In vitro digestibility and prebiotic activities of a sulfated polysaccharide from Gracilaria Lemaneiformis

In vitro human gut microbiota fermentation of litchi pulp polysaccharides as affected by Lactobacillus pre-treatment

In this study, litchi polysaccharides were obtained from unfermented or fermented pulp by Lactobacillus fermentum (denoted as LP and LPF, respectively). The differences between LP and LPF in the colonic fermentation characteristics and modulatory of gut microbiota growth and metabolism were investigated with an in vitro fecal fermentation model. Results revealed that the strategies of gut bacteria metabolizing LP and LPF were different and LPF with lower molecular weight (Mw) was readily utilized by bacteria. The monosaccharide utilization sequence of each polysaccharide was Ara > Gla > GalA > GlcA ≈ Glu ≈ Man. Moreover, LPF promoted stronger proliferation of Bifidobacterium, Megamonas, Prevotella, and Bacteroides and higher SCFAs production (especially acetic and butyric acids) than LP. Correlation analysis further revealed that Mw could represent an essential structural feature of polysaccharides associated with its microbiota-regulating effect. Overall, Lactobacillus fermentation pre-treatment of litchi pulp promoted the fermentation characteristics and prebiotic activities of its polysaccharide.

Fermented Gracilaria lemaneiformis polysaccharides alleviate food allergy by regulating Treg cells and gut microbiota

Food allergy has a significant impact on the health and well-being of individuals, affecting both their physical and mental states. Research on natural bioactive compounds, such as polysaccharides extracted from seaweeds, holds great promise in the treatment of food allergies. In this study, fermented Gracilaria lemaneiformis polysaccharides (F-GLSP) were prepared using probiotic fermentation. Probiotic fermentation of Gracilaria lemaneiformis reduces the particle size of polysaccharides. To compare the anti-allergic activity of F-GLSP with unfermented Gracilaria lemaneiformis polysaccharides (UF-GLSP), an OVA-induced mouse food allergy model was established. F-GLSP exhibited a significant reduction in OVA-specific IgE and mMCP levels in allergic mice. Moreover, it significantly inhibited Th2 differentiation and IL-4 production and significantly promoted Treg differentiation and IL-10 production in allergic mice. In contrast, UF-GLSP only reduced OVA-specific IgE and mMCP in the serum of allergic mice. Furthermore, F-GLSP demonstrated a more pronounced regulation of intestinal flora abundance compared to UF-GLSP, significantly influencing the populations of Firmicutes, Bacteroidetes, Lactobacillus, and Clostridiales in the intestines of mice with food allergy. These findings suggest that F-GLSP may regulate food allergies in mice through multiple pathways. In summary, this study has promoted further development of functional foods with anti-allergic properties based on red algae polysaccharides.

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.

Methylation-GC-MS/FID-Based Glycosidic Linkage Analysis of Unfractionated Polysaccharides in Red Seaweeds

Glycosidic linkage analysis was conducted on the unfractionated polysaccharides in alcohol-insoluble residues (AIRs) prepared from six red seaweeds (Gracilariopsis sp., Prionitis sp., Mastocarpus papillatus, Callophyllis sp., Mazzaella splendens, and Palmaria palmata) using GC-MS/FID analysis of partially methylated alditol acetates (PMAAs). The cell walls of P. palmata primarily contained mixed-linkage xylans and small amounts of sulfated galactans and cellulose. In contrast, the unfractionated polysaccharides of the other five species were rich in galactans displaying diverse 3,6-anhydro-galactose and galactose linkages with varied sulfation patterns. Different levels of cellulose were also observed. This glycosidic linkage method offers advantages for cellulose analysis over traditional monosaccharide analysis that is known for underrepresenting glucose in crystalline cellulose. Relative linkage compositions calculated from GC-MS and GC-FID measurements showed that anhydro sugar linkages generated more responses in the latter detection method. This improved linkage workflow presents a useful tool for studying polysaccharide structural variations across red seaweed species. Furthermore, for the first time, relative linkage compositions from GC-MS and GC-FID measurements, along with normalized FID and total ion current (TIC) chromatograms without peak assignments, were analyzed using principal component analysis (PCA) as a proof-of-concept demonstration of the technique's potential to differentiate various red seaweed species.

Characterization of Three Polysaccharide-Based Hydrogels Derived from Laminaria japonica and Their Hemostatic Properties

Three Laminaria japonica polysaccharides (LJPs) extracted via water extraction (LJP-W), acid extraction (LJP-A), and enzymatic extraction (LJP-E) were used as raw materials to be cross-linked with chitosan and polyvinyl alcohol to prepare hydrogels. Compared with conventional hydrogel systems, all three types of LJP-based polysaccharide hydrogels exhibited better swelling properties (14 times their original weight) and the absorption ability of simulated body fluid (first 2 h: 6-10%). They also demonstrated better rigidity and mechanical strength. Young's modulus of LJP-E was 4 times that of the blank. In terms of hemostatic properties, all three polysaccharide hydrogels did not show significant cytotoxic and hemolytic properties. The enzyme- and acid-extracted hydrogels (LJP-Gel-A and LJP-Gel-E) demonstrated better whole-blood coagulant ability compared with the water-extracted hydrogel (LJP-Gel-W), as evidenced by the whole blood coagulation index being half that of LJP-Gel-W. Additionally, the lactate dehydrogenase viabilities of LJP-Gel-A and LJP-Gel-E were significantly higher, at about four and three times those of water extraction, respectively. The above results suggested that LJP-Gel-A and LJP-Gel-E exhibited better blood coagulation capabilities than LJP-Gel-W, due to their enhanced platelet enrichment and adhesion properties. Consequently, these hydrogels are more conducive to promoting coagulation and have good potential for wound hemostasis.

Updated Progress on Polysaccharides with Anti-Diabetic Effects through the Regulation of Gut Microbiota: Sources, Mechanisms, and Structure-Activity Relationships

Diabetes mellitus (DM) is a common chronic metabolic disease worldwide. The disturbance of the gut microbiota has a complex influence on the development of DM. Polysaccharides are one type of the most important natural components with anti-diabetic effects. Gut microbiota can participate in the fermentation of polysaccharides, and through this, polysaccharides regulate the gut microbiota and improve DM. This review begins by a summary of the sources, anti-diabetic effects and the gut microbiota regulation functions of natural polysaccharides. Then, the mechanisms of polysaccharides in regulating the gut microbiota to exert anti-diabetic effects and the structure-activity relationship are summarized. It is found that polysaccharides from plants, fungi, and marine organisms show great hypoglycemic activities and the gut microbiota regulation functions. The mechanisms mainly include repairing the gut burrier, reshaping gut microbiota composition, changing the metabolites, regulating anti-inflammatory activity and immune function, and regulating the signal pathways. Structural characteristics of polysaccharides, such as monosaccharide composition, molecular weight, and type of glycosidic linkage, show great influence on the anti-diabetic activity of polysaccharides. This review provides a reference for the exploration and development of the anti-diabetic effects of polysaccharides.

Structural characterization and in vitro fermentation properties of polysaccharides from Polygonatum cyrtonema

Polysaccharides, the major active ingredient and quality control indicator of Polygomatum cyrtonema are in need of elucidation for its in vitro fermentation characteristics. This study aimed to investigate the structural characteristics of the homogeneous Polygomatum cyrtonema polysaccharide (PCP-80 %) and its effects on human intestinal bacteria and short chain fatty acids (SCFAs) production during the in vitro fermentation. The results revealed that PCP-80 % was yielded in 10.44 % and the molecular weight was identified to be 4.1 kDa. PCP-80 % exhibited a smooth, porous, irregular sheet structure and provided good thermal stability. The analysis of Gas chromatograph-mass spectrometer (GC-MS) suggested that PCP-80 % contained six glycosidic bonds, with 2,1-linked-Fruf residues accounted for a largest proportion. Nuclear magnetic resonance (NMR) provided additional evidence that the partial structure of PCP-80 % probably consists of →1)-β-D-Fruf-(2 → as the main chain, accompanied by side chains dominated by →6)-β-D-Fruf-(2→. Besides, PCP-80 % promoted the production of SCFAs and increased the relative abundance of beneficial bacteria such as Megamonas, Bifidobacterium and Phascolarctobacterium during in vitro colonic fermentation, which changed the composition of the intestinal microbiota. These findings indicated that Polygomatum cyrtonema polysaccharides were able to modulate the structure and composition of the intestinal bacteria flora and had potential probiotic properties.

Preparation, Structural Analysis, and Intestinal Probiotic Properties of a Novel Oligosaccharide from Enzymatic Degradation of Huangshui Polysaccharide

Huangshui polysaccharide (HSP) has attracted more and more interest due to its potential health benefits. Despite being an excellent source for the preparation of oligosaccharides, there are currently no relevant research reports on HSP. In the present study, a novel oligosaccharide (HSO) with a molecular weight of 1791 Da and a degree of polymerization of 11 was prepared through enzymatic degradation of crude HSP (cHSP). Methylation and NMR analyses revealed that the main chain of HSO was (1 → 4)-α-d-glucose with two O-6-linked branched chains. Morphological observations indicated that HSO exhibited smooth surface with lamellar and filamentary structure, and the glycan size ranged from 0.03 to 0.20 μm. Notably, HSO significantly promoted the proliferation of Bifidobacterium, Bacteroides, and Phascolarctobacterium, thereby making positive alterations in intestinal microbiota composition. Moreover, HSO markedly increased the content of short-chain fatty acids during in vitro fermentation. Metabolomics analysis illustrated the important metabolic pathways primarily involving glucose metabolism, amino acid metabolism, and fatty acid metabolism.

Production, structural and functional characteristics of soluble dietary fiber from fermented okara by Penicillium expansum

Soluble dietary fiber (SDF), an important prebiotic, has attracted growing attention, due to its great health effects and wide application. This study focused on the preparation of SDF from fermented okara. The yield of SDF obtained through Penicillium expansum fermentation (FSDF) reached 45.63 % (w/w) under the optimal conditions (pH 6.7, inoculum size 9.5 %, and time 29 h) by response surface methodology, which were 1.92 and 4.43 times higher than those of phosphate-citric acid treatment and untreated okara. Infrared spectra and X-ray diffraction indicated that three SDFs had similar spectral distribution and crystalline region. Moreover, FSDF displayed looser and more porous microstructures. Meanwhile, the composition ratio of monosaccharides has changed. FSDF exhibited higher water solubility (97.46 %), glucose adsorption capacity (203.73 mg/g), sodium cholate adsorption capacity (13.07 mg/g), cholesterol adsorption capacity (6.69- 7.62 mg/g) and radical (ABTS+, hydroxyl and DPPH) scavenging capacity. Additionally, three SDFs didn't degrade by upper gastrointestinal tract and could improve the proportion of beneficial intestinal flora in vitro, such as Lactobacillus and Bifidobacterium. Overall, the FSDF prepared in this study was a functional ingredient with great potential in foods.

Effect of in vitro digestion and fermentation of kiwifruit pomace polysaccharides on structural characteristics and human gut microbiota

Kiwifruit pomace is abundant in polysaccharides that exhibit diverse biological activities and prebiotic potential. This study delves into the digestive behavior and fermentation characteristics of kiwifruit pomace polysaccharides (KFP) through an in vitro simulated saliva-gastrointestinal digestion and fecal fermentation. The results reveal that following simulated digestion of KFP, its molecular weight reduced by 4.7%, and the reducing sugar (CR) increased by 9.5%. However, the monosaccharide composition and Fourier transform infrared spectroscopy characteristics showed no significant changes, suggesting that KFP remained undigested. Furthermore, even after saliva-gastrointestinal digestion, KFP retained in vitro hypolipidemic and hypoglycemic activities. Subsequently, fecal fermentation significantly altered the physicochemical properties of indigestible KFP (KFPI), particularly leading to an 89.71% reduction in CR. This indicates that gut microbiota could decompose KFPI and metabolize it into SCFAs. Moreover, after 48 h of KFPI fecal fermentation, it was observed that KFPI contributed to maintaining the balance of gut microbiota by promoting the proliferation of beneficial bacteria like Bacteroides, Lactobacillus, and Bifidobacterium, while inhibiting the unfavorable bacteria like Bilophila. In summary, this study offers a comprehensive exploration of in vitro digestion and fecal fermentation characteristics of KFP, providing valuable insights for potential development of KFP as a prebiotic for promoting intestinal health.

Sulfated Galactans from Agarophytes: Review of Extraction Methods, Structural Features, and Biological Activities

Agarophytes are important seaweeds of the Rhodophyta type, which have been highly exploited for industrial use as sources of a widely consumed polysaccharide of agar. In addition to that, sulfated galactans (SGs) from agarophytes, which consist of various functional sulfate groups, have attracted the attention of scientists in current studies. SGs possess various biological activities, such as anti-tumor, anticoagulant, anti-inflammatory, antioxidant, anti-obesity, anti-diabetic, anti-microbial, anti-diarrhea, and gut microbiota regulation properties. Meanwhile, the taxonomy, ecological factors, i.e., environmental factors, and harvest period, as well as preparation methods, i.e., the pretreatment, extraction, and purification conditions, have been found to influence the chemical compositions and fine structures of SGs, which have, further, been shown to have an impact on their biological activities. However, the gaps in the knowledge of the properties of SGs due to the above complex factors have hindered their industrial application. The aim of this paper is to collect and systematically review the scientific evidence about SGs and, thus, to pave the way for broader and otherwise valuable industrial applications of agarophytes for human enterprise. In the future, this harvested biomass could be sustainably used not only as a source of agar production but also as natural materials in functional food and pharmaceutical industries.

In vitro fermentation of Gracilaria lemaneiformis and its sulfated polysaccharides by rabbitfish gut microbes

This study intended to characterize the Gracilaria lemaneiformis (SW)-derived polysaccharide (GLP) and explore the fermentation aspects of SW and GLP by rabbitfish (Siganus canaliculatus) intestinal microbes. The GLP was mainly composed of galactose and anhydrogalactose (at 2.0:0.75 molar ratio) with the linear mainstay of α-(1 → 4) linked 3,6-anhydro-α-l-galactopyranose and β-(1 → 3)-linked galactopyranose units. The in vitro fermentation results showed that the SW and GLP could reinforce the short-chain fatty (SCFAs) production and change the diversity and composition of gut microbiota. Moreover, GLP boosted the Fusobacteria and reduced the Firmicutes abundance, while SW increased the Proteobacteria abundance. Furthermore, the adequacy of feasibly harmful bacteria (such as Vibrio) declined. Interestingly, most metabolic processes were correlated with the GLP and SW groups than the control and galactooligosaccharide (GOS)-treated groups. In addition, the intestinal microbes degrade the GLP with 88.21 % of the molecular weight reduction from 1.36 × 105 g/mol (at 0 h) to 1.6 × 104 g/mol (at 24 h). Therefore, the findings suggest that the SW and GLP have prebiotic potential and could be applied as functional feed additives in aquaculture.

Effects of dietary supplementation of Gracilaria lemaneiformis-derived sulfated polysaccharides on the growth, antioxidant capacity, and innate immunity of rabbitfish (Siganus canaliculatus)

The dietary supplementation of red seaweed-derived polysaccharides has been shown to be beneficial to fish and shellfish aquaculture. However, the function of red seaweed (Gracilaria lemaneiformis)-extracted polysaccharide (GLP) on the health status of rabbitfish (Siganus canaliculatus) is still unknown. This study explored the influences of GLP on growth performance, antioxidant activity, and immunity of rabbitfish. Herein, the fish were fed commercial pelleted feed incorporated with the diverse amount of GLP: 0 (control), 0.10 (GLP0.10), and 0.15 g kg^-1 (GLP0.15) for 60 days. The results demonstrated that dietary GLP0.15 significantly elevated FBW and WG, while feed utilization efficiency improved (reduced feed conversion ratio and increased protein efficiency ratio) upon GLP0.10 treatment, regarding the control (P < 0.05). Also, dietary administration of GLP0.15 suggestively improved the serum acid phosphatase and lysozyme activity as well as hepatic total antioxidant capacity, catalase, and superoxide dismutase activity. In contrast, GLP0.15decreased the serum alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and malonaldehyde activity when compared to the control (P<0.05). Moreover, the lipase (36.08 and 16.46 U/mgprot in GLP0.10 and GLP0.15, respectively) and amylase (0.43 and 0.23 U/mgprot in GLP0.10 and GLP0.15, respectively) activity recorded the maximum values than the control (8.61 and 0.13 U/mgprot, respectively).Further, the intestinal morphometry was developed (such as increased villus length, width, and area) in the fish fed with a GLP-supplemented diet compared to the control. The KEGG pathway analysis unveiled that several differentially expressed genes (DEGs) in control vs. GLP0.10 and control vs. GLP0.15 were associated with metabolic or immune-associated pathways like antigen processing and presentation, phagosome, complement and coagulation cascades, and platelet activation. The DEGs, namely C3, f5, fgb, MHC1, and cfb, were evaluated in control vs. GLP0.10 and C3 and MHC1 in control vs. GLP0.15, suggesting their possible contributions to GLP-regulated immunity. Additionally, the cumulative mortality of rabbitfish after the Vibrio parahaemolyticus challenge was lower in both GLP0.10 (8.88%) and GLP0.15 (11.11%) than in control (33.33%) (P<0.05). Thus, these findings direct the potential use of GLP as an immunostimulant and growth promoter in rabbitfish aquaculture.

Catabolism of Dictyophora indusiata Polysaccharide and Its Impacts on Gut Microbial Composition during In Vitro Digestion and Microbial Fermentation

Dictyophora indusiata is one of the most famous edible mushrooms in China. D. indusiata polysaccharide (DP) has attracted increasing attention because of its multiple beneficial effects. In this study, the in vitro simulated digestion and microbial fermentation were designed to reveal the potential catabolic property of DP and its impacts on the modulation of gut microbial composition. The results showed that the reducing sugar content, total polysaccharides content, molecular weight, and rheological property of DP were not significantly altered under in vitro simulated digestive conditions. However, the molecular weight, apparent viscosity, and total polysaccharides content of indigestible DP (DPI) significantly decreased during in vitro fecal fermentation, and the reducing sugar content and the release of free monosaccharides notably increased, suggesting that DP could be degraded and used by gut microbiota. Additionally, the relative abundances of several beneficial bacteria, such as Bacteroides, Catenibacterium, Parabacteroides, and Megamonas, increased significantly, indicating that DP can regulate the composition and abundance of gut microbiota. Moreover, DP could also promote the production of SCFAs, thus changing the acid-base environment of the large intestine. The results of this study are beneficial for deeply clarifying the catabolic behavior of DP in the gastrointestinal tract, which can provide a theoretical basis for developing microbiota-directed products based on DP.

Structure, anti-fatigue activity and regulation on gut microflora in vivo of ethanol-fractional polysaccharides from Dendrobium officinale

This study was to investigate the antifatigue, prebiotic effects and their relationships to the structure properties of three ethanol precipitated polysaccharides from Dendrobium officinale (EPDO), as EPDO-40, EPDO-60 and EPDO-80. EPDOs with anti-fatigue activity were screened out by forced swimming test, and blood lactic acid (BLA), blood urea nitrogen (BUN), superoxide dismutase (SOD), liver glycogen, muscle glycogen, and intestinal microflora were investigated. Results showed that purified EPDO-60, 277.3 kDa, with a backbone consisted of 4-Manp and 4-Glcp. EPDO-60 had the best anti-fatigue activity, because it could significantly prolong the forced swimming time, as well as down-regulating the levels of BLA and BUN, increasing SOD. Proportions of Bacteroidetes and Firmicutes and abundance of Lactobacillus and Bifidobacterium in gut microflora increased after treated with EPDO-60. Accordingly, EPDO-60 could affect the community structure of gut microflora, leading to promote the balance of oxidation and antioxidation, and accelerated the fatigue metabolism in vivo.

Characteristics and properties of a polysaccharide isolated from Wolfiporia cocos as potential dietary supplement for IBS

Introduction

As low FODMAP (Fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet therapy is recommended for most of Irritable Bowel Syndrome (IBS) patients, the consequent insufficient of dietary fibers (DFs) intake exert an adverse impact on intestinal health. It is necessary to find suitable DFs for IBS patients.

Methods

This study extracted a water-insoluble polysaccharide from Wolfiporia cocos (WIP) by alkali-extraction and acid-precipitation method. Its molecular weight was detected by high performance gel permeation chromatography (HPGPC) analysis. The structure of WIP was analyzed by Fourier transform infrared (FT-IR) spectrum, Nuclear Magnetic Resonance (NMR) spectra and X-ray diffraction (XRD). The properties related to stability, digestion, viscosity, osmotic activity, adsorption and fermentation were investigated, aimed to explore the feasibility of WIP as a new DF supplement for patients with IBS. In addition, 16S rRNA sequencing analysis was conducted to explore its effects on IBS-related gut microbiota.

Results and Discussion

The results showed that WIP had a single homogeneous composition and the molecular weight was 8.1 × 103 Da. WIP was indicated as a kind of pyranose form with β anomeric configuration and the main chain of WIP was 1,3-β-glucan with amorphous structure. In addition to good thermal stability, WIP also has low bioavailability and can reach the colon mostly without being digested. Moreover, the low viscosity and osmotic activity, the high water- swelling and water/oil-holding capacity, fructose adsorption capacity and poor fermentation performance of WIP demonstrated that it is suitable for IBS patients. It is worth noting that WIP regulates IBS associated gut microbiota effectively, such as the abundance of Lachnospiraceae and Prevotella. These findings provide a theoretical basis for the development of WIP as a dietary supplement for IBS patients with low FODMAP diet therapy.

GRAPHICAL ABSTRACT

Effects of in vitro digestion and fecal fermentation on physico-chemical properties and metabolic behavior of polysaccharides from Clitocybe squamulosa

The aim of this study was to establish a human digestion model in vitro to explore the degradation characteristics of a novel high-purity polysaccharide from Clitocybe squamulosa (CSFP2). The results showed that the content of reducing sugars (C_R ) of CSFP2 increased from 0.13 to 0.23 mg/mL, the molecular weight (Mw) of CSFP2 decreased significantly during the saliva-gastrointestinal digestion. The constituent monosaccharides of CSFP2, including galactose, glucose, and mannose, were stable during in vitro digestion, but their molar ratios were changed from 0.023: 0.737: 0.234 to 0.496: 0.478: 0.027. The surface of CSFP2 changes from a rough flaky structure to a scattered flocculent or rod-shaped structure after the gastrointestinal digestion. However, the apparent viscosity of CSFP2 was overall stable during in vitro digestion. Moreover, CSFP2 still maintains its strong antioxidant capacity after saliva-gastrointestinal digestion. The results showed that CSFP2 can be partially decomposed during digestion. Meanwhile, some physico-chemical properties of the fermentation broth containing CSFP2 changed significantly after gut microbiota fermentation. For example, the pH value (from 8.46 to 4.72) decreased significantly (p < 0.05) after 48 h of fermentation. the OD ₆₀₀ value increased first and then decreased (from 2.00 to 2.68 to 1.32) during 48-h fermentation. In addition, CSFP2 could also increase the amounts of short-chain fatty acids (SCFAs) (from 5.5 to 37.15 mmol/L) during fermentation (in particular, acetic acid, propionic acid, and butyric acid). Furthermore, the relative abundances of Bacteriodes, Bifidobacterium, Catenibacterium, Lachnospiraceae_NK4A136_group, Megasphaera, Prevotella, Megamonas, and Lactobacillus at genus level were markedly increased with the intervention of CSFP2. These results provided a theoretical basis for the further development of functional foods related to CSFP2.

In Vitro Fecal Fermentation of Euphorbia humifusa-Derived Polysaccharides and Their Protective Effect against Ulcerative Colitis in Mice

Euphorbia humifusa is a plant species with medicinal and food characteristics used to treat diarrhea and other intestinal diseases. This study investigated the prebiotic effects of E. humifusa-derived polysaccharides (EHPs) on human colonic microbiota and their regulatory effects on ulcerative colitis (UC). Structural characterization showed that EHPs mainly consisted of galactose, glucose, and glucuronic acid and were heteropolysaccharides having molecular weights of 7.70 × 10³ and 1.76 × 10² kDa, respectively. EHPs were identified as poorly absorbed macromolecules, verified by the apparent permeability coefficient values (Papp < 1.0 × 10^-6 cm/s) and cellular uptake by Caco-2 cell monolayers. During in vitro fermentation studies, the contents of acetic, propionic, and valeric acids increased significantly in EHP-supplemented samples after 24 h compared to that in the control sample. Moreover, EHPs could alter the intestinal microbiota composition by increasing the relative abundance of Bifidobacterium and Holdemanella and reducing that of Escherichia-Shigella, Tyzzerella, and Parasutterella at the genus level. In a dextran sulfate sodium (DSS)-induced UC mouse model, EHPs alleviated UC symptoms by increasing the colon length, reversing the colon tissue damage and inhibiting pro-inflammatory cytokines. Overall, these results suggest that EHPs could be utilized as a potential prebiotic or a promising nutritional strategy for UC management.

In Vitro Fermentation of Pleurotus eryngii Mushrooms by Human Fecal Microbiota: Metataxonomic Analysis and Metabolomic Profiling of Fermentation Products

Edible mushrooms contain biologically active compounds with antioxidant, antimicrobial, immunomodulatory and anticancer properties. The link between their anticancer and immunomodulatory properties with their possible prebiotic activity on gut micro-organisms has been the subject of intense research over the last decade. Lyophilized Pleurotus eryngii (PE) mushrooms, selected due to their strong lactogenic effect and anti-genotoxic, immunomodulatory properties, underwent in vitro static batch fermentation for 24 h by fecal microbiota from eight elderly apparently healthy volunteers (>65 years old). The fermentation-induced changes in fecal microbiota communities were examined using Next Generation Sequencing of the hypervariable regions of the 16S rRNA gene. Primary processing and analysis were conducted using the Ion Reporter Suite. Changes in the global metabolic profile were assessed by 1H NMR spectroscopy, and metabolites were assigned by 2D NMR spectroscopy and the MetaboMiner platform. PLS-DA analysis of both metataxonomic and metabolomic data showed a significant cluster separation of PE fermented samples relative to controls. DEseq2 analysis showed that the abundance of families such as Lactobacillaceae and Bifidobacteriaceae were increased in PE samples. Accordingly, in metabolomics, more than twenty metabolites including SCFAs, essential amino acids, and neurotransmitters discriminate PE samples from the respective controls, further validating the metataxonomic findings.

Domestic Cooking Affects the Prebiotic Performances of Chinese Yam

The appropriate domestic cooking methods can retain and protect the biological properties of foods well. Thus, the objective of this study was to unravel the effect of different cooking methods on the microbiota modulatory properties of yam and their non-starch polysaccharides by an in vitro simulated digestion and fermentation model. The results showed that different cooking processes led to different changes in polysaccharide content. The polysaccharide content of yam increased by 21.3~108.2% or decreased by 12.0% compared with that of raw yam. Additionally, the soluble polysaccharides contents in all cooked yam samples significantly increased by 16.85~119.97% after in vitro digestion. The regulation of whole-yam digesta on gut microbiota was partly related with yam polysaccharides. Both yam and yam polysaccharide fermentation appeared to promote beneficial bacteria, such as Bifidobacteria, Bacteroides spp. and Megasphaera and suppressed bacterial pathogens such as Ruminococcusforques and Escherichia-Shigella. Household cooking significantly influenced the prebiotic performances of yam and yam polysaccharides by changing the heat-sensitive microbial substrates and their physiology properties. According to our results, normal-pressure steaming and normal-pressure boiling processes can retain the microbiota modulatory effects of Chinese yam.

Influence of Molecular Weight of Polysaccharides from Laminaria japonica to LJP-Based Hydrogels: Anti-Inflammatory Activity in the Wound Healing Process

In this study, polysaccharides from Laminaria japonica (LJP) were produced by the treatment of ultraviolet/hydrogen peroxide (UV/H2O2) degradation into different molecular weights. Then, the degraded LJP were used to prepare LJP/chitosan/PVA hydrogel wound dressings. As the molecular weight of LJP decreased from 315 kDa to 20 kDa, the swelling ratio of the LJP-based hydrogels rose from 14.38 ± 0.60 to 20.47 ± 0.42 folds of the original weight. However, the mechanical properties of LJP-based hydrogels slightly decreased. With the extension of the UV/H2O2 degradation time, the molecular weight of LJP gradually decreased, and the anti-inflammatory activities of LJP-based hydrogels gradually increased. LJP that were degraded for 60 min (60-gel) showed the best inhibition effects on proinflammatory cytokines, while the contents of TNF-α, IL-6, and IL-1β decreased by 57.33%, 44.80%, and 67.72%, respectively, compared with the Model group. The above results suggested that low Mw LJP-based hydrogels showed great potential for a wound dressing application.

Characterization and in vitro simulated gastrointestinal digestion and fermentation of Mentha haplocalyx polysaccharide

An acidic polysaccharide (PMHP-3) obtained from the Mentha haplocalyx was structurally characterized, and in vitro simulated digestion and fermentation were investigated. PMHP-3 was mainly composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose with molecular weight of 21.82 kDa. After digestion in saliva and simulated gastric juice, the molecular weight, reducing sugar, total sugar and uronic acid contents of PMHP-3 did not change significantly (p > 0.05). After digestion in simulated intestinal juice, the molecular weight and uronic acid content of PMHP-3 did not change significantly, and there was no free monosaccharide production, but the total sugar and reducing sugar contents slightly decreased. During fermentation, the molecular weight, carbohydrate residue and free monosaccharides of PMHP-3 were decreased, suggesting that PMHP-3 could be degraded by microorganism and metabolized into a variety the short-chain fatty acids (SCFAs) such as acetic, propionic. Meanwhile, PMHP-3 modulated the gut microbiota by reducing the ratio of Firmicutes/Bacteroidetes, promoting the proliferation of beneficial bacteria such as Bacteroidaceae and Bifidobacteriaceae, and inhibiting harmful bacteria such as Lachnospiraceae and Enterobacteriaceae. These results indicate that PMHP-3 is beneficial to the gut health and can be developed as a potential prebiotic to prevent diseases by improving intestinal health.

Advances in anti-cancer effects and underlying mechanisms of marine algae polysaccharides

Cancer is a leading cause of death in both developing and developed countries. With the increase in the average global life expectancy, it has become a major health problem and burden for most public healthcare systems worldwide. Due to the fewer side effects of natural compounds than of chemotherapeutic drugs, increasing scientific attention is being focused on the development of anti-cancer drugs derived from natural sources. Marine algae are an interesting source of functional compounds with diverse health-promoting activities. Among these compounds, polysaccharides have attracted considerable interest for many years because of their excellent anti-cancer abilities. They improve the efficacy of conventional chemotherapeutic drugs with relatively low toxicity to normal human cells. However, there are few reviews summarising the unique anti-cancer effects and underlying mechanisms of marine algae polysaccharides (MAPs). Thus, the current review focuses on updating the advances in the discovery and evaluation of MAPs with anti-cancer properties and the elucidation of their mechanisms of action, including the signalling pathways involved. This review aims to provide a deeper understanding of the anti-cancer functions of the natural compounds derived from medicinal marine algae and thereby offer a new perspective on cancer prevention and therapy with high effectiveness and safety.

Effects of Marine Bioactive Compounds on Gut Ecology Based on In Vitro Digestion and Colonic Fermentation Models

Digestion and the absorption of food compounds are necessary steps before nutrients can exert a role in human health. The absorption and utilization of nutrients in the diet is an extremely complex dynamic process. Accurately grasping the digestion and absorption mechanisms of different nutrients or bioactive compounds can provide a better understanding regarding the relationship between health and nutrition. Several in vitro models for simulating human gastrointestinal digestion and colonic fermentation have been established to obtain more accurate data for further understanding of the metabolism of dietary components. Marine media is rich in a wide variety of nutrients that are essential for humans and is gaining increased attention as a research topic. This review summarizes some of the most explored in vitro digestion and colonic fermentation models. It also summarizes the research progress on the digestion and absorption of nutrients and bioactive compounds from marine substrates when subjected to these in vitro models. Additionally, an overview of the changes imparted by the digestion process on these bioactive compounds is provided, in order to support those marine resources that can be utilized for developing new healthy foods.

Dynamic variations in physicochemical characteristics of oolong tea polysaccharides during simulated digestion and fecal fermentation in vitro

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Wuyi rock tea polysaccharides (WYP) were slightly degraded after in vitro digestion.

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The indigestible WYP could be degraded and utilized during the fecal fermentation.

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Dynamic variations in physicochemical profiles of WYP were revealed.

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Beneficial bacteria, such as Lactococcus and Bifidobacterium, increased.

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Acetic, propionic, and n-butyric acids increased during fecal fermentation.

In this study, dynamic variations in physicochemical characteristics of polysaccharides from ‘Wuyi rock’ tea (WYP) at different simulated digestion and fecal fermentation stages in vitro were studied. Results revealed that physicochemical characteristics of WYP were slightly altered after the simulated digestion in vitro, and its digestibility was about 8.38%. Conversely, physicochemical characteristics of the indigestible WYP, including reducing sugar, chemical composition, constituent monosaccharide, molecular weight, and FT-IR spectrum, were obviously altered after the fecal fermentation in vitro, and its fermentability was about 42.18%. Notably, the indigestible WYP could remarkably modulate the microbial composition via promoting the proliferation of profitable intestinal microbes, such as Bacteroides, Lactococcus, and Bifidobacterium. Moreover, it could also enhance the generation of short-chain fatty acids. The results showed that WYP was slightly digested in the gastrointestinal tract in vitro, but could be obviously utilized by intestinal microbiota, and might possess the potential to improve intestinal health.

Fecal fermentation characteristics of Rheum tanguticum polysaccharide and its effect on the modulation of gut microbial composition

Background

Rheum tanguticum is utilized as one of the well known traditional Chinese medicine for the treatment of gastrointestinal diseases. Recently, R. tanguticum polysaccharides (RP) have received increasing attention due to their diversely pharmacological activities. Usually, the pharmacological activities of polysaccharides are closely correlated to their metabolic properties from the stomach to the intestine. However, the digestive behavior and fecal fermentation characteristics of RP are unknown, which need to be fully investigated.

Methods

In this study, an in vitro simulated gastrointestinal model was carried out for the investigation of the digestive behavior and fecal fermentation characteristics of RP. The possible changes in physicochemical properties of RP, such as molecular weight, monosaccharide composition, reducing sugar released, chemical composition, pH value, and short chain fatty acids, were determined during in vitro simulated digestion and human fecal fermentation, and its effect on the modulation of gut microbial composition was also evaluated.

Results

The results revealed that RP was indigestible under the in vitro simulated digestion conditions according to its stabilities in physicochemical properties. Conversely, the indigestible RP (RPI) could be notably utilized by colonic microbiota in human feces after the in vitro fermentation, especially, at the initial fermentation stage (0–6 h). The fecal fermentation characteristics of RPI were revealed. Results showed that the content of reducing sugars obviously increased from 0.177 to 0.778 mg/mL at the initial stage of fermentation, and its molecular weight notably declined from 2.588 × 10⁵ to 0.828 × 10⁵ Da at the end stage of fermentation. Notably, the utilization of arabinose and galactose in RPI by colonic bacteria was faster than that of galacturonic acid. Besides, RPI could obviously modulate gut microbial composition via promoting the relative abundances of several beneficial bacteria, such as genera Bacteroides, Bifidobacterium, and Megamonas, resulting in the promoted production of several short-chain fatty acids, such as acetic, propionic, and butyric acids.

Conclusions

Results from this study showed that RP was indigestible in the human upper gastrointestinal tract in vitro, but could be easily utilized by colonic microbiota in human feces at the initial stage of fermentation. RP could be used as potential prebiotics for the improvement of intestinal health.

Comfrey polysaccharides modulate the gut microbiota and its metabolites SCFAs and affect the production performance of laying hens

Effects of dietary supplementation of comfrey polysaccharides (CPs) on production performance, egg quality, and microbial composition of cecum in laying hens were evaluated. A total of 240 laying hens were allocated into 4 groups with 6 replicates per group. The laying hens were fed diets containing CPs at levels of 0, 0.5, 1.0, and 1.5 %, respectively. The results showed that the egg production rate increased by 5.97 %, the egg mass improved by 6.71 %, and the feed conversion rate reduced by 5.43 % in the 1.0 % supplementation group of CPs compared with those in the control group. The digestibility of ash, crude fat, and phosphorus was notably improved by the addition of CPs at 1.0 % (P < 0.05). The relative abundances of Bacteroidetes at the phylum level, Bacteroidaceae, Rikenellaceae, and Prevotellaceae at the family level were increased by CPs (P < 0.05). The relative abundances of Bacteroides, Megamonas, Rikenellaceae_RC9_gut_group, [Ruminococcus]_torques_group, Methanobrevibacter, Desulfovibrio, Romboutsia, Alistipes, and Intestinimonas at the genus level were increased by CPs (P < 0.05). Dietary supplementation of CPs could enhance the production performance of laying hens, which might be related to the improvement of nutrient digestibility and microbial community modulations in the cecum. Therefore, CPs have potential application value as prebiotics in laying hens.

An insight to the therapeutic potential of algae-derived sulfated polysaccharides and polyunsaturated fatty acids: Focusing on the COVID-19

Covid-19 pandemic severely affected human health worldwide. The rapidly increasing COVID-19 cases and successive mutations of the virus have made it a major challenge for scientists to find the best and efficient drug/vaccine/strategy to counteract the virus pathogenesis. As a result of research in scientific databases, regulating the immune system and its responses with nutrients and nutritional interventions is the most critical solution to prevent and combat this infection. Also, modulating other organs such as the intestine with these compounds can lead to the vaccines' effectiveness. Marine resources, mainly algae, are rich sources of nutrients and bioactive compounds with known immunomodulatory properties and the gut microbiome regulations. According to the purpose of the review, algae-derived bioactive compounds with immunomodulatory activities, sulfated polysaccharides, and polyunsaturated fatty acids have a good effect on the immune system. In addition, they have probiotic/prebiotic properties in the intestine and modulate the gut microbiomes; therefore, they can increase the effectiveness of vaccines produced. Thus, they with respectable safety, immune regulation, and modulation of microbiota have potential therapeutic against infections, especially COVID-19. They can also be employed as promising candidates for the prevention and treatment of viral infections, such as COVID-19.

The effects of dietary fibers from rice bran and wheat bran on gut microbiota: An overview

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The physicochemical properties of DFs are related to their digestive behaviors.

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DFs are degraded in the intestines due to the fermentation of gut microbiota.

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DFs and their metabolites exert beneficial effects on gut microbiota.

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The fermentation of DFs improve gut barrier function and immune function.

Whole grain is the primary food providing abundant dietary fibers (DFs) in the human diet. DFs from rice bran and wheat bran have been well documented in modulating gut microbiota. This review aims to summarize the physicochemical properties and digestive behaviors of DFs from rice bran and wheat bran and their effects on host gut microbiota. The physicochemical properties of DFs are closely related to their fermentability and digestive behaviors. DFs from rice bran and wheat bran modulate specific bacteria and promote SAFCs-producing bacteria to maintain host health. Moreover, their metabolites stimulate the production of mucus-associated bacteria to enhance the intestinal barrier and regulate the immune system. They also reduce the level of related inflammatory cytokines and regulate Tregs activation. Therefore, DFs from rice bran and wheat bran will serve as prebiotics, and diets rich in whole grain will be a biotherapeutic strategy for human health.

Gracilaria lemaneiformis polysaccharides alleviate colitis by modulating the gut microbiota and intestinal barrier in mice

Gracilaria lemaneiformis polysaccharide (GLP) has varieties of antioxidation, however, the therapeutic effects of GLP on ulcerative colitis (UC) and the potential mechanisms involved are still incomplete. In the study, the analysis of the ζ-potential, thermal, and morphology properties demonstrated that GLP was a negatively charged polymer, and had great thermostability and irregular network. Moreover, the GLP treatment has the effects of reducing the severity of colitis caused by dextran sulfate sodium by alleviating the colon damage of mice, and increasing the amount of short-chain fatty acids in the intestines, alleviating histopathological inflammation. The sequencing results and α-diversity analysis showed that GLP could improve biodiversity, restore the abundance of Bacteroidetes, and decrease the proportion of Firmicutes. The level of CCL-25 and CCR-9 were inhibited, CD40 and TGF-β1 were increased. In summary, GLP has potentiality to be utilized as a hopeful functional food to the UC patients.

Beneficial effects of seaweed-derived dietary fiber: Highlights of the sulfated polysaccharides

Seaweeds and their derivatives are important bioresources of natural bioactive compounds. Nutritional studies indicate that dietary fibers derived from seaweeds have great beneficial potentials in human health and can be developed as functional food. Moreover, sulfated polysaccharides are more likely to be the main bioactive components which are widely distributed in various species of seaweeds including Phaeophyceae, Rhodophyceae and Chlorophyceae. The catabolism by gut microbiota of the seaweeds-derived dietary fibers (DFs) may be one of the pivotal pathways of their physiological functions. Therefore, in this review, we summarized the latest results of the physiological characteristics of seaweed-derived dietary fiber and highlighted the roles of sulfated polysaccharides in the potential regulatory mechanisms against disorders. Meanwhile, the effects of different types of seaweed-derived dietary fiber on gut microbiota were discussed. The analysis of the structure-function correlations and gut microbiota related mechanisms and will contribute to further better applications in food and biotherapeutics.

In vitro digestion and fermentation by human fecal microbiota of polysaccharides from Clitocybe squamulose

The present study aimed to evaluate the effects of in vitro simulated saliva-gastrointestinal digestion and fecal fermentation behavior on the chemical composition, structure and bioactivity of polysaccharides from Clitocybe squamulosa (CSFP). Results showed that gastric digestion significantly changed the chemical composition and structural properties of CSFP, such as total uronic acid, reducing sugar, molecular weight, rheological properties, particle size, and microscopic morphology. In particular, the molecular weight decreased from 19,480 Da to 10,945 Da, while the reducing-sugar content increased from 0.149 mg/mL to 0.293 mg/mL. Gastric digestion also affected the biological activity of CSFP. Although after gastric digestion, CSFP retained its vigorous antioxidant activity, ability to inhibit α-amylase activity, and the binding ability to bile acid, fat, and free cholesterol in vitro. However, there was an apparent weakening trend. After in vitro fermentation of gut microbiota, the content of total sugar was significantly decreased from 11.6 mg/mL to 2.4 mg/mL, and the pH value in the fecal culture significantly decreased to 5.20, indicating that CSFP could be broken down and utilized by gut microbiota. Compared to the blank, the concentrations of total short-chain fatty acids (SCFAs) including acetic, propionic and n-butyric significantly increased. Simultaneously, CSFP could remarkably reduce the proportions of Firmicutes and Bacteroides (F/B) and promote the growth of some beneficial intestinal microbiota. Therefore, CSFP can potentially be a new functional food as prebiotics to promote human gut health.

Chemical characterization of a new sulfated polysaccharide from Gracilaria chouae and its activation effects on RAW264.7 macrophages

This study aimed to characterize the chemical composition of a new sulfated polysaccharide from the red alga Gracilaria chouae and evaluate its activation effects on RAW264.7 macrophages. It showed that the obtained G. chouae polysaccharide (GCP-3A) was a sulfated acidic polysaccharide with a molecular weight of 11.87 kDa. GCP-3A was composed of xylose, galactose, glucose, and mannose with a molar ratio of 3.00:29.28:0.63:0.45, and it contained α,β‍-glycosidic linkages. Scanning electron microscopy (SEM) and a Congo red test showed that it was a heterogeneous polysaccharide with irregular interwoven sheets and rods, and did not have a triple-helix conform‍ation. Furthermore, GCP-3A significantly promoted the proliferation of RAW264.7 macrophages and the secretion of nitric oxide (NO) in tests of 3-‍(4,‍5-dimethylthiahiazo-2-yl)‍-2,‍5-diphenytetrazoliumromide(MTT) and NO.

Bioactive polysaccharides from red seaweed as potent food supplements: a systematic review of their extraction, purification, and biological activities

Most marine macroalgae such as red seaweeds are potential alternative sources of useful bioactive compounds. Beside serving as food source, recent studies have shown that red seaweeds are rich sources of bioactive polysaccharides. Red seaweed polysaccharides (RSPs) have various physiological and biological activities, which allow them to be used as immunomodulators, anti-obesity agents, and prebiotic ingredients. Lack of summary information and human clinical trials on the various polysaccharides from red seaweeds, however limits industrial-scale utilization of RSPs in functional foods. This review summarizes recent information on the approaches used for RSPs extraction and purification, mechanistic investigations of their biological activities, and related molecular principles behind their purported ability to prevent diseases. The information here also provides a theoretical foundation for further research into the structure and mechanism of action of RSPs and their potential applications in functional foods.

Phytochemical profile, bioactivity and prebiotic potential of bound polyphenols released from Rosa Roxburghii fruit pomace dietary fiber during in vitro digestion and fermentation

The aim of this study was to elucidate liberation and phytochemical profile of bound polyphenols existed in dietary fiber (RPDF) isolated from Rosa roxburghii fruit pomace during in vitro simulated...

In vitro digestive characteristics and microbial degradation of polysaccharides from lotus leaves and related effects on the modulation of intestinal microbiota

Polysaccharides exist as one of the most abundant components in lotus leaves, which attract increasing attention owing to their promising health-promoting benefits. In this study, the digestive and microbial degradation characteristics of lotus leaf polysaccharides (LLP) were studied by using an in vitro gastrointestinal model. The results suggested that LLP was stable in the human upper gastrointestinal tract in vitro according to its digestive stabilities at different simulated digestion stages. Conversely, the indigestible LLP (LLPI) could be remarkably utilized by intestinal microbiota in human feces during in vitro fermentation, and its fermentability was 58.11% after the in vitro fermentation of 48 h. Indeed, the microbial degradation characteristics of LLPI during in vitro fermentation by human fecal inoculum were revealed. The results showed that the content of reducing sugars released from LLPI obviously increased from 0.498 to 2.176 mg/mL at the initial fermentation stage (0–6 h), and its molecular weight sharply decreased from 4.08 × 10⁴ to 2.02 × 10⁴ Da. Notably, the molar ratios of arabinose (Ara), galactose (Gal), and galacturonic acid (GalA) in LLPI decreased from 2.89 to 1.40, from 5.46 to 3.72, and from 21.24 to 18.71, respectively, suggesting that the utilization of arabinose and galactose in LLPI by intestinal microbiota was much faster than that of galacturonic acid at the initial fermentation stage. Additionally, LLPI could remarkably regulate gut microbial composition by increasing the abundances of several beneficial microbes, including Bacteroides, Bifidobacterium, Megamonas, and Collinsella, resulting in the promoted generation of several short-chain fatty acids, especially acetic, propionic, and butyric acids. The findings from the present study are beneficial to better understanding the digestive and microbial degradation characteristics of LLP, which indicate that LLP can be used as a potential prebiotic for the improvement of intestinal health.

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LLP was stable in the human upper gastrointestinal tract in vitro.

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The indigestible LLP could be remarkably utilized by intestinal microbiota.

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Arabinose and galactose were quickly utilized at the initial fermentation stage.

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Bacteroides, Bifidobacterium, Megamonas, and Collinsella obviously increased.

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SCFAs, especially acetic, propionic, and butyric acids, remarkably promoted.

Insights on preparation, structure and activities of Gracilaria lemaneiformis polysaccharide

Gracilaria lemaneiformis is a kind of edible economic red algae, which is rich in polysaccharide, phycobiliprotein, pigments, minerals and other nutrients and functional components. Polysaccharide is one of the main active components of Gracilaria lemaneiformis, which has been reported to present various physiological bioactivities, including regulation of glycolipid metabolism, immune, anti-tumor, anti-inflammatory and other biological activities. This paper aims to provide a brief summary of extraction, purification, structural characteristics, and physiological activities of Gracilaria lemaneiformis polysaccharide (GLP). This article is able to provide theoretical basis for the future research and exploitation of GLP, and improve its potential development to promote the healthy and sustainable processing and high value utilization industry of Gracilaria lemaneiformis.

Sulfation modification enhances the intestinal regulation of Cyclocarya paliurus polysaccharides in cyclophosphamide-treated mice via restoring intestinal mucosal barrier function and modulating gut microbiota

This work aimed to investigate the effects of a sulfated derivative of Cyclocarya paliurus polysaccharide (SCP3) on cyclophosphamide (CTX)-induced intestinal barrier damage and intestinal microbiota in mice. The results showed that SCP3 increased the intestine antioxidant defense, repaired the intestinal barrier via restoring villi length and crypt depth, and up-regulated the expression of tight junction proteins. Bacterial 16S rRNA sequencing results confirmed that SCP3 dramatically altered the structure of the gut microbiota, increased the diversity of gut microbiota, and regulated the relative abundances of specific bacteria, including increasing the abundances of Bacteroidetes, Firmicutes, Tenericutes, Oscillospira, and Akkermansia, and decreasing the abundances of Proteobacteria and Verrucomicrobia. In conclusion, SCP3 can improve intestinal function in CTX-treated mice via enhancing the intestinal oxidative stress capacity, repairing the intestinal mucosal barrier, and regulating intestinal microorganisms, and this study provides a scientific theoretical basis for the application of SCP3 in the food and pharmaceutical fields.

Ultrasonic-assisted extraction of polysaccharides from coix seeds: Optimization, purification, and in vitro digestibility

To optimize the extraction of polysaccharides from coix seeds (CSP), an auxiliary method of ultrasound was developed by response surface methodology (RSM). The maximum extraction yield (8.340%) was obtained under 480 W power, 16 min ultrasound extraction (UE) time and 21.00 mL/g water to raw material ratio. Compared to hot water extraction (HE), UE-treated CSP led to a higher extraction efficiency and decreased average CSP molecular weight. FT-IR indicated that CSP extracted by UE and HE were neutral polysaccharides, and linkages between sugar units were mainly in the α-conformation. Furthermore, NMR spectra indicated that UE-treated CSP was a neutral polysaccharide with (1 → 6)-linked α-d-glucopyranose in the main chain. Two polysaccharide components (CSP-A and CSP-B) were purified by anion exchange chromatography, therein, CSP-A was more resistant to the digestion in stomach and intestine. These results suggest that CSP-A has the potential to be a functional agent utilized by gut microbes.

In vitro fecal fermentation characteristics of bamboo shoot (Phyllostachys edulis) polysaccharide

The effects of Moso bamboo (Phyllostachys edulis) shoot polysaccharide (BSP) on the human gut microbiota composition and volatile metabolite components were investigated by in vitro fermentation. After fermentation for 48 h, BSP utilization reached 40.29% and the pH of the fermentation solution decreased from 6.89 to 4.57. Moreover, the total short-chain fatty acid concentration significantly (P < 0.05) increased from 13.46 mM (0 h) to 43.20 mM (48 h). 16S rRNA analysis revealed several differences in the gut microbiota community structure of the BSP-treated and water-treated (control) cultures. In the BSP group, the abundance of Firmicutes, Actinobacteria, and Proteobacteria was significantly increased, while that of Bacteroidetes and Fusobacteria significantly decreased. Moreover, the concentrations of benzene, its substituted derivatives, and carbonyl compounds in the volatile metabolites of the BSP-treated group decreased, while that of organic acids significantly increased after 48 h of fermentation. These results demonstrate that BSP improves gastrointestinal health.

Gut microbiota response to sulfated sea cucumber polysaccharides in a differential manner using an in vitro fermentation model

Sea cucumber Stichopus japonicus has been consumed as high-valued seafood in Asian, and its sulfated polysaccharide (SCSPsj) has been inferred to benefit the host health via modulating gut microbiota composition. The present study compared the responses of gut microbiota communities from different donors to SCSPsj, and the key bacteria were identified by 16S rRNA gene sequencing analysis and in vitro fermentation with specific bacteria. Gut microbiota communities from 6 donors (A ~ F) utilized the polysaccharides to different degrees in vitro fermentation. Further comparison of Samples A and C demonstrated that Sample C with the relatively strong SCSPsj utilization capability possessed more Parabacteroides while Sample A contained more Bacteroides. Further in vitro fermentation of SCSPsj with 10 Parabacteroides and Bacteroides species suggests that Parabacteroides distasonis, enriched in Sample C, plays a critical role in the utilization of the polysaccharides. Moreover, short chain fatty acids and the metabolite profiles of Samples A and C were also compared, and the results showed that more beneficial metabolites were accumulated by the microbiota community consuming more sulfated sea cucumber polysaccharides. Our findings revealed that certain key members of gut microbiota, such as Parabacteroides distasonis, are critical for SCSPsj utilization in gut so as to influence the benefits of the polysaccharide supplement for host. Thus, to obtain better functional outcome for sulfated sea cucumber polysaccharides and sea cucumber, more attention needs to be paid to the effects of inter-individual differences in microbiota community structure.