Chrymutasins: novel-aglycone antitumor antibiotics from a mutant of Streptomyces chartreusis. I. Taxonomy, mutation, fermentation, isolation and biological activities.

Three novel antibiotics, named chrymutasins A, B and C, were isolated from the fermentation products of a mutant strain obtained by NTG (N-methyl-N'-nitro-N-nitrosoguanidine) treatment. The mutant strain produced the chrymutasins, which differed in the aglycone moiety from chartreusin, and related compounds. The production of these compounds needed a characteristically long fermentation period. The antitumor activity of chrymutasin A is better in vivo than that of chartreusin, the cytotoxic activity against cell lines in vitro is equivalent, and the antimicrobial spectrum is narrower.