Anticariogenic properties of the extract of Cyperus rotundus.

Streptococcus mutans (S. mutans) is known as the causative bacteria in the formation of dental plaque and dental caries. The aim of this experiment was to investigate the effects of Cyperus rotundus (C. rotundus) tuber extract on the growth, acid production, adhesion, and water-insoluble glucan synthesis of S. mutans. The growth and acid production were reduced by the extract of C. rotundus in a dose dependent manner. The extract of C. rotundus markedly inhibited the adherence of S. mutans to saliva-coated hydroxyapatite beads (HAs). The adherence was repressed by more than 50% at the concentration of 0.5 mg/ml of the extract and complete inhibition was observed at the concentration of 4 mg/ml of the extract. On the activity of glucosyltransferase (GTFase) which synthesizes water-insoluble glucan from sucrose, the extract of C. rotundus showed more than 10% inhibition at a concentration of 2 mg/ml. These results suggest that C. rotundus may inhibit cariogenic properties of S. mutans. Further studies are necessary to clarify the active constituents of C. rotundus responsible for such biomolecular activities.