Probiotic Characterization and Anti-biofilm Activity of Ligilactobacillus salivarius: Implications for Periodontal Disease Management.

Porphyromonas gingivalis-driven periodontal disease is closely associated with pathogenic biofilm formation and oxidative stress-mediated tissue damage. This study evaluated the probiotic characteristics, antioxidant activity, and anti-biofilm effects of Ligilactobacillus salivarius and its cell-free supernatant (CFS). L. salivarius maintained growth under 0.8 mM H₂O₂, pH 5.0, and lysozyme exposure at 100 and 200 µg/mL, indicating tolerance to oxidative, acidic, and oral innate immune-related stresses. The strain showed an auto-aggregation rate of 56.6 ± 3.0% and co-aggregation rate with P. gingivalis of 46.7 ± 5.5%. Surface hydrophobicity was highest in chloroform (76.0 ± 3.0%), followed by ethyl acetate (39.1 ± 2.9%) and xylene (1.3 ± 0.9%). L. salivarius CFS exhibited strong antioxidant activity, with DPPH and ABTS radical-scavenging rates of 87.1 ± 4.0% and 97.8 ± 1.0%, respectively, and a FRAP value of 1.30 ± 0.06 µM FeE/mL. The MIC of CFS against P. gingivalis was 20% (v/v), and the inhibition zone was 12.5 mm. CFS treatment also reduced P. gingivalis biofilm biomass and increased non-viable cells within biofilms. No significant cytotoxicity toward gingival epithelial cells were observed at 2.5-20% CFS. These findings suggest that L. salivarius CFS has probiotic-associated, antioxidant, antibacterial, and anti-biofilm potential in vitro, although further studies are required to identify active components and validate its periodontal protective effects in vivo.