The effect of cocoa polyphenols on the growth, metabolism, and biofilm formation by Streptococcus mutans and Streptococcus sanguinis.
The aim of this study was to determine if cocoa polyphenols could interfere with biofilm formation byStreptococcus mutans or Streptococcus sanguinis, and reduce acid production from sucrose by S.mutans. The antimicrobial activity of cocoa polyphenols was assessed against cariogenic (S. mutans) and health-associated (S. sanguinis) species by minimum inhibitory concentration assays. Cocoapolyphenol dimer, tetramer, and pentamer inhibited the growth of S. sanguinis, whereas the growthof S. mutans was unaffected. However, pretreatment of surfaces with cocoa polyphenol pentamer (35 microM) reduced biofilm formation by S. mutans at 4 and 24 h, whereas the effects on S.sanguinis were less consistent. In contrast, brief exposure of preformed biofilms to pentamer either had no significant effect or resulted in increased counts of S. mutans under certain conditions. Cocoapolyphenol pentamer (500 microM) significantly reduced the terminal pH, and inhibited the rate of acid production by S. mutans at pH 7.0. In conclusion, cocoa polyphenols can reduce biofilmformation by S. mutans and S. sanguinis, and inhibit acid production by S. mutans.