UK-1, a novel cytotoxic metabolite from Streptomyces sp.  517-02.  I. Taxonomy, fermentation, isolation, physico-chemical and biological properties. 
A new benzoxazole, UK-1, was isolated from the mycelial cake of an actinomycete strain 517-02.  Based on morphological, cultural and physiological characteristics, strain 517-02 was seemed to be a close relative of Streptomyces morookaense.  UK-1 showed potent cytotoxic activity against B16, HeLa and P388 cells and did not show any antimicrobial activity.