Eugenol triggers different pathobiological effects on human oral mucosal fibroblasts

Area of Science:

• Oral pathology
• Cell biology
• Toxicology

Background:

• Betel quid (BQ) chewing is prevalent in some regions and linked to oral diseases.
• Eugenol is a major component of BQ with potential biological effects.
• Understanding eugenol's impact on oral tissues is crucial for disease prevention.

Purpose of the Study:

• To investigate the pathobiological effects of eugenol on oral mucosal fibroblasts.
• To determine the concentration- and time-dependent cytotoxicity of eugenol.
• To elucidate the mechanisms underlying eugenol's effects, including its impact on glutathione (GSH), ATP, and lipid peroxidation.

Main Methods:

• Cultured human oral mucosal fibroblasts were exposed to varying concentrations of eugenol.
• Cell viability was assessed using standard assays.
• Levels of intracellular glutathione (GSH) and ATP were measured.
• Lipid peroxidation and xanthine oxidase activity were evaluated.
• DNA strand break activity was assessed.

Main Results:

• Eugenol exhibited cytotoxicity to oral fibroblasts at concentrations >3 mmol/L in a dose- and time-dependent manner.
• Cytotoxicity was linked to intracellular glutathione (GSH) depletion.
• Eugenol decreased cellular ATP levels and inhibited lipid peroxidation.
• Inhibition of lipid peroxidation was partly due to dose-dependent inhibition of xanthine oxidase (IC50 ≈ 0.3 mmol/L).
• No DNA strand breaks were observed at concentrations up to 3 mmol/L.

Conclusions:

• High concentrations of eugenol from BQ may contribute to oral submucous fibrosis and oral cancer via cytotoxicity.
• Low concentrations (<1 mmol/L) of eugenol may offer cytoprotection against reactive oxygen species-induced genetic damage by inhibiting xanthine oxidase and lipid peroxidation.