Gambir, one of rubiaceae planted in Indonesia, is used as a favorite food and is traditionally considered as an effective protector of dental caries in Southeast Asia. A dried gambir, called catechu, containing much of catechin, one of the tannins, has been used as an astringent material for the mouth. In this study, the aqueous extract of gambir was examined for the inhibition of the synthesis of insoluble glucan (ISG) synthesis and the growth of mutans streptococci (MS)in vitro.
Gambir aqueous extract inhibits ISG synthesis by glcosyltransferase in MS and it is speculated that the principal ingredient which inhibits the glcosyltransferase activity is most probably tannins.