2010 Volume 53 Issue 3 Pages 296-303
Dental caries are manifestations of a disease caused by acid-producing bacteria in the oral cavity. They have also been elucidated as an endogenous disease caused by cariogenic bacteria, typified by Streptococcus mutans. Caries prevention is currently done by applying fluoride, which is intended to enhance the tooth structure of hosts as a preventive measure. Aside from this countermeasure, however, no effective caries prevention measure is widely used. Recently, various studies have been conducted on ways of reducing the morbidity rates of dental caries, and to prevent them. Various agents for oral use, as well as foods and beverages which have caries-prevention effects, have been created. Anthocyanin, a kind of flavonoid, is a pigment used as a food additive. It is of vegetable origin and is reported to have antioxidant effects, anti-hepatotoxic effects, and curative properties for optic nerve dysfunction and arterial sclerosis. In this study, we examined nasunin, a polyphenol included in the skin of eggplant and which is included among pigments of the anthocyanin family. This study investigated, using in vitro experiments, whether nasunin, belonging to delphinine-type anthocyanins, can prevent caries through its antibacterial effect. The following conclusions were obtained. 1. The minimum inhibitory concentration against S. mutans was revealed to be 500μg/ml. 2. The minimum inhibitory concentration against Streptococcus sobrinus was revealed to be 250μg/ml. 3. The minimum inhibitory concentration against Actinomyces viscosus was revealed to be 500μg/ml. 4. The antibacterial activities were found to be a bactericidal effect against resting cells of S. mutans, S. sobrinus and A. viscosus. 5. Nasunin considerably inhibited sucrose-dependent water insoluble glucan synthesis activity of crude glucosyltransferase produced by S. mutans PS-14 and S. sobrinus 6715. From the above, nasunin was found to have a prominent bactericidal effect against cariogenic bacteria, suggesting that it has anticariogenic effects.
