Melanomycin, A New Antitumor Substance from Streptomyces. I

Abstract

A search for antitumor agents, derived from streptomycetes, is now in progress in the world. As a result of this effort, not a few substances were discovered and described. The following tumor inhibitory agents have been extracted so far in our laboratory: luteomycin¹⁾, carzinophilin²⁾ and mitomycin³⁾.

A substance, described in this paper, was extracted from culture filtrate of a streptomyces isolated newly from a soil. Its inhibitory activity was limited only to the tumor growth, in contrast to the other three substances, which have also antibacterial properties. Using this substance, a mild but definite effect was obtained not only on Ehrlich ascitic tumor but on its subcutaneous tumor. As the cultural characteristics of the streptomyces were not in accordance with any described species of streptomyces, it was given the name of Streptomyces melanogenes.

Some physicochemical properties of active substance indicated it might be a melanin-like substance. For this reason the name of melanomycin was given to this active principle. Melanomycin was obtained as a blackish amorphous powder, not crystallized yet. It is the purpose of this paper to describe production, fermentation, assay method, purification, and physicochemical properties of melanomycin. The description of the melanomycin-producing strain and the experiments on the tumor-inhibitory activity will be the subject of later studies.