The Radical Scavenging Activity and Cytotoxicity of Resveratrol, Orcinol and 4-Allylphenol and their Inhibitory Effects on Cox-2 Gene Expression and Nf-κb Activation in RAW264.7 Cells Stimulated with Porphyromonas gingivalis-fimbriae.

Background/aim: Resveratrol is a polyphenol with efficient anti-oxidative and anti-inflammatory activity. To clarify the molecular mechanism responsible for its anti-inflammatory action, we investigated the radical scavenging activity, cytotoxicity and anti-inflammatory activity of resveratrol and its related compounds, orcinol and 4-allylphenol.

Materials And Methods: The radical scavenging activities of these compounds were determined by the DPPH (2,2'-diphenyl-1-picrylhydrazyl) assay and their cytotoxicities against RAW264.7 cells were determined using a cell-counting kit (CCK-8). The inhibitory effects of these compounds on cyclooxygenase-2 (Cox2) expression in RAW264.7 cells stimulated with Porphyromonas gingivalis (Pg) fimbriae were also determined using real-time polymerase chain reaction and western blot analysis, while inhibition of the fimbria-stimulated activation of nuclear factor-kappa B (Nf-κb) was evaluated using western blot analysis and enzyme-linked immunosorbent assay-like microwell colorimetric transcription factor activity assay, respectively. The quantum chemical parameters were calculated on the basis of the density function theory (DFT) BLYP/6-31G*.

Results: DPPH radical scavenging activity declined in the order resveratrol > orcinol > 4-allylphenol. The cytotoxicity of the compounds was in the order 4-allylphenol > resveratrol > orcinol. The inhibitory effect on Pg fimbria-stimulated Cox2 expression and Nf-κb activation was enhanced by resveratrol-alone. Resveratrol showed high electronegativity (χ) and softness (σ) values, as determined by quantum chemical calculations.

Conclusion: Resveratrol exerts potent anti-inflammatory activity in RAW264.7 cells stimulated with Pg-fimbriae and may be applicable as a therapeutic agent for inflammatory periodontal disease as a manifestation of systemic disease.