A Novel Macrolactam-trisaccharide Antifungal Antibiotic

A novel secondary metabolite SCH 42282 (1), with antifungal activity was isolated from the fermentation broth of a soil actinomycete identified as a Microtetraspora sp. The active compound was separated from the fermentation broth by butanol extraction and purified on a silica gel column and by multi-coil counter current chromatography. The compound was identified as a novel macrolactam trisaccharide related to SCH 38518 (4). The structure was established by hydrolysis of the parent compound and spectroscopic studies of the acetate derivative. The compound is active against Candida spp. (Geometric Mean MIC's, 18 μg/ml) but less active than SCH 42729 (3), the disaccharide (Geometric Mean MIC's, ≥10.7 μg/ml) and SCH 38518 (4), the monosaccharide (Geometric Mean MIC's, 3.8 μg/ml).