Among many microbiological products exhibiting inhibition against experimental animal tumors, there are those of macromolecular nature, such as Shear’s polysaccharide¹⁾, actinogan²⁾, melanomycin³⁾, carcinomycin⁴⁾, carzinocidin⁵⁾, marinamycin⁶⁾, kunomycin⁷⁾ and others. Similar to these macromolecular antitumor antibiotics, A114, C776, D92, D180, D284, D440, D847, Sgf334, A216 and A280 substances have been isolated from the culture filtrates of the selected ten Streptomyces species in this laboratory.

The present paper concerns the preliminary chemical and biological studies performed with these 10 substances, including some detailed experiments on A216 and A280 substances.