Effect of polysaccharide fractions from Fortunella margarita on the fecal microbiota of mice and SCFA production in vitro

Prebiotic characteristics of degraded polysaccharides from Acanthopanax senticosus polysaccharide on broilers gut microbiota based on in vitro digestion and fecal fermentation

This study aimed to evaluate the effect of low molecular weight Acanthopanax polysaccharides on simulated digestion, probiotics, and intestinal flora of broilers in vitro. The experiments were carried out by H2O2-Vc degradation of Acanthopanax polysaccharides, in vitro simulated digestion to evaluate the digestive performance of polysaccharides with different molecular weights, in vitro probiotic evaluation of the probiotic effect of polysaccharides on lactobacilli and bifidobacteria, in vitro anaerobic fermentation and high-throughput sequencing of 16S rRNA genes to study the impact of Acanthopanax polysaccharides on the intestinal flora of broilers, and the effect of Acanthopanax polysaccharides on the short-chain fatty acids of intestines were determined by GC-MS method. The results showed that the molecular weight of Acanthopanax polysaccharide (ASPS) was 9,543 Da, and the molecular weights of polysaccharides ASPS-1 and ASPS-2 were reduced to 4,288 Da and 3,822 Da after degradation, and the particle sizes, PDIs, and viscosities were also significantly decreased. ASPS-1 has anti-digestive properties and better in vitro probiotic properties. The addition of ASPS-1 regulates the structure of intestinal microorganisms by regulating fecalibacterium to produce short-chain fatty acids, promoting the colonization of beneficial bacteria such as fecalibacterium, paraprevotella and diminishing the prevalence of detrimental bacteria such as Fusobacteria. Interestingly the ASPS-1 group found higher levels of Paraprevotella, which degraded trypsin in the gut, reducing inflammation, acted as a gut protector, and was influential in increasing the levels of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and total SCFAs in the fermented feces. Therefore, the degraded ASPS-1 can better regulate the structure of intestinal flora and promote the production of SCFAs, creating possibilities for its use as a potential prebiotic, which is conducive to the intestinal health of poultry.

Structural characterization and human gut microbiota fermentation in vitro of a polysaccharide from Fucus vesiculosus

In this study, an acidic polysaccharide (FVP-7 A) was isolated from Fucus vesiculosus by DEAE-Sepharose™ fast flow. The chemical composition, glycosidic bonds and in vitro fecal fermentation characteristics of FVP-7 A were studied. Results shown that FVP-7 A was a homogenous polysaccharide with average molecular weight of 30.94 kDa. Combined with FT-IR, monosaccharide composition, methylation and NMR analysis, the glycosidic bonds of FVP-7 A mainly composed of →4)-β-D-Manp-(1→, →3)-α-L-Fucp-(1→, α-D-Manp-(1→, →3)-β-D-Manp-(1 → and →4,6)-α-D-Manp-(1→. The zeta potential and atomic force microscopy images indicated that FVP-7 A could exist stably as a single chain-like structure in dilute solution. After gut fermentation, FVP-7 A was utilized and promoted multiple short-chain fatty acids production, especially acetic acid, butyric acid and valeric acid. For prebiotics, FVP-7 A significantly increased the relative abundance of short-chain fatty acids producing bacteria such as Bacteroides, Lachnospira, Faecalibacterium, Ruminococcus, Oscillospira and Dialister, and inhiited the growth of the harmful bacteria Shigella. These results indicated that FVP-7 A could be used as a potential dietary supplement to improve intestinal health.

The use of an in vitro fecal fermentation model to uncover the beneficial role of omega-3 and punicic acid in gut microbiota alterations induced by a Western diet

The influence of gut microbiota in the onset and development of several metabolic diseases has gained attention over the last few years. Diet plays an essential role in gut microbiota modulation. Western diet (WD), characterized by high-sugar and high-fat consumption, alters gut microbiome composition, diversity index, microbial relative levels, and functional pathways. Despite the promising health effects demonstrated by polyunsaturated fatty acids, their impact on gut microbiota is still overlooked. The effect of Fish oil (omega-3 source) and Pomegranate oil (punicic acid source), and a mixture of both oils in gut microbiota modulation were determined by subjecting the oil samples to in vitro fecal fermentations. Cecal samples from rats from two different dietary groups: a control diet (CD) and a high-fat high-sugar diet (WD), were used as fecal inoculum. 16S amplicon metagenomics sequencing showed that Fish oil + Pomegranate oil from the WD group increased α-diversity. This sample can also increase the relative abundance of the Firmicutes and Bacteroidetes phylum as well as Akkermansia and Blautia, which were affected by the WD consumption. All samples were able to increase butyrate and acetate concentration in the WD group. Moreover, tyrosine concentrations, a precursor for dopamine and norepinephrine, increase in the Fish oil + Pomegranate oil WD sample. GABA, an important neurotransmitter, was also increased in WD samples. These results suggest a potential positive impact of these oils' mixture on gut-brain axis modulation. It was demonstrated, for the first time, the great potential of using a mixture of both Fish and Pomegranate oil to restore the gut microbiota changes associated with WD consumption.

Functional fractions of Astragalus polysaccharides as a potential prebiotic to alleviate ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory disease of the intestine that is significantly influenced by an imbalance in the gut microbiota. Astragalus membranaceus, particularly its polysaccharide components, has shown therapeutic potential for the treatment of UC, although the specific active constituents and their mechanistic pathways remain to be fully elucidated. In this study, we investigated two molecular weight fractions of Astragalus polysaccharides (APS), APS1 (Mw < 10 kDa) and APS2 (10 kDa < Mw < 50 kDa), isolated by ultrafiltration, focusing on their prebiotic effects, effects on UC, and the underlying mechanism. Our results showed that both APS1 and APS2 exhibit prebiotic properties, with APS1 significantly outperforming APS2 in ameliorating UC symptoms. APS1 significantly attenuated weight loss and UC manifestations, reduced colonic pathology, and improved intestinal mucosal barrier integrity. In addition, APS1 significantly reduced the levels of inflammatory cytokines in the serum and colonic tissue, and downregulated colonic chemokines. Furthermore, APS1 ameliorated dextran sulfate sodium salt (DSS)-induced intestinal dysbiosis by promoting the growth of beneficial microbes and inhibiting the proliferation of potential pathogens, leading to a significant increase in short-chain fatty acids. In conclusion, this study highlights the potential of APS1 as a novel prebiotic for the prevention and treatment of UC.

Prevention of cyclophosphamide-induced immune suppression by polysaccharides from Apocynum venetum flowers via enhancing immune response, reducing oxidative stress, and regulating gut microbiota in mice

Introduction

Emerging proof suggests that Apocynum venetum flowers polysaccharide (AVFP) has immunomodulatory effects in vitro. However, the action mechanism of AVFA is still unclear in vivo. The purpose of this study is to probe into the potential mechanism of AVFA in immunosuppressed mice by investigating organ index, cytokine levels, anti-oxidative stress capacity, transcriptomics, and gut microbiota.

Methods

Immunocompromised mice induced by cyclophosphamide (CTX) were divided into six groups. The enzyme-labeled method, hematoxylin and eosin, transcriptomics, and high-throughput sequencing were used to detect the regulatory effects of AVFP on immunocompromised mice and the function of AVFP on the concentration of short-chain fatty acids (SCFAs) by high-performance liquid chromatography (HPLC) analysis. The Spearman correlation analysis was used to analyze the correlation between the intestinal microbiota and biochemical indexes.

Results

The experimental results illustrated that AVFP has protective effects against CTX-induced immunosuppression in mice by prominently increasing the organ index and levels of anti-inflammatory factors in serum in addition to enhancing the antioxidant capacity of the liver. Meanwhile, it could also signally decrease the level of pro-inflammatory cytokines in serum, the activity of transaminase in serum, and the content of free radicals in the liver, and alleviate the spleen tissue damage induced by CTX. Transcriptomics results discovered that AVFP could play a role in immune regulation by participating in the NF-κB signaling pathway and regulating the immune-related genes Bcl3, Hp, Lbp, Cebpd, Gstp2, and Lcn2. Gut microbiota results illustrated that AVFP could increase the abundance of beneficial bacteria, reduce the abundance of harmful bacteria, and regulate the metabolic function of intestinal microorganisms while dramatically improving the content of SCFAs, modulating immune responses, and improving the host metabolism. The Spearman analysis further evaluated the association between intestinal microbiota and immune-related indicators.

Conclusion

These findings demonstrated that AVFP could enhance the immune effects of the immunosuppressed mice and improve the body's ability to resist oxidative stress.

Postbiotic properties of exopolysaccharide produced by Levilactobacillus brevis M-10 isolated from natural fermented sour porridge through in vitro simulated digestion and fermentation

The simulated digestion and fermentation characteristics in vitro of exopolysaccharide (EPS) of Levilactobacillus brevis M-10 were studied to evaluate its postbiotic properties. The simulated digestion results showed that EPS could not be degraded in saliva but could be very slightly degraded in gastric juice and could be degraded in intestinal juice. The results of simulated fermentation demonstrated that EPS could lower the intestine pH and be utilized by gut microbes to produce short-chain fatty acids such as propionic acid and butyric acid. Meanwhile, EPS significantly raised the diversity of human gut microbiota, and the relative abundances of Phascolarctobacterium were significantly increased, whereas Fusobacterium and Morganella significantly decreased. In conclusion, EPS from L. brevis M-10 was a good postbiotic as inulin. This was the first report about EPS as the postbiotic of L. brevis M-10 screened from broomcorn millet sour porridge in northwestern Shanxi Province, China.

Gut microbiota modulation, prebiotic and bioactive characteristics of date pomace polysaccharides extracted by microwave-assisted deep eutectic solvent

This study investigated the characteristics of polysaccharides from date pomace using microwave-assisted deep eutectic solvents. The impact on the gut microbiota and probiotics growth was examined in vitro. The study also examined its antioxidant properties, ability to inhibit enzymes linked to diabetes and high blood pressure, impact on cell growth, and physical properties. The isolated MPS had an average molecular weight of 8073.38 kDa and contained mannose, galacturonic acid, galactose, glucose, and fructose in specific proportions. At a concentration of 1000 mg/L, MPS showed strong antioxidant activity, with significant scavenging rates in various tests such as DPPH (57.0 ± 1.05 %) and ABTS (66.4 ± 2.48 %). MPS displayed 77 %, 80 %, and 43 % inhibition for α-amylase, α-glucosidase, and ACE-inhibition, respectively. MPS displayed significant antiproliferative effects, achieving 100 % and 99 % inhibition against Caco-2 and MCF-7 cells at 2500 mg/L, respectively. MPS showed broad-spectrum antibacterial properties against both Gram-positive and Gram-negative foodborne bacteria. Gemmiger formicilis, Blautia species, Collinsella aerofaciens, and Bifidobacterium longum showed strong positive correlations, suggesting increased SCFA production. Network analysis indicated species correlations, with 86 % showing negative correlations with Escherichia and Enterococcus saccharolyticus. MPS was abundant in Firmicutes, Actinobacteria, and Proteobacteria phyla. Date pomace could serve as a dietary fiber source, promoting better health.

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

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

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.

Ingesting retrograded rice (Oryza sativa) starch relieves high-fat diet induced hyperlipidemia in mice by altering intestinal bacteria

High-fat diet is a risk factor for many chronic diseases, whose symptoms are probably regulated by ingesting food ingredients such as resistant starch. For cooked rice stored in cold-chain, the starch component can retrograde to generate ordered structures (helices and crystallites) and become resistant. However, the role of retrograded starch in managing hyperlipidemia symptoms is insufficiently understood. Here, compared to the normal high-fat diet, ingesting retrograded starch reduced the triglyceride and low-density lipoprotein cholesterol levels of high-fat diet mice by 17.69% and 41.33%, respectively. This relieved hyperlipidemia could be linked to the changes in intestinal bacteria. Retrograded starch intervention increased the relative abundance of Bacteroides (2.30 times higher), which produces propionic acid (increased by 8.26%). Meanwhile, Bacteroides were positively correlated with butyric acid (increased by 98.4%) with strong anti-inflammatory functions. Hence, retrograded starch intervention may regulate the body's health by altering intestinal bacteria.

Gougunao tea polysaccharides ameliorate high-fat diet-induced hyperlipidemia and modulate gut microbiota

Many natural polysaccharides have been proven to have ameliorative effects on high-fat diet-induced hyperlipidemia with fewer side effects. However, similar data on Gougunao tea polysaccharides remain obscure. In this study, we aimed to investigate the role of Gougunao tea polysaccharides (GTP40) in the alleviation of hyperlipidemia and regulation of gut microbiota in C57BL/6J mice induced by a high-fat diet. The results indicated that GTP40 intervention inhibited the abnormal growth of body weight and the excessive accumulation of lipid droplets in the livers and ameliorated the biochemical parameters of serum/liver related to lipid metabolism in hyperlipidemia mice. The elevated levels of antioxidant enzyme and anti-inflammation cytokine in serum, as well as the up-regulating anti-inflammation gene in the liver, reflected that GTP40 might mitigate the oxidative and inflammatory stress induced by a high-fat diet. In addition, GTP40 could modulate the composition, abundance, and diversity of gut microbiota in hyperlipidemia mice. Besides, Spearman's correlation analysis implied that GTP40 intervention could enrich beneficial bacteria (e.g., Akkermansia, Bacteroides, Roseburia, and Alistipes), and decrease harmful bacteria (e.g., Blautia, Faecalibaculum, Streptococcus, and norank_f_Desulfovibrionaceae), which were correlated with the lipid metabolic parameters associated with hyperlipidemia. Moreover, it also indicated that there was a significant correlation between gut microbiota and SCFAs. Thus, GTP40 may be a novel strategy against fat accumulation, oxidative stress, and inflammation, as well as restoring the normal microbial balance of the gut in hyperlipidemia mice.

The Hypolipidemic Effect of Hawthorn Leaf Flavonoids through Modulating Lipid Metabolism and Gut Microbiota in Hyperlipidemic Rats

Objective. The purpose of this study was to explore the potential mechanisms of the lipid-regulating effects and the effect on modulating the gut microbiota of hawthorn leaf flavonoids (HLF) in the high-fat diet-induced hyperlipidemic rats. Methods. The hypolipidemic effect of HLF was investigated in the high-fat diet-induced hyperlipidemic rats. The action targets of HLF in the treatment of hyperlipidemia were predicted by network pharmacology and KEGG enrichment bubble diagram, which were verified by the test of western blotting. Meanwhile, we used 16S rRNA sequencing to evaluate the effects of HLF on the microbes. Results. The results of animal experiments showed that HLF could reduce the body weight and regulate the levels of serum lipid in high-fat diet (HFD) rats. Meanwhile, for the related targets of cholesterol metabolism, HLF could significantly upregulate the expression of LDLR, NR1H3, and ABCG5/ABCG8; reduce the expression of PCSK9; and increase the level of CYP7A1 in the intestinal tissue, whereas cholesterol biosynthetic protein expressions including HMGCR and SCAP were lowered by HLF. In addition, HLF increased the activities of plasma SOD, CAT, and GSH-Px and decreased the levels of Casp 1, NLRP3, IL-1β, IL-18, and TNF-α, improving the degree of hepatocyte steatosis and inflammatory infiltration of rats. Notably, HLF significantly regulated the relative abundance of major bacteria such as g_Lactobacillus, g_Anaerostipes, g_[Eubacterium]_hallii_group, g_Fusicatenibacter, g_Akkermansia, and g_Collinsella. Synchronously, we found that HLF could regulate the disorder of plasma HEPC and TFR levels caused by HFD. Conclusion. This study demonstrates that HLF can regulate metabolic hyperlipidemia syndromes and modulate the relative abundance of major bacteria, which illustrated that it might be associated with the modulation of gut microbiota composition and metabolites.

Monascuspiloin from Monascus-Fermented Red Mold Rice Alleviates Alcoholic Liver Injury and Modulates Intestinal Microbiota

Monascus-fermented red mold rice (RMR) has excellent physiological efficacy on lipid metabolism and liver function. This study investigated the ameliorative effects of monascuspiloin (MP) from RMR on alcoholic liver injury in mice, and further clarified its mechanism of action. Results showed that MP intervention obviously ameliorated lipid metabolism and liver function in mice with over-drinking. In addition, dietary MP intervention reduced liver MDA levels and increased liver CAT, SOD, and GSH levels, thus alleviating liver oxidative stress induced by excessive drinking. 16S rRNA amplicon sequencing showed that MP intervention was beneficial to ameliorate intestinal microbiota dysbiosis by elevating the proportion of norank_f_Lachnospiraceae, Lachnoclostridium, Alistipes, Roseburia, Vagococcus, etc., but decreasing the proportion of Staphylococcus, norank_f_Desulfovibrionaceae, Lachnospiraceae_UCG-001, Helicobacter, norank_f_Muribaculaceae, unclassified_f_Ruminococcaceae, etc. Additionally, correlation network analysis indicated that the key intestinal bacterial taxa intervened by MP were closely related to some biochemical parameters of lipid metabolism, liver function, and oxidative stress. Moreover, liver metabolomics analysis revealed that dietary MP supplementation significantly regulated the levels of 75 metabolites in the liver, which were involved in the synthesis and degradation of ketone bodies, taurine, and hypotaurine metabolism, and other metabolic pathways. Furthermore, dietary MP intervention regulated gene transcription and protein expression associated with hepatic lipid metabolism and oxidative stress. In short, these findings suggest that MP mitigates alcohol-induced liver injury by regulating the intestinal microbiome and liver metabolic pathway, and thus can serve as a functional component to prevent liver disease.

Therapeutic potential of non-starch polysaccharides on type 2 diabetes: from hypoglycemic mechanism to clinical trials

Non-starch polysaccharides (NSPs) have been reported to exert therapeutic potential on managing type 2 diabetes mellitus (T2DM). Various mechanisms have been proposed; however, several studies have not considered the correlations between the anti-T2DM activity of NSPs and their molecular structure. Moreover, the current understanding of the role of NSPs in T2DM treatment is mainly based on in vitro and in vivo data, and more human clinical trials are required to verify the actual efficacy in treating T2DM. The related anti-T2DM mechanisms of NSPs, including regulating insulin action, promoting glucose metabolism and regulating postprandial blood glucose level, anti-inflammatory and regulating gut microbiota (GM), are reviewed. The structure-function relationships are summarized, and the relationships between NSPs structure and anti-T2DM activity from clinical trials are highlighted. The development of anti-T2DM medication or dietary supplements of NSPs could be promoted with an in-depth understanding of the multiple regulatory effects in the treatment/intervention of T2DM.

Fu brick tea alleviates alcoholic liver injury by modulating the gut microbiota-liver axis and inhibiting the hepatic TLR4/NF-κB signaling pathway

This study first evaluated the protective effects of Fu brick tea water extracts (FTE) on alcoholic liver injury and its underlying mechanism in C57BL/6J mice. Oral administration of FTE by oral gavage (400 mg per kg bw) for 12 weeks significantly alleviated lipid metabolism disorder, reduced the activities of serum ALT and AST, decreased the expression of the liver CYP2E1 gene, and enhanced the antioxidant capacities of the livers in alcohol-fed mice (p < 0.05). FTE also relieved alcohol-induced gut microbiota dysbiosis by promoting the proliferation of probiotics such as Muribaculaceae and Lactobacillus, and subsequently increased the cecal levels of short-chain fatty acids (SCFAs) and decreased the tryptophan content of alcohol-fed mice (p < 0.05). Importantly, FTE was found to improve the alcohol-impaired gut barrier function by up-regulating the expression of the epithelial tight junction protein. Accordingly, FTE decreased the circulating lipopolysaccharide (LPS) and thus inhibited the hepatic TLR4/NF-κB signaling pathway to ameliorate alcoholic liver injury. Cumulatively, these findings shed light on the important role of the gut microbiota-liver axis behind the protective efficacy of FTE on alcoholic liver injury.

Protective effect of homogeneous polysaccharides of Wuguchong (HPW) on intestinal mucositis induced by 5-fluorouracil in mice

BACKGROUND

In hospitalized patients, drug side effects usually trigger intestinal mucositis (IM), which in turn damages intestinal absorption and reduces the efficacy of treatment. It has been discovered that natural polysaccharides can relieve IM. In this study, we extracted and purified homogenous polysaccharides of Wuguchong (HPW), a traditional Chinese medicine, and explored the protective effect of HPW on 5-fluorouracil (5-FU)-induced IM.

METHODS AND RESULTS

First, we identified the physical and chemical properties of the extracted homogeneous polysaccharides. The molecular weight of HPW was 616 kDa, and it was composed of 14 monosaccharides. Then, a model of small IM induced by 5-FU (50 mg/kg) was established in mice to explore the effect and mechanism of HPW. The results showed that HPW effectively increased histological indicators such as villus height, crypt depth and goblet cell count. Moreover, HPW relieved intestinal barrier indicators such as D-Lac and diamine oxidase (DAO). Subsequently, western blotting was used to measure the expression of Claudin-1, Occludin, proliferating cell nuclear antigen, and inflammatory proteins such as NF-κB (P65), tumour necrosis factor-α (TNF-α), and COX-2. The results also indicated that HPW could reduce inflammation and protect the barrier at the molecular level. Finally, we investigated the influence of HPW on the levels of short-chain fatty acids, a metabolite of intestinal flora, in the faeces of mice.

CONCLUSIONS

HPW, which is a bioactive polysaccharide derived from insects, has protective effects on the intestinal mucosa, can relieve intestinal inflammation caused by drug side effects, and deserves further development and research.