A new polyene antibiotic, flavomycoin. Structural investigations. II.

Flavomycoin is a polyene antibiotic isolated from the mycelium of Streptomyces roseoflavus ARAI 1951 var. jenensis nov. var. JA 5068 as yellow-green crystals. It shows inhibitive activities against yeasts and fungi as well as protozoa. It is optically active, exhibits an ultraviolet spectrum without fine structure with maxima at 363 nm and 263 nm. Analytical studies indicated that the molecular formula of the antibiotic is C41H68O10and the molecular weight 721. These results were confirmed by degradation to the parent hydrocarbon and by catalytic hydrogenation. As flavomycoin is different from the related substances mycoticin and flavofungin, it must be considered as a new antibiotic.