Oral spray containing plant-derived compounds is effective against common oral pathogens

Objectives: Plant-derived compounds are a good source of therapeutic agents and inhibitors of inflammatory process. Dental caries, periodontal diseases and candidiasis are common oral infections caused by virulent biofilms. The objectives of this study were to develop oral spray containing plant-derived compounds; alpha-mangostin (alpha-MG) and/or lawsone methyl ether (2-methoxy-1,4-naphthoquinone) (LME) and determine its antimicrobial, anti-biofilm, and anti-inflammatory activities. Design: Oral spray formulations were prepared containing alpha-MG (5 mg/ml) and/or LME (250 mu g/ml). Antimicrobial activity against Candida albicans, Streptococcus mutans, and Porphyromonas gingivalis and anti-biofilm formation activities were determined as well as cytotoxicity and anti-inflammatory effects. Results: The oral spray demonstrated antimicrobial activity against all three of the oral pathogens tested with stronger effects on C. albicans and S. mutans than P. gingivalis. The formulation containing alpha-MG (2.5 mg/ml) and LME (125 ug/ml) reduced growth of the microorganisms about 1-2 Log CFU/ml at 1-3 h and the killing effects were complete at 24 h. Based on biofilm assay, the oral spray containing both alpha-MG and LME showed greater inhibitory effects than those with alpha-MG or LME. In addition, the oral spray containing both alpha-MG and LME demonstrated more inhibition of nitric oxide production than alpha-MG alone. All the formulations were safe and demonstrated greater anti-inflammatory activity at lower concentration (< 6.25 mu/ml) than at a higher concentration. Conclusion: Oral spray containing alpha-MG and/or LME is effective against common oral pathogens without significant cytotoxicity. Thus, it has the potential to prevent the infections and may serve as adjunctive treatment to conventional therapy.