Hericium erinaceum (Yamabushitake) extract inhibits biofilm formation and degrades mature biofilm of the periodontopathogenic bacterium Eikenella corrodens

Abstract

Hericium erinaceum (Yamabushitake) is an edible mushroom that has been reported to display various pharmacological activities, including neuroprotective, anti-inflammatory, and antioxidant effects. In this study, we found that the water extract of H. erinaceum inhibited biofilm formation of the periodontopathogenic bacterium Eikenella corrodens; however, no inhibitory effect was observed with the methanol extract. Moreover, the biofilm inhibitory effect of H. erinaceum was observed in a dose-dependent manner and was not due to bactericidal activity against E. corrodens. H. erinaceum extract was fractionated by ammonium sulfate precipitation and biofilm inhibition was achieved with the 70% fraction. Heat treatment of the 70% fraction did not completely prevent biofilm inhibition, suggesting that partially heat-stable proteins are involved in the biofilm inhibition. Further fractionation of the 70% fraction by ultrafiltration indicated that the biofilm inhibitor may be a protein with a molecular weight of approximately 60 to 100 kDa. It is also suggested that H. erinaceum extract could degrade the biofilm once formed.