi-solid enzymolysis enhanced the protective effects of fruiting body powders and polysaccharides of Herinaceus erinaceus on gastric mucosal injury

This study demonstrated the effects of semi-solid enzymolysis on physicochemical properties of fruiting body powders and polysaccharides from Hericium erinaceus and protective effects on gastric mucosal injury. Semi-solid enzymolysis could reduce the particle size, change the microstructure of fruiting body powders, increase the contents of soluble polysaccharide (26.26-67.04 %) and uronic acid (16.97-31.12 %) and reduce the molecular weight of polysaccharides. The digestibility of fruiting body powder of H. erinaceus after semi-solid enzymolysis was increased by 31.4 %, compared with that of the fruiting body powder of H. erinaceus without enzymolysis. Semi-solid enzymolysis could enhance the protective effects of the fruiting body powders and polysaccharides on ethanol-induced human gastric mucosal epithelial cells (GES-1) cells, increase the production of superoxide dismutase (SOD, 0-37.33 %) and catalase (CAT, 2.47-18.46 %), and inhibit the production of malonaldehyde (MDA, 2.45-19.62 %), myeloperoxidase (MPO, 0-13.54 %), interleukin (IL-6, 4.39-24.62 %) and tumor necrosis factor-α (TNF-α, 5.97-12.25 %). Semi-solid enzymolysis could improve the inhibition rate of the fruiting body powder on gastric ulcer (32.70-46.26 %), inhibit oxidative stress and inflammation, and protect rats with acute gastric mucosal injury against the stimulation of ethanol on gastric mucosa. In conclusion, semi-solid enzymolysis may enhance the protective effects of the fruiting body powders and polysaccharides on gastric mucosal injury.

Structurally Orientated Rheological and Gut Microbiota Fermentation Property of Mannans Polysaccharides and Oligosaccharides

Three mannan polysaccharides and their oligosaccharides were investigated in terms of physicochemical characteristics and effects on gut microbiota. Oligosaccharides from guar gum had the fastest fermentation kinetics for SCFAs generation at the initial stage, while the locust bean of both polymers and oligosaccharides demonstrated the lowest SCFAs through the whole fermentation process. In contrast, konjac gum steadily increased SCFAs and reached its maximum level at 24 h fermentation, indicating its fermentation character may be associated with its rheological properties. Compared to their corresponding polysaccharides, all the oligosaccharides demonstrated a faster fermentation kinetics, followed by an enriched abundance of propionate-producing bacterial Prevotella and a decreased abundance of Megamonas and Collinsella. Meanwhile, oligosaccharides reduced the Firmicutes/Bacteroidota ratio as well as the abundance of Bacteroidetes and Escherichia-Shigella. The fermentation of konjac substrate significantly promoted the abundance of butyrate-producing bacterial Faecalibacterium. In contrast, although the fermentation of locust bean and guar gum substrates benefited Bifidobacterium abundance due to their similar structure and monosaccharides composition, the fermentation of locust bean gum led to greater Bifidobacterium than the others, which may be associated with its higher mannose composition in the molecules. Interestingly, the partial hydrolysis of the three polysaccharides slightly reduced their prebiotic function.

Inhibitive effects of phytic acid combined with glutathione on the browning and oxidation of King Oyster mushroom (Pleurotus eryngii) slices during drying and storage

Phytic acid and glutathione can inhibit polyphenoloxidase (PPO) activity and suppress browning. This study investigated the effects of phytic acid alone (Treatment-1) or combined with glutathione (Treatment-2) on inhibiting browning and oxidation resistance of King Oyster mushroom (Pleurotus eryngii) slices during drying and storage. In King Oyster mushroom slices, 0.08% phytic acid combined with 0.1% glutathione inhibited the PPO activity by 97.6%, suppressed browning by 78.09% after 6 h of drying at 60 °C and inhibited browning by 69.93% and oxidation by 78.75% after 12 months of storage at ∼ 20 °C. Results indicated that using phytic acid combined with glutathione may inhibit browning and suppress the oxidation of King Oyster mushroom slices during drying and storage.