A novel antibiotic, sohbumycin. Taxonomy, fermentation, isolation and physico-chemical and biological characteristics

A new antibiotic sohbumycin, was isolated from the culture broth of Streptomyces sp. No. 82-85. It appeared to belong to the peptide lactone type of antibiotics from physico-chemical studies and has an empirical formula of C31H47N8O10Cl. In in vitro studies, the antibiotic was found to possess potent cytocidal activity against HeLa S3 cells and antimicrobial activities against Gram-positive bacteria with MIC values about 0.3-0.6 microgram/ml, but showed no activity on the Gram-negative bacteria, yeast and fungi tested.