Inhibitory Effects of Oolong Tea Extract on Caries-Inducing Properties of Mutans Streptococci

M. Matsumoto, T. Minami, H. Sasaki, S. Sobue, S. Hamada, T. Ooshima

Research output: Contribution to journalArticlepeer-review

145 Citations (Scopus)


The inhibitory effects of oolong tea extract (OTE) on the caries-inducing properties of mutans streptococci were examined in vitro. OTE reduced the rate of acid production by mutans streptococci accompanied with the retardation of growth rate of mutans streptococci, while the action by chromatographically isolated oolong tea polyphenol (OTF6) was weak. On the other hand, both oolong tea products decreased cell surface hydrophobicity of almost all the oral streptococci examined in the present study, and also induced cellular aggregation of Streptococcus mutans, Streptococcus oralis, Streptococcus sanguis or Streptococcus gordonii. In these reactions, OTF6 showed a more pronounced activity than OTE. Furthermore, the oolong tea products inhibited the adherence of mutans streptococci to saliva-coated hydroxyapatite. These results suggest that OTF6 may inhibit bacterial adherence to the tooth surfaces by reducing the hydrophobicity of mutans streptococci, and OTE may inhibit caries-inducing activity of mutans streptococci by reducing the rate of acid production.

Original languageEnglish
Pages (from-to)441-445
Number of pages5
JournalCaries Research
Issue number6
Publication statusPublished - Nov 1 1999
Externally publishedYes


  • Dental caries
  • Hydrophobicity
  • Mutans streptococci
  • Oolong tea
  • Polyphenol

ASJC Scopus subject areas

  • General Dentistry


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