Evaluation of Thai Spice Essential Oils and Their Active Compounds for Anti-cariogenic Activity and Mechanism of Action

Abstract

© 2014, Har Krishan Bhalla & Sons. Essential oils of several plants have been used in ethnomedicine for their antimicrobial activities. The objective of this study was to investigate the inhibitory effect of Thai spice essential oils against cariogenic microbes (Porphyromonas gingivalis, Streptococcus mutans, and Streptococcus sanguinis). The greatest effectiveness was achieved by Cymbopocon (DC.) citratus Stapf.oil with MIC and MBC of 0.015-0.062 % v/v. Interestingly, C. citratus oil also exhibited significant antibiofilm formation property at the concentration of 0.062 % v/v with 96.34 % inhibition. Time kill study revealed that C. citratus oil had lethal effect on S. mutans and S. sanguinis within 12 h at the concentrations of 2 and 4 times of MIC while complete eradiation against P. gingivalis was observed after 4 h. Moreover, TEM revealed that C. citratus oil acted directly on the cell wall of P. gingivalis as demonstrated by loss of membrane integrity. The active component of C. citratus was determined by bioautography and GC/MS. Chemical analysis of essential oil showed that citral was the major active component of C. citratus oil. In conclusion, essential oil of C. citratus and its major compound gave the best anti-cariogenic and antibiofilm actions and could be potentially developed as the oral health care products.