Effect of a grape seed extract on Streptococcus mutans

Objectives: Streptococcus mutans plays a major role in the development of oral diseases like dental caries. One of the important virulence properties of this micro organism is its ability to colonize dental surfaces in the presence of dietary sucrose The aim of this work was to investigate the action of a Grape Seed Extract (GSE) on the growth and adherence of S. mutans.

Methods: Experiments were done in vitro on Streptococcus mutans ATCC 25175. Antimicrobial activity of the polyphenolic extract was examined by determining the MIC and MBC using the macro dilution broth technique.

The effect on growth was determined by the counting of CFU, after a 24 hours-exposure to the compound.

Its action on the adherence was tested on growing cells on a glass surface, according to the method of Hamada and Torii (1978). The concentration for total bacterial adherence inhibition (TBAI) was defined as the lowest concentration that allowed no visible cell adherence on the glass surface.

Positive control was made with chlorhexidine.

Results: GSE shows a bacteriostatical activity with MIC and MBC values of respectively 1000 and 4000 µg/ml. It significantly (student t test, p<0.05) inhibits the growth of S. mutans after the concentration of 500µg/ml.

At the concentration of 50µg/ml, GSE leads to the formation of a weakly adherent biofilm.

From the concentration of 200µg/ml, the formation of biofilm is totally inhibited.

Conclusion: GSE shows an interesting action on Streptococcus mutans and could be used for the lowering of this potentially cariogenic species in oral cavity.

This work was supported by the Laboratoire Pierre Fabre