Isolation of an antidermatophytic substance from the root of Salvia miltiorrhiza.

Dihydrotanshinone I was isolated from a Chinese crude drug "Danshen" (the root of Salvia miltiorrhiza) as an antidermatophytic substance against Trichophyton mentagrophytes. This compound inhibited the mycelial growth of six dermatophytes completely at a concentration as low as 1.56 to 6.25 μg/ml, depending on species, whereas its congener cryptotanshinone was found to be active only against T. tonsulans var. sulfureum at 100 μg/ml. Cryptotanshione, however, was as active as dihydrotanshinone I against four species of gram-positive bacteria at 0.195-50 μg/ml.