Sabinene suppresses growth, biofilm formation, and adhesion of Streptococcus mutans by inhibiting cariogenic virulence factors

Abstract

ABSTRACTBackground: Streptococcus mutans is one of the most important cariogenic bacteria associated with dental caries. Sabinene is a major component of several herbal essential oils. However, the anti-cariogenic effects of sabinene and the underlying mechanism remain to be elucidated.Objectives: We investigated the inhibitory effects of sabinene on the cariogenic activity and studied the underlying mechanism.Design: S. mutans were treated with various concentrations of sabinene and the inhibitory effects were evaluated based on the bacterial growth, acid production and biofilm formation. Real-time polymerase chain reaction (PCR) was performed for several virulence factors.Results: The growth and adherence of S. mutans were inhibited by sabinene. Consistent with the inhibitory effects on bacterial adhesion, gbpB level significantly decreased. Acid production and biofilm formation was also inhibited. In line with the inhibitory effects of sabinene on biofilm formation and pH tolerance, real-time PCR results showed the down regulation in the expression levels of gtfB, gtfC, gtfD, vicR, brpA, and relA. Moreover, high concentrations of sabinene exhibited bactericidal activity.Conclusion: Together our results suggest that sabinene serves as a useful component in the inhibition of the cariogenic activity of S. mutans, indicative of its possible applications in the development of oral healthcare products.