The effects of diallyl sulfide upon P orphyromonas gingivalis lipopolysaccharide stimulated proinflammatory cytokine expressions and nuclear factor‐kappa B activation in human gingival fibroblasts

Background and Objective Diallyl sulfide ( DAS ), a flavor compound from garlic, has varied potential therapeutic activities. Periodontitis is a disease that develops because of host‐mediated inflammation to periodontal pathogens. In this study, the effects of DAS on the common proinflammatory cytokines and nuclear factor‐kappa B ( NF ‐κ B ) in human gingival fibroblasts ( HGF s) being stimulated with lipopolysaccharide from P orphyromonas gingivalis , a potent periodontal pathogen, were evaluated. Material and Methods Cytotoxicities of DAS and lipopolysaccharide on HGF s were measured with MTS assay. The m RNA and protein expressions of proinflammatory cytokines, including interleukin ( IL )‐1β, IL ‐6 and tumor necrosis factor ( TNF )‐α, from the HGF s treated with lipopolysaccharide with and without DAS were examined with reverse transcription–polymerase chain reaction and immunocytochemistry, respectively. In addition, the activation and nuclear translocation of NF ‐κ B with and without DAS were compared. Results DAS and lipopolysaccharide treatments within 3 m m and 10 μg/mL, respectively, did not affect the survival rate of HGF s. Lipopolysaccharide (1 μg/mL) significantly increased the m RNA expressions of IL ‐1β, IL ‐6 and TNF ‐α; however, DAS (1 m m ) inhibited these expressions. The protein expressions of TNF ‐α, IL ‐1β, as well as the NF ‐κ B nuclear translocation were increased after lipopolysaccharide treatment, but decreased when there was a DAS pretreatment. Conclusion DAS diminished P . gingivalis lipopolysaccharide ‐stimulated cytokine expression and NF ‐κ B activation in HGF s; we therefore suggest DAS may be beneficial on periodontal inflammation.