Skin Barrier-Improving and Anti-Inflammatory Effects of Exosomes Derived from the <i>Fructobacillus fructosus</i> NSH-1 Strain Isolated from the <i>Campsis grandiflora</i> Flower

This study investigated the anti-inflammatory and skin barrier-improving activities of <i>Fructobacillus fructosus</i> strain NSH-1-derived exosomes in LPS-stimulated RAW 264.7 cells and HaCaT cells. Nanoparticle tracking and transmission electron microscopy analyses confirmed the concentration, purity, and morphology of NSH-1 exosomes. The exosomes showed no cytotoxicity at concentrations of 1.5 × 10⁷, 3.0 × 10⁷, and 6.0 × 10⁷ particles/ml, but demonstrated concentration-dependent inhibitory activity against nitric oxide production. Furthermore, NSH-1 exosomes significantly inhibited the production of pro-inflammatory mediators, including TNF-α, IL-6, IL-1β, and PGE₂. In HaCaT cells, treatment with NSH-1 exosomes enhanced skin barrier function by increasing the production of hyaluronan and collagen in a concentration-dependent manner and promoting wound-healing activity. Western blot analysis revealed that treatment with NSH-1 exosomes reduced the expression levels of inflammatory proteins iNOS and COX-2, while increasing the expression of skin barrier-related proteins such as filaggrin, involucrin, and loricrin. Overall, these findings indicate that NSH-1 exosomes exert strong anti-inflammatory activity by suppressing the expression of the pro-inflammatory cytokines iNOS and COX- 2, while simultaneously enhancing skin barrier integrity by upregulating filaggrin, involucrin, and loricrin. Thus, exosomes derived from <i>F. fructosus</i> NSH-1, isolated from <i>Campsis grandiflora</i> flowers, demonstrate promise as natural bioactive agents for anti-inflammatory and skin barrier-improving applications.