Antibacterial Activities of Cannabidiol Against Two Major Oral Pathogens

Abstract

Despite advances in oral health research, biofilm-mediated oral diseases continue to pose a health challenge. Preventive measures against biofilm-mediated disease aim to inhibit pathogenic biofilm formation on tooth surfaces. Cannabidiol (CBD), a Cannabis sativa L. L. extract, has shown antibacterial properties against various bacterial species, especially gram-positive cocci. This dissertation aimed to evaluate the antibacterial efficacy of CBD against Streptococcus mutans and Porphyromonas gingivalis bacterial growth and virulence factors. The effects of CBD on the planktonic, biofilm, and total growth of S. mutans with or without nicotine and P. gingivalis, were evaluated. The minimal inhibitory concentration (MIC), minimal biofilm inhibitory concentrations (MBIC), and minimal bactericidal concentrations (MBC) of CBD were assessed. CBD concentrations ≥ 2.5 μg/ml exhibited significant inhibition (p<0.001) against S. mutans biofilm growth, as well as, biofilm metabolic activity, lactate dehydrogenase (LDH) activity, and extracellular polysaccharides (EPS) production. In the presence of nicotine, which upregulates biofilm formation, CBD demonstrated the same inhibitory effects on S. mutans growth and activities. CBD concentrations ≥ 0.47 μg/ml exhibited significant inhibition (p<0.003) against P. gingivalis biofilm growth. CBD reduced the hemagglutination activities of P. gingivalis and reduced the overall proteolytic activity. Concentrations of CBD ≥ 0.63 μg/ml provided an inhibitory effect on lysine-specific gingipain. The results of these studies demonstrate that CBD has antibacterial activities against S. mutans and P. gingivalis growth and virulence factors related to caries and periodontal diseases, respectively.