Activity of Cytomycin and Blasticidin S Against Transplantable Animal Tumors

Abstract

Blasticidin S, a water-soluble and basic antibiotic active against certain genera of bacteria and fungi, was isolated in crystalline form and characterized in our laboratory¹⁾. It is especially effective against Piricularia oryzae in the field as well as in vitro, which is a causative agent of the most drastic rice plant disease in Japan. The antibiotic was, found to exhibit a considerable effect against transplantable animal tumors, although it is highly toxic to animals. It was also confirmed that this substance contains cytosine in the molecule. Cytomycin, a cytosine-containing component, was obtained by mild alkaline hydrolysis of blasticidin S or from the culture filtrate of the producing organism²⁾. Cytomycin was observed to have low toxicity and to be active against transplantable animal tumors. However, there seems to be a large difference in the weight of the effective doses of these antibiotics. The details of the results are described in this publication.