Growth Inhibition Properties of Shiitake Extract on Pathogenic Oral Anaerobes

Shiitake (Lentinula edodes) is an asian edible mushroom with the second largest cultivation percentages amongst edible mushrooms in the world. It is frequently consumed in many asian countries and occasionally by the rest of the world. Previous studies have shown its nutritional richness such as high quantities of proteins, minerals and vitamins have been shown widely. Moreover, in vitro and animal studies have displayed the medical importance of shiitake extracts, including antitumor, antiviral, antibiotic and hypocholesterolemic actions. Objective: The aim of this study was to investigate the antimicrobial activity of L. edodes essential oil against periodontal pathogens. Methods: Essential oil from shiitake mushrooms was extracted using the hydrodistillation method for 3 hours. The antibacterial activity of the extracted oil was tested against 7 periodontal pathogens, namely S. mutans, A. naeslundii, P. endodontalis, T. forsythus, F. nucleatum, A. actinomycetemcomitans and P. gingivalis by the disc-diffusion assay. Minimum inhibitory concentrations (MIC) of L. edodes oil for studied pathogens was determined by the micro-dilution method. Chlorhexidine digluconate was used as positive control at the concentrations 0.25 - 12 µg/ml. Results: Essential oil extracts of shiitake showed significant antimicrobial acivity on all periodontal pathogens with the highest effects on A. actinomycetemcomitans and P.gingivalis (19.7±3.3mm and 15.7±1.5mm in diameter, respectively). Moreover, the MIC values of the oil was found in the range of 1/4-1/16 dilutions. Conclusion: These results suggest that essential oil extract of Shiitake mushroom has significant antibacterial activity on important oral pathogens and can possibly be used in the control of important anaerobes involved in periodontitis.