Antibacterial Activity of Clove and Cinnamon Oils on Periodontopathic Bacteria

Objective: This study aimed to investigate the effects of two local herbs, Eugenia caryophyllata (clove) and Cinnamomum zeylanicum (cinnamon) on periodontopathic bacteria grown as biofilm. Methods: Biofilm was formed in-vitro by Porphyromonas gingivalis and Fusobacterium nucleatum. Clove and cinnamon essential oils were prepared using steam distillation technique in various concentrations. Anti-adhesion activities of the oils were determined by dispensing test bacteria at density of 0.5 McFarland standard (~1.5 x 10⁸ CFU/mL) in essential oils into 96-well plates and incubated for 48 hours. Biofilm disruption activities were determined by adding the oils into preformed biofilm grown for 72 hours. Ampicillin (5.00 – 0.08 mg/mL) and bacterial cultures without oils were used as positive and negative controls, respectively. The absorbance of growth turbidity was measured at OD₅₉₀. The effects on the morphology of the bacterial biofilm were assessed using scanning electron microscopy (SEM). Mann-Whitney test was carried out to compare difference values between the tested essential oils and the controls. Results: Both clove and cinnamon oils showed anti-adhesion activity at 5.00 - 0.63 mg/mL and 5.00 - 0.08 mg/mL respectively. Biofilm disruption activities were observed only on clove oil, at concentration of 5.00 - 1.25 mg/mL. SEM analyses showed changes on the surface of the bacterial cells in biofilm treated with both oils, with P. gingivalis visibly less in abundance in treated biofilm compared to negative control. Conclusion: Both clove and cinnamon essential oils exhibited anti-biofilm activities on the in-vitro formation of periodontopathic biofilm. Thus, these local herbs may have good potential to be developed as anti-biofilm agents for the management of periodontal diseases.