This study aimed to explore the protective effects of raffinose (Raf) against inflammatory bowel disease in mice with colitis. Mice were administered 100, 200, or 400 mg/kg Raf for 21 d, followed by drinking-water containing 3% dextran sulfate sodium salt (DSS) for 3 d. Thereafter, the phenotype, pathological lesions in the colon, cytokines levels, and gut microbiota were evaluated. Treatment with Raf reduced the severity of the pathological changes in the colon, mitigating the reduction in colon length. Following Raf intervention, serum levels of inflammatory cytokines (IL-2, IL-6, IL-1β, and TNF-α) tended to return to normal. These results suggest that the anti-inflammatory effects of Raf are associated with a reduction in TLR4–MyD88–NF-κB pathway expression in mouse colonic tissues. Analysis of gut microbiota abundance and its correlation with colitis parameters revealed that DSS-induced dysbiosis was partially mitigated by Raf. In conclusion, Raf exerts a protective effect in colitis by modulating the gut microbiota and TLR4-MyD88-NF-κB pathway.

This study evaluated the inhibitory activity of quercetin at sub-inhibitory concentrations on quorum-sensing (QS) molecules in vitro and the effects of dietary supplementation with quercetin (for 24 consecutive days) on enterotoxigenic Escherichia coli (ETEC)-induced inflammatory and oxidative stress responses in weaned piglets. The piglets were fed one of three diets: the basal diet (Con), ETEC challenge (K88) after the basal diet, or ETEC challenge (quercetin + K88) after the basal diet supplemented with 0.2% quercetin. In vitro experiments revealed that 5 mg/mL quercetin exhibited the strongest QS inhibitory activity and reduced pigment production by Chromobacterium violaceum ATCC12472 by 67.70%. In vivo experiments revealed that quercetin + K88 significantly increased immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) levels in the serum, ileum mucosa, and colon mucosa; increased glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) levels in the serum, liver, and colon mucosa; and decreased cluster of differentiation 3 (CD3) and cluster of differentiation 8 (CD8)activity in the serum compared with K88 alone. Quercetin + K88 significantly alleviated pathological damage to the liver and spleen and upregulated antioxidant genes (nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1(HO-1), CAT, SOD, and glutathione s-transferase (GST)). Inducible nitric oxide synthase (iNOS) and kelch-like ech-associated protein 1 (Keap1), which cause oxidative damage to the liver and spleen, were significantly downregulated. The acetic acid content in the cecum was significantly increased, and the E. coli count and QS signal molecule autoinducer-2 (AI-2) yield were significantly reduced. In conclusion, 0.2% dietary quercetin can alleviate ETEC-induced inflammation and oxidative stress in weaned piglets.

Salvia sclarea L. extract contains various bioactive components such as flavonoids and fatty acids, exhibiting anti-inflammatory, antioxidant, and antibacterial properties. This study aimed to investigate the effects of Salvia sclarea L. extract on the gut microbiota and serum metabolome in lambs. Sixty 2-month-old Chinese Merino female lambs (body weight 20 ± 2 kg) were randomly assigned to five groups. The control (CK) group received the basal diet only, while the treatment groups received the basal diet supplemented with 0.04 mL/kg (CL1), 0.08 mL/kg (CL2), 0.12 mL/kg (CL3), and 0.16 mL/kg (CL4) of Salvia sclarea L. extract, respectively. The results showed that Firmicutes, Bacteroidetes, Spirochaetes, and Proteobacteria were identified as the dominant phyla across all groups (>90%). Compared with the CK group, CL1 and CL2 groups significantly reduced the relative abundance of Tenericutes (decreased by 38.2% and 32.9%, respectively, p < 0.05); the relative abundance of Patescibacteria in the CL1 group was significantly lower (decreased by 55.2%, p < 0.05). At the genus level, Ruminococcaceae constituted a substantial proportion, including Ruminococcaceae UCG-005, UCG-010, UCG-014, and NK4A214 group. STAMP analysis revealed that Klebsiella was significantly enriched in CL2, CL3, and CL4 groups compared to the CK group (p < 0.05). Correlation analysis between microbiota and immune indices showed that Christensenellaceae R-7 group was significantly negatively correlated with TNF-α (p < 0.05); Ruminococcaceae UCG-005 was significantly negatively correlated with IFN-γ (p < 0.05) and showed a negative correlation trend with immunoglobulins (IgA, IgG, IgM). Conversely, Ruminococcaceae UCG-014 was significantly positively correlated with IL-4 (p < 0.05) but showed a negative correlation trend with IgM. Untargeted metabolomics analysis identified 8, 18, 25, and 20 differential metabolites in CL1, CL2, CL3, and CL4 groups, respectively. Notably, 3-hydroxy-7-methoxyflavone and Gamma-Glu-Cys were significantly upregulated across all treatment groups. KEGG pathway enrichment analysis indicated that these differential metabolites were primarily involved in nucleotide metabolism, fatty acid biosynthesis, and oxidative stress-related pathways. Further Spearman correlation analysis revealed significant associations between gut microbiota and differential metabolites. Specifically, g_Klebsiella was significantly positively correlated with 3-Hydroxycapric acid and 3-hydroxy-7-methoxyflavone (p < 0.05). In conclusion, Salvia sclarea L. extract modulates host energy metabolism by regulating nucleotide metabolism and fatty acid biosynthesis, and enhances immune function by alleviating oxidative stress, through the remodeling of gut microbiota and serum metabolome.