Dental Caries Prevention by Traditional Chinese Medicines*

The ether and methanol extracts of MAGNOLIAE CORTEX (barks of MAGNOLIA OBOVATA T HUNB. or M. OFFICINALIS R HED. et W ILS.) had potent antibacterial action against a cariogenic bacterium, STREPTOCOCCUS MATUANS. The active principles of the extracts were identified to be magnolol and honokiol, which were bactericidal in the minimal inhibitory concentration (MIC) of 6.3 μg/ml against S. MUTANS. The antibacterial action of both compounds was stronger than that of berberine, a typical antibacterial alkaloid (MIC: 50 μg/ml), Magnolol and honokiol, however, did not inhibit glucosyltransferase (EC 2.4. 1.5) activity obtained from S. MUTANS and adherence of the heat-treated cells to glass or smooth tooth surfaces in the presence of glucosyltransferase and sucrose IN VITRO.