Antibacterial Activities of Litsea cubeba Essential Oil Against Oral Pathogens.

Objectives: Periodontitis is mainly caused by the infection of gram (-) bacteria. Litsea cubeba essential oil (EOLC) is known to have the properties of anti-microorganisms. However, the antibacterial effects on oral pathogens are not clearly documented, especially in periodontitis related pathogens. Our aims are to determine the effects of EOLC against oral bacteria isolated from patients with periodontitis.
Methods: The essential oil was extracted from the L. cubeba fruits using Solvent-Free Microwave method. Chemical components of EOLC were identified by the Heracles II electronic nose based on ultra-fast gas chromatography. Oral bacteria were isolated from patients with periodontitis and were identified using MALDI-TOF method. Paper disk diffusion and minimum inhibitory concentration (MIC) were used to assess the antibacterial effect of EOLC.
Results: The extraction recovery rate was 5.5% (g/g). Major EOLC chemical constituents were D-Limonene (53.93%), myrcene (9.44%) and neral and geranial (6.89~8.77%). Three anaerobic bacteria and three aerobic bacteria were identified from participants with and without periodontitis. The results of inhibitory zone area of positive control (0.2% chlorhexidine) and the two-fold dilution of EOLC were 11~26mm in diameter and 17.78~35.56 mm in diameter, respectively. The inhibitory effect of EOLC against anaerobic bacteria was about 2-3 fold larger than that against aerobic bacteria. The MIC of EOLC was close to 100-fold dilution.
Conclusions: These results suggested that the EOLC exhibit the antibacterial effects against oral pathogens isolated from patients with periodontitis. The inhibitory effect of EOLC against oral bacteria is varied among different strains. It is worth to verify the antibacterial effects of EOLC major components against oral bacteria.