Rapamycin (AY-22,989), a new antifungal antibiotic. II. Fermentation, isolation and characterization.

Rapamycin is a new antifungal antibiotic produced by Streptomyces hygroscopicus NRRL 5491. It was isolated from the mycelium by solvent extraction, purified by silica gel column chromatography and crystallized as a colorless solid which melts at 183 approximately to 185 degrees C and has the empirical formula C56H89NO14. From its characteristic ultraviolet absorption spectrum rapamycin can be classified as a triene. It is highly active against various Candida species, especially Candida albicans. Its activity is compared with that of amphotericin B, candicidin and nystatin.