Dietary Turmeric Consumption Alleviates Ulcerative Colitis via Restoring Tryptophan Metabolism and Alleviating Gut Microbiota Dysbiosis in Mice

Essential oils ameliorate the intestinal damages induced by nonylphenol exposure by modulating tryptophan metabolism and activating aryl hydrocarbon receptor via gut microbiota regulation

Nonylphenol (NP) is a ubiquitous endocrine disruptor that persists in the environment and can significantly contribute to serious health hazards, particularly intestinal barrier injury. Plant essential oils (EOs) have recently gained widespread interest due to their potential for improving intestinal health. However, the precise mechanism and protective effects of EOs ameliorating the intestinal damages induced by NP exposure remain unclear. To clarify the potential mechanism and protective impact of EOs against intestinal injury induced by NP, a total of 144 one-day-old male ducks were randomly allocated to four groups: CON (basal diet), EO (basal diet + 200 mg/kg EOs), NP (basal diet + 40 mg/kg NP), and NPEO (basal diet + 200 mg/kg EOs + 40 mg/kg NP). The data revealed that NP exposure significantly damaged intestinal barrier, as evidenced by a reduction in the levels of tight junction gene expression and an increase in intestinal permeability. Additionally, it disturbed gut microbiota, as well as interfered with tryptophan (Trp) metabolism. The NP-induced disorder of Trp metabolism restrained the activation of aryl hydrocarbon receptor (AhR) and resulted in decreased the expression levels of CYP1A1, IL-22, and STAT3 genes, which were alleviated after treatment with EOs. Taken together, NP exposure resulted in impairment of the intestinal barrier function, disruption of gut microbiota, and disturbances in Trp metabolism. Dietary EOs supplementation alleviated the intestinal barrier injury induced by NP through the Trp/AhR/IL-22 signaling pathway.

Consumption of dietary turmeric promotes fat browning and thermogenesis in association with gut microbiota regulation in high-fat diet-fed mice

This study was designed to verify the anti-obesity effect of dietary turmeric powder (TP) as a traditional cooking spice and its underlying mechanism. The HFD-fed C57BL/6J mice were supplemented with or without TP (8%) for 12 weeks. The results indicated that the glucolipid metabolism disorder of high-fat diet (HFD)-fed mice was significantly ameliorated through the supplementation of TP. The consumption of TP also induced beige-fat development and brown adipose tissue (BAT)-derived nonshivering thermogenesis in HFD-fed obese mice. 16S rDNA-based microbiota or targeted metabolomics analysis indicated that TP ameliorated the intestinal microbiota dysbiosis and microbial metabolism abnormality caused by HFD, reflected by dramatically increasing the relative abundance of Muribaculaceae, Candidatus_Saccharimonas, and Bifidobacterium and production of short-chain fatty acids (SCFAs) and succinate. Interestingly, TP-induced BAT thermogenesis and iWAT browning were highly correlated with the reconstruction of the gut microbiome and formation of SCFAs and succinate. Collectively, these findings manifest beneficial actions of TP on the promotion of adipose browning and thermogenesis in association with gut microbiota reconstruction, and our findings may provide a promising way for preventing obesity.

Intracellular Polysaccharides of Eurotium cristatum Exhibited Anticolitis Effects in Association with Gut Tryptophan Metabolism

This study is to investigate the protective effects of Eurotium cristatum intracellular polysaccharides (ECIP) on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC). The oral administration of ECIP could downregulate the disease activity index (DAI) and ameliorate the colonic shortening, immune stress, and damage caused by DSS. In addition, ECIP treatment increased the colonic contents of SCFAs including acetic, propionic, and butyric acids in UC mice. Targeted and untargeted metabolic analysis suggested that ECIP dramatically altered the tryptophan metabolism in the feces of UC mice and promoted the conversion of tryptophan into indole metabolites including indolepyruvate and indole-3-acetic acid (IAA) and indolealdehyde (IAId). Moreover, ECIP observably increased the content of colonic IL-22 and stimulated the relative concentration and relative expression of tight junction molecules in mRNA and proteins levels. Conclusively, consumption of ECIP can improve colon damage and its related effects of UC by promoting the production of IAA and IAId to reinforce intestinal barriers.

Hericium erinaceus polysaccharides ameliorate nonalcoholic fatty liver disease via gut microbiota and tryptophan metabolism regulation in an aged laying hen model

Polysaccharides extracted from Hericium erinaceus (HEP) exhibit hepatoprotective activity in the alleviation of non-alcoholic fatty liver disease (NAFLD); however, the mechanisms underlying whether and how HEP regulation of the gut microbiota to alleviate liver-associated metabolic disorders are not well understood. This study used an aged laying hen model to explore the mechanisms through which HEP alleviates NAFLD, with a focus on regulatory function of HEP in the gut microbiome. The results showed that HEP ameliorated hepatic damage and metabolic disorders by improving intestinal barrier function and shaping the gut microbiota and tryptophan metabolic profiles. HEP increased the abundance of Lactobacillus and certain tryptophan metabolites, including indole-3-carboxylic acid, kynurenic acid, and tryptamine in the cecum. These metabolites upregulated the expression of ZO-1 and Occludin by activating the AhR and restoring the intestinal barrier integrity. The increased intestinal barrier functions decreased LPS transferring from the intestine to the liver, inhibited hepatic LPS/TLR4/MyD88/NF-κB pathway activation, and reduced hepatic inflammatory response and apoptosis. Fecal microbiota transplantation experiments further confirmed that the hepatoprotective effect is likely mediated by HEP-altered gut microbiota and their metabolites. Overall, dietary HEP could ameliorate the hepatic damage and metabolic disorders of NAFLD through regulating the "gut-liver" axis.

Bifidobacterium bifidum Ameliorates DSS-Induced Colitis in Mice by Regulating Microbial Metabolome and Targeting Gut Microbiota

Inflammatory bowel disease (IBD) is a recurrent inflammatory condition affecting the gastrointestinal tract, and its clinical treatment remains suboptimal. Probiotics have shown effectiveness in alleviating dextran sulfate sodium salt (DSS)-induced colitis, exhibiting strain-specific anti-inflammatory properties. In this study, we compared the therapeutic effects of five strains of Bifidobacterium bifidum isolated from healthy adult feces on DSS-induced colitis in mice. Additionally, we investigated the underlying mechanisms by examining gut microbiota composition and microbial metabolome. Our findings highlighted the superior efficacy of B. bifidum M1-3 compared to other strains. It significantly improved colitis symptoms, mitigated gut barrier disruption, and reduced colonic inflammation in DSS-treated mice. Moreover, gut microbiota composition analysis revealed that B. bifidum M1-3 treatment increased the abundance and diversity of gut microbiota. Specifically, it significantly increased the abundance of Muribaculaceae, Lactobacillus, Bacteroides, and Enterorhabdus, while decreasing the abundance of Escherichia-Shigella. Furthermore, our nontargeted metabolomics analysis illustrated that B. bifidum M1-3 treatment had a regulatory effect on various metabolic pathways, including tyrosine metabolism, lysine degradation, and tryptophan metabolism. Importantly, we confirmed that the therapeutic efficiency of B. bifidum M1-3 was dependent on the gut microbiota. These results are conducive to the development of probiotic products for alleviating colitis.

Nonextractable Polyphenols from Fu Brick Tea Alleviates Ulcerative Colitis by Controlling Colon Microbiota-Targeted Release to Inhibit Intestinal Inflammation in Mice

This study was designed to elucidate the colon microbiota-targeted release of nonextractable bound polyphenols (NEPs) derived from Fu brick tea and to further identify the possible anti-inflammatory mechanism in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice. 1.5% DSS drinking water-induced C57BL/6J mice were fed rodent chow supplemented with or without 8% NEPs or dietary fibers (DFs) for 37 days. The bound p-hydroxybenzoic acid and quercetin in NEPs were liberated up to 590.5 ± 70.6 and 470.5 ± 51.6 mg/g by in vitro human gut microbiota-simulated fermentation, and released into the colon of the mice supplemented with NEPs by 4.4- and 1.5-fold higher than that of the mice supplemented without NEPs, respectively (p < 0.05). Supplementation with NEPs also enhanced the colonic microbiota-dependent production of SCFAs in vitro and in vivo (p < 0.05). Interestingly, Ingestion of NEPs in DSS-induced mice altered the gut microbiota composition, reflected by a dramatic increase in the relative abundance of Dubosiella and Enterorhabdus and a decrease in the relative abundance of Alistipes and Romboutsia (p < 0.05). Consumption of NEPs was demonstrated to be more effective in alleviating colonic inflammation and UC symptoms than DFs alone in DSS-treated mice (p < 0.05), in which the protective effects of NEPs against UC were highly correlated with the reconstruction of the gut microbiome, formation of SCFAs, and release of bound polyphenols. These findings suggest that NEPs as macromolecular carriers exhibit targeted delivery of bound polyphenols into the mouse colon to regulate gut microbiota and alleviate inflammation.

Chicoric Acid Alleviates Colitis via Targeting the Gut Microbiota Accompanied by Maintaining Intestinal Barrier Integrity and Inhibiting Inflammatory Responses

Polyphenols have shown great potential to prevent ulcerative colitis. As a natural plant polyphenol, chicoric acid (CA) has antioxidant and anti-inflammatory properties. This study explored the intervention effects and potential mechanism of CA on dextran sodium sulfate (DSS)-induced colitis mice. The results showed that CA alleviated the symptoms of colitis and maintained the intestinal barrier integrity. CA significantly downregulated the mRNA expression levels of inflammatory factors including IL-6, IL-1β, TNF-α, IFN-γ, COX-2, and iNOS. In addition, CA modulated the gut microbiota by improving the microbial diversity, reducing the abundance of Gammaproteobacteriaand Clostridium_XI and increasing the abundance ofBarnesiellaandLachnospiraceae. Further fecal microbiota transplantation experiments showed that FM from CA donor mice significantly alleviated the symptoms of colitis, verifying the key role of gut microbiota. These results indicate that CA effectively relieves DSS-induced colitis via targeting gut microbiota along with preserving intestinal barrier function and suppressing inflammatory responses.

Modulating Effects of Turmeric Polysaccharides on Immune Response and Gut Microbiota in Cyclophosphamide-Treated Mice

Turmeric, a traditional medicinal herb, is commonly used as a dietary and functional ingredient. This study aimed to investigate the effect of turmeric polysaccharides (TPs) on intestinal immunity and gut microbiota in cyclophosphamide (Cy)-induced immunosuppressed BALB/c mice. We verified that the oral administration of TPs-0 and TPs-3 (200 and 400 mg/kg, bw) improved thymus and spleen indexes, increased the whole blood immune cells (WBC) and lymph count index, and stimulated the secretion of serum immunoglobulin IgG. More importantly, TPs-0 and TPs-3 could repair intestinal immune damage and reduce intestinal inflammation. The specific mechanism is ameliorating the intestinal pathological damage, promoting CD4+ T cell secretion, regulating the expression of related cytokines, and reducing the level of critical proteins in the NF-κB/iNOS pathway. Interestingly, the intake of TPs-0 and TPs-3 significantly increased the content of short-chain fatty acids (SCFAs). Moreover, TPs-0 and TPs-3 relieved the intestinal microbiota disorder via the proliferation of the abundance of Lactobacillus and Bacteroides and the inhibition of Staphylococcus. Cumulatively, our study suggests that TPs-0 and TPs-3 can relieve intestinal immune damage by repairing the immune barrier and regulating intestinal flora disorders. TPs have potential applications for enhancing immunity as a functional food.

Limosilactobacillus fermentum HF06-derived paraprobiotic and postbiotic alleviate intestinal barrier damage and gut microbiota disruption in mice with ulcerative colitis

BACKGROUND

Paraprobiotics and postbiotics have shown potential in the treatment of ulcerative colitis (UC). However, their in vivo application is still in its infancy and their mechanisms of action are not well understood.

RESULTS

Here, we investigated the mitigation effects of Limosilactobacillus fermentum HF06-derived paraprobiotic (6-PA) and postbiotic (6-PS) on dextran sulfate sodium induced UC and the potential mechanisms. Results indicated that the administration of 6-PA and 6-PS resulted in the inhibition of weight loss and colon shortening in mice with UC. Furthermore, they led to a significant reduction in both fecal moisture content and the levels of proinflammatory cytokines and oxidative stress in the intestine of the mice. 6-PA and 6-PS treatment strengthened the intestinal mucosal barrier by dramatically upregulating the levels of zonula occludens-1 and occludin proteins. In addition, 6-PA and 6-PS restored intestinal dysbiosis by regulating abundances of certain bacteria, such as Bifidobacterium, Faecalibaculum, Muribaculaceae, Corynebacterium, Escherichia-Shigella and Clostridium_sensu_stricto_1, and regulated the level of short-chain fatty acids.

CONCLUSION

These findings illustrated for the first time that L. fermentum HF06-derived paraprobiotic and postbiotic enhanced the intestinal barrier function, and restored gut microbiota alterations. © 2023 Society of Chemical Industry.

Porcine-derived antimicrobial peptide PR39 alleviates DSS-induced colitis via the NF-κB/MAPK pathway

PR39 is an antimicrobial peptide (AMP) with a variety of biological functions, including antimicrobial, wound healing, leukocyte chemotaxis, angiogenesis, and immunomodulation; however, its therapeutic efficacy in colitis (IBD) has rarely been reported. For this reason, the present study aimed to investigate the therapeutic effect of PR39 on IBD and its underlying mechanisms. In this experiment, a mouse model of ulcerative colitis (UC) was induced with 3 % dextran sulfate (DSS) and administered by rectal injection of PR39. The results of the study showed that 5 mg/kg of PR39 was able to ameliorate the clinical manifestations of DSS-induced UC mice by improving the clinical symptoms, colonic tissue damage, up-regulating the expression of tight junction proteins, and alleviating the systemic inflammation in mice in various ways. The mechanism of action may involve inhibition of the phosphorylation level of proteins related to the NF-κB/MAPK signaling pathway and modulation of the relative abundance of potentially pathogenic (Bacteroides, Pseudoflavonifractor, Barnesiella, and Oscillibacter) and potentially beneficial bacteria (Candidatus_Saccharibacteria, Desulfovibrio, Saccharibacteria) in the intestinal flora. The results enriched the biological functions of PR-39 and also suggested that PR-39 may be able to be used as a novel drug for the treatment of IBD.

The therapeutic potential of dietary intervention: based on the mechanism of a tryptophan derivative-indole propionic acid on metabolic disorders

Tryptophan (TRP) contributes to individual immune homeostasis and good condition via three complex metabolism pathways (5-hydroxytryptamine (5-HT), kynurenine (KP), and gut microbiota pathway). Indole propionic acid (IPA), one of the TRP derivatives of the microbiota pathway, has raised more attention because of its impact on metabolic disorders. Here, we retrospect increasing evidence that TRP metabolites/IPA derived from its proteolysis impact host health and disease. IPA can activate the immune system through aryl hydrocarbon receptor (AHR) and/or Pregnane X receptor (PXR) as a vital mediator among diet-caused host and microbe cross-talk. Different levels of IPA in systemic circulation can predict the risk of NAFLD, T2DM, and CVD. IPA is suggested to alleviate cognitive impairment from oxidative damage, reduce gut inflammation, inhibit lipid accumulation and attenuate the symptoms of NAFLD, putatively enhance the intestinal epithelial barrier, and maintain intestinal homeostasis. Now, we provide a general description of the relationships between IPA and various physiological and pathological processes, which support an opportunity for diet intervention for metabolic diseases.

Alamri M, Alfaifi J, I. E. Adam M, A. Saleh L, I. Farag A, A. Elmorsy E, S. El-Wakeel H, S. Doghish A, E. Shaker M, H. Hazem S, A. Ramadan H, S. Hamad R, A. Mohammed O. Unveiling the therapeutic potential of exogenous β-hydroxybutyrate for chronic colitis in rats: novel insights on autophagy, apoptosis, and pyroptosis

Ulcerative colitis (UC) is a chronic relapsing inflammatory disease of the colorectal area that demonstrates a dramatically increasing incidence worldwide. This study provides novel insights into the capacity of the exogenous β-hydroxybutyrate and ketogenic diet (KD) consumption to alleviate dextran sodium sulfate (DSS)-induced UC in rats. Remarkably, both interventions attenuated disease activity and colon weight-to-length ratio, and improved macro and microstructures of the damaged colon. Importantly, both β-hydroxybutyrate and KD curbed the DSS-induced aberrant NLRP3 inflammasome activation as observed in mRNA and protein expression analysis. Additionally, inhibition of the NLRP3/NGSDMD-mediated pyroptosis was detected in response to both regimens. In parallel, these modalities attenuated caspase-1 and its associated consequences of IL-1β and IL-18 overproduction. They also mitigated apoptosis as indicated by the inactivation of caspase-3. The anti-inflammatory effects of BHB and KD were confirmed by the reported decline in the levels of inflammatory markers including MPO, NFκB, IL-6, and TNF-α. Moreover, these interventions exhibited antioxidative properties by reducing ROS production and improving antioxidative enzymes. Their effectiveness in mitigating UC was also evident in the renovation of normal intestinal epithelial barrier function, as shown by correcting the discrepancies in the levels of tight junction proteins ZO-1, OCLN, and CLDN5. Furthermore, their effects on the intestinal microbiota homeostasis were investigated. In terms of autophagy, exogenous β-hydroxybutyrate upregulated BECN-1 and downregulated p62, which may account for its superiority over KD in attenuating colonic damage. In conclusion, this study provides experimental evidence supporting the potential therapeutic use of β-hydroxybutyrate or β-hydroxybutyrate-boosting regimens in UC.

Colon-Targeted Release of Turmeric Nonextractable Polyphenols and Their Anticolitis Potential via Gut Microbiota-Dependent Alleviation on Intestinal Barrier Dysfunction in Mice

Solid evidence has emerged supporting the role of nonextractable polyphenols (NEPs) and dietary fibers (DFs) as gut microbiota modulators. This study aims to elucidate gut microbiota-dependent release of turmeric NEPs and examine the possible anti-inflammatory mechanism in the dextran sulfate sodium-induced ulcerative colitis (UC) model. 1.5% DSS drinking water-induced C57BL/6J mice were fed a standard rodent chow supplemented with or without 8% extractable polyphenols (EPs), NEPs, or DFs for 37 days. The bound curcumin, demethoxycurcumin, and bisdemethoxycurcumin in NEPs were released up to 181.5 ± 10.6, 65.2 ± 6.0, and 69.5 ± 7.6 μg/mL by in vitro gut microbiota-simulated fermentation and released into the colon of NEP-supplemented mice by 5.7-, 11.0-, and 7.8-fold higher than pseudo germ-free mice, respectively (p < 0.05). NEPs also enhanced the colonic microbiota-dependent production of short-chain fatty acids in vitro and in vivo (p < 0.05). Interestingly, NEP feeding significantly improved the DSS-caused gut microbiota disorder, epithelial barrier damage, and inflammation of UC mice better than EPs or DFs (p < 0.05). Meanwhile, the pseudo germ-free mice supplemented with NEPs failed to ameliorate UC symptoms. These findings manifest that turmeric NEPs as macromolecular carriers exert the target delivery of polyphenols into the colon for regulating gut microbiota to restore the impaired gut barrier function for alleviation of inflammation.

Dietary (poly)phenols mitigate inflammatory bowel disease: Therapeutic targets, mechanisms of action, and clinical observations

Inflammatory bowel diseases (IBD), which include Crohn's disease and ulcerative colitis, are a rapidly growing public health concern worldwide. These diseases are heterogeneous at the clinical, immunological, molecular, genetic, and microbial level, but characteristically involve a disrupted immune-microbiome axis. Shortcomings in conventional treatment options warrant the need for novel therapeutic strategies to mitigate these life-long and relapsing disorders of the gastrointestinal tract. Polyphenols, a diverse group of phytochemicals, have gained attention as candidate treatments due to their array of biological effects. Polyphenols exert broad anti-inflammatory and antioxidant effects through the modulation of cellular signaling pathways and transcription factors important in IBD progression. Polyphenols also bidirectionally modulate the gut microbiome, supporting commensals and inhibiting pathogens. One of the primary means by which gut microbiota interface with the host is through the production of metabolites, which are small molecules produced as intermediate or end products of metabolism. There is growing evidence to support that modulation of the gut microbiome by polyphenols restores microbially derived metabolites critical to the maintenance of intestinal homeostasis that are adversely disrupted in IBD. This review aims to define the therapeutic targets of polyphenols that may be important for mitigation of IBD symptoms, as well as to collate evidence for their clinical use from randomized clinical trials.

Urolithin A Alleviates Colitis in Mice by Improving Gut Microbiota Dysbiosis, Modulating Microbial Tryptophan Metabolism, and Triggering AhR Activation

Urolithin A (UroA) is a microbial metabolite derived from ellagitannins and ellagic acid with good bioavailability. In this study, we explored the anticolitis activity of UroA and clarified the mechanism by 16S rDNA sequencing and metabonomics. UroA alleviated dextran sulfate sodium (DSS)-induced colitis in mice, characterized by a decreased disease activity index, increased colon length, and improved colonic histopathological lesions, along with inhibited phosphorylation of the mitogen-activated protein kinase signaling pathway. In addition, UroA improved gut microbiota dysbiosis and modulated the microbiota metabolome. Furthermore, targeted metabolomics focused on tryptophan catabolites showed that UroA significantly increased the production of indole-3-aldehyde (IAld) and subsequently led to increased colonic expression of aryl hydrocarbon receptor (AhR) and promoted the serum content of IL-22 in mice with colitis. Collectively, our data identified a novel anticolitis mechanism of UroA by improving gut microbiota dysbiosis, modulating microbial tryptophan metabolism, promoting IAld production, and triggering AhR/IL-22 axis activation. However, a limitation noted in this study is that these beneficial effects of UroA were found at 50 μM in vitro and 20 mg/kg in vivo, which were nonphysiological concentrations.

Evolving interplay between natural products and gut microbiota

Growing evidence suggests gut microbiota status affects human health, and microbiota imbalance will induce multiple disorders. Natural products are gaining increasing attention for their therapeutical effects and less side effects. The emerging studies support that the activities of many natural products are dependent on gut microbiota, meanwhile gut microbiota is modulated by natural products. In this review, we summarized the interplay between the gut microbiota and host disease, and the emerging molecular mechanisms of the interaction between natural products and gut microbiota. Focusing on gut microbiota metabolite of various natural products, and the effects of natural products on gut microbiota, we summarized the biotransformation pathways of natural products, and discussed the effect of natural products on the composition modulation of gut microbiota, protection of gut mucosal barrier and modulation of the gut microbiota metabolites. Dissecting the interplay between gut microbiota and natural products will help elucidate the therapeutic mechanisms of natural products.