An antimutagenic metabolite, streptovaricin C, isolated from Streptomyces sp.

Streptomyces sp. KM1-30 was isolated from soil as a producer of antimutagen s by screening with a modified Ames test. The chemical structure of the ant imutagenic metabolite was identified as streptovaricin C, which is known to inhibit DNA dependent RNA polymerase from E. coli and RNA dependent DNA po lymerase from RNA tumor viruses, by MS and H-1-, C-13-NMR analyses. Additio n of streptovaricin C to the cultures of UV treated Salmonella typhimurium TA100 or Trp-P-2-treated S. typhimurium TA98 decreased the frequency of mut ation without a decrease in viable cell counts. The effect of streptovarici n C to the mutation induced by UV and Trp-P-2 was not desmutagenic, but ant imutagenic.