IADR Abstract Archives
Inhibition of Streptococcus mutans Biofilm Formation by an Oxazole Derivative
Objectives: Oxazole and its derivatives have been shown to possess significant biological activities, though it is still unknown whether oxazole alkaloids are capable of affecting the major cariogenic bacterium, Streptococcus mutans (S. mutans) and development of dental caries. The aim of this study was to investigate the effects of an oxazole derivative, named 5H6 on S. mutans biofilm formation, extracellular polysaccharides (EPS) synthesis and its virulence.
Methods: The inhibitory effect of 5H6 on S. mutans biofilm formation and maturation was investigated using biofilm formation assays. Atomic force microscopy (AFM) was utilized to characterize the adhesion forces of S. mutans biofilms in the presence and absence of 5H6. The effect of 5H6 on EPS synthesis in S. mutans biofilms was visualized using confocal laser scanning microscopy (CLSM) and quantitatively analyzed by anthrone-sulfuric method. In addition, changes of cell-free glucosyltransferase (Gtf) activity after 5H6 treatment were measured by zymogram assays. We also evaluated the in vivo anti-caries efficacy of 5H6 in a rat model.
Results: Compared with the vehicle control, 5H6 significantly inhibited S. mutans biofilm formation and maturation (P<0.05) without any bactericidal activity or inhibitory effect on planktonic growth. The results of AFM suggested that 5H6 was able to reduce adhesion forces of S. mutans biofilm to surfaces. CLSM, anthrone-sulfuric method and zymogram assays showed that 5H6 inhibited synthesis of water-insoluble EPS by antagonizing Gtfs. In the animal experiments, 5H6 significantly reduced the incidence and severity of smooth-surface and sulcal-surface caries with a lower percentage of S. mutans in the animals’ dental plaque compared to the vehicle control group (P<0.05).
Conclusions: Our results showed the oxazole derivative, 5H6, is able to inhibit biofilm formation, synthesis of water-insoluble EPS and cariogenicity of S. mutans. It shows promise for the future development of alternative anticariogenic therapies.
Methods: The inhibitory effect of 5H6 on S. mutans biofilm formation and maturation was investigated using biofilm formation assays. Atomic force microscopy (AFM) was utilized to characterize the adhesion forces of S. mutans biofilms in the presence and absence of 5H6. The effect of 5H6 on EPS synthesis in S. mutans biofilms was visualized using confocal laser scanning microscopy (CLSM) and quantitatively analyzed by anthrone-sulfuric method. In addition, changes of cell-free glucosyltransferase (Gtf) activity after 5H6 treatment were measured by zymogram assays. We also evaluated the in vivo anti-caries efficacy of 5H6 in a rat model.
Results: Compared with the vehicle control, 5H6 significantly inhibited S. mutans biofilm formation and maturation (P<0.05) without any bactericidal activity or inhibitory effect on planktonic growth. The results of AFM suggested that 5H6 was able to reduce adhesion forces of S. mutans biofilm to surfaces. CLSM, anthrone-sulfuric method and zymogram assays showed that 5H6 inhibited synthesis of water-insoluble EPS by antagonizing Gtfs. In the animal experiments, 5H6 significantly reduced the incidence and severity of smooth-surface and sulcal-surface caries with a lower percentage of S. mutans in the animals’ dental plaque compared to the vehicle control group (P<0.05).
Conclusions: Our results showed the oxazole derivative, 5H6, is able to inhibit biofilm formation, synthesis of water-insoluble EPS and cariogenicity of S. mutans. It shows promise for the future development of alternative anticariogenic therapies.