1988 Volume 41 Issue 10 Pages 1366-1373
A new antitumor antibiotic porothramycin was produced by a new strain of Streptomyces albus1, 2). The antibiotic was isolated in two active forms, the natural free hydroxyl form (porothramycin A) or the crystalline methyl ether form (porothramycin B) depending upon the isolation process used. Structural studies established that porothramycin is a new member of the pyrrolo[1, 4]benzodiazepine group antibiotics having only one substituent on the benzene ring. The antibiotic exhibited antimicrobial activity against Gram-positive bacteria and anaerobes and significantly prolonged the survival times of mice implanted with experimental tumors.