In vitro Antifungal Activity of Japanese Folk Herb Extracts against Trichophyton rubrum

Folk herbs are vital to the Japanese health care system, with some being used to treat fungal skin infections. We tested folk herbs used in traditional Japanese medicine for in vitro antifungal activity against Trichophyton rubrum, the most common pathogen in patients with superficial dermatitis. Acetone, ethanol, methanol, water, and acetic acid extracts from 15 species of Japanese folk herbs (Bi-wa, Aka-me-gashiwa, Ta-mushi-ba, Yomogi, Shi-so, Ku-ko, So-ba, Yama-momo, Kuro-mo-ji, Ichi-ji-ku, Kaki-no-ki, Kuwa-no-ki, Kusa-gi, Chimaki-zasa, and 1-buki-jya-kou-sou) were evaluated for fungal growth inhibition, as measured by absorbance. Crude acetic acid extracts of Aka-me-gashiwa, Ta-mushi-ba, Yomogi, Ku-ko, Kaki-no-ki, and 1-buki-jya-kou-sou exhibited antifungal activity comparable to that of amphotericin B. Although the active compounds and underlying antifungal mechanisms are not known, the data contribute to the development of new and safe antifungal drugs, highlight new extraction methods for herbs, and support the traditional use of Japanese folk herbs against fungal infections.