New antitumor antibiotics, FR-900405 and FR-900406. II. Production, isolation, characterization and antitumor...

The new antitumor antibiotics, FR-900405 and FR-900406, were isolated from the culture broth of Actinomadura pulveracea sp. nov. No. 6049. These compounds which contain sulfur in the molecule, represent a novel class of antitumor agents. FR-900405 and FR-900406 are highly active in mice against experimental tumors and exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi.