Abstract
Objective The purpose of our study was to evaluate plant-derived essential oils (EOs) as natural
alternatives to commercial alcohol-based mouthwashes in the prevention of dental caries
since several recent studies have linked high incidence of oral cancer among users
with a history of prolonged use of alcohol-based mouthwashes.
Materials and Methods Lemongrass, Citronella Java, Gingergrass, and Caraway seed EOs were tested against
commonly occurring multidrug-resistant (MDR) oral bacteria namely Micrococcus luteus, Enterococcus faecalis, Streptococcus oralis, and Streptococcus salivarius. Agar well diffusion method was used to determine the antibacterial effectiveness
of these EOs. Samples of Citronella Java and Lemongrass EO were also analyzed by gas
chromatography (GC).
Results Lemongrass and Citronella Java exhibited the highest antibacterial activity against
all four bacterial strains. Inhibition zones of Lemongrass were 12, 21.3, 28.3, and
32 mm in diameter against E. faecalis, M. luteus, S. oralis, and S. salivarius, respectively. In comparison, inhibition zones of Citronella Java were 11.5, 17,
20.7, and 20.2 mm in diameter against E. faecalis, M. luteus, S. oralis, and S. salivarius, respectively. A significant finding in our study was that antibacterial activity
of Lemongrass was much higher than that of tetracycline, a broad-spectrum antibiotic,
against S. oralis and S. salivarius, while the inhibitory effects of Citronella Java against these two oral streptococci
were comparable to tetracycline. The major components of Citronella Java identified
by GC were citronellal, citronellol, and geraniol, whereas Lemongrass was primarily
composed of cis and trans forms of citral.
Conclusion Our results suggest that Lemongrass and Citronella Java could be promising natural
alternatives to alcohol-based mouthwashes against MDR oral bacteria in the prevention
of dental caries.
Keywords
essential oils - oral cancer - alcohol-based mouthwashes - oral microbiome - gas chromatography
- Gram staining - agar well diffusion