Clostridium dalinum: A Novel Lactic Acid Bacterium with Excellent Antioxidant and Anti-inflammatory Functions Through NF-κB, Keap1-Nrf2-ARE Signaling Pathways.

The health benefits of probiotics are widely acknowledged, and the development of probiotics with antioxidant and anti-inflammatory properties is expected to further advance the probiotic industry and enhance human health. This study reports a novel lactic acid strain, Clostridium dalinum, isolated from soil. As a member of the Clostridium genus, this strain demonstrates strong coagulation properties and a high safety profile. Notably, C. dalinum exhibits exceptional gastrointestinal tolerance, retaining viability under acidic conditions (pH 3.0 for 2 h) and high bile stress (3% bile for 3 h). Evaluation using Caco-2 cells confirmed that both the strain and the yogurt fermented with it exhibit antioxidant and anti-inflammatory functions mediated through the NF-κB and Keap1-Nrf2-ARE signaling pathways. Metabolomics analysis identified significantly elevated levels of antioxidant and anti-inflammatory metabolites including Chavicol, Neocnidilide, Procaine, and 6-Phosphogluconic acid in the C. dalinum group, functionally linked to amino acid, lipid, and cofactor metabolism pathways. Pathway enrichment analysis further demonstrated specific activation of butanoate metabolism by C. dalinum. In the D-yogurt group, key metabolites were similarly upregulated, while purine metabolism was uniquely downregulated. These findings confirm that C. dalinum is a safe probiotic with notable antioxidant and anti-inflammatory properties, demonstrating potential for immune modulation and therapeutic applications in intestinal damage and inflammation. Importantly, this discovery offers a novel perspective for probiotic development.