Choosing the Right Essential Oil for a Mouthwash: Chemical, Antimicrobial and Cytotoxic Studies

Thirteen commercial essential oils were assessed for their possible inclusion in a mouthwash formulation based on their inhibitory effect against potentially pathogenic anaerobic oral bacterial isolates from subgingival plaque, and their cytotoxicity towards gingival cells. The essential oils, originating from species belonging to seven major aromatic plant families, were chosen to provide the necessary diversity in chemical composition that was analyzed in detail by GC and GC/MS. Multivariate statistical analysis, performed using the in vitro microbiological/toxicological assays and compositional data, revealed that the major components of the essential oils were probably not the main carriers of the activities observed. A formulation of 'designer' mouthwashes is proposed based on the selective action of certain essential oils towards specific bacterial isolates (e. g., Citrus bergamia vs. Parvimonas micra), and non-toxicity to gingival cells at antimicrobially active concentrations.