Investigation of Components in Roasted Green Tea That Inhibit Streptococcus mutans Biofilm Formation

Area of Science:

• Oral Microbiology
• Food Chemistry
• Natural Product Chemistry

Background:

• Streptococcus mutans are primary causative agents of dental caries by forming oral biofilms.
• Green tea catechins exhibit biofilm inhibitory activity, but roasted green tea (RGT) specific compounds remain under-investigated.
• The roasting process of green tea generates unique polyphenols with potential functional properties.

Purpose of the Study:

• To evaluate the inhibitory effect of RGT on Streptococcus mutans biofilm formation.
• To identify and characterize the specific compounds within RGT responsible for this inhibitory activity.

Main Methods:

• Fractionation of RGT extract based on hydrophobicity.
• Biofilm inhibitory assays against S. mutans using the RGT fractions.
• Purification and molecular weight determination of active compounds.

Main Results:

• RGT fractions with medium-high hydrophobicity, rich in phenolic hydroxyl groups and devoid of catechins, demonstrated significant biofilm inhibitory activity.
• A purified fraction containing compounds with molecular weights of 918 (mw918) and 1050 (mw1050) exhibited strong inhibitory effects.
• The mw918 polyphenol, unique to RGT and likely formed during roasting, was identified as a key active ingredient.

Conclusions:

• Roasted green tea contains novel polyphenols, beyond catechins, that effectively inhibit Streptococcus mutans biofilm formation.
• Specific compounds, including the RGT-unique mw918 polyphenol, are responsible for the anti-biofilm activity.
• RGT possesses potential as a safe and effective natural agent for preventing dental caries.