α-D-1,6-glucan from Castanea mollissima Blume alleviates dextran sulfate sodium-induced colitis in vivo

Chestnut Nonstarch Polysaccharides Enhance Intestinal Barrier Integrity and Modulate Gut Microbiota to Ameliorate DSS-Induced Colitis in Mice

This study investigated the biological activity of chestnut nonstarch polysaccharide (CNP) after removing starch. CNP was isolated from chestnut, with its monosaccharide composition identified as rhamnose, mannose, fructose, glucuronic acid, ribose, and galacturonic acid. Animal experiments showed that CNP can significantly alleviate the inflammatory response induced by dextran sodium sulfate (DSS) in a murine model of ulcerative colitis (UC). CNP alleviates colitis in mice by boosting antioxidant enzymes, reducing pro-inflammatory cytokines, increasing anti-inflammatory cytokines, strengthening the intestinal barrier via tight junction proteins, and suppressing inflammation through the PI3K/NF-κB pathway. Results from 16S rDNA sequencing demonstrated that CNP intake significantly improved the richness and composition of the gut microbial community. These findings suggest that CNP exerts a protective effect against DSS-induced colitis by enhancing intestinal barrier integrity, mitigating oxidative stress, regulating cytokine levels, and restoring gut microbial balance. The results of this study highlight the important application value of CNP in the development of functional foods.

Protective effects of Sulforaphene on kidney damage and gut dysbiosis in high-fat diet plus streptozotocin-induced diabetic mice

Diabetic nephropathy (DN) is one of the most serious and prevalent complications associated with diabetes. Consequently, antidiabetic drugs or foods potentially protecting the kidneys are of significant therapeutic value. Sulforaphene (SFE) is a natural isothiocyanate derived from radish seeds, known for its anti-inflammatory and antioxidant properties. However, no studies have investigated on the ability of SFE to prevent or treat DN. This study established a high-fat diet combined with a streptozotocin-induced type II diabetes mellitus mouse model. We administered SFE treatment to examine its protective effects on renal and intestinal homeostasis in DN mice. After 4 weeks of treatment, SFE (50 mg/kg b.w.) not only reduced blood glucose concentration (20.3 %, P < 0.001), kidney to body weight ratio (26.2 %, P < 0.01), and levels of serum total cholesterol (40.6 %, P < 0.001), triglycerides (38.2 %, P < 0.01), creatinine (36.7 %, P < 0.01), and urea nitrogen (45.0 %, P < 0.001) in DN mice compared to control mice but also increased the kidney superoxide dismutase (72.7 %, P < 0.001), catalase (51.1 %, P < 0.001), and glutathione peroxidase activities (31.6 %, P < 0.01), as well as glutathione levels (39.2 %, P < 0.01) in comparison to DN mice. Furthermore, SFE decreased levels of reactive oxygen species (55.4 %, P < 0.01), 4-hydroxyalkenals (36.9 %, P < 0.001), malondialdehyde (42.6 %, P < 0.001), and 8-hydroxy-deoxyguanosine (26.3 %, P < 0.001), accompanied by a meliorating kidney morphological abnormalities. Notably, a reduction in renal inflammatory factors was also observed in SFE-treated DN mice compared to untreated DN mice, particularly in the C-X-C motif chemokine ligand 8 factors (54.8 %, P < 0.001). Western blotting results indicated that SFE significantly down-regulated the protein expression of TLR4 and MyD88 (1.9, 1.7-fold, P < 0.001). Additionally, SFE improved gut microbiota (GM) dysbiosis and intestinal homeostasis, as evidenced by increased expression of antimicrobial peptides and tight junction proteins in colon tissue. SFE appeared to enhance the proliferation of probiotics, such as Bacteroidota, Lachnospiraceae_NK4A136_group and norank_f__Muribaculaceae, while also decreasing harmful bacteria to a greater extent compared to STZ treatment. These findings suggest that SFE modulates GM and improves intestinal homeostasis, providing a theoretical basis for its use in the treatment of DN.

Efficacy Evaluation of Selenium-enriched Akkermansia muciniphila in the Treatment of Colon Tumor Mice

Selenium (Se)-enriched probiotics possess a variety of beneficial properties and are widely used in specialty foods and biomedical applications. Akkermansia muciniphila (AM) is being considered a promising candidate for the "next generation probiotics (NGPs)," which play an essential role in the field of tumor therapy. However, there are no studies on the efficacy of Se-enriched A. muciniphila (Se-AM) in the field of tumor therapy. The present study utilized inorganic Se bio-enrichment for the preparation of Se-AM. To evaluate the killing effect of Se-AM on CT26 cells, the actual efficacy and safety of Se-AM were investigated in a mouse model of colon cancer. The results showed that the Se-AM-cell lysate was able to significantly kill CT26 cells, but this killing effect was progressively weakened with decreasing concentrations of Se-AM-cell lysate. The results of animal experiments showed that Se-AM was able to safely and effectively curb the disease course of mice with colon tumors, reduce the tumor volume, lower the levels of IL-1β and IL-6, and increase the levels of TNF-α in the colon of mice. Furthermore, treatment with Se-AM in mice led to a restoration of gut microbiota diversity, reaching levels similar to those observed in healthy controls. This restoration was accompanied by a significant enrichment of beneficial genera, such as Turicibacter, Butyricimonas, Prevotella, and Akkermansia. In summary, Se-AM prepared in this study was able to produce effective killing of CT26 cells directly and played a substantial therapeutic role in a mouse model of colon tumors constructed from CT26 cells. Se-AM had no adverse effect on the heart, liver, spleen, lungs, and kidney of mice and demonstrated a high level of safety. Meanwhile, Se-AM significantly raised the level of the Shannon index and the ratio of Firmicutes to Bacteroidetes of the gut microbiota in mice, indicating its ability to regulate the homeostasis of the microbiota. These results imply that Se-AM has great application value in the field of colon cancer treatment.

Polysaccharides from Lycium barbarum, yam, and sunflower ameliorate colitis in a structure and intrinsic flora-dependent manner

Polysaccharides have been suggested to ameliorate metabolic diseases. However, their differential colitis-mitigating effects in mouse models with different colony structures remain poorly understood. Therefore, this study investigated the effects of polysaccharides from Lycium barbarum (LBP), sunflower (SP), and yam (YP) on colitis in C57BL/6 J (B6) mice born via vaginal delivery (VD) and in both caesarean section (CS)- and VD-born Institute of Cancer Research (ICR) mice. LBP was mainly composed of glucose (30.2 %), galactose (27.5 %), and arabinose (26.9 %). The main components of SP and YP were galacturonic acid (75.8 %) and glucose (98.1 %), respectively. Interestingly, LBP effectively alleviated body weight loss, reduced inflammatory cytokine levels, and restored intestinal barrier function in all three mouse models. Moreover, LBP decreased the abundance of norank_f__norank_o__Clostridia_UCG-014, Coriobacteriaceae_UCG-002, and norank_f_Eubacterium_coprostanoligenes_group in B6 mice, and the abundance of these genera positively correlated with pro-inflammatory cytokine levels. LBP increased the abundance of Lactobacillus, which was positively correlated with the levels of the protective factor, IL-10, in CS-born ICR mice. Collectively, our study suggests the potential application of LBP in the treatment of ulcerative colitis. We also provide an alternative method for restoring intestinal homeostasis in CS-born offspring.

Codonopsis pilosula polysaccharide alleviates ulcerative colitis by modulating gut microbiota and SCFA/GPR/NLRP3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Codonopsis pilosula (Franch.) Nannf. (CP) is a Chinese herb commonly used in traditional Chinese medicine to treat ulcerative colitis (UC). C. pilosula polysaccharide (CPPS) is an important bioactive compound in CP. Polysaccharides are degraded by and interact with the gut microbiota, exerting therapeutic effects. However, the mechanism of action of CPPS in treating UC by regulating gut microbiota is unclear.

AIM OF THE STUDY

This study aimed to elucidate the therapeutic efficacy of CPPS on UC mice and its mechanism of action.

MATERIALS AND METHODS

Size-exclusion chromatography with multi-angle laser-light scattering and refractive index analysis was employed to ascertain the molecular weight of CPPS, while its monosaccharide composition was determined using ion chromatography. An experimental colitis mouse model was induced by administering 3% (dextran sulfate sodium) DSS in drinking water for five consecutive days. Three doses of CPPS were administered to evaluate their therapeutic effects on UC. CPPS was administered for seven days, and salicylazosulfapyridine was used as a positive control. Inflammatory cytokine secretion in the colon tissue was measured, and histopathological evaluation was performed on colon sections. Alterations in the abundance of the intestinal microbiota species were also analyzed. We then quantified short-chain fatty acids (SCFAs) in the cecal content and verified the G protein-coupled receptor (GPR)/nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) pathways using Western blot. Furthermore, the ameliorative effect of gut microbiota on DSS-induced UC symptoms was verified using the fecal microbiota transplantation (FMT) experiment.

RESULTS

CPPS comprised of rhamnose, arabinose, galactose, glucose, and galacturonic acid. CPPS significantly alleviated DSS-induced UC. Compared to the DSS group, CPPS treatment significantly increased the ratio of the Firmicutes to the Bacteroidetes and upregulated the abundance of beneficial bacteria such as g__Ligilactobacillus, g_Akkermansia, g_Faecalibaculum, g_Odoribacter. The release of acetic acid and butyric acid were further promoted. CPPS can inhibit NLRP3 activation by binding SCFAs to GPR proteins, thereby reducing intestinal inflammation. FMT confirmed that the gut microbiota in the CPPS-trans group sufficiently mitigated DSS-induced UC symptoms.

CONCLUSIONS

CPPS ameliorates the symptoms of DSS-induced UC primarily through the gut microbiota modulation and SCFA/GPR/NLRP3 pathways, making it a promising candidate for UC treatment.

Ameliorative effects of insoluble dietary fiber and its bound polyphenols from adzuki bean seed coat on acute murine colitis induced by DSS: The inflammatory response, intestinal barrier and gut microbiota

The incidence of ulcerative colitis (UC) is closely associated with dietary fiber (DF) intake. This study aims to evaluate the ameliorative effects of insoluble dietary fiber from adzuki bean seed coat (AIDF) on dextran sulfate sodium (DSS)-induced UC in mice, both with and without bound polyphenols (BPs). We employed a model based on the "remove/backfill" of components. Compared to dephenolized dietary fiber (AIDF-DF) and AIDF-DF with replaced BPs (AIDF-BP), AIDF was found to effectively reduce the splenic index, alleviate colonic histopathological damage, lower serum levels of inflammatory mediators (TNF-α, IL-1β, IFN-γ, IL-6), decrease activities of LPS, DAO, MPO, and iNOS, regulate intestinal tight junction (TJ) mRNA and protein expression, and restore the integrity of the colonic epithelial cell barrier. AIDF mitigated the inflammatory response in UC by inhibiting the TLR4/NF-κB inflammatory signaling pathway. It increased the abundance of beneficial gut microbiota (e.g., Akkermansia, Verrucomicrobiota) while reducing the abundance of harmful bacteria (e.g., Proteobacteria), thereby alleviating intestinal disturbances in DSS-induced colitis in mice. In conclusion, the presence of BPs in AIDF plays a critical role in attenuating DSS-induced UC in mice.

Effect of the arabinogalactan from Ixeris chinensis (Thunb.) Nakai. attenuates DSS-induced colitis and accompanying depression-like behavior

An arabinogalactan (ICPA) was extracted from the medicinal and edible plant Ixeris chinensis (Thunb.) Nakai., and ICPA exhibited excellent immunomodulatory activity. In this research, the impact of ICPA on DSS-induced ulcerative colitis was investigated. The results indicated that ICPA ameliorated the symptoms of colitis mice including loss of body weight, decrease of disease activity index, shortness of colon length and reduction of spleen index that caused by DSS. After treatment with ICPA, inflammatory cell infiltration and crypt loss were alleviated, and the number of goblet epithelial cells was enriched. ICPA inhibited the overproduction of TNF-α, IL-1β, and NLRP3, and promoted the secretion of IL-10 in colon tissues. Meanwhile, the intestinal barrier integrity was restored through increasing the expression of ZO-1 and occludin. ICPA could also regulate the structure of gut microbiota through elevating the abundance of Turicibacter and Bifidobacterium, and decreasing the ratio of Bacteroidetes/Firmicutes. In addition, ICPA improved the depression-like behavior of UC mice, and reduced the expression of proteins NLRP3, GFAP, and Iba-1 in brain tissues. These results suggested ICPA had an alleviative effect on UC and accompanied depression-like behavior, and could be developed as a dietary supplement for the prevention and treatment of UC.

Degradation of (1→3)(1→6)-α-D-dextran by ultrasound: Molecular weight, viscosity and kinetics

The (1→3)(1→6)-α-D-dextran (alternating dextran) produced by Leuconostoc citreum SK24.002 is a novel functional exopolysaccharide, and its low molecular weight derivatives have potential applications in the food, pharmaceutical, and chemical industries. In this work, we used sonication, a green polysaccharide disruption method, to study the degradation process of this dextran by changing the intensity and duration of the sonication treatment and the concentration of the dextran solution. The molecular weight and viscosity of the dextran products were measured with a high-performance size exclusion column chromatography-multi-angle laser light scattering-refractive index system and by rheometry, respectively. The degradation efficiency of dextran was directly affected by the duration and intensity of the ultrasonic treatment and the concentration of the dextran solution. The polydispersity index fluctuated as the duration of the sonication treatment increased. The combination of a high intensity (672 W/cm2) and long (120 min) sonication treatment and a low solution concentration (3 g dextran/100 mL) was most effective for reducing the apparent and complex viscosities of dextran. The storage modulus of dextran was always slightly larger than its loss modulus, indicating that it formed a gel-like structure. The second-order kinetic model (1/Mwt - 1/Mw0 = kt) was the best fit to explain the degradation dynamics of dextran by sonication at intensities of 168 W/cm2-834 W/cm2 and with dextran solution concentrations of 1 g/100 mL - 7 g/100 mL. Our findings show that sonication is an effective way to reduce the molecular weight of alternating dextran.

Structural elucidation of a capsular polysaccharide from Bacteroides uniformis and its ameliorative impact on DSS-induced colitis in mice

Capsular polysaccharides derived from Bacteroides species have emerged as potential mitigators of intestinal inflammation in murine models. However, research on capsular polysaccharides from B. uniformis, a Bacteroides species with reduced abundance in colons of patients with ulcerative colitis, remains scarce. In this study, we extracted a neutral polysaccharide component from B. uniformis ATCC8492, termed BUCPS1B, using ultrasonic disruption, ethanol precipitation, and anion exchange chromatography. Structural characterization revealed BUCPS1B as a water-soluble polysaccharide with an α-1,4-glucan main chain adorned with minor substituent sugar residues. BUCPS1B alleviated intestinal inflammation in a mouse model of colitis and induced polarization of macrophages into M2-type. Furthermore, BUCPS1B modulated the gut microbiota composition, increased the abundance of the probiotic Akkermansia muciniphila and altered the gut metabolic profile to promote phenylalanine and short chain fatty acids metabolism. BUCPS1B is therefore a promising candidate to prevent inflammation and augment intestinal health.

The ethanolic extract of domesticated Amauroderma rugosum alleviated DSS-induced ulcerative colitis via repairing the intestinal barrier

Amauroderma rugosum (Blume and T. Nees) Torrend (Ganodermataceae) (A. rugosum) has been found to have anti-inflammatory ability in previous studies. The present study aimed to verify the therapeutic benefits of A. rugosum in the treatment of ulcerative colitis and to investigate its underlying mechanism of action. Acute experimental ulcerative colitis was induced by feeding the mice drinking water supplemented with dextran sodium sulfate (DSS). The findings indicated that the ethanolic extract of domesticated A. rugosum exhibited therapeutic efficacy comparable to Salazosulfapyridine (SASP) in mitigating clinical symptoms and the pathological score of the colon. Furthermore, A. rugosum exhibited the capacity to enhance the expression of tight junction (TJ) proteins, while concurrently decreasing the levels of TNF-ɑ and IL-6. A noteworthy finding is that it exhibited the capability to diminish the nuclear translocation of NF-κB p65. In conclusion, A. rugosum attenuates DSS-induced ulcerative colitis by enhancing intestinal barrier function and inhibiting mucosal inflammation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01565-5.

Yeast β-glucan attenuates dextran sulfate sodium-induced colitis: Involvement of gut microbiota and short-chain fatty acids

Yeast β-glucan intervention offers a promising strategy for managing colitis; however, the mechanisms remain unknown. In the present work, the protective effects of yeast β-glucan on DSS-induced colitis in mice was evaluated, focusing on its interaction with gut microbiota. The result showed yeast β-glucan significantly alleviated colitis symptoms, evidenced by reduced weight loss, lower disease activity index (DAI) scores, and minimized intestinal damage. It enhanced intestinal barrier integrity via upregulation of tight junction proteins, suppressed lipopolysaccharide (LPS) release, and decreased pro-inflammatory cytokines production. Additionally, yeast β-glucan boosted short-chain fatty acids (SCFAs) production, and activated their receptors, increased the relative abundances of beneficial microbes like Lactobacillus and Lachnospiraceae_UCG-006. Transcriptomic analyses suggest that yeast β-glucan mitigates inflammation by downregulating gene expression related to IL-17 pathway. Our findings highlight potential of yeast β-glucan as a therapeutic agent for colitis through modulation of gut microbiota and inflammatory responses.

Angiotensin-(1-7) improves intestinal microbiota disturbances and modulates fecal metabolic aberrations in acute pancreatitis

Acute pancreatitis (AP) is a serious health problem that dysregulates intestinal microbiota. Angiotensin (Ang)-(1-7) plays a protective role in the intestinal barrier in AP, but its effect on intestinal microbiota remains clear. To investigate the impact of Ang-(1-7) on AP-induced intestinal microbiota disorder and metabolites. We collected blood and fecal samples from 31 AP patients within 48 h after admission to the hospital, including 11 with mild AP (MAP), 14 with moderately severe AP (MSAP), six with severe AP (SAP). Mice were divided into four groups: control, AP, AP + Ang-(1-7) via tail vein injection, and AP + Ang-(1-7) via oral administration. The samples of mice were collected 12 h after AP. Pancreatic and intestinal histopathology scores were analyzed using the Schmidt and Chiu scores. Fecal microbiota and metabolites analysis was performed via 16S rDNA sequencing and nontargeted metabolomics analysis, respectively. In patients, the abundance of beneficial bacteria (Negativicutes) decreased and pathogenic bacteria (Clostridium bolteae and Ruminococcus gnavus) increased in SAP compared with MAP. Ang-(1-7) levels were associated with changes in the microbiota. There were differences in the intestinal microbiota between control and AP mice. Ang-(1-7) attenuated intestinal microbiota dysbiosis in AP mice, reflecting in the increase in beneficial bacteria (Odoribacter and Butyricimonas) than AP, as well as pancreatic and intestinal injuries. Oral administration of Ang-(1-7) reversing AP-induced decreases in metabolisms: secondary bile acids, emodin, and naringenin. Ang-(1-7) may improve intestinal microbiota dysbiosis and modulate fecal metabolites in AP, thereby reducing the damage of AP.

Structural characteristics of a polysaccharide from Armillariella tabescens and its protective effect on colitis mice via regulating gut microbiota and intestinal barrier function

A new polysaccharide fraction (ATP) was obtained from Armillariella tabescens mycelium. Structural analysis suggested that the backbone of ATP was →4)-α-D-Glcp(1 → 2)-α-D-Galp(1 → 2)-α-D-Glcp(1 → 4)-α-D-Glcp(1→, which branched at O-3 of →2)-α-D-Glcp(1 → and terminated with T-α-D-Glcp or T-α-D-Manp. Besides, ATP significantly alleviated ulcerative colitis (UC) symptoms and inhibited the production of pro-inflammation cytokines (IL-1β, IL-6). Meanwhile, ATP could improve colon tissue damage by elevating the expression of MUC2 and tight junction proteins (ZO-1, occludin and claudin-1) levels and enhance intestinal barrier function through inhibiting the activation of MMP12/MLCK/p-MLC2 signaling pathway. Further studies exhibited that ATP could increase the relative abundance of beneficial bacteria such as f. Muribaculacese, g. Muribaculaceae, and g. Alistips, and decrease the relative abundance of g. Desulfovibrio, g. Colidextribacter, g. Ruminococcaceae and g.Oscillibacter, and regulate the level of short-chain fatty acids. Importantly, FMT intervention with ATP-derived microbiome certified that gut microbiota was involved in the protective effects of ATP on UC. The results indicated that ATP was potential to be further developed into promising therapeutic agent for UC.

Qingzhuan dark tea polysaccharides-zinc alleviates dextran sodium sulfate-induced ulcerative colitis

BACKGROUND

Qingzhuan dark tea polysaccharides (QDTP) have been complexed with Zinc (Zn) to form the Qingzhuan dark tea polysaccharides-Zinc (QDTP-Zn) complex. The present study investigated the protective effects of QDTP-Zn on ulcerative colitis (UC) in mice. The UC mouse model was induced using dextran sodium sulfate (DSS), followed by oral administration of QDTP-Zn (0.2 and 0.4 g kg-1 day-1).

RESULTS

QDTP-Zn demonstrated alleviation of UC symptoms in mice, as evidenced by a decrease in disease activity index scores. QDTP-Zn also regulated colon tissue injury by upregulating ZO-1 and occludin protein expression, at the same time as downregulating tumor necrosis factor-α and interleukin-6β levels. Furthermore, QDTP-Zn induced significant alterations in the abundance of bacteroidetes and firmicutes and notably increased levels of short-chain fatty acids (SCFAs), particularly acetic acid, propionic acid, and butyric acid.

CONCLUSION

In summary, QDTP-Zn exhibits therapeutic potential in alleviating enteritis by fortifying the colonic mucosal barrier, mitigating inflammation and modulating intestinal microbiota and SCFAs levels. Thus, QDTP-Zn holds promise as a functional food for both the prevention and treatment of UC. © 2024 Society of Chemical Industry.

Dietary α-linolenic acid supplementation enhances resistance to Salmonella Typhimurium challenge in chickens by altering the intestinal mucosal barrier integrity and cecal microbes

Salmonella is an important foodborne pathogen. Given the ban on the use of antibiotics during the egg-laying period in China, finding safe and effective alternatives to antibiotics to reduce Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) infections in chickens is essential for the prevention and control of this pathogen and the protection of human health. Numerous studies have shown that unsaturated fatty acids have a positive effect on intestinal inflammation and resistance to infection by intestinal pathogens. Here we investigated the protective effect of α-linolenic acid (ALA) against S. Typhimurium infection in chickens and further explored its mechanism of action. We added different proportions of ALA to the feed and observed the effect of ALA on S. Typhimurium colonization using metagenomic sequencing technology and physiological index measurements. The role of gut flora on S. Typhimurium colonization was subsequently verified by fecal microbiota transplantation (FMT). We found that ALA protects chickens from S. Typhimurium infection by reducing intestinal inflammation through remodeling the gut microbiota, up-regulating the expression of ileocecal barrier-related genes, and maintaining the integrity of the intestinal epithelium. Our data suggest that supplementation of feed with ALA may be an effective strategy to alleviate S. Typhimurium infection in chickens.

Structural characterization of the glucan from Gastrodia elata Blume and its ameliorative effect on DSS-induced colitis in mice

The polysaccharide glucan was extracted from Gastrodia elata Blume, and its structural characterizations and beneficial effects against acute dextran sulfate sodium (DSS)-induced ulcerative colitis were investigated. The results showed that a polysaccharide GP with a molecular weight of 811.0 kDa was isolated from G. elata Blume. It had a backbone of α-D-1,4-linked glucan with branches of α-d-glucose linked to the C-6 position. GP exhibited protective effects against DSS-induced ulcerative colitis, and reflected in ameliorating weight loss and pathological damages in mice, increasing colon length, inhibiting the expression of inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), decreasing the levels of inflammatory related proteins NLRP3 and ASC, and elevating the anti-inflammatory cytokine interleukin-10 (IL-10) level in mouse colon tissues. GP supplementation also reinforced the intestinal barrier by promoting the expression of ZO-1, Occludin, and MUC2 of colon tissues, and positively regulated intestinal microbiota. Thus, GP treatment possessed a significant improvement in ulcerative colitis in mice, and it was expected to be developed as a functional food.

Isolation and identification of anti-inflammatory and analgesic polysaccharides from Coix seed (Coix lacryma-jobi L.var. Ma-yuen (Roman.) Stapf)

Coix seed is a nutrient-rich food and traditional Chinese medicine with anti-inflammatory and analgesic properties. Polysaccharides from Coix seed have been rarely investigated for structure and activities. In this study, the analgesic and anti-inflammatory effects were investigated in vivo and in vitro. The results showed that Coix seed had a significant influence on reducing the number of writhing, increasing the pain threshold and alleviating the swelling degree caused by acute inflammation. Column chromatography was used to obtain two active compounds of Coix seed. Compound 1 was (1→6)-α-glucan with a molecular weight of 6.81 × 105 Da. The chemical connection of compound 2 was as follows: α-Frup (2→ [1)-α-Glcp (6]5→1)-α-Glcp (4→1)-α-Glcp, which was isolated in Coix seed for the first time. LPS-induced inflammation in RAW264.7 cells was well inhibited by compounds. These findings offered a preliminary investigation into the analgesic and anti-inflammatory properties of Coix seed, which may be helpful for application.

Effects of Freshwater Acidification on the Gut Microbial Community of Trachemys scripta elegans

Freshwater acidification (FA) has become a global environmental problem, posing a potential threat to freshwater ecosystems. The gut microbiota plays a crucial role in the host's response and adaptation to new environments. In this study, we investigated the changes in microbial communities in Red-eared slider (Trachemys scripta elegans) under acidic conditions to reveal the ecological impacts of acidification on freshwater turtles. The results showed that there were significant differences in β-diversity (p = 0.03), while there were no significant differences in the α-diversity of gut microbiota in T. s. elegans between the different levels of acidification (pH of 5.5, 6.5, 7.5). Both the Gut Microbiome Health Index (GMHI) and the Microbial Dysbiosis Index (MDI) exhibited significant differences when comparing environments with a pH of 5.5 to those with a pH of 6.5 (p < 0.01). A comparative analysis between pH levels of 5.5 and 6.5 also revealed substantial differences (p < 0.01). Likewise, a comparative analysis between pH levels of 6.5 and 7.5 also revealed substantial differences (p < 0.01). At the phylum level, Firmicutes, Fusobacteria, and Bacteroidota formed a major part of the gut microbial community, Fusobacteria showed significant differences in different acidity environments (p = 0.03). At the genus level, Cetobacterium, Turicibacter, unclassified Eubacteriaceae, and Anaerorhabdus_furcosa_group showed significant differences in different acidity environments. The pH reduced interactivity in the gut microbiota of T. s. elegans. In addition, LEfSe analysis and functional prediction revealed that the potentially_pathogenic and stress_tolerant functional characteristics also showed significant differences in different acidity environments. The findings underscore the pivotal role of the gut microbiota in T. s. elegans in response to freshwater acidification and provide a foundation for further exploration into the impacts of acidification on freshwater ecosystems.

Matrine Ameliorates DSS-Induced Colitis by Suppressing Inflammation, Modulating Oxidative Stress and Remodeling the Gut Microbiota

Matrine (MT) possesses anti-inflammatory, anti-allergic and antioxidative properties. However, the impact and underlying mechanisms of matrine on colitis are unclear. The purpose of this research was to examine the protective impact and regulatory mechanism of matrine on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. MT alleviated DSS-induced UC by inhibiting weight loss, relieving colon shortening and reducing the disease activity index (DAI). Moreover, DSS-induced intestinal injury and the number of goblet cells were reversed by MT, as were alterations in the expression of zonula occludens-1 (ZO-1) and occludin in colon. Simultaneously, matrine not only effectively restored DSS-induced oxidative stress in colonic tissues but also reduced the production of inflammatory cytokines. Furthermore, MT could treat colitis mice by regulating the regulatory T cell (Treg)/T helper 17 (Th17) cell imbalance. We observed further evidence that MT alleviated the decrease in intestinal flora diversity, reduced the proportion of Firmicutes and Bacteroidetes, decreased the proportion of Proteobacteria and increased the relative abundance of Lactobacillus and Akkermansia in colitis mice. In conclusion, these results suggest that MT may mitigate DSS-induced colitis by enhancing the colon barrier integrity, reducing the Treg/Th17 cell imbalance, inhibiting intestinal inflammation, modulating oxidative stress and regulating the gut microbiota. These findings provide strong evidence for the development and application of MT as a dietary treatment for UC.

Dual engineered bacteria improve inflammatory bowel disease in mice

Currently, there are many different therapies available for inflammatory bowel disease (IBD), including engineered live bacterial therapeutics. However, most of these studies focus on producing a single therapeutic drug using individual bacteria, which may cause inefficacy. The use of dual drugs can enhance therapeutic effects. However, expressing multiple therapeutic drugs in one bacterial chassis increases the burden on the bacterium and hinders good secretion and expression. Therefore, a dual-bacterial, dual-drug expression system allows for the introduction of two probiotic chassis and enhances both therapeutic and probiotic effects. In this study, we constructed a dual bacterial system to simultaneously neutralize pro-inflammatory factors and enhance the anti-inflammatory pathway. These bacteria for therapy consist of Escherichia coli Nissle 1917 that expressed and secreted anti-TNF-α nanobody and IL-10, respectively. The oral administration of genetically engineered bacteria led to a decrease in inflammatory cell infiltration in colon and a reduction in the levels of pro-inflammatory cytokines. Additionally, the administration of engineered bacteria did not markedly aggravate gut fibrosis and had a moderating effect on intestinal microbes. This system proposes a dual-engineered bacterial drug combination treatment therapy for inflammatory bowel disease, which provides a new approach to intervene and treat IBD. KEY POINTS: • The paper discusses the effects of using dual engineered bacteria on IBD • Prospects of engineered bacteria in the clinical treatment of IBD.

Multi-targeting inulin-based nanoparticles with cannabidiol for effective prevention of ulcerative colitis

The pathogenesis of ulcerative colitis (UC) is closely related to severe inflammation, damaged colonic mucosal barrier, increased oxidative stress and intestinal ecological imbalance. However, due to the nonspecific distribution and poor bioavailability of drugs, UC treatment is still a serious challenge. Here, a mitochondria/colon dual targeted nanoparticles based on redox response was developed to effectively alleviate UC. Cannabidiol nanoparticles (CBD NPs) with a particle size of 143.2 ± 3.11 nm were prepared by self-assembly using polymers (TPP-IN-LA) obtained by modifying inulin with (5-carboxypentyl) triphenyl phosphonium bromide (TPP) and α-lipoic acid (α-LA). Excitingly, the constructed CBD NPs showed excellent mitochondrial targeting, with a Pearson correlation coefficient of 0.76 at 12 h. The results of animal imaging in vivo showed that CBD NPs could be effectively accumulated in colon tissue. Not only that, CBD showed significant glutathione stimulated release in the presence of 10 mM glutathione at pH 7.4. The results of in vivo animal experiments showed that CBD NPs significantly ameliorated DSS-induced colonic inflammation by modulating the TLR4-NF-κB signaling pathway. Moreover, CBD NPs significantly improved the histological damage of colon in UC mice, increased the expression level of tight junction protein ZO-1, and effectively restored the intestinal mucosal barrier function and intestinal mucosal permeability. More importantly, CBD NPs significantly improved the species composition, abundance and amount of short chain fatty acids of intestinal flora in UC mice, thus effectively maintaining the balance of intestinal flora. The dual-targeted and glutathione-responsive nanoparticles prepared in this study provide a promising idea for achieving targeted delivery of CBD for effective treatment of UC.

Structural characteristics of steamed Polygonatum cyrtonema polysaccharide and its bioactivity on colitis via improving the intestinal barrier and modifying the gut microbiota

Steamed Polygonatum cyrtonema has been commonly used clinically for its gaining effect, whose main active ingredient is a polysaccharide. A water-soluble polysaccharide named PSP-W-1 was isolated from steamed Polygonatum cyrtonema. PSP-W-1 was characterized as a galactan having a backbone consisting predominately of 1,4-β-linked Galp branched at the C-6 position by T-β-linked Galp with a molecular weight of 14.4 kDa. PSP-W-1 could inhibit the overproduction of inflammatory factors and inflammatory mediators (iNOS, IL-6, COX-2) in dextran sodium sulfate-induced colitis mice. Oral administration of PSP-W-1 dramatically alleviated colonic pathological damage, repaired the intestinal barrier (occludin and ZO-1) and regulated the intestinal microbiota by increasing the abundance of norank_f_Muribaculaceae, Lactobacillus and norank_f_norank_o_Clostridia UCG-014, while decreasing the abundance of Bacteroides and Escherichia-Shigella to alleviate colitis symptoms. Overall, our findings suggest that PSP-W-1 might be a therapeutic option for both the prevention and treatment of colitis.

Lacticaseibacillus paracasei CCFM1222 Ameliorated the Intestinal Barrier and Regulated Gut Microbiota in Mice with Dextran Sulfate Sodium-Induced Colitis

Lacticaseibacillus paracasei has been regarded as a probiotic bacterium because of its role in anti-inflammatory properties and maintenance of intestinal barrier permeability. Here, we explored the anticolitic effects and mechanism of L. paracasei CCFM1222. The results showed that L. paracasei CCFM1222 supplementation could suppress the disease activity index (DAI) and colon length shortening in colitis mice, accompanied by a moderate increase in colonic tight junction proteins (ZO-1, occludin and claudin-1). L. paracasei CCFM1222 intervention significantly suppressed the levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and significantly elevated the activities of antioxidant enzymes (including SOD, GSH-Px, and CAT) in the colon by regulating the TLR4/MyD88/NF-κB and Nrf2 signaling pathways in colitis mice. In addition, L. paracasei CCFM1222 significantly shifted the gut microbiota, including elevating the abundance of Catabacter, Ruminiclostridium 9, Alistipes, and Faecalibaculum, as well as reducing the abundance of Mucispirillum, Escherichia-Shigella, and Salmonella, which was associated with the improvement of colonic barrier damage. Overall, these results suggest that L. paracasei CCFM1222 is a good candidate for probiotic of improving colonic barrier damage and associated diseases.

Orally administered selenium-containing α-D-1,6-glucan and α-D-1,6-glucan relief early cognitive deficit in APP/PS1 mice

Alzheimer's disease (AD) is a complex, progressive and deadly disorder that exhibits various typical pathological characteristics. Till now no effective treatment has been found that can prevent or reverse AD. Here, the effects of 2 months of treatment with α-D-1,6-glucan (CPA) and selenium-containing α-D-1,6-glucan (Se-CPA) on early cognitive dysfunction and neuropathology were explored in the 3-month-old APP/PS1 transgenic mouse. The results of the Morris water maze and open-field test revealed that Se-CPA exerted more significant effects than CPA in improving cognitive function and depressive-like behavior by attenuating the oxidative stress, decreasing serum LPS level, downregulating the inflammation of astrocytes and microglia through inhibiting the activation of NLRP3 inflammasome, mitigating neuronal cells loss and improving synaptic plasticity. Moreover, Se-CPA exerted beneficial effects on reshaping gut microbiome by increasing the microbial α-diversity, enhancing the proportion of beneficial bacteria such as Akkermansia muciniphila and promoting the SCFAs concentration. These findings provide evidence that Se-CPA might be a potentially viable compound for AD prevention.

2D Nanozymes Modulate Gut Microbiota and T-Cell Differentiation for Inflammatory Bowel Disease Management

Intestinal commensal microbiota dysbiosis and immune dysfunction are significant exacerbating factors in inflammatory bowel disease (IBD). To address these problems, Pluronic F-127-coated tungsten diselenide (WSe2 @F127) nanozymes are developed by simple liquid-phase exfoliation. The abundant valence transitions of elemental selenium (Se2- /Se4+ ) and tungsten (W4+ /W6+ ) enable the obtained WSe2 @F127 nanozymes to eliminate reactive oxygen/nitrogen species. In addition, the released tungsten ions are capable of inhibiting the proliferation of Escherichia coli. In a model of dextran sodium sulfate-induced colitis, WSe2 @F127 nanozymes modulate the gut microbiota by increasing the abundance of bacteria S24-7 and significantly reducing the abundance of Enterobacteriaceae. Moreover, WSe2 @F127 nanozymes inhibit T-cell differentiation and improve intestinal immune barrier function in a model of Crohn's disease. The WSe2 @F127 nanozymes effectively alleviate IBD by reducing oxidative stress damage, modulating intestinal microbial populations, and remodeling the immune barrier.

Structural elucidation of a highly branched α-D-glucan from Huangjiu and its hepatoprotective activity via gut microbiome regulation and intestinal barrier repairment

Polysaccharides in Huangjiu, a traditional fermented food, are expected to be potentially effective ingredients in protecting against alcoholic liver disease (ALD). Elucidating their precise structural and functional characteristics is essential for in-depth understanding of structure-activity relationships of hepatoprotective polysaccharides. Herein, a major polysaccharide component HJPS1-2 was purified from Huangjiu with an average molecular weight of 3.49 kDa. Structural analyses inferred that HJPS1-2 backbone was composed of (1 → 4)-linked α-D-Glcp and a single α(1 → 6)-D-Glcp-α(1 → 6)-D-Glcp branched unit for every three α(1 → 4)-D-Glcp. An ALD mouse model was further established to clarify the underlying effect of HJPS1-2 on ALD alleviation. Biochemical detection and histopathological assessment revealed that HJPS1-2 intervention remarkably improved ethanol-induced hepatic dysfunction and steatosis. HJPS1-2 treatment ameliorated gut microbiota dysbiosis of ALD mice in a dose-dependent manner, mainly manifested as restoration of microbial diversities, community structure and bacterial interaction patterns. Compared with ethanol group, the strikingly elevated intestinal short-chain fatty acids' levels and enhanced intestinal barrier function after HJPS1-2 intake might contribute to reduced serum and liver lipopolysaccharide levels and subsequently suppressed release of hepatic inflammatory cytokines, thus mitigating ALD. Collectively, this research supports the potential of food-derived polysaccharides to hinder the early formation and progression of ALD through maintaining intestinal homeostasis.

An inulin-type fructan isolated from Serratula chinensis alleviated the dextran sulfate sodium-induced colitis in mice through regulation of intestinal barrier and gut microbiota

Herein, we aimed to explore the polysaccharide material basis of Serratula chinensis and establish its beneficial effects against colitis. A neutral polysaccharide (SCP) was extracted from S. chinensis in high yield using hot water. The molecular weights were calculated by HPSEC as Mw = 2928 Da, Mn = 2634 Da, and Mw/Mn = 1.11. FT-IR and 1D/2D-NMR spectroscopic analyses confirmed that SCP was an inulin-type fructan with α-D-Glcp-(1 → [1)-β-D-Fruf-(2]17) linkages. Treatment with SCP (200 or 400 mg/kg) alleviated dextran sulfate sodium (DSS)-induced mouse colitis symptoms, including the loss of body weight, increase of disease activity index score, and shortening of colon length. Histopathological and immunofluorescence assessments revealed that SCP could reduce pathological damage to the colon, restore the number of goblet cells, increase the content of glycoproteins in goblet cells and mucins in crypts, and enhance the expression of tight junction proteins ZO-1 and occludin. In addition, metagenomic sequencing revealed that SCP could improve the dysbiosis of gut microbiomes and act on multiple microbial functions. Moreover, SCP treatment increased the content of colonic acetic acid and butanoic acid. Collectively, these results indicated that SCP could alleviate the DSS-induced colitis in mice through regulation of intestinal barrier and gut microbiota.

Anti-inflammatory and intestinal microbiota modulation properties of Ganoderma lucidum β-d-glucans with different molecular weight in an ulcerative colitis model

This study systematically investigated the therapeutic effects and the corresponding mechanisms of β-D-glucans from Ganoderma lucidum (G. lucidum) with different molecular weights (Mws) on ulcerative colitis (UC). Results showed that three β-d-glucans (GLPS, GLPN and GLPW) from G. lucidum with different Mws exhibited the significant activities on the reduction of typical symptoms of UC by regulating inflammatory cytokine levels, modulating intestinal immunity, improving intestinal microbiota and metabolism of short-chain fatty acids (SCFAs) in the dextran sulfate sodium (DSS)-induced mice model. Among them, the effects of the microwave assisted degraded fraction (GLPW) mainly containing two fractions with smaller Mw (1.33 × 104 and 3.51 × 103 g/mol) on the regulation of inflammatory factors and SCFAs metabolism were found to be comparable to those of GLPN with medium Mw (3.49 × 104 g/mol), and superior to those of GLPS with large Mw (2.42 × 106 g/mol). The effect of GLPW on regulation of intestinal microbiota was even better than that of GLPN. These findings suggested that lowering Mw by means of physical degradation could improve the anti-inflammatory activities of G. lucidum β-d-glucans. The analysis of anti-inflammatory mechanism also provided a feasible and theoretical basis for potential use of degraded β-d-glucans in the prevention and treatment of UC.

Xylooligosaccharides from corn cobs alleviate loperamide-induced constipation in mice via modulation of gut microbiota and SCFA metabolism

This study aimed to optimize the structure and efficacy of xylooligosaccharides (XOSs) from corn cobs in constipated mice. Structural analysis revealed that XOSs from corn cobs were composed of β-Xyl-(1 →4)-[β-Xyl-(1→4)]n-α/β-Xyl (n = 0-5) without any other substituents. XOS administration significantly reduced the defecation time, increased the gastrointestinal transit rate, restored the gastrointestinal neurotransmitter imbalance, protected against oxidative stress, and reversed constipation-induced colonic inflammation. Fecal metabolite and microbiota analysis showed that XOS supplementation significantly increased short chain fatty acid (SCFA) levels and improved the gut microbial environment. These findings highlighted the potential of XOSs from corn cobs as an active ingredient for functional foods or as a therapeutic agent in constipation therapy.

Dextran-Sulfate-Sodium-Induced Colitis-Ameliorating Effect of Aqueous Phyllanthus emblica L. Extract through Regulating Colonic Cell Gene Expression and Gut Microbiomes

The anti-inflammation effect of aqueous Phyllanthus emblica L. extract (APE) and its possible underlying mechanism in dextran sulfate sodium (DSS)-induced mice chronic colonic inflammation were studied. APE treatment significantly improved the colitic symptoms, including ameliorating the shortening of the colon, increasing the DSS-induced body weight loss, reducing the disease activity index, and reversing the condition of colon tissue damage of mucus lost and goblet cell reduction. Overproduction of serum pro-inflammatory cytokines were suppressed by the treatment of APE. Gut microbiome analysis showed that APE remodeled the structure of gut bacteria in phylum and genus levels, upregulating the abundance of phylum Bacteroidetes, family Muribaculaceae, and genus Bacteroides and downregulating the abundance of phylum Firmicutes. The reshaped gut microbiome caused metabolic functions and pathway change with enhanced queuosine biosynthesis and reduced polyamine synthesis pathway. Colon tissue transcriptome analysis further elucidated APE-inhibited mitogen-activated protein kinase (MAPK), cytokine-cytokine receptor interaction, and tumor necrosis factor (TNF) signaling pathways and the expressions of the genes that promote the progress of colorectal cancer. It turned out that APE reshaped the gut microbiome and inhibited MAPK, cytokine-cytokine receptor interaction, and TNF signaling pathways as well as the colorectal-cancer-related genes to exert its colitis protective effect.

Natamycin Has an Inhibitory Effect on Neofusicoccum parvum, the Pathogen of Chestnuts

This research aimed to investigate natamycin's antifungal effect and its mechanism against the chestnut pathogen Neofusicoccum parvum. Natamycin's inhibitory effects on N. parvum were investigated using a drug-containing plate culture method and an in vivo assay in chestnuts and shell buckets. The antifungal mechanism of action of natamycin on N. parvum was investigated by conducting staining experiments of the fungal cell wall and cell membrane. Natamycin had a minimum inhibitory concentration (MIC) of 100 μg/mL and a minimum fungicidal concentration (MFC) of 200 μg/mL against N. parvum. At five times the MFC, natamycin had a strong antifungal effect on chestnuts in vivo, and it effectively reduced morbidity and extended the storage period. The cell membrane was the primary target of natamycin action against N. parvum. Natamycin inhibits ergosterol synthesis, disrupts cell membranes, and causes intracellular protein, nucleic acid, and other macromolecule leakages. Furthermore, natamycin can cause oxidative damage to the fungus, as evidenced by decreased superoxide dismutase and catalase enzyme activity. Natamycin exerts a strong antifungal effect on the pathogenic fungus N. parvum from chestnuts, mainly through the disruption of fungal cell membranes.

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

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

Huangshan Floral Mushroom Polysaccharide Ameliorates Dextran Sulfate Sodium-Induced Colitis in Mice by Modulating Th17/Treg Balance in a Gut Microbiota-Dependent Manner

SCOPE

Ulcerative colitis (UC) is a common chronic recurrent inflammatory bowel disease. This study attempts to reveal the improvement mechanism of floral mushroom polysaccharide (FMPS) on UC from the perspective of coordinated interaction between intestinal microbes and intestinal helper T cell 17 (Th17)/regulatory T cell (Treg) balance.

METHODS AND RESULTS

Dextran sulfate sodium (DSS)-induced colitis mice model is used for the experiment. The results suggest that FMPS up-regulated the expression of occludin, ZO-1, and MUC2, and down-regulated the secretion of TNF-α, IL-1β, and IL-6 in colitis mice. Importantly, FMPS restores intestinal Th17/Treg balance. Meanwhile, FMPS can regulate intestinal microorganisms and improve the level of short-chain fatty acids (SCFAs) in colitis mice. Intestinal microbial depletion and fecal microbiota transplantation (FMT) experiments reveal that FMPS ameliorated UC is mediated by intestinal microbiome. Flow cytometry further proves that FMPS restores intestinal Th17/Treg balance in a microbial-dependent manner.

CONCLUSION

These results indicate that FMPS has the potential to improve UC, and its mechanism depends on the restoration of Th17/Treg balance mediated by intestinal microorganisms. Therefore, it is suggested that FMPS dietary supplement can be potentially used to intervene UC.

Prebiotic activity of chitooligosaccharides and their ability to alleviate necrotizing enterocolitis in newborn rats

Chitooligosaccharides (COS) have many bioactive functions and favorable prospects in the fields of biomedicine and functional foods. In this study, COS was found to significantly improve the survival rate of neonatal necrotizing enterocolitis (NEC) model rats, alter the composition of the intestinal microbiota, inhibit the expression of inflammatory cytokines, and alleviate intestinal pathological injury. In addition, COS also increased the abundance of Akkermansia, Bacteroides, and Clostridium sensu stricto 1 in the intestines of normal rats (the normal rat model is more universal). The in vitro fermentation results found that COS was degraded by the human gut microbiota to promote the abundance of Clostridium sensu stricto 1 and produced numerous short-chain fatty acids (SCFAs). In vitro metabolomic analysis revealed that COS catabolism was associated with significant increases in 3-hydroxybutyrate acid and γ-aminobutyric acid. This study provides evidence for the potential of COS as a prebiotic in food products and to ameliorate NEC development in neonatal rats.

Apigenin remodels the gut microbiota to ameliorate ulcerative colitis

Introduction

Ulcerative colitis (UC), a chronic non-specific colorectal inflammatory disease with unclear etiology, has long plagued human health. Gut microbiota dysbiosis destroy homeostasis of the colon, which is closely related to ulcerative colitis progress. Apigenin, a flavonoid widely present in celery, has been found to improve ulcerative colitis. However, the potential molecular mechanism of apigenin ameliorating ulcerative colitis through protecting intestinal barrier and regulating gut microbiota remains undefined.

Methods

Dextran sodium sulfate (DSS)-induced colitis mouse model was conducted to evaluate the effect of apigenin on UC. Disease activity index score of mice, colon tissue pathological, cytokines analysis, intestinal tight junction proteins expression, and colonic content short-chain fatty acids (SCFAs) and 16S rRNA gene sequencing were conducted to reflect the protection of apigenin on UC.

Results

The results indicated that apigenin significantly relieved the intestinal pathological injury, increased goblet cells quantity and mucin secretion, promoted anti-inflammatory cytokines IL-10 expression, and inhibited the expression of proinflammatory cytokines, TNF-α, IL-1β, IL-6 and MPO activity of colon tissue. Apigenin increased ZO-1, claudin-1 and occludin expressions to restore the integrity of the intestinal barrier. Moreover, apigenin remodeled the disordered gut microbiota by regulating the abundance of Akkermansia, Turicibacter, Klebsiella, Romboutsia, etc., and its metabolites (SCFAs), attenuating DSS-induced colon injury. We also investigated the effect of apigenin supplementation on potential metabolic pathways of gut microbiota.

Conclusion

Apigenin effectively ameliorated DSS-induced UC via balancing gut microbiome to inhibit inflammation and protect gut barrier. With low toxicity and high efficiency, apigenin might serve as a potential therapeutic strategy for the treatment of UC via regulating the interaction and mechanism between host and microorganism.