Antimicrobial activity of Punica Granatum (pomegranate) against oral pathogens

Objectives: Imbalances between the host and the natural microflora in the oral cavity may arise, resulting in the development of disease. The most common disease in the mouth is dental caries which is the disease of the mineralized tissue such as tooth caused mainly by Streptococcus mutans and Lactobacilli and periodontal diseases which is the disease of the tooth supporting tissues caused by many bacteria including Porphyromonas gingivalis, Prevotella intermidia, Capnocytophaga species and Fusobacterium nucleatum. Medicinal plants are often used as antimicrobial agents in the prevention and control of these diseases. Punica granatum commonly known as pomegranate, is grown all over the world including South Africa. Fruit of this plant is known to have antimicrobial effect against enteric pathogens. This study investigated the antimicrobial effect of P. granatum against oral pathogens.

Methods: Fruits were collected from local markets in Johannesburg metropolitan region, peel was harvested, dried in a shady area, milled and stored at 4oC until required. Crude extracts were prepared using acetone and methanol. Laboratory strains and clinical isolates and ATCC cultures were obtained from Oral Microbiology laboratory and Minimum bactericidal concentrations (MBC) were obtained using double dilution technique. Five clinical strains of S. mutans and Lactobacilli, one clinical strain of P. gingivalis Capnocytophaga sp., P. intermedia ATCC 25611 and F. nucleatum 25586 were tested three times.

Results: Both the extracts killed S. mutans at 6.25 to 25 mg/ml and Lactobacilli at 3.125 to 25 mg/ml. The MBC for P. gingivalis and P. intermedia were 0.1 mg/ml and 0.78 mg/ml respectively. Capnocytophaga was completely eliminated at 0.39 mg/ml.

Conclusion: Although crude extract of P. granatum was unable to inhibit S. mutans at low concentrations, it inhibits the growth of periodontal pathogens. Our preliminary results have shown that P. granatum have potential to be used to prevent periodontal diseases.