Inhibition of Streptococcus mutans biofilm accumulation and development of dental caries in vivo by 7-epiclusianone and fluoride

Abstract

7-Epiclusianone (7-epi), a novel naturally occurring compound isolated from Rheedia brasiliensis, effectively inhibits the synthesis of exopolymers and biofilm formation by Streptococcus mutans. In the present study, the ability of 7-epi, alone or in combination with fluoride (F), to disrupt biofilm development and pathogenicity of S. mutans in vivo was examined using a rodent model of dental caries. Treatment (twice-daily, 60s exposure) with 7-epi, alone or in combination with 125 ppm F, resulted in biofilms with less biomass and fewer insoluble glucans than did those treated with vehicle-control, and they also displayed significant cariostatic effects in vivo (p < 0.05). The combination 7-epi + 125 ppm F was as effective as 250 ppm F (positive-control) in reducing the development of both smooth- and sulcal-caries. No histopathological alterations were observed in the animals after the experimental period. The data show that 7-epiclusianone is a novel and effective antibiofilm/anticaries agent, which may enhance the cariostatic properties of fluoride.

Keywords:

• benzophenone
• Streptococcus mutans
• dental caries
• biofilms
• fluoride
• extracellular polysaccharides

Acknowledgements

The authors are grateful to Katia Borges Batista and José Carlos Gregorio for technical assistance, and to Dr Paulo N. D. Salvia for histopathological analysis. This research was supported by FAPESP grant 06/56379-4 (State of São Paulo Research Foundation, Brazil), CNPq grant 304803/2005-7 (National Council for Scientific and Technological Development, Brazil) and USPHS Research grant R01 DE018023 from the National Institute of Dental and Craniofacial Research (National Institutes of Health, USA). The authors thank the Brazilian Government Agencies for fellowship to R.M.M. (CNPq 141253/2005-3; CAPES BEX 0154/06-7). This publication is part of the PhD thesis submitted by the first author to the Piracicaba Dental School (UNICAMP, Brazil).