[Isolation, identification, and characteristics of the phytotoxin produced by the fungus Alternaria cirsinoxia].

An individual substance (20 mg/l) exhibiting phytotoxic properties, which, on the basis its spectral characteristics, was identified as zinniol, was obtained from the fungus Alternaria cirsinoxia. The nonspecific activity of this phytotoxin, with respect to plants of different families, was demonstrated. The minimum concentration (200 microg/ml) at which zinniol damages creeping thistle leaves and the median inhibition concentration (IC50) for rat embryonic fibroblasts (264 microg/ml) were determined.