Natural products for dental caries prevention.

Selected natural compounds were evaluated for their effects on dental caries due to different strains of Streptococcus mutans bacteria. Out of 39 tested compounds, four (catechol, emetine, quinine, and flavone) showed potent inhibitory activity on different strains of S. mutans at 6.25 microg/mL or less with inhibition of adherence <50%, two compounds (5,7-dihydroxy-4'-methoxy isoflavone and ellagic acid) exhibited a moderate inhibitory effect at 12.5 microg/mL with inhibition to adherence <50%, and 12 compounds exhibited weak antibacterial activity at 125 microg/mL or more with inhibition of adherence <25%. These compounds represent three major classes of natural products: tannins, alkaloids, and flavonoids. Further study for possible application of these compounds as inhibitors for dental caries is underway.