Known and novel terpenes from Buddleja globosa displaying selective antifungal activity against dermatophytes

Lipophilic extracts of the stembark of Buddleja globosa were found to have antifungal activity at 125 microg/mL against three dermatophytic fungal species but had no activity at 1000 microg/mL against four other fungal species or two yeast species. Bioassay-guided fractionation of Si gel column eluates using the sensitive fungal species resulted in active fractions from which were isolated five compounds that were characterized by spectroscopic methods as one novel and four known compounds. The known compounds were the diterpene buddlejone (1), the bisditerpene maytenone, and the two sesquiterpenes buddledin A and buddledin B, while the novel compound was characterized as the diterpene deoxybuddlejone (2). The minimum inhibitory concentration of all the compounds was determined against all the microorganisms under test, and buddledins A and B were shown to exhibit the greatest antifungal activity, with values of 43 microM and 51 microM, respectively, against the sensitive fungi Trichophyton rubrum, Tricophyton interdigitale, and Epidermophyton floccosum.