7-oxostaurosporine selectively inhibits the mycelial forum of Candida albicans

Abstract

In the course of screening for specific inhibitors against the mycelial form of Candida albicans from natural resources, we have isolated and identified A6792-1 from Streptomyces sp. A6792 by using several chromatographies. By spectral analyses, this compound was determined as 7-oxostaurosporine, having a structure of staurosporine aglycon moiety. 7-Oxostaurosporine exhibited a selective growth inhibitory activity against the mycelial form of Candida spp. up to 100 μg/disc in bioassay. It also exhibited a specific antifungal activity against the mycelial form of Candida spp. including C. krusei, C. albicans, C. tropicalis, and C. lusitaniae with MICs ranging from 3.1 to 25 μg/ml. 7-Oxostaurosporine demonstrated no in vivo toxicity in SPF ICR mice. Therefore, this compound may have a considerable potential as an antifungal agent based on the preferential inhibition against growth of the mycelial form of Candida spp., dimorphic fungi.