Preventive Effect and Mechanism of Apple polyphenols on Experimental Dental Caries in Hamsters

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13672178
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 矯正・小児・社会系歯学
• Research Institution: Tsurumi University
• Principal Investigator: MATSUDAIRA Fumio Tsurumi University, Dental Medicine, Assistant professor, 歯学部, 助教授 (10014135)
• Co-Investigator(Kenkyū-buntansha): YANAGIDA Akio Tokyo University of Pharmacy and Life Science, Assistant, 薬学部, 助手 (40318192) ; YAMADA Hidenori Tsurumi University, Dental Medicine, Assistant, 歯学部, 助手 (60240032)
• Project Period (FY): 2001 – 2002
• Keywords: polyphenol / procyanidin / glucosyltransferase / chromatography / S.mutans / caries / hamster / fluoride

Research Abstract

We developed an effective purification method of bacterial glucosyltransferase (GTF) from a cell-lysate of S. mutans and a cultured-media of S. sobrinus. The GTF in the cell-lysate and/or the cultured-media was concentrated and purified by counter-current and hydroxyapatite chromatographies. Among all polyphenolic compounds in apple, procyanidin was the most effective inhibitor against the purified GTF activity (IC_<50> = 0.6 μmL), and the dissociation constant (K_D) of interaction between procyanidin and the purified GTF was estimated at about 10 nM by an interaction analysis using IAsys optical biosensor. We then investigated the effects of procyanidins extracted from apple polyphenols on the inhibition of experimental dental caries of hamsters and on plaque formation by determining its mechanism on the activation of GTF in vitro. Fifty-one 3-week-old male golden hamsters were all infected orally with strains of S. mutans MT8148. For 12 weeks all the animals were given diet 2000 (56% of sucrose). At 6 weeks' age, the animals were divided into 3 balanced groups : one control (CONT group) and two groups received topical applications of solutions of either 0.25% procyanidin (APP group) or 500ppm of sodium fluoride (NaF group). The topical applications were done 3 times a week for a 6-week period and a mini-syringe was used to rinse 0.2ml of the APP and NaF solutions onto the animals' molars. All the molar surfaces were assessed for plaque accumulation and caries severity using a 0-5 scoring reference. No severe caries developed in the three groups. Plaque and caries scores were significantly lower in the NaF group as compared with the CONT group (p<0.05). No significant differences were found between the APP and CONT groups. These findings served as a preliminary investigation to determine possible effects of caries-preventive substances other than fluoride, which might be beneficial for controlling dental caries.