Chamaecyparis obtusaSuppresses Virulence Genes inStreptococcus mutans

Abstract

Chamaecyparis obtusa (C. obtusa)is known to have antimicrobial effects and has been used as a medicinal plant and in forest bathing. This study aimed to evaluate the anticariogenic activity of essential oil ofC. obtusaonStreptococcus mutans, which is one of the most important bacterial causes of dental caries and dental biofilm formation. Essential oil fromC. obtusawas extracted, and its effect on bacterial growth, acid production, and biofilm formation was evaluated.C. obtusaessential oil exhibited concentration-dependent inhibition of bacterial growth over 0.025 mg/mL, with 99% inhibition at a concentration of 0.2 mg/mL. The bacterial biofilm formation and acid production were also significantly inhibited at the concentration greater than 0.025 mg/mL. The result of LIVE/DEAD® BacLight™Bacterial Viability Kit showed a concentration-dependent bactericidal effect onS. mutansand almost all bacteria were dead over 0.8 mg/mL. Real-time PCR analysis showed that gene expression of some virulence factors such asbrpA, gbpB, gtfC,andgtfDwas also inhibited. In GC and GC-MS analysis, the major components were found to beα-terpinene (40.60%), bornyl acetate (12.45%),α-pinene (11.38%),β-pinene (7.22%),β-phellandrene (3.45%), andα-terpinolene (3.40%). These results show thatC. obtusaessential oil has anticariogenic effect onS. mutans.