Beneficial effects of sulfated polysaccharides from the red seaweed Gelidium pacificum Okamura on mice with antibiotic-associated diarrhea

Potential Probiotic Weizmannia coagulans WC10 Improved Antibiotic-Associated Diarrhea in Mice by Regulating the Gut Microbiota and Metabolic Homeostasis

Antibiotic-associated diarrhea (AAD) is a common side effect of long-term and heavy antibiotic therapy. Weizmannia coagulans (W. coagulans) is an ideal probiotic because of its high viability, stability, and numerous health benefits to the host. In this study, the strains were first screened for W. coagulans WC10 (WC10) with a high combined ability based on their biological properties of gastrointestinal tolerance, adhesion, and short-chain fatty acid production ability. The effect of WC10 on mice with AAD was further evaluated. The results showed that WC10 was effective in improving the symptoms of AAD, effectively restoring antibiotic-induced weight loss, and reducing diarrhea status score and fecal water content. In addition, WC10 decreased the expression of pro-inflammatory cytokines and increased the expression of anti-inflammatory cytokines, alleviated intestinal tissue damage and inflammation, and improved intestinal epithelial barrier function by decreasing serum levels of enterotoxin, DAO, and D-lactic acid, and by increasing the expression of the intestinal mucosal immune factors sIgA and occludin. Importantly, the composition and function of the gut microbiota gradually recovered after WC10 treatment, increasing the number of SCFAs-producing Bifidobacterium and Roseburia. Subsequently, the short-chain fatty acid (SCFA) content was examined and WC10 significantly increased acetate, propionate, and butyrate production. Additionally, metabolomic analysis also showed that WC10 reversed the antibiotic interference with major metabolic pathways. These findings provide a solid scientific basis for the future application of W. coagulans WC10 in the treatment of AAD.

Bifidobacterium adolescentis CCFM1285 combined with yeast β-glucan alleviates the gut microbiota and metabolic disturbances in mice with antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is a self-limiting condition that can occur during antibiotic therapy. Our previous studies have found that a combination of Bacteroides uniformis and Bifidobacterium adolescentis can effectively alleviate AAD. However, the use of B. uniformis is still strictly limited. Therefore, this study attempted to use yeast β-glucan to enrich the abundance of B. uniformis in the intestine and supplement Bifidobacterium adolescentis to exert a synergistic effect. The lincomycin hydrochloride-induced AAD model was administered yeast β-glucan or a mixture of B. adolescentis CCFM1285 by gavage for one week. Subsequently, changes in the colonic histopathological structure, inflammatory factors, intestinal epithelial permeability and integrity, metabolites, and gut microbiota diversity were assessed. We found that yeast β-glucan, alone or in combination with B. adolescentis CCFM1285, can help attenuate systemic inflammation, increase the rate of tissue structural recovery, regulate metabolism, and restore the gut microbiota. Specifically, the combination of yeast β-glucan and B. adolescentis CCFM1285 was more effective in decreasing interleukin-6 levels, improving pathological changes in the colon, and upregulating occludin expression. Therefore, our study showed that the combination of yeast β-glucan and B. adolescentis CCFM1285 is an efficacious treatment for AAD.

Dietary tangeretin improved antibiotic-associated diarrhea in mice by enhancing the intestinal barrier function, regulating the gut microbiota, and metabolic homeostasis

Antibiotic-associated diarrhea is mediated by antibiotic treatment and is usually caused by the disruption of the intestinal barrier, gut microbiota, and metabolic balance. To identify a dietary strategy that can mitigate the side effects of antibiotics, this study investigated the effect of tangeretin on antibiotic-associated diarrhea in C57BL/6 mice. The results revealed that dietary tangeretin significantly ameliorated symptoms of antibiotic-associated diarrhea, as evidenced by the decreased diarrhea status scores, the reduced fecal water content, the decreased caecum/body weight ratio, and the alleviated colonic tissue damage. Dietary tangeretin also exhibited a protective effect on the intestinal barrier function by upregulating the mRNA and protein expression of claudin-1 and ZO-1. Furthermore, analysis of the gut microbiota using 16S rRNA gene sequencing indicated that dietary tangeretin modulated the gut microbiota of mice with antibiotic-associated diarrhea via increasing the gut microbiota diversity and the abundance of beneficial bacteria, e.g., Lactobacillaceae and Ruminococcaceae, and decreasing the abundance of harmful bacteria, e.g., Enterococcus and Terrisporobacter. Additionally, dietary tangeretin restored the levels of short-chain fatty acids and modulated metabolic pathways by enriching purine metabolism, bile acid metabolism, ABC transporters, and choline metabolism in cancer. Collectively, these findings provide a solid scientific basis for the rational use of tangeretin as a preventive and therapeutic agent for antibiotic-associated diarrhea.

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.

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

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

Effects of Lactobacillus plantarum and Weissella viridescens on the Gut Microbiota and Serum Metabolites of Mice with Antibiotic-Associated Diarrhea

Antibiotic-associated diarrhea (AAD) refers to diarrhea caused by gut microbiota disorders after the use of antibiotics, which seriously threatens the health of humans and animals. Therefore, it is necessary to find an effective therapy to treat AAD. This research aimed to explore the effects of Lactobacillus plantarum H-6 (L. plantarum H-6) and Weissella viridescens J-1 (W. viridescens J-1) on alleviating antibiotic-associated diarrhea induced by lincomycin hydrochloride (LH) in mice. The results show that L. plantarum H-6 could significantly reduce the expression of pro-inflammatory factors such as IL-1β and IL-6 in colon tissue. At the same time, L. plantarum H-6 significantly increased the abundance of Lactobacillus and Akkermansia, decreased the abundance of Bacteroides, and increased the contents of L-tryptophan, LysoPC (20:4 (8Z, 11Z, 14Z, 17Z)), reduced riboflavin, threoninyl-methionine, and N-palmitoyl in serum. However, W. viridescens J-1 had little effect on the treatment of AAD. It can be concluded that L. plantarum H-6 can regulate mice's colonic microbial composition, improve their serum metabolic process, and alleviate antibiotic-associated diarrhea. This research may provide a novel therapeutic option for AAD.

Akkermansia muciniphila Protects Against Antibiotic-Associated Diarrhea in Mice

Probiotics are used to prevent antibiotic-associated diarrhea (AAD) via the restoration of the gut microbiota. However, the precise effects of Akkermansia muciniphila (Akk), which is a promising probiotics, on AAD are unknown. Here, AAD models were established via the administration of lincomycin and ampicillin with or without pasteurized Akk or Amuc_1100 treatment. A diffusion test revealed that Akk was susceptible to the majority of the antibiotics, such as ampicillin. These effects were confirmed by the reduced Akk abundance in AAD model mice. Pasteurized Akk or Amuc_1100 significantly decreased the diarrhea status score and colon injury of AAD model mice. Additionally, these treatments significantly decreased the relative abundance of Citrobacter at genus level and reshaped the metabolic function of gut microbiota. Notably, pasteurized Akk or Amuc_1100 significantly changed the serum metabolome of AAD model mice. In addition, pasteurized Akk or Amuc_1100 suppressed intestinal inflammation by upregulating the expression of GPR109A and SLC5A8 and downregulating the expression of TNFα, IFNγ, IL1β, and IL6. Furthermore, they enhanced water and electrolyte absorption by upregulating AQP4, SLC26A3, and NHE3. Pasteurized Akk or Amuc_1100 also restored intestinal barrier function by ameliorating the downregulation of ZO-1, OCLN, CLDN4, and Muc2 in AAD model mice. In summary, optimizing intestinal health with pasteurized Akk or Amuc_1100 may serve as an approach for preventing AAD.

Beyond cellulose: pharmaceutical potential for bioactive plant polysaccharides in treating disease and gut dysbiosis

Polysaccharides derived from plants, algae, or fungi serve as the major components of some human diets. Polysaccharides have been shown to exhibit diverse biological activities in improving human health, and have also been proposed to function as potent modulators of gut microbiota composition, thus playing a bi-directional regulatory role in host health. Here, we review a variety of polysaccharide structures potentially linked to biological functions, and cover current research progress in characterizing their pharmaceutical effects in various disease models, including antioxidant, anticoagulant, anti-inflammatory, immunomodulatory, hypoglycemic, and antimicrobial activities. We also highlight the effects of polysaccharides on modulating gut microbiota via enrichment for beneficial taxa and suppression of potential pathogens, leading to increased microbial expression of carbohydrate-active enzymes and enhanced short chain fatty acid production. This review also discusses polysaccharide-mediated improvements in gut function by influencing interleukin and hormone secretion in host intestinal epithelial cells.

The Potential Effect of Polysaccharides Extracted from Red Alga Gelidium spinosum against Intestinal Epithelial Cell Apoptosis

Gut injury is a severe and unpredictable illness related to the increased cell death of intestinal epithelial cells (IECs). Excessive IEC apoptotic cell death during the pathophysiological state entails chronic inflammatory diseases. This investigation was undertaken to assess the cytoprotective action and underlying mechanisms of polysaccharides from Tunisian red alga, Gelidium spinosum (PSGS), on H2O2-induced toxicity in IEC-6 cells. The cell viability test was initially carried out to screen out convenient concentrations of H2O2 and PSGS. Subsequently, cells were exposed to 40 µM H2O2 over 4 h in the presence or absence of PSGS. Findings revealed that H2O2 caused oxidative stress manifested by over 70% cell mortality, disturbed the antioxidant defense, and increased the apoptotic rate in IEC-6 cells (32% than normal cells). Pretreatment of PSGS restored cell viability, especially when used at 150 µg/mL and normal cell morphology in H2O2-callenged cells. PSGS also equally sustained superoxide dismutase and catalase activities and hindered the apoptosis induced by H2O2. This protection mechanism of PSGS may be associated with its structural composition. The ultraviolet visible spectrum, Fourier-transformed infrared (FT-IR), X-ray diffraction (XRD), and high-performance liquid chromatography (HPLC) demonstrated that PSGS is mainly sulfated polysaccharides. Eventually, this research work provides a deeper insight into the protective functions and enhances the investment of natural resources in handling intestinal diseases.

Effects of Nemacystus decipiens polysaccharide on mice with antibiotic associated diarrhea and colon inflammation

Antibiotic associated diarrhea (AAD) is a common side effect of antibiotic therapy in which gut microbiota plays an important role in the disease. However, the function of gut microbiota in this disease is still not entirely clear. Polysaccharides have shown strong activity in shaping gut microbiota. Whether the polysaccharide can intervene with the microbiota to improve ADD has not been determined. In this study, we extract crude polysaccharides from Nemacystus decipiens (N. decipiens), a traditional Chinese medicine (TCM), named NDH0. The crude polysaccharide NDH0 might significantly relieve the symptom of mice with AAD, including a reduction in body weight, shortening of cecum index and the infiltration of inflammatory cells into the colon. NDH0-treated mice exhibited more abundant gut microbial diversity; significantly increased the abundance of Muribaculum, Lactobacillus, and Bifidobacterium and decreased the abundance of Enterobacter and Clostridioides at genus level. NDH0 treatment down-regulated the level of pro-inflammatory cytokines, including IL-1β and IL-6 in colon tissue. NDH0 protected the integrity of colon tissues and partially inactivated the related inflammation pathway by maintaining occludin and SH2-containing Inositol 5'-Phosphatase (SHIP). NDH0 could alleviate symptoms of diarrhea by modulating gut microbiota composition, improving intestinal integrity and reducing inflammation. The underlying protective mechanism was to reduce the abundance of opportunistic pathogens and maintain SHIP protein expression. Collectively, our results demonstrated the role of NDH0 as a potential intestinal protective agent in gut dysbiosis.

Marine prebiotics mediate decolonization of Pseudomonas aeruginosa from gut by inhibiting secreted virulence factor interactions with mucins and enriching Bacteroides population

BACKGROUND

Pseudomonas aeruginosa intestinal carriage rates are significantly higher in immunosuppressed individuals and hospitalized patients who therefore have increased risk of infections and antibiotic-associated diarrhea. To combat intestinal dysbiosis and decolonize P. aeruginosa from gastrointestinal tract, we investigated the anti-adherence and gut microbiota modulation properties of marine prebiotic fucoidans.

METHODS

Proteomic analysis of culture supernatant was performed by LC-MS/MS. Using lectin-based enzyme-linked immunosorbent assay, hemagglutinin domain interaction and inhibition with biomolecules were studied. We investigated the role of nutritional grade fucoidans in a mouse model and used 16S ribosomal RNA sequencing to examine fecal microbiota composition.

RESULTS

Analysis of culture supernatant proteins indicated the secretion of two-partner secretion (TPS) family proteins, including TpsA1/CdiA2 and TpsA2/CdiA1. Lectin like activity at the N-terminal of TpsA due to a conserved hemagglutinin domain (Pfam identifier [ID] PF05860) mediates binding to mucins that carry multiple fucosylated glycans. Fucose-rich sulfated polysaccharides (fucoidans) and sulfated dextrans were found to be potent inhibitors of the recombinant N-terminal hemagglutinin domain of TpsA (TpsA-NT-HAD) binding to mucins. In a mouse model, antibiotic-induced dysbiosis was essential for P. aeruginosa gastrointestinal colonization. After prophylactic oral fucoidans supplementation, a higher proportion (60%) of the mice were decolonized over time and resisted re-colonization, this was associated with remarkable expansion of Bacteroides (post-infection day-3 abundance, 29-50%) and consequential reductions in bloom of Enterobacteriaceae and Enterococcaceae populations. In the non-supplemented group, Parabacteroides mediated recovery from dysbiosis but failed to decolonize P. aeruginosa.

CONCLUSIONS

Supplementing diet with marine prebiotic fucoidans can mediate earlier recovery from dysbiosis and decolonization of P. aeruginosa from gut by inhibiting secreted virulence factor (TpsA/CdiA) interaction with mucins and promoting the growth of beneficial Bacteroides population. We suggest the prophylactic use of nutritional grade fucoidans to decolonize P. aeruginosa from gastrointestinal tract of at-risk individuals to prevent infection and transmission of colonizing P. aeruginosa.

Complex probiotics alleviate ampicillin-induced antibiotic-associated diarrhea in mice

Aim

Antibiotic-associated diarrhea (AAD) is a common side effect during antibiotic treatment, which can cause dysbacteriosis of the gut microbiota. Previous studies have shown beneficial effects in AAD treatment with Bifidobacterium lactis XLTG11, Lactobacillus casei Zhang, Lactobacillus plantarum CCFM8661, and Lactobacillus rhamnosus Probio-M9. However, no studies have been conducted on the immunomodulatory effects and protective intestinal barrier function of four complex probiotics. The aim of our study is to investigate the alleviation effects of complex probiotics on ampicillin-induced AAD.

Methods

Thirty-six BALB/c mice were randomly divided into six groups: normal control group (NC), model control group (MC), low-, medium-, and high-dose probiotics groups (LD, MD, and HD), and positive drug (Bifico, 1 × 10⁷ cfu) control group (PDC; Bifico, also known as Bifidobacterium Triple Live Capsule, is composed of Bifidobacterium longum, Lactobacillus acidophilus, and Enterococcus faecalis). An AAD model was established by intragastric administration of ampicillin, by gavage of different doses of complex probiotics and Bifico. The weight gain, fecal water content, loose stool grade, intestinal permeability, total protein and albumin levels, intestinal barrier, cytokine levels, and gut microbiota were determined.

Results

The results showed that complex probiotics significantly decreased the fecal water content, loose stool grade, intestinal permeability, and ileum tissue damage. Their application increased the weight gain, SIgA, TP, and ALB levels. Additionally, complex probiotics significantly decreased the levels of pro-inflammatory cytokines and increased those of anti-inflammatory cytokines. Meanwhile, the mRNA expression levels of ZO-1, occludin, claudin-1, and MUC2 were significantly upregulated in the probiotic-treated group. Furthermore, the complex probiotics increased the gut microbiota diversity and modulated the changes in the gut microbiota composition caused by ampicillin. At the phylum level, the abundance of Proteobacteria in the HD group was lower than that in the MC group, whereas that of Bacteroidetes was higher. At the genus level, the abundances of Klebsiella and Parabacteroides in the HD group were lower, whereas those of Bacteroides, Muribaculaceae, and Lactobacillus were higher than those in the MC group. Moreover, Spearman's correlation analysis also found that several specific gut microbiota were significantly correlated with AAD-related indicators.

Conclusion

We found that complex probiotics improved the diarrhea-related indexes, regulated gut microbiota composition and diversity, increased the expression levels of intestinal protective barrier-related genes, preserved the intestinal barrier function, and relieved inflammation and intestinal injury, thereby effectively improving AAD-associated symptoms. Graphical Abstract.

The effects of fucoidan as a dairy substitute on diarrhea rate and intestinal barrier function of the large intestine in weaned lambs

This paper explores the effects of fucoidan on the frequency of diarrhea, colon morphology, colon antioxidant status, cytokine content, short-chain fatty acids, and microflora of cecal contents in early weaned lambs in order to provide a reference for the intestinal health of young ruminants. Fucoidan is a natural active polysaccharide extracted from kelp and other large brown algae. It has many biological effects, such as improving immunity, nourishing the stomach and intestines, and anti-tumor properties. This study investigated the effects of fucoidan supplementation in milk replacer on the large intestine's ability to act as an intestinal barrier in weaned lambs. With six duplicate pens and one lamb per pen, a total of 24 weaned lambs (average starting body weight of 7.32 ± 0.37 kg) were randomly assigned to one of four milk replacer treatments. Four concentrations of fucoidan supplementation (0, 0.1, 0.3, and 0.6% dry matter intake) were employed to investigate the effects of fucoidan on cecal fermentation and colon microbial organization. The test period lasted 37 days (1 week before the test and 1 month after the test), and lamb cecal contents and colon organization were collected for examination. In addition, the fecal status of all lambs was observed and recorded daily, allowing us to calculate the incidence of diarrhea in weaned lambs. The findings demonstrated that fucoidan may significantly increase the concentration of short-chain fatty acids (propionic acid and butyric acid) in the cecal digesta of weaned lambs. In weaned lambs, 16S rDNA testing showed that fucoidan at 0.3-0.6% (dry matter intake) was beneficial for boosting the variety of the intestinal bacteria and modifying the relative abundance of a few bacterial strains. In addition, fucoidan enhanced colon antioxidant and immune functions and decreased the diarrhea rate to relieve weaning stress. This result demonstrates that milk replacer supplementation with fucoidan contributes to the improvement in the large intestinal health of weaned lambs.

In vitro fermentation of Bangia fusco-purpurea polysaccharide by human gut microbiota and the protective effects of the resultant products on Caco-2 cells from lipopolysaccharide-induced injury

Polysaccharide extracted from red seaweed Bangia fusco-purpurea (BFP) is a novel sulfated galactan, differed from agarans and carrageenans in fine structure. In this study, in vitro fermentation characteristics of BFP by human gut microbiota and its protective effect on lipopolysaccharide (LPS)-induced injury in Caco-2 cells were investigated. Our results showed that BFP was mainly degraded at transverse colon for 18 h fermentation by gut microbiota with reduced molecular weight. Meanwhile, BFP fermentation was associated with increased short-chain fatty acids (SCFAs) as compared to control group, especially acetic acid was increased to 129.53 ± 0.24 from 82.14 ± 0.23 mmol/L, and butyric acid was up to 1.56 ± 0.004 from 0.62 ± 0.01 mmol/L. Furthermore, BFP promoted abundances of Bacteroidetes and Firmicutes, while decreased numbers of Proteobacteria. The up-regrated beneficial differential metabolites were SCFAs, L-proline, arginine, folic acid, pyridoxamine, thiamine, etc. (p < 0.05), and their related metabolic pathways mainly included mTOR, arginine biosynthesis, and vitamin metabolism. Notably, BFP fermentation products at transverse colon significantly restored cell viability of LPS-treated Caco-2 cells from 73.79 ± 0.48 % to 93.79-99.64 %, which might be caused by increased beneficial differential metabolites (e.g., SCFAs). Our findings suggest that BFP has prebiotic potential and can enhance gut health.

Phragmites rhizoma polysaccharide-based nanocarriers for synergistic treatment of ulcerative colitis

The purpose of this study was to construct Phragmites rhizoma polysaccharide-based nano-drug delivery systems (PRP2-SeNPs-H/Aza-Lips) for synergistically alleviating ulcerative colitis and to investigate the important roles of Phragmites rhizoma polysaccharide-based nanocarriers in PRP2-SeNPs-H/Aza-Lips. Phragmites rhizoma polysaccharide (PRP2) was isolated and used for the preparation of Phragmites rhizoma polysaccharide selenium nanoparticles with low selenium content (PRP2-SeNPs-L) and high selenium content (PRP2-SeNPs-H). Based on the electrostatic attraction between PRP2-SeNPs-H and azathioprine liposomes (Aza-Lips), PRP2-SeNPs-H/Aza-Lips were constructed for precise delivery of the model drug azathioprine (Aza) to colon lesions. Results showed that PRP2 significantly alleviated the clinical symptoms and colon tissue damage and down-regulated the levels of inflammatory factors in serum and colon, demonstrating beneficial effects on mice with ulcerative colitis. PRP2-SeNPs-L had better relieving effects on ulcerative colitis. Phragmites rhizoma polysaccharide-based nanocarriers may protect azathioprine liposomes against gastrointestinal digestion, enhance the therapeutic effects on ulcerative colitis, and significantly reduce liver damage from azathioprine, which helps to improve the efficacy and toxicity of clinical drugs.

Regulatory Effect of Lactiplantibacillus plantarum 2-33 on Intestinal Microbiota of Mice With Antibiotic-Associated Diarrhea

Diarrhea is one of the common adverse reactions in antibiotic treatment, which is usually caused by the imbalance of intestinal flora, and probiotics play an important role in the structure of intestinal flora. Therefore, this experiment studied the regulatory effect of Lactiplantibacillus plantarum 2-33 on antibiotic-associated diarrhea (AAD) mice. First, the AAD mice model was established by the mixed antibiotic solution of gentamicin sulfate and cefradine. Then, the physiological indexes and diarrhea of mice were observed and recorded by gastric perfusion of low dose (1.0 × 10⁷ CFU/ml), medium dose (1.0 × 10⁸CFU/ml), and high dose (1.0 × 10⁹ CFU/ml) strain 2-33. 16S rRNA gene V3-V4 regions were sequenced in colon contents of mice in control group, model group, self-healing group, and experimental group, respectively, and the diversity of intestinal flora and gene function prediction were analyzed. The results showed that the intestinal flora of AAD mice was not significantly regulated by gastric perfusion of strain 2-33 to 7 days, but the relative abundance and diversity of intestinal flora of AAD mice were significantly improved by gastric perfusion to 14 days (p < 0.05). In addition, at the genus level, the relative abundance of Lactobacillus increased significantly, and the relative abundance of Enterococcus and Bacillus decreased significantly (p < 0.05). In addition, the regulation of strain 2-33 on intestinal flora of AAD mice was time- and dose-dependent, short-term gastric perfusion, and low dose had no significant effect (p > 0.05). Strain 2-33 can significantly increase the levels of anti-inflammatory cytokines IL-4 and IL-10, significantly decrease the levels of proinflammatory cytokines TNF-α and IFN-γ (p < 0.05), and can also adjust carbohydrate metabolism, amino acid metabolism, and energy metabolism to normal levels, thus accelerating the recovery of intestinal flora structure of AAD mice. In summary, strain 2-33 can improve the structure and diversity of intestinal flora of AAD mice, balance the level of substance and energy metabolism, and play a positive role in relieving diarrhea, maintaining and improving the intestinal microecological balance.

Bifidobacterium animalis subsp. lactis XLTG11 improves antibiotic-related diarrhea by alleviating inflammation, enhancing intestinal barrier function and regulating intestinal flora

Antibiotic-associated diarrhea (AAD) is a common side effect during antibiotic treatment. In this study, we evaluated the regulatory effect of Bifidobacterium animalis subsp. lactis XLTG11 on mouse diarrhea caused by antibiotic-induced intestinal flora disturbance. Then, two strains of Bifidobacterium animalis subsp. lactis XLTG11 and Bifidobacterium animalis subsp. lactis BB-12 were administered to AAD mice. We found that the recovery effect of using B. lactis XLTG11 was better than that of B. lactis BB-12. B. lactis XLTG11 reduced the pathological characteristics of the intestinal tract, and significantly reduced the levels of lipopolysaccharide (LPS), D-lactic acid (D-LA) and diamine oxidase (DAO) to decrease intestinal permeability. In addition, these two strains significantly increased the expression of aquaporin and tight junction proteins, and inhibited toll-like receptor 4 (TLR4)/activation of the nuclear factor-κB (NF-κB) signaling pathway, significantly increased the levels of anti-inflammatory cytokines and decreased levels of pro-inflammatory cytokines. Moreover, after treatment with B. lactis XLTG11, the contents of acetic acid, propionic acid, butyric acid and total short-chain fatty acids were significantly increased. Compared with the MC group, B. lactis XLTG11 increased the abundance and diversity of the intestinal flora and changed the composition of the intestinal flora. We found that B. lactis XLTG11 can promote the recovery of intestinal flora and mucosal barrier function, thereby effectively improving AAD-related symptoms, providing a scientific basis for future clinical applications.

The Prebiotic Effect of Australian Seaweeds on Commensal Bacteria and Short Chain Fatty Acid Production in a Simulated Gut Model

Diet is known to affect the composition and metabolite production of the human gut microbial community, which in turn is linked with the health and immune status of the host. Whole seaweeds (WH) and their extracts contain prebiotic components such as polysaccharides (PS) and polyphenols (PP). In this study, the Australian seaweeds, Phyllospora comosa, Ecklonia radiata, Ulva ohnoi, and their PS and PP extracts were assessed for potential prebiotic activities using an in vitro gut model that included fresh human faecal inoculum. 16S rRNA sequencing post gut simulation treatment revealed that the abundance of several taxa of commensal bacteria within the phylum Firmicutes linked with short chain fatty acid (SCFA) production, and gut and immune function, including the lactic acid producing order Lactobacillales and the chief butyrate-producing genera Faecalibacteria, Roseburia, Blautia, and Butyricicoccus were significantly enhanced by the inclusion of WH, PS and PP extracts. After 24 h fermentation, the abundance of total Firmicutes ranged from 57.35−81.55% in the WH, PS and PP samples, which was significantly greater (p ≤ 0.01) than the inulin (INU) polysaccharide control (32.50%) and the epigallocatechingallate (EGCG) polyphenol control (67.13%); with the exception of P. comosa PP (57.35%), which was significantly greater than INU only. However, all WH, PS and PP samples also increased the abundance of the phylum Proteobacteria; while the abundance of the phylum Actinobacteria was decreased by WH and PS samples. After 24 h incubation, the total and individual SCFAs present, including butyric, acetic and propionic acids produced by bacteria fermented with E. radiata and U. ohnoi, were significantly greater than the SCFAs identified in the INU and EGCG controls. Most notably, total SCFAs in the E. radiata PS and U. ohnoi WH samples were 227.53 and 208.68 µmol/mL, respectively, compared to only 71.05 µmol/mL in INU and 7.76 µmol/mL in the EGCG samples. This study demonstrates that whole seaweeds and their extracts have potential as functional food ingredients to support normal gut and immune function.

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.

Antimicrobial Activity of Red Alga Flour (Gelidium sp.) and Its Effect on Quality Retention of Scomber scombrus during Refrigerated Storage

This study analyzed the antimicrobial effect of aqueous extracts of flour obtained from red alga (Gelidium sp.) both in vitro, against most common food pathogenic and spoilage bacteria, and in a food model system during the chilled storage of Atlantic mackerel (Scomber scombrus). Results of in vitro assays allowed the conclusion that the aqueous flour extracts have antimicrobial activity against Gram-negative bacteria such as Enterobacteriaceae (Escherichia coli, Enterobacter aerogenes, and Klebsiella pneumoniae) and proteobacteria (Vibrio alginolyticus), and against Gram-positive bacteria such as Bacillus cereus and B. subtilis. In the food model study, different concentrations of the flour extract were present in the icing medium, microbial and chemical analyses being carried out in fish muscle at different storage times. An inhibitory effect (p < 0.05) on microbial growth (aerobes, psychrotrophs, Enterobacteriaceae, and proteolytic and lipolytic bacteria) and on chemical quality indices (pH, total volatile amines, and trimethylamine) was concluded. This effect was more pronounced when the flour extract concentration in the ice increased and at advanced storage times. This study provides a first approach to the beneficial use of flour of the alga Gelidium as a new preserving strategy for chilled fish.

Panax quinquefolius Polysaccharides Ameliorate Antibiotic-Associated Diarrhoea Induced by Lincomycin Hydrochloride in Rats via the MAPK Signaling Pathways

American ginseng (Panax quinquefolius L.) is an herbal medicine with polysaccharides as its important active ingredient. The purpose of this research was to identify the effects of the polysaccharides of P. quinquefolius (WQP) on rats with antibiotic-associated diarrhoea (AAD) induced by lincomycin hydrochloride. WQP was primarily composed of galacturonic acid, glucose, galactose, and arabinose. The yield, total sugar content, uronic acid content, and protein content were 6.71%, 85.2%, 31.9%, and 2.1%, respectively. WQP reduced the infiltration of inflammatory cells into the ileum and colon, reduced the IL-1β, IL-6, IL-17A, and TNF-α levels, increased the levels of IL-4 and IL-10 in colon tissues, improved the production of acetate and propionate, regulated the gut microbiota diversity and composition, improved the relative richness of Lactobacillus and Bacteroides, and reduced the relative richness of Blautia and Coprococcus. The results indicated that WQP can enhance the recovery of the intestinal structure in rats, reduce inflammatory cytokine levels, improve short-chain fatty acid (SCFA) levels, promote recovery of the gut microbiota and intestinal mucosal barrier, and alleviate antibiotic-related side effects such as diarrhoea and microbiota dysbiosis caused by lincomycin hydrochloride. We found that WQP can protect the intestinal barrier by increasing Occludin and Claudin-1 expression. In addition, WQP inhibited the MAPK inflammatory signaling pathway to improve the inflammatory status. This study provides a foundation for the treatment of natural polysaccharides to reduce antibiotic-related side effects.

Modulatory effects of polysaccharides from plants, marine algae and edible mushrooms on gut microbiota and related health benefits: A review

Naturally occurring carbohydrate polymers containing non-starch polysaccharides (NPs) are a class of biomacromolecules isolated from plants, marine algae, and edible mushrooms, and their biological activities has shown potential uses in the prevention and treatment of human diseases. Importantly, NPs serve as prebiotics to provide health benefits to the host through stimulating the proliferation of beneficial gut microbiota (GM) and enhancing the production of short-chain fatty acids (SCFAs). The composition and diversity of GM play a critical role in regulating host health and have been extensively studied in recent years. In this review, the extraction, isolation, purification, and structural characterization of NPs derived from plants, marine algae, and edible mushrooms are outlined. Importantly, the degradation and metabolism of these NPs in the intestinal tract, the effects of NPs on the microbial community and SCFAs generation, and the beneficial effects of NPs on host health by modulating GM are systematically highlighted. Overall, we hope that this review can provide some theoretical references and a new perspective for applications of NPs as prebiotics in functional food and drug development.

Structure analysis and anti-inflammatory effect of a polysaccharide from Hippocampus mohnikei

The purpose of this study was to analyze the structure of a polysaccharide (HMP-1) from Hippocampus mohnikei, and to explore its anti-inflammatory effect. HMP-1 was obtained from Hippocampus mohnikei by ethanol sedimentation and secondary column chromatography purification. Its structural characteristics were analyzed by gel permeation chromatography (GPC), fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and scanning electron micrograph (SEM). Results showed its molecular weight (Mw) was 7296 Da, and it mainly consisted of six residues, 1,3-β-Glcp, 1,4-α-Manp, 1,4-α-GalpA, 1,4-β-GlcpA2S, 1,4-α-Galp3S, 1,4-β-GlcNAc. HMP-1 could protect RAW246.7 cells from the cytotoxic effect induced by LPS. HMP-1 also could reduce the levels of nitric oxide and reactive oxygen species produced by LPS stimulation, suggesting that HMP-1 has anti-inflammatory activities within a certain concentration range.

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.

Cereus sinensis Polysaccharide Alleviates Antibiotic-Associated Diarrhea Based on Modulating the Gut Microbiota in C57BL/6 Mice

The present study investigated whether the purified polysaccharide from Cereus sinensis (CSP-1) had beneficial effects on mice with antibiotic-associated diarrhea (AAD). The effects of CSP-1 on gut microbiota were evaluated by 16S rRNA high-throughput sequencing. Results showed that CSP-1 increased the diversity and richness of gut microbiota. CSP-1 enriched Phasecolarctobacterium, Bifidobacterium and reduced the abundance of Parabacteroides, Sutterella, Coprobacillus to near normal levels, modifying the gut microbial community. Microbial metabolites were further analyzed by gas chromatography-mass spectrometry (GC-MS). Results indicated CSP-1 promoted the production of various short-chain fatty acids (SCFAs) and significantly improved intestinal microflora dysfunction in AAD mice. In addition, enzyme linked immunosorbent assay and hematoxylin-eosin staining were used to assess the effects of CSP-1 on cytokine levels and intestinal tissue in AAD mice. Results demonstrated that CSP-1 inhibited the secretion of interleukin-2 (IL-2), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) and improved the intestinal barrier. Correspondingly, the daily records also showed that CSP-1 promoted recovery of diarrhea status score, water intake and body weight in mice with AAD. In short, CSP-1 helped alleviate AAD by regulating the inflammatory cytokines, altering the composition and richness of intestinal flora, promoting the production of SCFAs, improving the intestinal barrier as well as reversing the dysregulated microbiota function.

Effects of Bacteroides-Based Microecologics against Antibiotic-Associated Diarrhea in Mice

Antibiotic-associated diarrhea (AAD) is a self-limiting disease mediated by antibiotic therapy. In clinical practice, several types of probiotics are used in treating AAD, but minimal research has been done on Bacteroides-based microecologics. Our aim was to evaluate the therapeutic effects of Bacteroidetes uniformis FGDLZ48B1, B. intestinalis FJSWX61K18, Bifidobacterium adolescentis FHNFQ48M5, and B. bifidum FGZ30MM3 and their mixture on AAD in mice. The lincomycin hydrochloride-induced AAD models were gavaged with a single strain or a probiotic mixture for a short period to assess the changes in colonic histopathology and cytokine concentrations, intestinal epithelial permeability and integrity, short-chain fatty acids (SCFAs), and the diversity of intestinal microbiota. Our data indicated that both the sole use of Bacteroides and the combination of Bacteroides and Bifidobacterium beneficially weakened systemic inflammation, increased the recovery rate of tissue structures, increased the concentrations of SCFAs, and restored the gut microbiota. Moreover, the probiotic mixture was more effective than the single strain. Specifically, B. uniformis FGDLZ48B1 combined with the B. adolescentis FHNFQ48M5 group was more effective in alleviating the pathological features of the colon, downregulating the concentrations of interleukin (IL)-6, and upregulating the expression of occludin. In summary, our research suggests that administration of a mixture of B. uniformis FGDLZ48B1 and B. adolescentis FHNFQ48M5 is an effective approach for treating AAD.

Seaweed Components as Potential Modulators of the Gut Microbiota

Macroalgae, or seaweeds, are a rich source of components which may exert beneficial effects on the mammalian gut microbiota through the enhancement of bacterial diversity and abundance. An imbalance of gut bacteria has been linked to the development of disorders such as inflammatory bowel disease, immunodeficiency, hypertension, type-2-diabetes, obesity, and cancer. This review outlines current knowledge from in vitro and in vivo studies concerning the potential therapeutic application of seaweed-derived polysaccharides, polyphenols and peptides to modulate the gut microbiota through diet. Polysaccharides such as fucoidan, laminarin, alginate, ulvan and porphyran are unique to seaweeds. Several studies have shown their potential to act as prebiotics and to positively modulate the gut microbiota. Prebiotics enhance bacterial populations and often their production of short chain fatty acids, which are the energy source for gastrointestinal epithelial cells, provide protection against pathogens, influence immunomodulation, and induce apoptosis of colon cancer cells. The oral bioaccessibility and bioavailability of seaweed components is also discussed, including the advantages and limitations of static and dynamic in vitro gastrointestinal models versus ex vivo and in vivo methods. Seaweed bioactives show potential for use in prevention and, in some instances, treatment of human disease. However, it is also necessary to confirm these potential, therapeutic effects in large-scale clinical trials. Where possible, we have cited information concerning these trials.

Health effects of dietary sulfated polysaccharides from seafoods and their interaction with gut microbiota

Various dietary sulfated polysaccharides (SPs) have been isolated from seafoods, including edible seaweeds and marine animals, and their health effects such as antiobesity and anti-inflammatory activities have attracted remarkable interest. Sulfate groups have been shown to play important roles in the bioactivities of these polysaccharides. Recent in vitro and in vivo studies have suggested that the biological effects of dietary SPs are associated with the modulation of the gut microbiota. Dietary SPs could regulate the gut microbiota structure and, accordingly, affect the production of bioactive microbial metabolites. Because of their differential chemical structures, dietary SPs may specifically affect the growth of certain gut microbiota and associated metabolite production, which may contribute to variable health effects. This review summarizes the latest findings on the types and structural characteristics of SPs, the effects of different processing techniques on the structural characteristics and health effects of SPs, and the current understanding of the role of gut microbiota in the health effects of SPs. These findings might help in better understanding the mechanism of the health effects of SPs and provide a scientific basis for their application as functional food.

The Impact of Antarctic Ice Microalgae Polysaccharides on D-Galactose-Induced Oxidative Damage in Mice

Antarctic ice microalgae (Chlamydomonas sp.) are a polysaccharide-rich natural marine resource. In this study, we evaluated the impact of Antarctic ice microalgae polysaccharides (AIMP) on D-galactose-induced oxidation in mice. We conducted biological and biochemical tests on tissue and serum samples from mice treated with AIMP. We found that AIMP administration was associated with improved thymus, brain, heart, liver, spleen, and kidney index values. We also found that AIMP treatment inhibited the reduced aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, superoxide dismutase, glutathione peroxidase, and glutathione levels as well as the increased serum, splenic, and hepatic nitric oxide and malondialdehyde levels arising from oxidation in these animals. Pathological examination revealed that AIMP also inhibited D-galactose-induced oxidative damage to the spleen, liver, and skin of these animals. AIMP was additionally found to promote the upregulation of neuronal nitric oxide synthase, endothelial nitric oxide synthase, cuprozinc-superoxide dismutase, manganese superoxide dismutase, catalase, heme oxygenase-1, nuclear factor erythroid 2-related factor 2, γ-glutamylcysteine synthetase, and NAD(P)H dehydrogenase [quinone] 1 as well as the downregulation of inducible nitric oxide synthase in these animals. High-performance liquid chromatography analysis revealed AIMP to be composed of five monosaccharides (mannitol, ribose, anhydrous glucose, xylose, and fucose). Together, these results suggest that AIMP can effectively inhibit oxidative damage more readily than vitamin C in mice with D-galactose-induced oxidative damage, which underscores the value of developing AIMP derivatives for food purposes.

Preventive Effect of Depolymerized Sulfated Galactans from Eucheuma serra on Enterotoxigenic Escherichia coli-Caused Diarrhea via Modulating Intestinal Flora in Mice

In this work, the preventive effect of depolymerized sulfated polysaccharides from Eucheuma serra (DESP) on bacterial diarrhea by regulating intestinal flora was investigated in vivo. Based on the enterotoxigenic Escherichia coli (ETEC)-infected mouse diarrhea model, DESP at doses ranging from 50 mg/kg to 200 mg/kg alleviated weight loss and decreased the diarrhea rate and diarrhea index. Serological tests showed that the levels of inflammation-related factors were effectively suppressed. Furthermore, the repaired intestinal mucosa was verified by morphology and pathological tissue section observations. Compared with the model group, the richness and diversity of the intestinal flora in the DESP group increased according to the 16S rRNA high-throughput sequencing of the gut microbiota. Specifically, Firmicutes and Actinobacteria increased, and Proteobacteria decreased after DESP administration. At the family level, DESP effectively improved the abundance of Lactobacillaceae, Bifidobacteriaceae, and Lachnospiraceae, while significantly inhibiting the growth of Enterobacteriaceae. Therefore, the antimicrobial diarrhea function of DESP may be related to the regulation of intestinal microbiota.

Modulation of gut microbiota and intestinal barrier function during alleviation of antibiotic-associated diarrhea with Rhizoma Zingiber officinale (Ginger) extract

Antibiotic-associated diarrhea (AAD) is typically mediated by antibiotic therapy, which has increased in prevalence in recent years. Previous studies have suggested that ginger, a common spice and herbal medicine, can modulate the composition of gut microbiota and is beneficial against gastrointestinal disease. This study investigates the therapeutic effects of fresh ginger extract on AAD in a rat model. Gut microbiota and intestinal barrier function were also studied. Ginger was administered to rats with AAD. Diarrhea symptoms were assessed, and 16s rRNA sequencing analysis of gut microbiota was performed. An AAD model was successfully established, and ginger was found to effectively ameliorate AAD-related diarrhea symptoms. After the intervention of ginger decoction, the diversity (rather than richness) of gut microbiota was significantly improved, and the gut microbiota recovery was accelerated. At the genus level, Escherichia_Shigella and Bacteroides levels decreased and increased the most, respectively. Additionally, these changes were demonstrated to be coincidental with the moderate restoration of intestinal barrier function, especially the restoration of tight junction protein ZO-1. Our data indicate that ginger could restore gut microbiota and intestinal barrier function during alleviation of AAD.

Marine polysaccharides from Gelidium pacificum Okamura and Cereus sinensis reveal prebiotic functions

Many marine polysaccharides as prebiotics can promote host health by modulating gut microbiota. This study investigated the beneficial effects of purified marine plant-derived Gelidium pacificum Okamura polysaccharide (GPOP-1) and marine animal-derived Cereus sinensis polysaccharide (CSP-1) on normal mice by modulating gut microbiota. The composition and diversity of gut microbiota were evaluated using 16S rRNA high-throughput sequencing. The results showed that GPOP-1 and CSP-1 altered the composition of the gut microbiota and promoted the growth of beneficial bacteria. At the genus level, GPOP-1 increased the relative abundance of Bacteroides, Phascolarctobacterium, and decreased the relative abundance of Ruminococcus, Helicobacter, Allobaculum, Dorea and AF12. While CSP-1 increased the relative abundance of Coprococcus, Adlercreutzia, Roseburia, Phascolarctobacterium, and decreased the relative abundance of Bacteroides, Ruminococcus and Oscillospira. The changes in the gut microbiota may affect the body weight, immune organ index and the production of short-chain fatty acids in normal mice. Compared to the normal control group, GPOP-1 decreased average weight gain while CSP-1 increased average weight gain. Furthermore, both GPOP-1 and CSP-1 significantly increased thymus and spleen indexes and total short chain fatty acids production in mice. In summary, GPOP-1 and CSP-1 exerted prebiotic effects on normal mice.