Cimicifuga foetida L. polysaccharide alleviates ulcerative colitis by inhibiting pyroptosis and regulating gut microbiota

Preparation and chemical characterization of polyphenol-rich extract from Tsaoko Fructus: alleviation of ulcerative colitis in mice by modulating gut microbiota and suppressing the JNK1-cJun signaling.

BACKGROUND Tsaoko Fructus, a traditional Chinese medicinal herb, has long been used to alleviate gastritis and enteritis. Nevertheless, the active constituents and underlying anti-inflammatory mechanisms remain insufficiently characterized. PURPOSE This study aims to optimize a polyphenol-rich fraction (3CB) from Tsaoko Fructus, evaluate its effects against ulcerative colitis (UC), and reveal the underlying mechanisms of action. METHODS The preparation of 3CB was optimized using response surface methodology (RSM), and its major constituents were identified by LC-PDA-MS analysis. A murine UC model was established by administering dextran sulfate sodium (DSS). To evaluate the effects of 3CB on UC mice, metagenomic sequencing of the intestinal microbiome and RNA sequencing of colon tissues were conducted. The anti-inflammatory activity of 3CB and its principal constituents was further verified by quantitative real-time PCR (qPCR), Enzyme linked immunosorbent assay (ELISA), Western blotting, immunohistochemical staining, and histopathological analysis. Network pharmacology, molecular docking, and surface plasmon resonance (SPR) assays were employed to elucidate the molecular mechanisms underlying the anti-inflammatory effects of 3CB. RESULTS 3CB significantly alleviated UC symptoms in DSS-induced mice, reshaped the gut microbiota with reducing pathogenic Pseudomonadota and Deferribacterota while enriching beneficial Bacteroidota, and restored microbial amino sugar and nucleotide sugar metabolism pathways of intestinal flora. Additionally, 3CB preserved colonic oxidative phosphorylation, protected the mucus barrier, and suppressed inflammatory cell infiltration and the expression of cytokines. Seven major polyphenols were identified in 3CB, with epicatechin (3) and epiafzelechin (6) being the most abundant. Mechanistic investigation revealed that the anti-inflammatory effect of 3CB was partially dependent on the JNK1-modulated MAPK signaling pathway. JNK1 was identified as a direct target of 3CB, with epiafzelechin (6) exhibiting a high binding affinity (Kd = 10.4 μM). CONCLUSION 3CB ameliorates UC potentially through modulation of gut microbiota, protection of the mucus barrier, and JNK1-targeted anti-inflammatory effects, highlighting its potential as a protective intervention for inflammatory bowel disease (IBD).

Ethanolic Extract of Selaginella tamariscina Alleviates DSS-induced Ulcerative Colitis by Restoring Epithelial Barrier Function.

ETHNOPHARMACOLOGICAL RELEVANCE Selaginella tamariscina (P. Beauv.) Spring is a traditional Chinese herbal medicine used to treat hematemesis, metrorrhagia, hematochezia, rectal prolapse, and other diseases. Based on its efficacy in treating bloody stools, S. tamariscina is also used in formulations for ulcerative colitis (UC). AIM OF THE STUDY This study aimed to investigate the efficacy and the potential mechanism of S. tamariscina ethanol extract (STE) against UC. METHODS STE samples were prepared by reflux extraction. The UC mouse model was induced by freely drinking 3% DSS solution. The therapeutic efficacy of STE in UC was assessed by measuring the disease activity index (DAI), histopathological score, colon length, and cytokine expression levels. Intestinal permeability was evaluated using a FITC-dextran permeability assay. Differentially expressed genes in colon tissues were analyzed using transcriptomics. Calcium imaging was performed to detect the effect of STE on intracellular Ca2+ levels in HT-29 cells. Cell proliferation was detected using BrdU staining. Epithelial barrier destruction of HT-29 cells was induced by exposure to a combination of LPS and IFNγ. Expression levels of junction proteins in colon tissue and HT-29 cells were detected by Western blot and immunofluorescence. Epithelial barrier integrity was assessed using the transepithelial electrical resistance (TEER) assay. RESULTS STE dose-dependently alleviated body weight loss, colon shortening, DAI scores, pathological changes, epithelial barrier function, and inflammatory status (including TNF-α, IL-6, and IL-1β) in colon tissues of UC mice. Mechanistically, STE induced a concentration-dependent increase in intracellular Ca2+ levels in HT-29 cells (EC50 = 33 μg/mL). This response was completely abolished in Ca2+-free medium, indicating that STE primarily promotes extracellular Ca2+ influx rather than Ca2+ release from intracellular stores. STE alone (3 μg/mL) promoted HT-29 cell proliferation, upregulated Cyclin D1 expression, and increased ERK1/2 and p38 MAPK phosphorylation, while ERK1/2 and p38 inhibitors (U0126, SB203580) suppressed STE-induced proliferation. Ca2+ deprivation diminished STE-induced ERK1/2 and p38 phosphorylation. In parallel, under inflammatory conditions, STE inhibited the aberrantly activated JAK2-STAT3 pathway, upregulated tight junction proteins (ZO-1, Occludin, Claudin-1), and restored TEER in LPS/IFN-γ-treated HT-29 cells. The JAK2 agonist Coumermycin A1 reversed these protective effects. Collectively, STE activates the Ca2+/ERK/p38 MAPK pathway to promote regeneration while suppressing the JAK2-STAT3 pathway to counteract junctional disruption, operating as parallel and complementary mechanisms to restore intestinal epithelial barrier function. CONCLUSION STE significantly ameliorated UC symptoms and restored intestinal barrier integrity in UC mice. These protective effects are mediated through Ca2+-dependent activation of the ERK/p38 MAPK pathway and inhibition of the JAK-STAT signaling cascade.

Astragalus polysaccharides ameliorate irinotecan-induced gut toxicity by regulating gut microbiota and suppressing the MAPK signaling.

Findings suggest that APS, the key active fraction of AM against IGT, mitigate IGT by modulating microbiota-metabolite-MAPK axis, offering novel mechanistic insight for the ethnopharmacological use of AM to mitigate chemotherapy-induced intestinal toxicity.

A natural pectic polysaccharide from rhubarb reprograms dysbiotic gut microbiota and resolves mucosal inflammation in ulcerative colitis.

BACKGROUND Ulcerative colitis (UC) remains a major therapeutic challenge. Although natural polysaccharides exhibit therapeutic potential, their structure-activity relationships are still unclear, which limits their clinical application. PURPOSE This study aimed to investigate the protective effect of a rhubarb-derived pectic polysaccharide (RP-2) against UC and elucidate its underlying mechanisms. METHODS The structural characteristics of RP-2 were determined by monosaccharide composition analysis, methylation analysis, and the thiobarbituric acid assay. Its distribution within the colon was observed through in vivo fluorescence imaging, and the therapeutic activity was assessed using a DSS-induced UC model. Changes in the gut microbiota caused by RP-2 were investigated through 16S rRNA sequencing together with an antibiotic depletion experiment. The possible immunomodulatory actions were also explored by ELISA, flow cytometry, western blotting, and qRT-PCR, focusing on the TLR4/MyD88/NF-κB pathway, Th17/Treg balance, and maintenance of intestinal barrier integrity. RESULTS Structural characterization indicated that RP-2 is a complex pectic polysaccharide containing homogalacturonan, rhamnogalacturonan-I, and rhamnogalacturonan-II domains, and it exhibited prolonged retention in the inflamed colon. In RAW264.7 macrophages, RP-2 reduced the release of pro-inflammatory cytokines and the generation of reactive oxygen species following LPS stimulation. In DSS-induced UC mice, RP-2 markedly alleviated disease severity, reducing colon shortening and improving histological scores. Furthermore, RP-2 modulated gut microbial composition by enriching beneficial SCFA-producing bacteria, restored intestinal immune homeostasis, and attenuated DSS-induced intestinal barrier disruption. Notably, antibiotic-mediated microbiota depletion largely abrogated the protective effects of RP-2, highlighting the critical role of gut microbiota in its therapeutic efficacy. Mechanistically, RP-2 suppressed activation of the TLR4/MyD88/p65 pathway and restored the Th17/Treg balance. CONCLUSION These findings demonstrated that RP-2 alleviates UC through the microbiota-dependent "microbiota-metabolite-immune-barrier" axis, providing a scientifically grounded, natural product-based strategy for UC treatment.

Flavonoids from Chroogomphus rutilus attenuate DSS-induced colitis, exhibiting anti-inflammatory, antioxidant, and gut microbiota-modulating effects

Introduction Chroogomphus rutilus (CR) is an edible mushroom valued for its bioactive polysaccharides and flavonoids. It possesses antioxidant and anti-inflammatory properties; however, whether it can confer protection against the onset of ulcerative colitis (UC) remains unclear. Methods Initial network pharmacology analysis was performed to evaluate the potential influence of the flavonoid fraction of CR (CRF) on UC-related targets involved in inflammatory signaling and oxidative stress. The effects of CRF pretreatment were subsequently investigated in a mouse model of dextran sulfate sodium (DSS)-induced colitis. Mice received oral CRF pretreatment at doses of 100 or 400 mg/kg, followed by induction of acute colitis with 3% DSS. Results CRF pretreatment suppressed colonic proinflammatory cytokine expression and preserved antioxidant defense. 16S rRNA gene sequencing revealed that CRF modulated the gut microbiota composition by suppressing potentially harmful bacteria, such as Bacteroides and Erysipelatoclostridium, and enriching beneficial genera including Bifidobacterium, Dubosiella, and Faecalibaculum. Discussion These correlative findings suggest that CRF pretreatment attenuates DSS-induced colitis, and that this attenuation is accompanied by reduced inflammation, alleviated oxidative stress, and microbiota remodeling. The data support the hypothesis that CRF acts through multi-target preventive effects, highlighting its potential as a candidate functional food ingredient for further development.

Rhamnogalacturonan-I type polysaccharide from Curcuma longa attenuates DSS-induced colitis by modulating inflammatory responses