Polysaccharides from Sargassum fusiforme after UV/H2O2 degradation effectively ameliorate dextran sulfate sodium-induced colitis

Fructus Mori polysaccharides modulate the axial distribution of gut microbiota and fecal metabolites to improve symptoms of hyperglycemia in type 2 diabetic mice

To understand the gut microbiota composition in different intestinal segments is essential to clarify the structure-hypoglycemic relationship of Fructus Mori Polysaccharides (MFP). In this study, the spatial distribution of gut microbiota and fecal metabolites affected by MFP in type 2 diabetes mice was investigated using the 16S rRNA high-throughput sequencing technology and gas chromatography. The results showed that MFP could control body weight and reduce the blood glucose level. After MFP intervention, the abundance of Lactobacillus and Bifidobacterium increased by 3.43 and 33.47 times in the ascending colon mucus layer, and Prevotella increased by 102.25 times in the transverse colon content, while Helicobacter and Treponspirillum was reduced by 99.28 % and 79.38 % in the ascending colon mucus layer, and Ruminococcus reduced by 68.77 % in the cecum contents. Moreover, the MFP increased the contents of short-chain fatty acids (SCFAs) with significantly difference along the longitudinal axis of intestine. The results suggested that the MFP relieve the hyperglycemia of diabetic may through modulating the microorganism in ascending colon mucus layer, transverse colon content and cecum.

Refining microbiome diversity analysis by concatenating and integrating dual 16S rRNA amplicon reads

Understanding the role of human gut microbiota in health and disease requires insights into its taxonomic composition and functional capabilities. This study evaluates whether concatenating paired-end reads enhances data output for gut microbiome analysis compared to the merging approach across various regions of the 16S rRNA gene. We assessed this approach in both mock communities and Korean cohorts with or without ulcerative colitis. Our results indicate that using the direct joining method for the V1-V3 or V6-V8 regions improves taxonomic resolution compared to merging paired-end reads (ME) in post-sequencing data. While predicting microbial function based on 16S rRNA sequencing has inherent limitations, integrating sequencing reads from both the V1-V3 and V6-V8 regions enhanced functional predictions. This was confirmed by whole metagenome sequencing (WMS) of Korean cohorts, where our approach improved taxa detection that was lost using the ME method. Thus, we propose that the integrated dual 16S rRNA sequencing technique serves as a valuable tool for microbiome research by bridging the gap between amplicon sequencing and WMS.

Enhancing palm kernel cake nutritional quality through combined bacterial fermentation and enzymatic hydrolysis

BACKGROUND

Palm kernel cake (PKC), a non-conventional feed resource, contains a large amount of crude fibre (CF), mainly manna-polysaccharides, which are key limiting factors in regard to monogastric animal production. In this study, we have developed a synergistic bacteria-enzyme co-fermentation system to enhance the nutritional profile of PKC and evaluated its digestion dynamics using a physiologically relevant porcine in vitro gastrointestinal model.

RESULTS

Sequential fermentation with Lactobacillus plantarum LY19 and Bacillus natto ND1 (48 h, 37 °C) degraded 3.0% crude fiber, yielding 9.30 g kg-1 reducing sugars. Enzymatic treatment (β-mannanase 45 U g-1 + cellulase 160 U g-1 + acid protease 125 U g-1) synergistically enhanced nutrient release: soluble protein increased 214% (0.72% to 2.26%), reducing sugars surged 13.8-fold (4.45 to 61.21 g kg-1), with 55.3% fibre reduction (15.40% to 6.88%). In vitro digestion demonstrated an improvement in regard to dry matter (7.1% increase) and protein digestibility (17.0% increase), whereas colonic fermentation showed decreased concentrations of short-chain fatty acids and gases production during 48 h. 16S ribosomal RNA analysis revealed increased beneficial Lachnospiraceae NK4A136 alongside decreased pathogens (i.e. Escherichia-Shigella) and fibre-degrading taxa (i.e. Christensenellaceae R-7, UCG-005).

CONCLUSION

The integrated bacterial-enzymatic co-fermentation process significantly enhanced the nutritional profile of PKC through fibre reduction, protein solubilisation, and sugar release. This pretreatment improved in vitro small intestinal digestibility and modulated colonic fermentation patterns, as evidenced by favourable microbial community shifts. These findings demonstrate the potential of this bioprocessing strategy to expand PKC utilisation in swine nutrition. © 2025 Society of Chemical Industry.

Sargassum fusiforme polysaccharides protect mice against Citrobacter rodentium infection via intestinal microbiota-driven microRNA-92a-3p-induced Muc2 production

Sargassum fusiforme, widely consumed in Asian countries, has been proven to have various biological activities. However, the impacts and mechanisms of Sargassum fusiforme polysaccharides (SFPs) on intestinal bacterial infection are not yet fully understood. Our findings indicate that SFPs pretreatment ameliorates intestinal inflammation by reducing C. rodentium colonization, increasing colon length and levels of IL-10 and IL-22, decreasing IL-1β, IL-6, TNF-α, and IL-17 levels, inhibiting colonic crypt elongation and hyperplasia, and enhancing the intestinal mucosal barrier. The protective effects against intestinal bacterial infection are linked to enhanced clearance of C. rodentium and improvements in the intestinal mucosal barrier and C. rodentium-induced intestinal microbiota dysbiosis. Fecal microbiota transplantation experiments were conducted to evaluate the functional impact of microbiota induced by SFPs. The results suggest that intestinal microbiota modified by SFPs effectively countered C. rodentium infection. In addition, our study identified that miRNA-92a-3p is partially complementary to the 3'-UTR of the Notch1 gene, thereby repressing the Notch1-Hes1 signaling pathway and enhancing Muc2 secretion. Taken together, these findings reveal that SFPs protect mice from C. rodentium infection by activating the miR-92a-3p/Notch1-Hes1 regulatory axis driven by the intestinal microbiota, which stimulates Muc2 production to maintain intestinal barrier homeostasis.

Exercise-driven gut microbiota alterations enhance colonization resistance against methicillin-resistant Staphylococcus aureus

Gut microbiota plays a crucial role in resisting the invasion of pathogens, particularly multidrug-resistant (MDR) bacteria, which pose a significant threat to public health. While exercise offers numerous health benefits, its impact on host colonization resistance remains largely unclear. In this study, we demonstrate that moderate exercise significantly reduces gut colonization by methicillin-resistant Staphylococcus aureus (MRSA), a clinically important MDR pathogen. Moreover, we identify an understudied strain of the intestinal probiotic Dubosiella newyorkensis (L8) as a critical factor in mediating exercise-induced colonization resistance against MRSA. Mechanistically, L8 enhances the deprivation of fucose, a crucial carbon source essential for MRSA growth and pathogenicity. This process relies on the high binding affinity of pyruvate to the ILE257 site of the lactate dehydrogenase in L8. Overall, our work highlights the importance of moderate exercise in maintaining host colonization resistance and demonstrates L8 as a probiotic in protecting against MRSA colonization.

Structural Characterization of Foxtail Millet (Setaria italica) Polysaccharides and Evaluation of Its Antioxidant and Immunostimulatory Activities

A water-soluble polysaccharide from foxtail millet (FM-D1) was isolated and purified through gradient ethanol precipitation and column chromatography. Size-Exclusion Chromatography-Multi-Angle Light Scattering-Refractive Index (SEC-MALLS-RI) and high-performance anion-exchange chromatography (HPAEC) analyses revealed that FM-D1 constitutes a highly purified neutral polysaccharide exclusively composed of glucose as the sugar unit, with a molecular weight of 14.823 kDa. The structural characterization results obtained from gas chromatography-mass spectrometer (GC-MS) and nuclear magnetic resonance spectroscopy (NMR) spectra suggest that FM-D1 primarily consists of a main chain linked by →4)-α-D-Glcp-(1→ and minor quantities of →4,6)-α-D-Glcp-(1→ to form the main chain, with branching mainly composed of α-D-Glcp-(1→ attached to the O-6 position of →4,6)-α-D-Glcp-(1→ sugar residues. Based on these findings, the antioxidant and immunomodulatory activities of FM-D1 were evaluated in vitro. The results indicated that FM-D1 exhibited moderate 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging capacity and total antioxidant capacity (TAOC). Furthermore, FM-D1 stimulated macrophage proliferation and inhibited the production of nitric oxide (NO) and inflammatory factors (TNF-α, IL-1β, and IL-6) in lipopolysaccharide (LPS)-stimulated RAW 246.7 cells. Overall, the findings of this study suggest that foxtail millet holds promise as a potential antioxidant agent and immunologic substance in functional foods.

Protocatechuic acid/sodium alginate multilayer coating induced by metal ion enhanced the ulcerative colitis alleviations of Lactiplantibacillus plantarum

Oral intake of probiotics is a promising approach to alleviate colitis. However, environmental sensitivity of the gastrointestinal tract and poor adhesion of probiotics to the intestine hamper the remedial effects. In this study, a simple yet effective novel probiotic multilayer coating consisting of Fe3+-protocatechuic acid (PCA) crosslinked network and Ca2+-induced sodium alginate (SA) for arming Lactiplantibacillus plantarum (LP) was developed. In the dextran sulfate sodium-induced colitis mouse model, SA-PCA-LP effectively alleviated colitis by regulating the expression of inflammatory cytokines, and repairing gut barriers. In addition, SA-PCA-LP regulated the gut microbiota and promoted the production of short-chain fatty acids, which further promoted the remission of colitis. Untargeted metabolomics also revealed that the scymnol, adenosine 5'-monophosphat, guanidylic acid, and 9H-purine-9-ol were significantly up-regulated in SA-PCA-LP group. In general, the novel coating strategies developed in the present study will motivate researchers to arm probiotics with various prebiotics to effectively alleviate colitis.

Effects of traditional Chinese medicine polysaccharides on chronic diseases by modulating gut microbiota: A review

Intestinal tract is the largest immune system of human body. Gut microbiota (GM) can produce a large number of metabolites, such as short-chain fatty acids and bile acids, which regulate the physiological health of the host and affect the development of disease. In recent years, traditional Chinese medicine (TCM) polysaccharides have attracted extensive attention with multiple biological activities and low toxicity. TCM polysaccharides can promote the growth of intestinal beneficial bacteria and inhibit the growth of harmful bacteria by regulating the structure and function of GM, thus playing a crucial role in preventing or treating chronic diseases such as inflammatory bowel disease (IBD), obesity, type 2 diabetes mellitus (T2DM), liver diseases, cancer, etc. In this paper, the research progress of TCM polysaccharides in the treatment of chronic diseases such as inflammatory bowel disease, obesity, T2DM, liver diseases, cancer, etc. by modulating GM was reviewed. Meanwhile, this review makes an in-depth discussion on the shortcomings of the research of TCM polysaccharides on chronic diseases by modulating GM, and new valuable prospection for the future researches of TCM polysaccharides are proposed, which will provide new ideas for the further study of TCM polysaccharides.

Hizikia fusiforme polysaccharides synergized with fecal microbiota transplantation to alleviate gut microbiota dysbiosis and intestinal inflammation

Ulcerative colitis (UC) is closely associated with disruptions in gut microbiota. Restoring balance to gut microbiota and reducing intestinal inflammation has become a promising therapeutic approach for UC. However, challenges remain, including limited efficacy in some treatments. This study explores the synergistic effects and underlying mechanisms of Hizikia fusiforme polysaccharides (HFP) combined with fecal microbiota transplantation (FMT) to improve UC symptoms. Seven-week-old C57/BL6J mice were induced with UC using dextran sodium sulfate (DSS). Supplementation with either FMT alone or in combination with HFP effectively alleviated UC symptoms, reduced colonic inflammation, and corrected gut microbiota imbalance. Notably, HFP combined with FMT yielded showed better effects in ameliorating DSS-induced UC in mice than did FMT alone. Enrichment of probiotics, such as Bifidobacterium, and upregulation of beneficial metabolites, such as betaine, were identified as potential mechanisms for the enhanced effects of HFP combined with FMT against DSS-induced UC. These findings suggest that the combination of Hizikia fusiforme polysaccharides with FMT has potential applications in rectifying dysbiosis and ameliorating inflammatory bowel diseases.

Calcium Transport Activity of UV/H2O2-Degraded Fucoidans and Their Structural Characterization

Calcium-chelated polysaccharides have been increasingly considered as promising calcium supplements. In this study, degraded fucoidans (DFs) with different molecular weights (Mws) were prepared after UV/H2O2 treatment; their calcium-chelating capacities and intestinal absorption properties were also investigated. The results showed that the calcium-chelating capacities of DFs were improved with a decrease in Mw. This was mainly ascribed to the increased carboxyl content, which was caused by free-radical-mediated degradation. Meanwhile, the conformation of DF changed from a rod-like chain to a shorter and softer chain. The thermodynamic analysis demonstrated that DF binding to calcium was spontaneously driven by electrostatic interactions. Additionally, DF-Ca chelates with lower Mw showed favorable transport properties across a Caco-2 cell monolayer and could effectively accelerate the calcium influx through intestinal enterocytes. Furthermore, these chelates also exhibited a protective effect on the epithelial barrier by alleviating damage to tight junction proteins. These findings provide an effective free-radical-related approach for the development of polysaccharide-based calcium supplements with improved intestinal calcium transport ability.

Prebiotics Mitigate the Detrimental Effects of High-Fat Diet on memory, anxiety and microglia functionality in Ageing Mice

Ageing is characterised by a progressive increase in systemic inflammation and especially neuroinflammation. Neuroinflammation is associated with altered brain states that affect behaviour, such as an increased level of anxiety with a concomitant decline in cognitive abilities. Although multiple factors play a role in the development of neuroinflammation, microglia have emerged as a crucial target. Microglia are the only macrophage population in the CNS parenchyma that plays a crucial role in maintaining homeostasis and in the immune response, which depends on the activation and subsequent deactivation of microglia. Therefore, microglial dysfunction has a major impact on neuroinflammation. The gut microbiota has been shown to significantly influence microglia from birth to adulthood in terms of development, proliferation, and function. Diet is a key modulating factor that influences the composition of the gut microbiota, along with prebiotics that support the growth of beneficial gut bacteria. Although the role of diet in neuroinflammation and behaviour has been well established, its relationship with microglia functionality is less explored. This article establishes a link between diet, animal behaviour and the functionality of microglia. The results of this research stem from experiments on mouse behaviour, i.e., memory, anxiety, and studies on microglia functionality, i.e., cytochemistry (phagocytosis, cellular senescence, and ROS assays), gene expression and protein quantification. In addition, shotgun sequencing was performed to identify specific bacterial families that may play a crucial role in the brain function. The results showed negative effects of long-term consumption of a high fat diet on ageing mice, epitomised by increased body weight, glucose intolerance, anxiety, cognitive impairment and microglia dysfunction compared to ageing mice on a control diet. These effects were a consequence of the changes in gut microbiota modulated by the diet. However, by adding the prebiotics fructo- and galacto-oligosaccharides, we were able to mitigate the deleterious effects of a long-term high-fat diet.

The Use of Polysaccharide AOP30 from the Rhizome of Alpinia officinarum Hance to Alleviate Lipopolysaccharide-Induced Intestinal Epithelial Barrier Dysfunction and Inflammation via the TLR4/NfκB Signaling Pathway in Caco-2 Cell Monolayers

Alpinia officinarum Hance is rich in carbohydrates and is flavored by natives. The polysaccharide fraction 30 is purified from the rhizome of A. officinarum Hance (AOP30) and shows excellent immunoregulatory ability when administered to regulate immunity. However, the effect of AOP30 on the intestinal epithelial barrier is not well understood. Therefore, the aim of this study is to investigate the protective effect of AOP30 on the intestinal epithelial barrier using a lipopolysaccharide (LPS)-induced intestinal epithelial barrier dysfunction model and further explore its underlying mechanisms. Cytotoxicity, transepithelial electrical resistance (TEER) values, and Fluorescein isothiocyanate (FITC)-dextran flux are measured. Simultaneously, the protein and mRNA levels of tight junction (TJ) proteins, including zonula occludens-1 (ZO-1), Occludin, and Claudin-1, are determined using Western blotting and reverse-transcription quantitative polymerase chain reaction methods, respectively. The results indicate that AOP30 restores the LPS-induced decrease in the TEER value and cell viability. Furthermore, it increases the mRNA and protein expression of ZO-1, Occludin, and Claudin-1. Notably, ZO-1 is the primary tight junction protein altered in response to LPS-induced intestinal epithelial dysfunction. Additionally, AOP30 downregulates the production of TNFα via the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Collectively, the findings of this study indicate that AOP30 can be developed as a functional food ingredient or natural therapeutic agent for addressing intestinal epithelial barrier dysfunction. It sheds light on the role of AOP30 in improving intestinal epithelial function.

Chemically modified seaweed polysaccharides: Improved functional and biological properties and prospective in food applications

Seaweed polysaccharides are natural biomacromolecules with unique physicochemical properties (e.g., good gelling, emulsifying, and film-forming properties) and diverse biological activities (e.g., anticoagulant, antioxidant, immunoregulatory, and antitumor effects). Furthermore, they are nontoxic, biocompatible and biodegradable, and abundant in resources. Therefore, they have been widely utilized in food, cosmetics, and pharmaceutical industries. However, their properties and bioactivities sometimes are not satisfactory for some purposes. Modification of polysaccharides can impart the amphiphilicity and new functions to the biopolymers and change the structure and conformation, thus effectively improving their functional properties and biological activities so as to meet the requirement for targeted applications. This review outlined the modification methods of representative red algae polysaccharides (carrageenan and agar), brown algae polysaccharides (fucoidan, alginate, and laminaran), and green algae polysaccharides (ulvan) that have potential food applications, including etherification, esterification, degradation, sulfation, phosphorylation, selenylation, and so on. The improved functional properties and bioactivities of the modified seaweed polysaccharides and their potential food applications are also summarized.

Exploring the therapeutic potential of porphyran extracted from Porphyra haitanensis in the attenuation of DSS-induced intestinal inflammation

Ulcerative colitis is a chronic, spontaneous inflammatory bowel disease that primarily affects the colon. This study aimed to explore how Porphyra haitanensis porphyran (PHP) modulates the immune response and the associated mechanisms that alleviate dextran sulphate sodium-induced colitis in mice. Histological assessments via H&E staining and AB-PAS staining revealed that PHP intervention partially restored the number of goblet cells and improved intestinal mucosal function. Immunohistochemical and Western blot analyses of claudin-1, occludin, and MUC-2 demonstrated that PHP could repair the intestinal barrier and reduce colon damage by upregulating the expression of these proteins. PHP intervention was associated with a decrease in pro-inflammatory cytokine expression and an increase in anti-inflammatory cytokine expression. Moreover, the expression of proteins involved in intestinal immune homing, such as CCR-9, CCL-25, MAdCAM-1, and α4β7, was significantly suppressed in response to PHP treatment. Conversely, PHP upregulates the expression of CD40 and TGF-β1, both of these can promote healing and reduce inflammation in the gut lining. This study demonstrates that PHP can ameliorate ulcerative colitis by enhancing the intestinal barrier and modulating immune responses. These findings offer valuable insights into the potential utility of P. haitanensis as a promising natural product for managing ulcerative colitis.

Intervention effects of low-molecular-weight chondroitin sulfate from the nasal cartilage of yellow cattle on lipopolysaccharide-induced behavioral disorders: regulation of the microbiome-gut-brain axis

Chondroitin sulfate (CS) is a sulfated linear polysaccharide with different functional activities, including antioxidant, anti-inflammatory, lipid-lowering, and immune regulation. As natural sulfated polysaccharides have high molecular weight, high apparent viscosity, low water solubility, complex structure, and high negative charge, they have difficulty binding to receptors within cells across tissue barriers, resulting in low bioavailability and unclear structure-activity relationships. In this study, an H2O2-Vc oxidative degradation system was employed to perform environmentally friendly and controllable degradation of CS extracted from the nasal cartilage of Shaanxi Yellow cattle. Two low-molecular-weight chondroitin sulfates (LMWCSs), CS-1 (14.8 kDa) and CS-2 (50.9 kDa), that exhibit strong in vitro free radical scavenging ability were obtained, and their structures were characterized. Mice intraperitoneally administered lipopolysaccharide (LPS) were used to explore the cognitive intervention effects of LMWCS. Supplementing CS-1 and CS-2 significantly downregulated the levels of the serum inflammatory factors, TNF-α and IL-1β, promoted the expression of GSH in the brain, and inhibited the production of the lipid peroxidation product, malondialdehyde (MDA), ultimately inhibiting LPS-induced cognitive impairment in mice. Surprisingly, compared to the LPS model group, the abundances of Streptococcus, Eisenbergiella, Vampirovibrio, Coprococcus, Enterococcus and Lachnoanaerobaculum were significantly increased in the intestines of mice in the CS-1 and CS-2 group, whereas those of Parabacteroides and Mycoplasma were significantly decreased. Altogether, this study provides a theoretical basis for the comprehensive utilization of agricultural and animal resources and the application of brain nutrition, anti-inflammatory, and LMWCS health products.

Effects of UV/H2O2 Degradation on the Physicochemical and Antibacterial Properties of Fucoidan

The applications of fucoidan in the food industry were limited due to its high molecular weight and low solubility. Moderate degradation was required to depolymerize fucoidan. A few studies have reported that fucoidan has potential antibacterial activity, but its antibacterial mechanism needs further investigation. In this study, the degraded fucoidans were obtained after ultraviolet/hydrogen peroxide treatment (UV/H2O2) at different times. Their physicochemical properties and antibacterial activities against Staphylococcus aureus and Escherichia coli were investigated. The results showed that the average molecular weights of degraded fucoidans were significantly decreased (up to 22.04 times). They were mainly composed of fucose, galactose, and some glucuronic acid. Fucoidan degraded for 90 min (DFuc-90) showed the strongest antibacterial activities against Staphylococcus aureus and Escherichia coli, with inhibition zones of 27.70 + 0.84 mm and 9.25 + 0.61 mm, respectively. The minimum inhibitory concentrations (MIC) were 8 mg/mL and 4 mg/mL, respectively. DFuc-90 could inhibit the bacteria by damaging the cell wall, accumulating intracellular reactive oxygen species, reducing adenosine triphosphate synthesis, and inhibiting bacterial metabolic activity. Therefore, UV/H2O2 treatment could effectively degrade fucoidan and enhance its antibacterial activity.

Mechanism of Mulberry Leaves and Black Sesame in Alleviating Slow Transit Constipation Revealed by Multi-Omics Analysis

Traditional Chinese medicine (TCM) possesses the potential of providing good curative effects with no side effects for the effective management of slow transit constipation (STC), an intestinal disease characterized by colonic dyskinesia. Mulberry leaves (Morus alba L.) and black sesame (Sesamum indicum L.), referred to as SH, are processed and conditioned as per standardized protocols. SH has applications as food and medicine. Accordingly, we investigated the therapeutic potential of SH in alleviating STC. The analysis of SH composition identified a total of 504 compounds. The intervention with SH significantly improved intestinal motility, reduced the time for the first black stool, increased antioxidant activity, and enhanced water content, thereby effectively alleviating colon damage caused by STC. Transcriptome analysis revealed the SH in the treatment of STC related to SOD1, MUC2, and AQP1. The analysis of 16S rRNA gene sequences indicated notable differences in the abundance of 10 bacteria between the SH and model. Metabolomic analysis further revealed that SH supplementation increased the levels of nine metabolites associated with STC. Integrative analysis revealed that SH modulated amino acid metabolism, balanced intestinal flora, and targeted key genes (i.e., SOD1, MUC2, AQP1) to exert its effects. SH also inhibited the AQP1 expression and promoted SOD1 and MUC2 expression.

Degradation Mechanisms of Six Typical Glucosidic Bonds of Disaccharides Induced by Free Radicals

Increasing hydrogen peroxide (H2O2)-based systems have been developed to degrade various polysaccharides due to the presence of highly reactive free radicals, but published degradation mechanisms are still limited. Therefore, this study aimed to clarify the degradation mechanism of six typical glucosidic bonds from different disaccharides in an ultraviolet (UV)/H2O2 system. The results showed that the H2O2 concentration, disaccharide concentration, and radiation intensity were important factors affecting pseudo-first-order kinetic constants. Hydroxyl radical, superoxide radical, and UV alone contributed 58.37, 18.52, and 19.17% to degradation, respectively. The apparent degradation rates ranked in the order of cellobiose ≈ lactose > trehalose ≈ isomaltose > turanose > sucrose ≈ maltose. The reaction pathways were then deduced after identifying their degradation products. According to quantum chemical calculations, the cleavage of α-glycosidic bonds was more kinetically unfavorable than that of β-glycosidic bonds. Additionally, the order of apparent degradation rates depended on the energy barriers for the formation of disaccharide-based alkoxyl radicals. Moreover, energy barriers for homolytic scissions of glucosidic C1-O or C7-O sites of these alkoxyl radicals ranked in the sequence: α-(1 → 2) ≈ α-(1 → 3) < α-(1 → 4) < β-(1 → 4) < α-(1 → 6) < α-(1 → 1) glucosidic bonds. This study helps to explain the mechanisms of carbohydrate degradation by free radicals.

Fabrication of zein-tamarind seed polysaccharide-curcumin nanocomplexes: their characterization and impact on alleviating colitis and gut microbiota dysbiosis in mice

In this work, a zein-tamarind seed polysaccharide (TSP) co-delivery system was fabricated using an anti-solvent precipitation method. The formation mechanism, characterization, and effect on alleviating colitis and gut microbiota dysbiosis in mice of zein-TSP-curcumin (Z/T-Cur) nanocomplexes were investigated. Hydrogen bonding and the hydrophobic effect played a key role in the formation of Z/T-Cur nanocomplexes, and the interactions were spontaneous and driven by enthalpy. The encapsulation efficiency, loading capacity, and bioavailability increased from 60.8% (Zein-Cur) to 91.7% (Z/T-Cur1:1), from 6.1% (Zein-Cur) to 18.3% (Z/T-Cur1:1), and from 4.7% (Zein-Cur) to 20.0% (Z/T-Cur1:1), respectively. The Z/T-Cur significantly alleviated colitis symptoms in DSS-treated mice. Additionally, the prepared nanocomplexes rebalanced the gut microbiota composition of colitis mice by increasing the abundance of Akkermansia. Odoribacter and Monoglobus were rich in the Z-T-Cur treatment group, and Turicibacter and Bifidobacterium were rich in the zein-TSP treatment group. This study demonstrated that the TSP could be helpful in the targeted drug delivery system.

Protective Effects of Four Structurally Distinct Sanshools Ameliorate Dextran Sodium Sulfate-Induced Ulcerative Colitis by Restoring Intestinal Barrier Function and Modulating the Gut Microbiota

Hydroxy-α-sanshool (HAS), hydroxy-β-sanshool (HBS), hydroxy-γ-sanshool (HRS), and γ-sanshool (RS) are the key components from the Zanthoxylum genus, processing a range of pharmacological activities. The present study investigated the protective capacities of four sanshools on a dextran sulfate sodium (DSS)-induced model of ulcerative colitis (UC). The results showed that sanshool administration alleviated the colitis symptoms by reducing body weight loss and disease activity index (DAI) score, increasing the colon length, and improving colonic injury and the change in immune organ weight. Furthermore, sanshools enhanced the antioxidant enzyme activities, and RS exhibited the lowest effect on the improvement in total antioxidative capacity (T-AOC) and antioxidant abilities compared to the other three sanshools. The p65 nuclear factor κB (p65 NFκB) signaling pathway was inhibited to prevent hyperactivation and decreased the production of inflammatory factors. The gut barrier function in DSS-induced mice was restored by increasing goblet cell number and levels of tight junction proteins (zonula occludens-1, occludin, and claudin-1), and the levels of protein in HAS and HRS groups were higher than that in the HBS group, significantly. The analysis of gut microbiota suggested that sanshool administration significantly boosted the abundance of Lachnospiraceae, Muribaculaceae, Oscillospiraceae, and Alistipes and reduced the level of Buchnera in colitis mice. Collectively, the sanshool treatment could ameliorate colitis by resisting colon injury and regulating intestinal barrier dysfunction and gut microbiota dysbiosis; meanwhile, HRS and HAS have better improvement effects.

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.

UV/H2O2-Degraded Polysaccharides from Sargassum fusiforme: Purification, Structural Properties, and Anti-Inflammatory Activity

The main purpose of this study was to analyze the structural properties and anti-inflammatory activity of the purified fractions derived from UV/H2O2-degraded polysaccharides from Sargassum fusiforme. Results indicated that twofractions with different monosaccharide compositions and morphological characteristics, PT-0.25 (yield 39.5%) and PT-0.5 (yield 23.9%), were obtained. The average molecular weights of PT-0.25 and PT-0.5 were 14.52 kDa and 22.89 kDa, respectively. In addition, PT-0.5 exhibited better anti-inflammatory activity with a clear dose dependence. The mechanism was associated with the inhibition of LPS-activated Toll-like receptor 4-mediated inflammatory pathways in RAW264.7 cells. The results showed that PT-0.5 was a complex polysaccharide mainly composed of 4-Fucp, t-Manp, 6-Galp, t-Fucp, and 3,4-GlcAp. These results would provide theoretical support for studying the structural properties and biological activities of UV/H2O2-degraded polysaccharides.

Insights into the mechanisms underlying the degradation of xylooligosaccharides in UV/H2O2 system

UV/H₂O₂ process is increasingly used to degrade carbohydrates, though the underlying mechanisms remain unclear. This study aimed to fill this knowledge gap, focusing on mechanisms and energy consumption involved in hydroxyl radical (•OH)-mediated degradation of xylooligosaccharides (XOSs) in UV/H₂O₂ system. Results showed that UV photolysis of H₂O₂ generated large amounts of •OH radicals, and degradation kinetics of XOSs fitted with a pseudo-first-order model. Xylobiose (X₂) and xylotriose (X₃), main oligomers in XOSs, were attacked easier by •OH radicals. Their hydroxyl groups were largely converted to carbonyl groups and then carboxy groups. The cleavage rate of glucosidic bonds was slightly higher than that of pyranose ring, and exo-site glucosidic bonds were more easily cleaved than endo-site bonds. The terminal hydroxyl groups of xylitol were more efficiently oxidized than other hydroxyl groups of it, causing an initial accumulation of xylose. Oxidation products from xylitol and xylose included ketoses, aldoses, hydroxy acids and aldonic acids, indicating the complexity of •OH radical-induced XOSs degradation. Quantum chemistry calculations revealed 18 energetically viable reaction mechanisms, with the conversion of hydroxy-alkoxyl radicals to hydroxy acids being the most energetically favorable (energy barriers <0.90 kcal/mol). This study will provide more understanding of •OH radicals-mediated degradation of carbohydrates.

Integration of taxa abundance and occurrence frequency to identify key gut bacteria correlated to clinics in Crohn's disease

Bacteria abundance alternation in the feces or mucosa of Crohn's disease (CD) patients has long been applied to identify potential biomarkers for this disease, while the taxa occurrence frequency and their correlations with clinical traits were understudied. A total of 97 samples from the feces and gut mucosa were collected from CD patients and healthy controls (HCs), 16S rRNA-based analyses were performed to determine the changes in taxa abundance and occurrence frequency along CD and to correlate them with clinical traits. The results showed that bacteria communities were divergent between feces and mucosa, while the taxa abundance and occurrence frequency in both partitions showed similar exponential correlations. The decrease of specific fecal bacteria was much more effective in classifying the CD and HCs than that of the mucosal bacteria. Among them, Christensenellaceae_R-7_group and Ruminococcus were predicted as biomarkers by using random forest algorithm, which were persistently presented (> 71.40% in frequency) in the feces of the HCs with high abundance, whereas transiently presented in the feces (< 5.5% in frequency) and mucosa (< 18.18% in frequency) of CD patients with low abundance. Co-occurrence network analysis then identified them as hub taxa that drive the alternations of other bacteria and were positively correlated to the circuiting monocytes. The loss of specific bacteria in the healthy gut may cause great disturbance of gut microbiota, causing gut bacteria dysbiosis and correlated to immune disorders along CD, which might not only be developed as effective noninvasive biomarkers but also as therapy targets.

Enhanced In Vitro Anti-Photoaging Effect of Degraded Seaweed Polysaccharides by UV/H2O2 Treatment

The high molecular weight and poor solubility of seaweed polysaccharides have limited their function and application. In this study, ultraviolet/hydrogen peroxide (UV/H2O2) treatment was used to prepare low-molecular-weight seaweed polysaccharides from Sargassum fusiforme. The effects of UV/H2O2 treatment on the physicochemical properties and anti-photoaging activity of S. fusiforme polysaccharides were studied. UV/H2O2 treatment effectively degraded polysaccharides from S. fusiforme (DSFPs), reducing their molecular weight from 271 kDa to 26 kDa after 2 h treatment. The treatment did not affect the functional groups in DSFPs but changed their molar percentage of monosaccharide composition and morphology. The effects of the treatment on the anti-photoaging function of S. fusiforme polysaccharides were investigated using human epidermal HaCaT cells in vitro. DFSPs significantly improved the cell viability and hydroxyproline secretion of UVB-irradiated HaCaT cells. In particular, DSFP-45 obtained from UV/H2O2 treatment for 45 min showed the best anti-photoaging effect. Moreover, DSFP-45 significantly increased the content and expression of collagen I and decreased those of pro-inflammatory cytokines, including interleukin-1β, interleukin-6, and tumor necrosis factor-α. Thus, UV/H2O2 treatment could effectively improve the anti-photoaging activity of S. fusiforme polysaccharides. These results provide some insights for developing novel and efficient anti-photoaging drugs or functional foods from seaweed polysaccharides.

Regulation strategy, bioactivity, and physical property of plant and microbial polysaccharides based on molecular weight

Structural features affect the bioactivity, physical property, and application of plant and microbial polysaccharides. However, an indistinct structure-function relationship limits the production, preparation, and utilization of plant and microbial polysaccharides. Molecular weight is an easily regulated structural feature that affects the bioactivity and physical property of plant and microbial polysaccharides, and plant and microbial polysaccharides with a specific molecular weight are important for exerting their bioactivity and physical property. Therefore, this review summarized the regulation strategies of molecular weight via metabolic regulation; physical, chemical, and enzymic degradations; and the influence of molecular weight on the bioactivity and physical property of plant and microbial polysaccharides. Moreover, further problems and suggestions must be paid attention to during regulation, and the molecular weight of plant and microbial polysaccharides must be analyzed. The present work will promote the production, preparation, utilization, and investigation of the structure-function relationship of plant and microbial polysaccharides based on their molecular weight.

The Mechanism of Peach Gum Polysaccharide Preventing UVB-Induced Skin Photoaging by Regulating Matrix Metalloproteinanse and Oxidative Factors

Exposure to ultraviolet light can cause oxidative damage and accelerate skin aging and is one of the main causes of skin aging. Peach gum polysaccharide (PG) is a natural edible plant component that has many biological activities, such as regulating blood glucose and blood lipids and improving colitis, as well as antioxidant and anticancer properties. However, there are few reports on the antiphotoaging effect of peach gum polysaccharide. Therefore, in this paper, we study the basic composition of the raw material peach gum polysaccharide and its ability to improve UVB-induced skin photoaging damage in vivo and in vitro. The results show that peach gum polysaccharide is mainly composed of mannose, glucuronic acid, galactose, xylose, and arabinose, and its molecular weight (Mw) is 4.10 × 10⁶ g/mol. The results of the in vitro cell experiments show that PG could significantly alleviate UVB-induced apoptosis of human skin keratinocytes, promote cell growth repair, reduce the expression of intracellular oxidative factors and matrix metal collagenase, and improve the extent of oxidative stress repair. Moreover, the results from the in vivo animal experiments showed that PG could not only effectively improve the phenotype of UVB-induced photoaged skin in model mice but also significantly improve their oxidative stress status, regulate the contents of ROS and the levels of SOD and CAT, and repair the oxidative skin damage induced by UVB in vivo. In addition, PG improved UVB-induced photoaging-mediated collagen degradation in mice by inhibiting the secretion of matrix metalloproteinases. The above results indicate that peach gum polysaccharide has the ability to repair UVB-induced photoaging and may be used as a potential drug and antioxidant functional food to resist photoaging in the future.

Porphyran from Porphyra haitanensis Enhances Intestinal Barrier Function and Regulates Gut Microbiota Composition

In this study, the effects of a homogenous porphyran from Porphyra haitanensis (PHP) on the intestinal barrier and gut microbiota were investigated. The results showed that oral administration of PHP resulted in a higher luminal moisture content and a lower pH environment for the growth of beneficial bacteria in the colon of mice. PHP significantly increased the production of total short-chain fatty acids during the fermentation process. PHP made the intestinal epithelial cells of mice arrange more tidily and tightly with a significant increase in mucosal thickness. PHP also increased the amount of mucin-producing goblet cells and the expression of mucin in the colon, which maintained the structure and function of the intestinal mucosal barrier. Moreover, PHP up-regulated the expression of tight junctions including ZO-1 and occludin, improving the intestinal physical barrier function. The results of 16S rRNA sequencing showed that PHP regulated the composition of gut microbiota in mice, increasing the richness and diversity of gut microbiota and the ratio of Firmicutes to Bacteroidetes. This study revealed that the intake of PHP is beneficial for the gastrointestinal tract and PHP could be a potential source of prebiotics in the functional food and pharmaceutical industries.

LRRK2 deficiency mitigates colitis progression by favoring resolution of inflammation and restoring homeostasis of gut microbiota

Leucine rich-repeat kinase 2 (LRRK2) has been considered a susceptibility gene for ulcerative colitis (UC), and its protein abundance was enhanced in the peripheral blood mononuclear cells (PBMCs) from UC cohorts as compared to healthy volunteers. In preclinical models of colitis, Lrrk2 deficiency ameliorated dextran sodium sulfate (DSS)-induced colitis progression, whereas the processes were aggravated by R1441C mutation. While intestinal macrophages (MФs) from Lrrk2 knock-out (Lrrk2^-/-) mice exhibited a tendency to transit to alternatively activated MФs, R1441C MФs mutation facilitated the pro-inflammatory phenotype polarization, determined by RNA sequencing and qPCR. Moreover, we characterized their microbiota profiles and found that loss of Lrrk2 increased the bacterial richness and altered bacterial community structure, and this shift contributed to the alleviation of colitis development and progression. We proposed that Lrrk2 deficiency promotes M2 MФ transition and facilitates probiotics colonization, providing a protective role during colitis.

Structural characterization and anti-photoaging activity of a polysaccharide from Sargassum fusiforme

In this study, a purified algal polysaccharide (P1) was isolated from Sargassum fusiforme and its structural characteristics and anti-photoaging activity were studied. Results showed that P1 had a molecular weight of 289 kDa and was mainly composed of mannuronic acid, guluronic acid and fucose with molar ratio of 7.67:2.35:1.00. The backbone of P1 was →4)-β-ManA-(1→4)-α-GulA-(1→4)-β-ManA-(1→4)-β-ManA-(1→4)-α-GulA-(1→4)-β-ManA-(1→3,4)-β-ManA-(1→ with a terminal group of α-Fucp-(1→ linked to O-3 position of →3,4)-β-ManA-(1→. In addition, P1 could inhibit the expressions of MMPs (MMP-1, MMP-3 and MMP-9) in the UVB-irradiated HaCaT cells, indicating that P1 could reduce collagen loss caused by UVB irradiation. It also reduced the contents of ROS and inflammatory factors (TNF-α, IL-6 and IL-1β), indicating that P1 could reduce the oxidative stress and inflammation response. Thus, Sargassum fusiforme polysaccharide P1 could be used as a potential functional food to relieve skin photoaging.

Structural characterization and hypolipidemic activity of Gracilaria lemaneiformis polysaccharide and its degradation products

This research aimed to analyze structural characterization and hypolipidemic activity in vitro of G. lemaneiformis polysaccharide (GLP) and its degradation products. The results presented that the content of galacturonic acid declined and glucuronic acid level enhanced, average particle size decreased from 99.9 μm to 25.7 μm, and color brightness of polysaccharide strengthened after degraded by H₂O₂-Vc. There was no significant change in thermal stability of polysaccharide before and after degradation. It was observed in AFM analysis, polysaccharide changed to smaller, delicacy and dispersion after degradation. As seen in FT-IR, H₂O₂-Vc degradation never change the structure of polysaccharide. Polysaccharide and its degradation products showed a significant inhibition effect on pancreatic lipase and cholesterol esterase in a dose-dependent manner, which presented the mixed type of competitive and non-competitive for pancreatic lipase, and non-competitive for cholesterol esterase, respectively. The fluorescence quenching type was static on pancreatic lipase and dynamic on cholesterol esterase.

Oryzanol Attenuates High Fat and Cholesterol Diet-Induced Hyperlipidemia by Regulating the Gut Microbiome and Amino Acid Metabolism

Hyperlipidemia is intricately associated with the dysregulation of gut microbiota and host metabolomes. This study explored the antihyperlipidemic function of oryzanol and investigated whether the function of oryzanol affected the gut microbiome and its related metabolites. Hamsters were fed a standard diet (Control) and a high fat and cholesterol (HFCD) diet with or without oryzanol, separately. Our results showed that oryzanol significantly decreased HFCD-induced fat accumulation, serum total cholesterol, low-density lipoprotein cholesterol (LDL-c), LDL-c/HDL-c ratio, triglyceride, and liver steatohepatitis, attenuated HFCD-induced gut microbiota alterations, and altered amino acid concentrations in feces and the liver. We investigated the role of the gut microbiota in the observed beneficial effects; the protective effects of oryzanol were partly diminished by suppressing the gut bacteria of hamsters after using antibiotics. A fecal microbiota transplantation experiment was carried out by transplanting the feces from HFCD group hamsters or hamsters given oryzanol supplementation (as a donor hamster). Our results showed that administering the fecal liquid from oryzanol-treated hamsters attenuated HFCD-induced hyperlipidemia, significantly decreased the abundance of norank_f__Erysipelotrichaceae, norank_f__Eubacteriaceae, and norank_f__Oscillospiraceae and the concentration of tyrosine. These outcomes are significantly positively correlated with serum lipid concentration. This study illustrated that gut microbiota is the target of oryzanol in the antihyperlipidemic effect.

Optimized Degradation and Inhibition of α-glucosidase Activity by Gracilaria lemaneiformis Polysaccharide and Its Production In Vitro

Gracilaria lemaneiformis polysaccharide (GLP) exhibits good physiological activities, and it is more beneficial as it is degraded. After its degradation by hydrogen peroxide combined with vitamin C (H₂O₂-Vc) and optimized by Box–Behnken Design (BBD), a new product of GLP-HV will be generated. While using GLP as control, two products of GLP-H (H₂O₂-treated) and GLP-V (Vc-treated) were also produced. These products chemical characteristics (total sugar content, molecular weight, monosaccharide composition, UV spectrum, morphological structure, and hypolipidemic activity in vitro) were assessed. The results showed that the optimal conditions for H₂O₂-Vc degradation were as follows: H₂O₂-Vc concentration was 18.7 mM, reaction time was 0.5 h, and reaction temperature was 56 °C. The total sugar content of GLP and its degradation products (GLP-HV, GLP-H and GLP-V) were more than 97%, and their monosaccharides are mainly glucose and galactose. The SEM analysis demonstrated that H₂O₂-Vc made the structure loose and broken. Moreover, GLP, GLP-HV, GLP-H, and GLP-V had significantly inhibition effect on α-glucosidase, and their IC₅₀ value were 3.957, 0.265, 1.651, and 1.923 mg/mL, respectively. GLP-HV had the best inhibition effect on α-glucosidase in a dose-dependent manner, which was the mixed type of competitive and non-competitive. It had a certain quenching effect on fluorescence of α-glucosidase, which may be dynamic quenching.