Three kinds of antibacterial substances from Lentinus edodes (Berk.) Sing. (Shiitake, an edible mushroom)

Three kinds of antibacterial substances were extracted by chloroform, ethylacetate or water from dried Shiitake mushrooms (Lentinus edodes). These substances possess efficient antibacterial activities against Streptococcus spp., Actinomyces spp., Lactobacillus spp., Prevotella spp., and Porphyromonas spp. of oral origin. In contrast, other general bacteria, such as Enterococcus spp., Staphylococcus spp., Escherichia spp., Bacillus spp., and Candida spp. were relatively resistant to these substances. Chloroform extracts had bactericidal activity against both growing and resting bacterial cells of S. mutans and P. intermedia, whereas the other two extracts showed bacteriostatic activity against both growing and resting bacterial cells of S. mutans and resting bacterial cell of P. intermedia. The antibacterial activity of chloroform extracts and ethylacetate extracts were relatively heat-stable. The water extract was heat-labile.