2007 Volume 50 Issue 2 Pages 140-145
Dental caries are caused by endogenous infection with bacteria resident in the oral cavity. The mutans streptococci are generally accepted as the main bacteria responsible for dental caries. Recently, many investigators have reported experimental studies of caries prevention using various antibacterial products. We focused on Diospyros Kaki Thunb. extracts, which have been used as crude drugs of plants since ancient times in Japan. The aim of this study was to determine the inhibitory effects of Diospyros Kaki Thunb. extracts as an anticariogenic component In vivo rat caries experiments were performed as follows JCL-Sprague-Dawley rats were infected orally with Streptococcus mutans PS-14. After sacrifice, the caries scores of the mandibles were determined by the Keyes method. Crude glucosyltransferase (GTase) was prepared from S. mutans PS-14 and activity was tested by measuring the total amounts of water-insoluble glucan (WIG). The following conclusions were obtained: 1. A significantly lower caries score was observed in specific pathogen-free rats infected with S.mutans PS-14 and fed with a cariogenic Diet 2000 containing 0.05% ursolic acid or 0.05% oleanolic acid as compared with controls fed the cariogenic Diet 2000 without Diospyros Kaki Thunb. extracts. 2. Diospyros Kaki Thunb. extracts showed an inhibitory effect on WIG formation from sucrose by crude GTase of S.mutans PS-14. In conclusion, the results of these in vivo rat experiments suggested that Diospyros Kaki Thunb. extracts have antibacterial activity against S.mutans.
