Lemon myrtle extract inhibits lactate production by Streptococcus mutans

Area of Science:

• Oral microbiology
• Natural product chemistry
• Dental caries research

Background:

• Streptococcus mutans is a primary pathogen in dental caries.
• S. mutans produces glucansucrase, crucial for biofilm formation.
• Lactate production by S. mutans demineralizes tooth enamel.

Purpose of the Study:

• To investigate the effect of Backhousia citriodora (lemon myrtle) extract on S. mutans lactate production.
• To determine if major lemon myrtle polyphenols inhibit S. mutans virulence factors.
• To assess the potential of lemon myrtle extract in preventing dental caries.

Main Methods:

• Culturing S. mutans and measuring glycolytic pH drop.
• Quantifying lactate production and lactate dehydrogenase activity.
• Analyzing the impact of lemon myrtle extract and its polyphenols on S. mutans viability.

Main Results:

• Lemon myrtle extract reduced glycolytic pH drop and inhibited lactate production by over 46%.
• Key polyphenols (ellagic acid, quercetin, hesperetin, myricetin) reduced pH drop and lactate production but not lactate dehydrogenase activity.
• These polyphenols also decreased the viable S. mutans cell count.

Conclusions:

• Lemon myrtle extract effectively inhibits S. mutans lactate production.
• The polyphenols in lemon myrtle contribute to inhibiting S. mutans virulence.
• Lemon myrtle extract shows promise in preventing dental caries by reducing oral acidification.