Fermentation, isolation, and antitumor activity of sterigmatocystins.

In a screening program for antitumor substances from microbial fermentations, a compound was isolated from the mycelium of an Aspergillus species which proved to be the mycotoxin 5-methoxysterigmatocystin. This and the subsequently isolated sterigmatocystin gave significant inhibition of the transplanted mouse leukemias P-388 and L-1210. Preparation and testing of several derivatives of 5-methoxysterigmatocystin suggest that certain functions in the molecule are essential for tumor inhibition. Although slight antitumor effects have been reported for the chemically related aflatoxins, we believe this is the first report of antitumor activity of sterigmatocystins.