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 . Key Word Index Magnolia obovata - Magnolia officinalis - Magnoliaceae - Streptococcus mutans - Magnolol - Honokiol - Dental Caries - Antibacterial Action