Exosome-like Nanovesicles from Hordeum vulgare L. Fermented with Lactiplantibacillus plantarum BMSE-HMP251 Ameliorate LPS-Induced Inflammation in HT-29 and RAW 264.7 Cells

Human breast milk harbors commensal lactic acid bacteria with probiotic potential, and microbial fermentation may enhance the bioactivity of plant-derived exosome-like nanovesicles (EVs); this study evaluated whether <i>L. plantarum</i> BMSE-HMP251 isolated from breast milk could safely ferment <i>Hordeum vulgare</i> L. and improve the anti-inflammatory activity of derived EVs. BMSE-HMP251 was identified by 16S rRNA sequencing and characterized by biochemical, safety, and genomic analyses. EVs derived from <i>Hordeum vulgare</i> L. extract and BMSE-HMP251-fermented broth were evaluated for physicochemical properties, antioxidant activity, cytotoxicity, and anti-inflammatory activity in LPS-stimulated HT-29 and RAW 264.7 cells. EVs derived from <i>Hordeum vulgare</i> L. fermentation exhibited a distinct size distribution and significantly enhanced bioactivity, including higher DPPH radical scavenging activity and greater suppression of nitric oxide production and proinflammatory cytokine (TNF-α and IL-1β) mRNA expression, compared with EVs from unfermented extracts. These effects were observed following fermentation with the human breast milk-derived strain <i>L. plantarum</i> BMSE-HMP251, which showed species-consistent phenotypic and genomic characteristics and no safety concerns. Overall, fermentation markedly enhances the anti-inflammatory potential of plant-derived EVs, supporting fermentation as a safe and effective strategy to improve their functional value.