Propionic acid-rich fermented blueberry supernatant improves DSS-induced colitis symptoms by regulating inflammatory pathways

This study investigated the anti-inflammatory effects of a short-chain fatty acid (SCFA)-enriched fermented blueberry supernatant (BBS) and its key component, propionic acid (PropA), in both in vitro and in vivo models of colitis. High-performance liquid chromatography confirmed the presence of PropA in BBS at a concentration of 1.86 mg/mL. In LPS-stimulated RAW 264.7 macrophages, BBS significantly reduced nitric oxide, monocyte chemoattractant protein-1, and interleukin-6 production in a dose-dependent manner. Western blotting revealed that BBS suppressed the expression of inducible nitric oxide synthase, COX-2, and NF-κB. In a DSS-induced colitis mouse model, BBS administration significantly improved disease indicators, including body weight loss, colon shortening, and spleen enlargement. Moreover, BBS restored serum IgG and colonic IgA levels and reduced systemic and local inflammatory mediators. These findings highlight the potential of SCFA-enriched fermented blueberry as a functional postbiotic food capable of modulating inflammatory responses through NF-κB and COX-2 signaling pathways in colitis. • SCFA-enriched fermented blueberry supernatant (BBS) was successfully developed. • BBS and propionic acid suppressed NF-κB and COX-2 activation in inflamed cells. • BBS alleviated DSS-induced colitis by reducing inflammation and restoring gut immunity. • BBS improved colonic IgA and systemic IgG levels in colitis-induced mice. • BBS shows promise as a postbiotic functional food for colitis management.