Evaluation of Coenzyme Q₀ for the Control of Breath Odour

Anaerobic bacteria implicated in periodontal disease and bad breath can only survive in highly reduced conditions with low redox potentials (Eh) such as those found in the periodontal pocket or crypts of the tongue dorsum. Consequently, redox agents that are able to raise Eh will inhibit the growth of anaerobic bacteria and may improve oral health and reduce oral malodour. Objectives: To determine in vitro the potential of redox agent Coenzyme Q₀ (CoQ₀) to reduce oral malodour. Methods: The antibacterial action of CoQ₀ was determined by minimum inhibitory concentration (MIC) and enzyme inhibition assays against a number of oral isolates. The effect of CoQ₀ on bacterial odour generation and biofilm viability was determined using tongue microcosms grown in Constant Depth Film Fermentors (CDFF). Volatile sulphur compound (VSC) levels were measured using a halimeter. Reaction products between CoQ₀ and VSC were identified by LC-MS. Results: Fusobacterium nucleatum, Prevotella intermedia and Peptostreptococcus anaerobius were susceptible to CoQ₀ with MICs of 10mM, 2.5mM and <0.625mM respectively. Sub-inhibitory levels of CoQ₀ (<5mM) inhibited proteolytic activity of Porphyromonas gingivalis by 86%. Treatment of tongue derived biofilms with CoQ₀ reduced VSC generation by approximately 85% but without significantly reducing bacterial numbers, suggesting an additional, non-antibacterial mode of action. This was investigated in further experiments where hydrogen sulphide and methyl mercaptan were found to react with CoQ₀ in solution to generate non-volatile reaction products, with a concurrent loss of odour. Conclusion: CoQ₀  is a potential new active agent for the control of oral malodour through multiple modes of action.