two new antibiotics, each of which exhibits a high hemmande effect to tillvexten of leukaemia cells.

摘要

Neothramycin A and neothramycin B are obtained by culturing a neothramycin-producing strain of the genus Streptomyces under aerobic conditions in a medium containing assimilable carbon and sources of nitrogen. The resulting mixture can be fractionated. Treatment of each of the two neothramycins with methanol yields a mixture of methylneothramycin A and methylneothramycin B, which can again be fractionated. All the four compounds are valuable pharmaceuticals for use against leukaemia.