Review of the relationships among polysaccharides, gut microbiota, and human health

Gastrointestinal Degradation and Toxicity of Disinfection Byproducts in Drinking Water Using In Vitro Models and the Roles of Gut Microbiota

Disinfection byproducts (DBPs) in drinking water are mainly exposed to the human body after oral ingestion and degradation in the gastrointestinal tract. The role of gastrointestinal degradation in the toxic effects of DBPs still needs further investigation. In this study, the degradation of five categories of DBPs (22 DBPs) in the stomach and small intestine was investigated based on a semicontinuous steady-state gastrointestinal simulation system, and 22 DBPs can be divided into three groups based on their residual proportions. The degradation of chloroacetonitrile (CAN), dibromoacetic acid (DBAA), and tetrabromopyrrole (FBPy) was further analyzed based on the Simulator of the Human Intestinal Microbial Ecosystem inoculating the gut microbiota, and approximately 60% of CAN, 45% of DBAA, and 80% of FBPy were degraded in the stomach and small intestine, followed by the complete degradation of remaining DBPs in the colon. Meanwhile, gastrointestinal degradation can reduce oxidative stress-mediated DNA damage and apoptosis induced by DBPs in DLD-1 cells, but the toxicity of DBPs did not disappear with the complete degradation of DBPs, possibly because of their interferences on gut microbiota. This study provides new insights into investigating the gastrointestinal toxic effects and mechanisms of DBPs through oral exposure.

An UPLC-MS/MS method for targeted analysis of microbial and host tryptophan metabolism after administration of polysaccharides from Atractylodes macrocephala Koidz. in ulcerative colitis mice

Botanic polysaccharides can be metabolized by gut microbiota into short-chain fatty acids (SCFAs) to exert extensive bioactivities, yet targeted analysis of the effect of botanic polysaccharides on other gut microbial metabolites is scarcely seen. Tryptophan metabolites such as indole and indole derivatives play import roles in health and disease development. Using polysaccharides from Atractylodes macrocephala Koidz. (AMP) in treating ulcerative colitis as the example, we checked the effects of AMP on tryptophan metabolites. After examination of pharmacological effects of AMP, we established an ultra-performance liquid chromatography coupled with mass spectrometry/mass spectrometry (UPLC-MS/MS) method to simultaneously determinate the levels of 30 tryptophan metabolites and used the method to determine the levels of these metabolites in feces and plasma. The detection results showed that 12 metabolites in feces can be detected, and 17 metabolites can be detected in plasma samples. In addition, we found out that total levels of aryl hydrocarbon receptor ligands were decreased in colitis model whereas AMP treatment can increase the levels of total ligands in both feces and plasma. The results indicated that the therapeutical effect of AMP on colitis was associated with modulation of fecal and host tryptophan metabolism. This study provides new insight into the molecular mechanisms of polysaccharides that the beneficial effects of polysaccharides can be achieved by modulating microbial tryptophan metabolism in addition to SCFAs.

Fecal fermentation and high-fat diet-induced obesity mouse model confirmed exopolysaccharide from Weissella cibaria PFY06 can ameliorate obesity by regulating the gut microbiota

Obesity associated with diet and intestinal dysbiosis is a worldwide public health crisis, and exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) have prebiotic potential to ameliorate obesity. Therefore, the present study obtained LAB with the ability to produce high EPS, examined the structure of EPS, and explained its mechanism of alleviating obesity by in vivo and in vitro models. The results showed that Weissella cibaria PFY06 with a high EPS yield was isolated from strawberry juice, and pure polysaccharide (PFY06-EPS) was purified by Sephadex G-100. The structural characteristics of PFY06-EPS showed that the molecular weight was 8.08 × 10⁶ Da and composed of α-(1,6)-D glucosyl residues. An in vitro simulated human colon fermentation test demonstrated that PFY06-EPS increased the abundance of Prevotella and Bacteroides. Cell tests confirmed that PFY06-EPS after fecal fermentation inhibited fat accumulation by promoting the secretion of endogenous gastrointestinal hormones and insulin and inhibiting the secretion of inflammatory factors. Notably, PFY06-EPS reduced weight gain, fat accumulation, inflammatory reactions and insulin resistance in a high-fat diet-induced obesity mouse model and improved glucolipid metabolism. PFY06-EPS intervention reversed obesity-induced microflora disorders, such as reducing the Firmicutes/Bacteroides ratio and increasing butyrate-producing bacteria (Roseburia and Oscillibacter), and reduced endotoxemia to maintain intestinal barrier integrity. Therefore, in vivo and in vitro models showed that PFY06-EPS had potential as a prebiotic that may play an anti-obesity role by improving the function of the gut microbiota.

Physicochemical properties and anti-diabetic ability of polysaccharides from a thinned peach fruit

Thinned peach fruit is a by-product with abundant yields. However, it is barely utilized. This study aimed to study the physicochemical properties and anti-diabetic ability of polysaccharides (PPSs) from a thinned peach fruit to investigate its application potential. Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) characterizations were performed together with tests to determine rheology properties, monosaccharide composition, and molecular weight of the obtained polysaccharide. Moreover, the antioxidant activity, α-amylase inhibitory activity, binding abilities to bile salts, and effects on type 2 diabetic mice were analyzed. The results indicated that PPS consisted of two components with molecular weights of 287.38 kDa and 12.02 kDa, accounting for 89.83% and 10.17% of the composition, respectively. The dominant monosaccharides were galactose, galacturonic acid, and arabinose, exhibiting α-configurations. The concentration was positively related to the viscosity of PPS. As the temperature was increased from 25 °C to 37 °C and the pH from 2.0 to 7.0, the viscosity decreased. The IC50 values for scavenging DPPH and ABTS were around 0.22 and 1.47 mg mL-1. Also, PPS could inhibit α-amylase ability and bind bile salts. The administration of PPS significantly inhibited emaciation, organ damage, improved oral glucose tolerance and insulin resistance, enhanced the content of short-chain fatty acids (SCFAs), and regulated blood lipid profiles and the composition and structure of colon microbiota in type-2 diabetic mice. These results provide new evidence for the potential of PPS as a bioactive ingredient with anti-diabetic properties for use in the food industry.

Relationship among Chinese herb polysaccharide (CHP), gut microbiota, and chronic diarrhea and impact of CHP on chronic diarrhea

Chronic diarrhea, including diarrhea-predominant irritable bowel syndrome (IBS-D), osmotic diarrhea, bile acid diarrhea, and antibiotic-associated diarrhea, is a common problem which is highly associated with disorders of the gut microbiota composition such as small intestinal bacterial overgrowth (SIBO) and so on. A growing number of studies have supported the view that Chinese herbal formula alleviates the symptoms of diarrhea by modulating the fecal microbiota. Chinese herbal polysaccharides (CHPs) are natural polymers composed of monosaccharides that are widely found in Chinese herbs and function as important active ingredients. Commensal gut microbiota has an extensive capacity to utilize CHPs and play a vital role in degrading polysaccharides into short-chain fatty acids (SCFAs). Many CHPs, as prebiotics, have an antidiarrheal role to promote the growth of beneficial bacteria and inhibit the colonization of pathogenic bacteria. This review systematically summarizes the relationship among gut microbiota, chronic diarrhea, and CHPs as well as recent progress on the impacts of CHPs on the gut microbiota and recent advances on the possible role of CHPs in chronic diarrhea.

Oral pectin/oligochitosan microspheres for colon-specific controlled release of quercetin to treat inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, life quality-reducing disease with no cures available yet. To develop an effective medication suitable for long-term use is an urgent but unmet need. Quercetin (QT) is a natural dietary flavonoid with good safety and multifaceted pharmacological activities against inflammation. However, orally administrated quercetin yields unproductive outcomes for IBD treatment because of its poor solubility and extensive metabolism in the gastrointestinal tract. In this work, a colon-targeted QT delivery system (termed COS-CaP-QT) was developed, of which the pectin (PEC)/Ca²⁺ microspheres were prepared and then crosslinked by oligochitosan (COS). The drug release profile of COS-CaP-QT was pH-dependent and colon microenvironment-responsive, and COS-CaP-QT showed preferential distribution in the colon. The mechanism study showed that QT triggered the Notch pathway to regulate the proliferation of T helper 2 (Th2) cells and group 3 innate lymphoid cells (ILC3s) and the inflammatory microenvironment was remodeled. The in vivo therapeutic results revealed that COS-CaP-QT could relieve the colitis symptoms and maintain the colon length and intestinal barrier integrity.

Effect of the β-glucan from Lentinus edodes on colitis-associated colorectal cancer and gut microbiota

Colorectal cancer is the third most common cancer in the world, and therapies with safety are in great need. In this study, the β-glucan isolated from Lentinus edodes was successfully fractionated into three fractions with different weight-average molecular weight (M_w) by ultrasonic degradation and used for the treatment of colorectal cancer. In our findings, the β-glucan was successfully degraded with the M_w decreased from 2.56 × 10⁶ Da to 1.41 × 10⁶ Da, exhibiting the triple helix structure without conformation disruption. The in vitro results indicate that β-glucan fractions inhibited colon cancer cell proliferation, induced colon cancer cell apoptosis, and reduced inflammation. The in vivo results based on Azoxymethane (AOM)/dextran sulfate sodium (DSS) mouse model demonstrate that the lower-molecular weight β-glucan fraction showed stronger anti-inflammatory and anti-colon cancer activities by reconstructing intestinal mucosal barrier, increasing short chain fatty acids (SCFAs) content, regulating metabolism of gut microbiota, and rebuilding the gut microbiota structure with the increased Bacteroides and the decreased Proteobacteria at the phylum level, as well as with the decreased Helicobacter and the increased Muribaculum at the genus level. These findings provide scientific basis for using the β-glucan to regulate gut microbiota as an alternative strategy in the clinical treatment of colon cancer.

Insights into the cellular, molecular, and epigenetic targets of gamma-aminobutyric acid against diabetes: a comprehensive review on its mechanisms

Diabetes is a metabolic disease due to impaired or defective insulin secretion and is considered one of the most serious chronic diseases worldwide. Gamma-aminobutyric acid (GABA) is a naturally occurring non-protein amino acid commonly present in a wide range of foods. A number of studies documented that GABA has good anti-diabetic potential. This review summarized the available dietary sources of GABA as well as animal and human studies on the anti-diabetic properties of GABA, while also discussing the underlying mechanisms. GABA may modulate diabetes through various pathways such as inhibiting the activities of α-amylase and α-glucosidase, promoting β-cell proliferation, stimulating insulin secretion from β-cells, inhibiting glucagon secretion from α-cells, improving insulin resistance and glucose tolerance, and increasing antioxidant and anti-inflammatory activities. However, further mechanistic studies on animals and human are needed to confirm the therapeutic effects of GABA against diabetes.

Research progress of colon-targeted oral hydrogel system based on natural polysaccharides

The quality of life is significantly impacted by colon-related diseases. There have been a lot of interest in the oral colon-specific drug delivery system (OCDDS) as a potential carrier to decrease systemic side effects and protect drugs from degradation in the upper gastrointestinal tract (GIT). Hydrogels are effective oral colon-targeted drug delivery carriers due to their high biodegradability, substantial drug loading, and great biocompatibility. Natural polysaccharides give the hydrogel system unique structure and function to effectively respond to the complex environment of the GIT and deliver drugs to the colon. In this paper, the physiological factors of colonic drug delivery and the pathological characteristics of common colonic diseases are summarized, and the latest advances in the design, preparation and characterization of natural polysaccharide hydrogels are reviewed, which are expected to provide new references for colon-targeted oral hydrogel systems using natural polysaccharides as raw materials.

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.

Polygonum sibiricum polysaccharides exert the antidepressant-like effects in chronic unpredictable mild stress-induced depressive mice by modulating microbiota-gut-brain axis

Polygonum sibiricum polysaccharides (PSP) are one of the main active components of Polygonatum sibiricum, which is a traditional Chinese medicine with food and drug homologies. Recent studies have revealed the antidepressant-like effects of PSP. However, the precise mechanisms have not been clarified. Therefore, the present study was conducted to explore that whether PSP could exert the antidepressant-like effects via microbiota-gut-brain (MGB) axis in chronic unpredictable mild stress (CUMS)-induced depressive mice by transplantation of fecal microbiota (FMT) from PSP administration mice. FMT markedly reversed the depressive-like behaviors of CUMS-induced mice in the open field, the sucrose preference, the tail suspension, the forced swimming, and the novelty-suppressed feeding tests. FMT significantly increased the levels of 5-hydroxytryptamine and norepinephrine, decreased the levels of the pro-inflammatory cytokines in the hippocampus and reduced the levels of corticosterone, an adrenocorticotropic-hormone, in the serum of CUMS-induced mice. In addition, administration of PSP and FMT significantly increased the expressions of ZO-1 and occludin in the colon and decreased the levels of lipopolysaccharide and interferon-γ in the serum of CUMS-induced mice. Moreover, administration of PSP and FMT regulated the signaling pathways of PI3K/AKT/TLR4/NF-κB and ERK/CREB/BDNF. Taken together, these findings indicated that PSP exerted antidepressant-like effects via the MGB axis.

Comparative Study on In Vitro Fermentation Characteristics of the Polysaccharides Extracted from Bergamot and Fermented Bergamot

This study aimed to compare the in vitro fermentation characteristics of polysaccharides from Bergamot and Laoxianghuang (fermented 1, 3, and 5 years from bergamot) using the stable in vitro human gut fermentation model. Results showed that bergamot polysaccharide (BP) and Laoxianghuang polysaccharides (LPs) with different surface topographies were characterized as mannorhamnan (comprising Mannose and Rhamnose) and polygalacturonic acid (comprising Galacturonic acid and Galactose), respectively. The distinct effects on the gut microbiota and metabolome of BP and LPs may be due to their different monosaccharide compositions and surface morphologies. BP decreased harmful Fusobacterium and promoted beneficial Bifidobacterium, which was positively correlated with health-enhancing metabolites such as acetic acid, propionic acid, and pyridoxamine. Lactobacillus, increased by LPs, was positively correlated with 4-Hydroxybenzaldehyde, acetic acid, and butyric acid. Overall, this study elucidated gut microbiota and the metabolome regulatory discrepancies of BP and LPs, potentially contributing to their development as prebiotics in healthy foods.

Effects of Solid Fermentation on Polygonatum cyrtonema Polysaccharides: Isolation, Characterization and Bioactivities

Polygonati Rhizoma is a widely used traditional Chinese medicine (TCM) with complex pre-processing steps. Fermentation is a common method for processing TCM to reduce herb toxicity and enhance their properties and/or produce new effects. Here, in this study, using Bacillus subtilis and Saccharomyces cerevisiae, we aimed to evaluate the potential application of solid fermentation in isolating different functional polysaccharides from Polygonatum cyrtonema Hua. With hot water extraction, ethanol precipitation, DEAE anion exchange chromatography and gel filtration, multiple neutral and acidic polysaccharides were obtained, showing different yields, content, compositions and functional groups after fermentation. Combining in vitro experiments and in vivo aging and immunosuppressed mouse models, we further compared the antioxidant and immunomodulating bioactivities of these polysaccharides and found a prominent role of a natural polysaccharide (BNP) from fermented P. cyrtonema via Bacillus subtilis in regulating intestinal antioxidant defense and immune function, which may be a consequence of the ability of BNP to modulate the homeostasis of gut microbiota. Thus, this work provides evidence for the further development and utilization of P. cyrtonema with fermentation, and reveals the potential values of BNP in the treatment of intestinal disorders.

Structural characterization of a heteropolysaccharide from the fruit of Crataegus pinnatifida and its bioactivity on the gut microbiota of immunocompromised mice

Crataegus pinnatifida is a common food in China, Europe and North America. In order to confirm polysaccharide was the material basis for C. pinnatifida to exert immune regulation. A polysaccharide (CPP) with a molecular weight of 13.58 kDa was isolated from C. pinnatifida. The structure of CPP was determined to be a backbone composed of → 3,5)-α-l-Araf-(1→, with two branches consisting of → 4)-α-d-Galp-(1 → and → 5)-α-l-Araf-(1→, with α-l-Araf and α-d-Manp as the terminal unit. CPP (10 ∼ 500 μg/mL) could promote the secretion of nitric oxide, interleukin-2, interleukin-6 and tumor necrosis factor-α in vitro. CPP could significantly restore the body weight of immunosuppressive mice and improve the immune organ index and interleukin-2, interleukin-6, and tumor necrosis factor-α secretion. In addition, CPP increased the abundance of Bacteroidetes and Verrucomicrobia and decreased the abundance of Proteobacteria at the phylum level. So CPP can regulate the gut microbiota and play an important role in immune regulation.

Effects of different steaming times on the composition, structure and immune activity of Polygonatum Polysaccharide

ETHNOPHARMACOLOGICAL RELEVANCE

As a commonly used traditional Chinese herbal medicine, Polygonati Rhizoma has high medicinal value, it can enhance the immune capacity of the body, regulate the metabolism of blood glucose and lipids, treat weakness of the stomach and intestines and physical fatigue, and so on. There are three plant varieties of Polygonati Rhizoma recorded in Chinese Pharmacopoeia, including Polygonatum sibiricum Red., Polygonatum kingianum Coll. et Hemsl. and Polygonatum cyrtonema Hua, compared with the first two, Polygonatum cyrtonema Hua is less studied. Polygonatum cyrtonema Hua is one of the basal plants of the Chinese herb Polygonati Rhizoma, that strengthens the spleen, moistens the lungs, and benefits the kidneys. Polygonatum polysaccharide is the main active substance of Polygonatum cyrtonema Hua, which has various biological effects of regulating immune system, anti-inflammatory, anti-antidepressant, antioxidant and other effects.

AIM OF THE STUDY

In order to analyze the necessity and scientificity of multiple cycles of steaming during the traditional nine-steaming and nine-drying process of the concoction of Polygonatum, we investigated the changes in the composition and structure of polysaccharides, and explored its immunomodulatory activity and molecular biological mechanism.

METHODS

The structural characterization and molecular weight of polysaccharides were studied by scanning electron microscope (SEM), high-performance size exclusion chromatography-evaporative light scattering detector (HPSEC-ELSD) and Matrix.assisted laser resolutionu ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The composition and proportion of monosaccharides were determined by PMP-HPLC method. A mouse immunosuppression model was established by intraperitoneal injection of cyclophosphamide to compare the immunomodulatory effects and mechanisms of different steaming times of Polygonatum, The changes of body mass and immune organ indices of mice were measured; the secretion levels of interleukin-2 (IL-2), interferon γ (IFN-γ) and the expression levels of immunoglobulin M (IgM) and immunoglobulin A (IgA) in serum were determined by enzyme-linked immunosorbent assay; and then flow cytometry was used to detect T-lymphocyte subpopulations to evaluate the differences of immunomodulatory effects of polysaccharides during the processing and preparation of Polygonatum. Finally, the Illumina MiSeq high-throughput sequencing platform was used to analyze short-chain fatty acids and to investigate the effects of different steaming times of Polygonatum polysaccharides on immune function and intestinal flora in immunosuppressed mice.

RESULTS

The structure of the Polygonatum polysaccharide with different steaming times changed significantly, the relative molecular weight of Polygonatum polysaccharide decreased significantly, and the monosaccharide composition of Polygonatum cyrtonema Hua with different steaming times was the same but the content was different. The immunomodulatory activity of the Polygonatum polysaccharide was enhanced after concoction, which significantly increased the spleen index and thymus index, and increased the expression of IL-2, IFN-γ, IgA and IgM. The CD4+/CD8+ ratio of Polygonatum polysaccharide also increased gradually with different steaming times, indicating enhanced immune function and significant immunomodulatory effect. The content of short-chain fatty acids in the feces of mice in both six steaming six sun-drying of Polygonatum polysaccharides (SYWPP) and nine steaming nine sun-drying of Polygonatum polysaccharides (NYWPP) groups increased significantly, including the content of propionic acid, isobutyric acid, valeric acid, and isovaleric acid, and also had a good effect on the regulation and improvement of microbial community abundance and diversity, SYWPP and NYWPP increased the relative abundance of Bacteroides and the ratio of Bacteroides and Firmicutes (B:F), while SYWPP significantly increased the abundance of Bacteroides, Alistipes and norank_f__Lachnospiraceae, but the effect of raw Polygonatum polysaccharides (RPP) and NYWPP was not significant than SYWPP.

CONCLUSION

Overall, both SYWPP and NYWPP could significantly enhance the immune activity of the organism, improve the imbalance of intestinal flora in immunosuppressed mice, and increase the content of intestinal short chain fatty acids (SCFAs), it is noteworthy that SYWPP has a better effect on the improvement of the immune activity of the organism. These findings can explore the stage of the concoction process of Polygonatum cyrtonema Hua to achieve the best effect, provide a reference basis for the development of quality standards, and at the same time promote the application of new therapeutic agents and health foods in raw and different steaming times of Polygonatum polysaccharide.

Lycium barbarum polysaccharides improve lipid metabolism disorders of spotted sea bass Lateolabrax maculatus induced by high lipid diet

This experiment explored the effects of Lycium barbarum polysaccharides (LBP) on lipid metabolism of spotted sea bass Lateolabrax maculatus. Blank and experimental control diets with 100 and 150 g/kg lipid were designed, respectively, and three dosages of LBP (0.75, 1.00, 1.25 g/kg) were supplemented in the experimental control diet. A total 375 of spotted sea bass (19.33 ± 0.15) g were divided into 5 groups, and were given experimental diets for 56 days, respectively. Results showed fish were induced to lipid metabolism disorders with dietary 150 g/kg lipid intake, which manifested in reduced feeding, oxidative stress, elevated serum lipid, and more severe hepatic damage. Dietary LBP improved the lipid metabolism disorders of fish, as indicated by significant enhancements in weight gain, digestion, superoxide dismutase activity, and decreases in malonaldehyde content, and activity of alanine aminotransferase and aspartate aminotransferase. Accordingly, an improvement in the hepatic morphological and expression of lipid metabolism related genes, including FAS, PPAR-α, CPT1 and ATGL, was observed. Nevertheless, no significant variation in serum triglyceride and total cholesterol was observed. Overall, dietary LBP can improve the growth, digestion, antioxidant capacity, and liver health of spotted sea bass, thereby improving the lipid metabolism disorders induced by 150 g/kg dietary lipid intake.

Dextran-Cholesterol Carrier Encapsulated Efficient Photosensitizer for the Photodynamic Killing of Cancer Cells

Selective photodynamic therapy (PDT) for cancer cells is more efficient and much safer. Most selective PDTs are realized by antigene-biomarker or peptide-biomarker interactions. Here, we modified dextran with hydrophobic cholesterol as a photosensitizer carrier to selectively target cancer cells, including colon cancer cells, and fulfilled selective PDT. The photosensitizer was designed with regular Aggregation-Induced Emission (AIE) units, including triphenylamine and 2-(3-cyano-4,5,5-trimethylfuran-2-ylidene)propanedinitrile. The AIE units can help to decrease the quenching effect in the aggregate state. The efficiency of the photosensitizer is further improved via the heavy atom effect after bromination modification. We found that the obtained photosensitizer nanoparticles could selectively target and ablate cancer cells after encapsulation into the dextran-cholesterol carrier. This study indicates that the polysaccharide-based carrier may have potential for cancer-targeting therapy beyond expectations.

Eucommiae cortex polysaccharides attenuate gut microbiota dysbiosis and neuroinflammation in mice exposed to chronic unpredictable mild stress: Beneficial in ameliorating depressive-like behaviors

BACKGROUND

Chronic stress alters gut microbiota composition, as well as induces inflammatory responses and behavioral deficits. Eucommiae cortex polysaccharides (EPs) have been reported to remodel gut microbiota and ameliorate obesogenic diet-induced systemic low-grade inflammation, but their role in stress-induced behavioral and physiological changes is poorly understood.

METHODS

Male Institute of Cancer Research (ICR) mice were exposed to chronic unpredictable stress (CUMS) for 4 weeks and then supplemented with EPs at a dose of 400 mg/kg once per day for 2 weeks. Behavioral test-specific antidepressant and anxiolytic effects of EPs were assessed in FST, TST, EPM, and OFT. Microbiota composition and inflammation were detected using 16S ribosomal RNA (rRNA) gene sequencing, quantitative RT-PCR, western blot, and immunofluorescence.

RESULTS

We found that EPs ameliorated gut dysbiosis caused by CUMS, as evidenced by increasing the abundance of Lactobacillaceae and suppressing the expansion of the Proteobacteria, thereby mitigating intestinal inflammation and barrier derangement. Importantly, EPs reduced the release of bacterial-derived lipopolysaccharides (LPS, endotoxin) and inhibited the microglia-mediated TLR4/NFκB/MAPK signaling pathway, thereby attenuating the pro-inflammatory response in the hippocampus. These contributed to restoring the rhythm of hippocampal neurogenesis and alleviating behavioral abnormalities in CUMS mice. Correlation analysis showed that the perturbed-gut microbiota was strongly correlated with behavioral abnormalities and neuroinflammation.

LIMITATIONS

This study did not clarify the causal relationship between EPs remodeling the gut microbiota and improved behavior in CUMS mice.

CONCLUSIONS

EPs exert ameliorative effects on CUMS-induced neuroinflammation and depression-like symptoms, which may be strongly related to their beneficial effects on gut microbial composition.

Metabolomic Characteristics of Cecum Contents in High-Fat-Diet-Induced Obese Mice Intervened with Different Fibers

The aim of this study was to demonstrate the effect of single or mixed fibers (arabinoxylan, β-glucan, xyloglucan, and inulin) on the metabolome of cecum content in mice with obesity caused by a high-fat diet. Twenty-eight six-week-old male mice were divided randomly into seven groups (n = 4/group), including a normal-diet group (CON), a high-fat-diet group (HFD), and groups with the same high-fat diet but supplemented with arabinoxylan (HFAX), arabinoxylan + β-glucan (HFAβ), arabinoxylan + xyloglucan (HFAG), xyloglucan (HFXG), and xyloglucan + inulin (HFXI). A total of 66 molecules were identified and quantified in cecum content by proton nuclear magnetic resonance (1 H-NMR). The metabolomic profiles combined with statistical analysis revealed compounds distinguishing the control group from those supplemented with fibers. In detail, a high-fat diet could significantly elevate the concentrations of acetone and methionine (p < 0.05) while decreasing the levels of methanol, arabinose, acetate, and 3-hydroxyphenylacetate (p < 0.05) in the cecum contents of mice. Compared to HFD, the supplementation caused higher levels of fumarate and hypoxanthine (p < 0.05) and lower levels of phenylacetate, acetate, fucose, formate, proline, betaine, and trimethylamine N-oxide (TMAO) (p < 0.05). An enrichment analysis highlighted that the pathways mainly altered were amino sugar metabolism, aspartate metabolism, and arginine and proline metabolism. In conclusion, non-starch polysaccharide (NSP) supplementation could change the metabolomic profiles of cecum contents in obese mice as a result of a high-fat diet. Moreover, mixed NSPs exhibited more beneficial effects than singular form on gut metabolism.

Managing metabolic diseases: The roles and therapeutic prospects of herb-derived polysaccharides

Metabolic diseases have become a public health problem worldwide. Effective, novel and natural therapies are urgently needed to treat metabolic diseases. As natural bioactive compounds, polysaccharides have many physiological and medicinal properties. Recently, herb-derived polysaccharides have shown beneficial effects in the treatment of metabolic diseases, but the underlying mechanisms remain unclear. This review comprehensively summarizes the pharmacological progress and clinical evidence of herb-derived polysaccharides in the treatment of three metabolic diseases, namely type 2 diabetes mellitus, nonalcoholic fatty liver disease and obesity, and more importantly, discusses the molecular mechanism involved. Existing evidence has proved that herb-derived polysaccharides can maintain glucose homeostasis, promote insulin secretion, improve insulin resistance, reduce weight gain and hepatic steatosis, inhibit lipogenesis, alleviate oxidative stress and inflammation, and improve gut microbiota disorders in rodents with metabolic diseases. Notably, so far, human clinical trials of herb-derived polysaccharides for these three metabolic diseases remain rare. All in all, herb-derived polysaccharides may have good potential as drug candidates for the prevention and management of metabolic diseases. More high-quality clinical trials are needed to further validate its effectiveness and safety in human subjects.

Structure and hepatoprotective activity of Usp10/NF-κB/Nrf2 pathway-related Morchella esculenta polysaccharide

The water-soluble Morchella esculenta polysaccharide 2 (MEP2) was purified and isolated from an aqueous extract of the Morchella esculenta fruiting bodies. MEP2, having a molecular weight of 959 kDa, has a →4)-α-D-Glcp-(1→ glucan backbone, and this branch was substituted at the H-6 position by an α-D-Glcp-(1 → 4)-α-D-Glcp-(1→ residue and an α-D-Glcp-(1→ residue. The hepatoprotective activity and potential mechanism of action of MEP2 were also investigated. MEP2 ameliorated severe liver damage and regulated the liver function indicators and the alcohol-related enzyme levels in chronic alcohol-induced mice. Combined with biochemical detection, the gut microbiota, metabolites, and proteomics results revealed that MEP2 regulates the levels of hepatic cytokines related to inflammatory response and oxidative stress, as well as those of intestinal Bacteroides, Oscillospira, Parabacteroides, Alistipes, and Prevotella, through the ubiquitin-specific peptidase 10 (Usp10)/nuclear factor κB (NF-κB)/nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway in the liver of mice induced by long-term alcohol intake. These data provide experimental evidence for the application of MEP2 in chronic alcohol-induced liver injury.

IBD disease-modifying therapies: insights from emerging therapeutics

Inflammatory bowel disease (IBD) pathogenesis is associated with gut mucosal inflammation, epithelial damage, and dysbiosis leading to a dysregulated gut mucosal barrier. However, the extent and underlying mechanisms remain largely unknown. Current treatment regimens have focused mainly on treating IBD symptoms; however, such treatment strategies do not address mucosal epithelial repair, barrier homeostasis, or intestinal dysbiosis. Although attempts have been made to identify new therapeutic modalities to enhance gut barrier functions, these are at an early developmental stage and have not been wholly successful. We review conventional therapies, the possible relevant role of gut barrier-protecting agents, and biomaterial strategies relating to combination therapies that may pave the way towards developing new therapeutic approaches for IBD.

Fingerprint profiling and gut microbiota regulation of polysaccharides from Fritillaria species

Few studies reported the quality evaluation and gut microbiota regulation effect of polysaccharides from Fritillaria species. In this study, polysaccharides extracted from ten Fritillaria species were compared and distinguished through multi-levels evaluation strategy and data fusion. Furthermore, the gut microbiota regulation effect of polysaccharides among different species was analyzed and evaluated. The fingerprint profiling of IR, molecular weight distribution of polysaccharides, chromatogram of partially hydrolyzed polysaccharides (oligosaccharides) and completely hydrolyzed polysaccharides (monosaccharides) were similar, and no exclusive signals were observed. However, the signal strength of functional group, oligosaccharides abundance and monosaccharides proportion showed obvious differences in inter- and intra-species. Glucan may be the main component of polysaccharides in Fritillaria species, CIRR derived from CIR, PRZ, DEL, TAI, UNI possessed higher total polysaccharides content, polymerization degree, oligosaccharides abundance (DP 2-4), and glucose content than the others. Meanwhile, data fusion model was established for identification of affinis and multi-original species, the accuracy of which proved to be 100 %. In addition, Fritillaria polysaccharides could increase the bacterial community richness and diversity, regulate the gut microbiota composition and possessed potential therapeutic effects on gastrointestinal diseases and nervous system diseases.

Neuroprotection of Food Bioactives in Neurodegenerative Diseases: Role of the Gut Microbiota and Innate Immune Receptors

Gut-brain connections may be mediated by an assortment of microbial molecules, which can subsequently traverse intestinal and blood-brain barriers and impact neurological function. Pattern recognition receptors (PRRs) are important innate immune proteins in the gut. Gut microbiota act in concert with the PRRs is a novel target for regulating host-microbe signaling and immune homeostasis, which may involve the pathogenesis of neurodegenerative diseases. Natural food bioactives bestow a protective advantage on neurodegenerative diseases through immunomodulatory effects of the modified gut microbiota or alterations in the landscape of microbiota-produced metabolites via PRRs modulation. In this review, we discuss the effect of natural food bioactives on the gut microbiota and the role of PRRs in the gut-brain crosstalk. We focused on the neuroprotective mechanisms of natural bioactive compounds behind the action of the gut microbiota and PRRs. Research advances in natural food bioactives as antineurodegeneration agents were also presented.

Bioactive polysaccharides promote gut immunity via different ways

Numerous kinds of bioactive polysaccharides are identified as having intestinal immunomodulatory activity; however, the ways in which the different polysaccharides work differ. Therefore, we selected nine representative bioactive polysaccharides, including xanthan gum, inulin, guar gum, arabinogalactan, carrageenan, glucomannan, araboxylan, xylan, and fucoidan, and compared their intestinal immunomodulatory mechanisms. A cyclophosphamide (CTX)-induced immunosuppressed model was used in this experiment, and the effects of these polysaccharides on the number of T cells in the intestinal mucosa, expression of transcription factors and inflammatory factors, intestinal metabolome and gut microbiota were compared and discussed. The results revealed that the nine polysaccharides promote intestinal immunity in different ways. In detail, guar gum, inulin and glucomannan better alleviated immune suppression in intestinal mucosal T cells. Inulin improved the intestinal microenvironment by significantly upregulating the abundance of Lactobacillus and Monoglobus and promoted short chain fatty acid (SCFA) production. Fucoidan and carrageenan promoted the colonization of the beneficial bacteria Rikenella and Roseburia. In addition, fucoidan, inulin and carrageenan inhibited the colonization of harmful bacteria Helicobacter, upregulated the abundance of Clostridia_UCG-014 and alleviated the accumulation of amino acids, bile acids and indoles in the large intestine. In conclusion, our study uncovered the different intestinal immunomodulatory mechanisms of the different polysaccharides and provided a guideline for the development of superior intestinal immunomodulatory polysaccharides.

Effects of kiwi fruit (Actinidia chinensis) polysaccharides on metabolites and gut microbiota of acrylamide-induced mice

Introduction

Kiwifruit (Actinidia chinensis) has rich nutritious and medicinal properties. It is widely consumed worldwide for the intervention of metabolism disorders, however, the underlying mechanism remains unclear. Acrylamide, a well-known toxic ingredient, mainly forms in high-temperature processed carbohydrate-rich food and causes disorders of gut microbiota and systemic metabolism.

Methods

This study explored the protective effects and underlying mechanisms of kiwifruit polysaccharides against acrylamide-induced disorders of gut microbiota and systemic metabolism by measuring the changes of gut microbiota and serum metabolites in mice.

Results

The results showed that kiwifruit polysaccharides remarkably alleviated acrylamide-induced toxicity in mice by improving their body features, histopathologic morphology of the liver, and decreased activities of liver function enzymes. Furthermore, the treatment restored the healthy gut microbiota of mice by improving the microbial diversity and abundance of beneficial bacteria such as Lactobacillus. Metabolomics analysis revealed the positive effects of kiwifruit polysaccharides mainly occurred through amino and bile acid-related metabolism pathways including nicotinate and nicotinamide metabolism, primary bile acid biosynthesis, and alanine, aspartate and glutamate metabolism. Additionally, correlation analysis indicated that Lactobacillus exhibited a highly significant correlation with critical metabolites of bile acid metabolism.

Discussion

Concisely, kiwifruit polysaccharides may protect against acrylamide-induced toxicity by regulating gut microbiota and metabolism.

Structural characteristics and ameliorative effect of a polysaccharide from Corbicula fluminea industrial distillate against acute liver injury induced by CCl4 in mice

Corbicula fluminea distillate as an important industrial by-product of C. fluminea during steaming process is rich in amino acids, proteins and polysaccharides, showing potential hepatoprotective effect. In this study, a polysaccharide (CFDP) was obtained from C. fluminea distillate by three-phase partitioning combined with (NH₄)₂SO₄ precipitation at a saturation of 60 %. The structural characteristics, antioxidant activity in vitro, and hepatoprotection against mice CCl₄-induced acute liver damage of CFDP were studied. Results demonstrated that CFDP was a water-soluble homogenous polysaccharide predominantly comprising glucose (>98 %), with a weight-average molecular weight of 1.4 × 10⁷ Da, and exhibiting potent antioxidant benefits in vitro. CFDP had a backbone of (1 → 4)-α-d-glucopyranosyl (Glcp) and a small amount of (1 → 4, 6)-α-D-Glcp. The branch formed at C-6 comprised by (1→)-α-D-Glcp and (1→)-α-D-N-acetylglucosamine. CFDP possessed excellent hepatoprotective activity against acute liver damage caused by CCl₄ in mice, mainly by ameliorating weight reduction and organ injures, alleviating hepatic function and serum lipid metabolism, suppressing oxidative stress and inflammatory responses, as directly verified by histopathological examination. Moreover, CFDP improved gut microbiota by up-regulating the relative abundance of total bacteria and probiotics such as Firmicutes, Bacteroidete, Rumminococcaceae, Lactobacillaceae, accompanied by promoting short chain fatty acid production. Therefore, our findings indicated that CFDP can be developed as a healthy food supplement for the prevention of chemical livery injury.

Rhamnogalacturonan-I enriched pectin from steamed ginseng ameliorates lipid metabolism in type 2 diabetic rats via gut microbiota and AMPK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Meyer (Ginseng) has traditionally been used to treat diabetes. Polysaccharide is the main active component of ginseng, and has been proved to have hypoglycaemic and hypolipidaemic effects, but its mechanism remains unclear.

AIM OF THE STUDY

This study aimed to evaluate the effect and the potential mechanism of rhamnogalacturonan-I enriched pectin (GPS-1) from steamed ginseng on lipid metabolism in type 2 diabetes mellitus (T2DM) rats.

MATERIALS AND METHODS

GPS-1 was prepared by water extraction, ion-exchange and gel chromatography. High-glucose/high-fat diet combined with streptozotocin was used to establish T2DM rat models, and lipid levels in serum and liver were tested. 16S rRNA sequencing and gas chromatography-mass spectrometry were used to detect the changes of gut microbiota and metabolites. The protein and mRNA levels of lipid synthesis-related genes were detected by Western blot and quantitative real-time polymerase chain reaction.

RESULTS

The polyphagia, polydipsia, weight loss, hyperglycaemia, hyperlipidaemia and hepatic lipid accumulation in T2DM rats were alleviated after GPS-1 intervention. GPS-1 modulated the gut microbiota composition of T2DM rats, increased the levels of short-chain fatty acids, and promoted the secretion of glucagon-like peptide-1 and peptide tyrosine tyrosine. Further, GPS-1 activated AMP-activated protein kinases, phosphorylated acetyl-CoA carboxylase, reduced the expression of sterol regulatory element-binding protein-1c and fatty acid synthases in T2DM rats.

CONCLUSIONS

The regulation effects of GPS-1 on lipid metabolism in T2DM rats are related to the regulation of gut microbiota and activation of AMP-activated protein kinase pathway.

Poria cocos oligosaccharides ameliorate dextran sodium sulfate-induced colitis mice by regulating gut microbiota dysbiosis

Poria cocos, a widely accepted function food in China, has multiple pharmacological activities. This study aimed to investigate the therapeutic effect and molecular mechanism of Poria cocos oligosaccharides (PCOs) against dextran sodium sulfate (DSS)-induced mouse colitis. In this study, BALB/c mice were treated with 3% (w/v) DSS for seven days to establish a colitis model. The results showed that oral administration of PCOs (200 mg per kg per day) significantly reversed the changes in the physiological indices in colitis mice, including body weight, disease activity index scores (DAI), spleen index, and colon length. From the qRT-PCR assay, it was observed that PCOs suppressed the mRNA expression of pro-inflammatory cytokines, such as Tnf-α, Il-1β, and Il-6. In addition, PCOs protected the intestinal barrier from damage by promoting the expression of mucins and tight junction proteins at both mRNA and protein levels. Upon 16S rDNA sequencing, it was observed that PCO treatment partly reversed the changes in the gut microbiota of colitis mice by selectively regulating the abundance of specific bacteria. And Odoribacter, Muribaculum, Desulfovibrio, Oscillibacter, Escherichia-Shigella, and Turicibacter might be the critical bacteria in improving colitis via PCOs. Finally, using antibiotic mixtures to destroy the intestinal bacteria, we documented that PCO fermentation broth (PCO FB) instead of PCOs prevented the occurrence of colitis in gut microbiota-depleted mice. In conclusion, PCOs showed a protective effect on colitis by reversing gut microbiota dysbiosis. Our study sheds light on the potential application of PCOs as a prebiotic for treating colitis.

A pectic polysaccharide from fresh okra (Abelmoschus esculentus L.) beneficially ameliorates CCl4-induced acute liver injury in mice by antioxidation, inhibition of inflammation and modulation of gut microbiota

Okra [Abelmoschus esculentus (Linn.) Moench], as a well-known medicinal and food plant, has important physiological activities and health benefits, and polysaccharide is its main bioactive component. In this study, a pectic polysaccharide (OPS-50) prepared from fresh okra pods by three-phase partitioning and gradient (NH4)2SO4 precipitation at a saturation of 50% was employed in carbon tetrachloride (CCl4)-caused acute liver damage in mice to evaluate the hepatoprotective potential. Results indicated that OPS-50 was mainly composed of a limited linear homogalacturonan backbone and abundant rhamnogalacturonan-I domains as side chains. OPS-50 exerted positively protective effects on acute liver damage induced by CCl4 in mice through relieving weight reduction and organ damage, ameliorating liver function and dyslipidemia, alleviating oxidative stress, suppressing pro-inflammatory cytokines, modulating gut microbiota, and promoting short-chain fatty acid secretion. Moreover, liver histopathology demonstrated the protective benefit of OPS-50 on CCl4-caused acute liver damage in mice. Therefore, our data suggested that the pectic OPS-50, as a dietary supplement, have great potential in preventing and treating chemical liver damages.

Impact of Dietary Arachidonic Acid on Gut Microbiota Composition and Gut-Brain Axis in Male BALB/C Mice

Although arachidonic acid (ARA) is the precursor of the majority of eicosanoids, its influence as a food component on health is not well known. Therefore, we investigated its impact on the gut microbiota and gut-brain axis. Groups of male BALB/c mice were fed either a standard diet containing 5% lipids (Std-ARA) or 15%-lipid diets without ARA (HL-ARA) or with 1% ARA (HL + ARA) for 9 weeks. Fatty acid profiles of all three diets were the same. The HL-ARA diet favored the growth of Bifidobacterium pseudolongum contrary to the HL + ARA diet that favored the pro-inflammatory Escherichia-Shigella genus in fecal microbiota. Dietary ARA intake induced 4- and 15-fold colic overexpression of the pro-inflammatory markers IL-1β and CD40, respectively, without affecting those of TNFα and adiponectin. In the brain, dietary ARA intake led to moderate overexpression of GFAP in the hippocampus and cortex. Both the hyperlipidic diets reduced IL-6 and IL-12 in the brain. For the first time, it was shown that dietary ARA altered the gut microbiota, led to low-grade colic inflammation, and induced astrogliosis in the brain. Further work is necessary to determine the involved mechanisms.

In Vitro Digestion and Fecal Fermentation of Peach Gum Polysaccharides with Different Molecular Weights and Their Impacts on Gut Microbiota

In the present study, we investigated the in vitro digestion and fermentation characteristics of three peach gum polysaccharides (PGPs) of different molecular weights; i.e., AEPG2 (1.64 × 107 g/mol), DPG2 (5.21 × 105 g/mol), and LP100R (8.50 × 104 g/mol). We observed that PGPs were indigestible during the oral, gastrointestinal, and intestinal stages. However, they were utilized by the gut microbiota with utilization rates in the order of DPG2 > AEPG2 > LP100R. Furthermore, arabinose in PGPs was preferentially utilized by the gut microbiota followed by galactose and xylose. Fermentation of peach gum polysaccharides could significantly increase the production of short-chain fatty acids (SCFAs), especially n-butyric acid. In addition, PGPs with different molecular weights values were predominantly fermented by different bacterial species. AEPG2 and DPG2 were fermented by the Bacteroidetes bacteria Bacteroides, while the dominant n-butyrate-producing bacteria was Faecalibacterium. While the LP100R was fermented by Bacteroides, Parabacteroides, Phascolarctobacterium, Dialister, Lachnospiraceae, and Blautia, the dominant n-butyrate-producing bacteria was Megamonas. These results indicated that PGPs are potential prebiotics for the food industry.

Tremella fuciformis polysaccharide reduces obesity in high-fat diet-fed mice by modulation of gut microbiota

Obesity is a metabolic disease associated with gut microbiota and low-grade chronic inflammation. Tremella fuciformis is a medicinal and edible fungus; polysaccharide (TP) is the main active component, which has a variety of biological activities, such as hypoglycemic and hypolipidemic. However, the anti-obesity effects and potential mechanisms of TP have never been reported. This study was conducted to elucidate the inhibitory effect of TP on high-fat diet (HFD)-induced obesity in mice. Mice were split into five groups: normal chow diet (NCD) group, NCD_TP_H group, HFD group, HFD_TP_L group and HFD_TP_H group. Our study showed that TP inhibited high-fat diet-induced weight gain and fat accumulation in mice and reduced blood glucose, hyperlipidemia and inflammation. TP also improved gut microbiota disorders by reducing the Firmicutes/Bacteroidetes ratio and modulating the relative abundance of specific gut microbiota. We also found that the anti-obesity and gut microbiota-modulating effects of TP could be transferred to HFD-fed mice via faecal microbiota transplantation (FMT), confirming that the gut microbiota was one of the targets of TP for obesity inhibition. Further studies showed that TP increased the production of short-chain fatty acids and the secretion of intestinal hormones. Our studies showed that TP inhibited obesity by modulating inflammation and the microbe-gut-brain axis, providing a rationale for developing TP to treat obesity and its complications.

A comparison study on polysaccharides extracted from Rosa sterilis S.D.Shi using different methods: Structural and in vitro fermentation characterizations

In this study, the structural and in vitro fermentation characterizations of Rosa sterilis S.D.Shi polysaccharides (RSP), extracted by hot water (HW), acid (AA), alkali (AK) and enzyme (EM) were investigated for the first time. The results indicated that extraction methods exhibited significant effects on the structure of RSPs, thus resulting in different probiotic effects. HW-RSP and AA-RSP had high contents of Gal, Glc and GalA, while AK-RSP and EM-RSP mainly contained Ara, Gal and GalA. EM-RSP was rich in RG-I and its size of average side chain were the largest. Moreover, HW-RSP and AK-RSP exhibited the smallest (57.55 kDa) and largest (922.20 kDa) molecular weights, respectively. All RSPs promoted the production of total SCFAs and the growth of beneficial bacteria like Bifidobacterium, Bacteroides, Faecalibacterium and Paraclostrium to varying degrees, but inhibited the growth of pathogenic bacteria such as Escherichia-shigella, thereby regulating the composition of gut microbiota. Furthermore, the function prediction results showed that EM-RSP had the most special metabolic pathways. Collectively, our findings provide new insights into the relationship between the structure and probiotic function of RSPs, and offer theoretical basis for the development of functional products of Rosa sterilis S.D.Shi.

Combination of Houttuynia cordata polysaccharide and Lactiplantibacillus plantarum P101 alleviates acute liver injury by regulating gut microbiota in mice

BACKGROUND

Polysaccharides and probiotics can play an outstanding role in the treatment of liver disease by regulating gut microbiota. Recently, the combined therapeutic effect of probiotics and polysaccharides has attracted the attention of researchers. Houttuynia cordata polysaccharide (HCP) combined with Lactiplantibacillus plantarum P101 was used to prevent carbon tetrachloride (CCl₄ )-induced acute liver injury (ALI) in mice, and its effect on gut microbiota regulation was explored.

RESULTS

Results showed that, in mice, HCP combined with L. plantarum P101 significantly alleviated oxidative stress and inflammatory injury in the liver by activating Nrf2 signals and inhibiting NF-κB signals. The analysis of gut microbiota revealed that the combination of HCP and L. plantarum P101 increased the abundance of beneficial bacteria such as Alloprevotella, Roseburia, and Akkermansia, but reduced that of the pro-inflammatory bacteria Alistipes, Enterorhabdus, Anaerotruncus, and Escherichia-Shigella. Correlation analysis also indicated that the expression of Nrf2 and TLR4/NF-κB was connected to the changes in gut microbiota composition. Houttuynia cordata polysaccharide combined with L. plantarum P101 can regulate the gut microbiota and then mediate the gut-liver axis to activate the antioxidant pathway and inhibit inflammatory responses, thereby alleviating CCl₄ -induced ALI.

CONCLUSION

Our study provided a new perspective on the use of polysaccharides combined with probiotics in the treatment of liver disease. © 2022 Society of Chemical Industry.

Effects of black soldier fly larvae as protein or fat sources on apparent nutrient digestibility, fecal microbiota, and metabolic profiles in beagle dogs

Black soldier fly (Hermetia illucens) larvae (BSFL) act as a biological system converting organic waste into protein and fat with great potential application as pet food. To evaluate the feasibility of BSFL as a protein and fat source, 20 healthy beagle dogs were fed three dietary treatments for 65 days, including (1) a basal diet group (CON group), (2) a basal diet that replaced 20% chicken meal with defatted black soldier fly larvae protein group (DBP group), and (3) a basal diet that replaced 8% mixed oil with black soldier fly larvae fat group (BF group). This study demonstrated that the serum biochemical parameters among the three groups were within the normal range. No difference (p > 0.05) was observed in body weight, body condition score, or antioxidant capacity among the three groups. The mean IFN-γ level in the BF group was lower than that in the CON group, but there was no significant difference (p > 0.05). Compared with the CON group, the DBP group had decreasing (p < 0.05) apparent crude protein and organic matter digestibility. Furthermore, the DBP group had decreasing (p < 0.05) fecal propionate, butyrate, total short-chain fatty acids (SCFAs), isobutyrate, isovalerate, and total branched-chain fatty acids (BCFAs) and increased (p < 0.05) fecal pH. Nevertheless, there was no difference (p > 0.05) in SCFAs or BCFAs between the CON and BF groups. The fecal microbiota revealed that Lachnoclostridium, Clostridioides, Blautia, and Enterococcus were significantly enriched in the DBP group, and Terrisporobacter and Ralstonia were significantly enriched in the BF group. The fecal metabolome showed that the DBP group significantly influenced 18 metabolic pathways. Integrating biological and statistical correlation analysis on differential fecal microbiota and metabolites between the CON and DBP groups found that Lachnoclostridium, Clostridioides, and Enterococcus were positively associated with biotin. In addition, Lachnoclostridium, Clostridioides, Blautia, and Enterococcus were positively associated with niacinamide, phenylalanine acid, fumaric acid, and citrulline and negatively associated with cadavrine, putrescine, saccharopine, and butyrate. In all, 20% DBP restrained the apparent CP and OM digestibility, thereby affecting hindgut microbial metabolism. In contrast, 8% BF in the dog diet showed no adverse effects on body condition, apparent nutrient digestibility, fecal microbiota, or metabolic profiles. Our findings are conducive to opening a new avenue for the exploitation of DBP and BF as protein and fat resources in dog food.

Hypoglycemic activity in vitro and vivo of a water-soluble polysaccharide from Astragalus membranaceus

The polysaccharide AMP as one main bioactive component of Astragalus membranaceus (Fisch.) Bunge was separated and characterized. The results showed that AMP was a typical acidic heteropolysaccharide dominated by glucose, galacturonic acid and arabinose with typical shear-thinning and fluid-like behavior. Scanning electron microscopy images showed that AMP existed in the state of lamellar aggregates with a smooth compact surface. In addition, AMP exhibited strong antioxidant activity with an oxygen radical absorption capacity value of 278.68 ± 9.31 μM TE per g, and excellent α-glucosidase inhibitory activity and cholate binding ability. Furthermore, in vivo, AMP treatment significantly decreased blood glucose and serum insulin levels, improved glucose intolerance and insulin resistance, regulated the blood lipid profile, alleviated oxidative stress, and relieved liver damage in type 2 diabetes mellitus (T2DM) mice. Pearson correlation analysis suggested that the mitigation of oxidative stress contributed to the hypoglycemic effect of AMP, indicating that it is a beneficial functional food ingredient for T2DM.

Regulatory effects of marine polysaccharides on gut microbiota dysbiosis: A review

The gut microbiota dysbiosis is a state which the physiological combinations of flora are transformed into pathological combinations caused by factors such as diets, pollution, and drugs. Increasing evidence shows that dysbiosis is closely related to many diseases. With the continuous development and utilization of marine resources, marine polysaccharides have been found to regulate dysbiosis in many studies. In this review, we introduce the types of dysbiosis and the degree of it caused by different factors. We highlight the regulating effects of marine polysaccharides on dysbiosis as a potential prebiotic. The mechanisms of marine polysaccharides to regulate dysbiosis including protection of intestinal barrier, regulatory effect on gut microbiota, alteration for related metabolites, and some other possible mechanisms were summarized. And we aim to provide some references for the high-value utilization of marine polysaccharides and new targets for the treatment of gut microbiota dysbiosis by this review.

Extraction, Characterization, and Platelet Inhibitory Effects of Two Polysaccharides from the Cs-4 Fungus

Cardiovascular diseases are associated with platelet hyperactivity, and downregulating platelet activation is one of the promising antithrombotic strategies. This study newly extracted two polysaccharides (purified exopolysaccharides, EPSp and purified intercellular exopolysaccharides, IPSp) from Cordyceps sinensis Cs-4 mycelial fermentation powder, and investigated the effects of the two polysaccharides and their gut bacterial metabolites on platelet functions and thrombus formation. EPSp and IPSp are majorly composed of galactose, mannose, glucose, and arabinose. Both EPSp and IPSp mainly contain 4-Galp and 4-Glcp glycosidic linkages. EPSp and IPSp significantly inhibited human platelet activation and aggregation with a dose-dependent manner, and attenuated thrombus formation in mice without increasing bleeding risk. Furthermore, the EPSp and IPSp after fecal fermentation showed enhanced platelet inhibitory effects. The results have demonstrated the potential value of Cs-4 polysaccharides as novel protective ingredients for cardiovascular diseases.

Protective Effect of Dietary Polysaccharides from Yellow Passion Fruit Peel on DSS-Induced Colitis in Mice

Inflammatory bowel disease (IBD) is a complex inflammatory disorder characterized by chronic and spontaneously relapsing inflammation of the gastrointestinal tract. IBD includes two idiopathic disorders: Crohn’s disease (CD) and ulcerative colitis (UC). In particular, UC causes inflammation and ulceration of the colon and rectum. There is no cure for UC. The pharmacological treatment is aimed at controlling and/or reducing the inflammatory process and promoting disease remission. The present study investigated the possible protective effects of soluble dietary fiber (SDF) isolated from yellow passion fruit peel in the dextran sulfate sodium- (DSS-) induced colitis model in mice, induced by 5% of DSS. The animals were treated with SDF (10, 30, or 100 mg/kg (po)), and the disease activity index was monitored. Colon tissues were collected, measured, and prepared for oxidative stress, inflammation, and histology analysis. SDF improved body weight loss, colon length, and disease activity index and prevented colonic oxidative stress by regulating GSH levels and SOD activity. Furthermore, SDF reduced colonic MPO activity, TNF-α, and IL-1β levels and increased IL-10 and IL-6 levels. As observed by histological analysis, SDF treatment preserved the colonic tissue, the mucus barrier, and reduced inflammatory cell infiltration. Although this is a preliminary study, taken together, our data indicate that SDF may improve the course of DSS-UC. More studies are needed to explore and understand how SDF promotes this protection.

Polysaccharides from fermented coix seed modulates circulating nitrogen and immune function by altering gut microbiota

Coix lachryma-jobi L. seed is an important food item in Asia with culinary and medicinal values. The effects of non-fermented coix seed (NFC), fermented coix seed with Lactobacillus plantarum NCU137 (FC) and polysaccharides from NFC, FC (FCP) on mice circulating nitrogen and immune disorder induced by high relative humidity (RH, 90 ± 2%) exposure were compared. All the treatments reduced circulating nitrogen (BUN and ammonia) might via increasing excretion of fecal nitrogen induced by altering gut microbiota. In comparison, FC and FCP restored erythrocyte morphology by promoting erythrocyte Na⁺/K⁺ ATPase activity more effectively, and immune function was modulated by reducing plasma IgM and IFN-γ levels, up-regulating IL-4 and IL-6 levels. Herein, these results indicated that FCP, as the main active ingredient in FC, modulated circulating nitrogen through altering gut microbiota, and restored immune homeostasis by regulating Th1/Th2 cytokines in mice receiving high RH exposure.