A new pentanorlanostane derivative, cladosporide A, as a characteristic antifungal agent against Aspergillus fumigatus, isolated from Cladosporium sp.

Abstract

In the course of searching for new antifungal agents, a new pentanorlanostane derivative, cladosporide A (1), was isolated along with ergosterol, ergosterol peroxide and 23,24,25,26,27-pentanorlanost-8-ene-3β,22-diol (2) from Cladosporium sp. as a characteristic antifungal agent against the human pathogenic filamentous fungus Aspergillus fumigatus. The structure of 1 was established as 3β,22-dihydroxy-23,24,25,26, 27-pentanorlanostane-29-al by spectroscopic and chemical investigation and X-ray crystallographic analysis. Inhibitory activity against A. fumigatus (IC80 0.5 - 4.0 μg/ml) was observed for cladosporide A (1), but no activity was observed against pathogenic yeasts, Candida albicans and Cryptococcus neoformans, and other pathogenic filamentous fungi, Aspergillus niger and A. flavus. The 4β-aldehyde residue in 1 might be essential for the antifungal activity, since 23,24,25,26,27-pentanorlanost-8-ene-3β,22,diol (2) showed no inhibition against the above four fungi.