Three antibiotics have been obtained from a culture liquid of a streptomyces, characters of which will be reported in another paper. The one of them inhibited the growth of fungi and its ultraviolet absorption was similar to that of trichomycin, ascosin, or candicidin. According to the classification of polyene antifungal substances made by Utahara and others⁽¹⁾, it was one of trichomycin-ascosin-candicidin group substances. The others inhibited the growth of bacteria. The one of the antibacterial substances was extracted and found to inhibit the growth of B. subtilis and to be strongly toxic. Another was extracted and purified. It was found to be a new antibiotic and named phleomycin by the authors.

Phleomycin was adsorbed by the cation exchange resin and eluted by sodium chloride solution. It was purified as its reineckate. It was stable in neutral and weakly alkaline solutions, but very unstable in acid. It inhibited the growth of mycobacteria and weakly the growth of various kinds of other bacteria. It did not have the delayed toxicity.

In this paper, the production, isolation, and characters of phleomycin are presented.