Low Dietary Flavonoid Consumption Is Associated to Severe Inflammatory Bowel Disease

Decoding polyphenol metabolism in patients with Crohn's disease: Insights from diet, gut microbiota, and metabolites

Crohn's disease (CD) is a chronic and progressive inflammatory disease that can involve any part of the gastrointestinal tract. The protective role of dietary polyphenols has been documented in preclinical models of CD. Gut microbiota mediates the metabolism of polyphenols and affects their bioactivity and physiological functions. However, it remains elusive the capacity of microbial polyphenol metabolism in CD patients and healthy controls (HCs) along with its correlation with polyphenols intake and polyphenol-derived metabolites. Thus, we aimed to decode polyphenol metabolism in CD patients through aspects of diet, gut microbiota, and metabolites. Dietary intake analysis revealed that CD patients exhibited decreased intake of polyphenols. Using metagenomic data from two independent clinical cohorts (FAH-SYSU and PRISM), we quantified abundance of polyphenol degradation associated bacteria and functional genes in CD and HCs and observed a lower capacity of flavonoids degradation in gut microbiota residing in CD patients. Furthermore, through analysis of serum metabolites and enterotypes in participants of FAH-SYSU cohort, we observed that CD patients exhibited reduced levels of serum hippuric acid (HA), one of polyphenol-derived metabolites. HA level was higher in healthier enterotypes (characterized by dominance of Ruminococcaceae and Prevotellaceae, dominant by HCs) and positively correlated with multiple polyphenols intake and abundance of bacteria engaged in flavonoids degradation as well as short-chain fatty acid production, which could serve as a biomarker for effective polyphenol metabolism by the gut microbiota and a healthier gut microbial community structure. Overall, our findings provide a foundation for future work exploring the polyphenol-based or microbiota-targeted therapeutic strategies in CD.

The chemical composition, protective effect of Rheum officinale leaf juice and its mechanism against dextran sulfate sodium-induced ulcerative colitis

BACKGROUND

Rhubarb is widely distributed and cultivated worldwide, and its leaves presented antioxidant activity and could be used as food additive. However, the chemical ingredients, and protective effect of Rheum officinale leaf juice (JROL) on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) are still unclear.

PURPOSE

This paper sought to the characterization and functional properties of JROL, and explore the underlying mechanism on UC mice.

METHODS

UPLC-ESI-Q-TOF/MS and other analytical instruments were employed to determine the chemical ingredients of JROL. After inducing UC model using 3% DSS, multiple biological methods were used to evaluate its protective effect and the potential mechanism.

RESULTS

JROL is rich in proximate compositions and minerals and has high nutritional value, and contains reducing sugars, polysaccharides and pectin. Fifteen compounds were identified using UPLC-ESI-Q-TOF/MS. Among them, rutin has the highest content (2.22 %) in UPLC analysis. JROL presented protective effect on DSS-induced UC, and alleviated morphological alterations and ultra-structural feature of tissue, and the polysaccharides and flavonoids may contribute to its protective effect. JROL inhibited NF-κB/NLRP3 signaling pathway to alleviate inflammatory response, oxidative stress and intestinal injury by decreasing the expression of p-p65, p-IκBα, NLRP3, ASC, etc.. Moreover, it up-regulated the expression of tight junction proteins, and re-balanced the disturbance of gut microbiota to regulate the inflammatory response. Finally, a correlation among the inflammatory response, NF-κB/NLRP3 pathway and gut microbiota was established. Moreover, JROL presented the safety in the acute toxicity test.

CONCLUSION

JROL could be used as a potential new source for treating UC.

Effect of a Flavonoid Combination of Apigenin and Epigallocatechin-3-Gallate on Alleviating Intestinal Inflammation in Experimental Colitis Models

Inflammatory bowel disease (IBD) is an autoimmune disease that leads to severe bowel symptoms and complications. Currently, there is no effective treatment, and the exact cause of IBD remains unclear. In the last decades, numerous studies have confirmed that flavonoids can have a positive impact on the treatment of IBD. Therefore, this study investigated the protective effect of a flavonoid combination of apigenin and epigallocatechin-3-gallate (EGCG) on IBD. In vitro studies in which Caco-2 cell monolayers were incubated with different concentrations of flavonoids found that the flavonoid-treated group exhibited increased transepithelial electrical resistance (TEER) at high concentrations, indicating a protective effect on the barrier function of the intestinal epithelium. In vivo studies showed that flavonoids significantly attenuated inflammatory levels in both chronic and acute hapten-mediated experimental colitis models in a time- and dose-dependent manner. In addition, the activity of myeloperoxidase (MPO) and the level of proinflammatory cytokines in the colon tissue were significantly reduced. Interestingly, the levels of anti-inflammatory cytokines were also dramatically increased. Finally, flavonoids were found to positively modulate the composition of the gut microbiota in the colon. Therefore, a combination of flavonoids could be a promising therapeutic agent for the future adjunctive treatment of IBD.