Studies ON THE MECHANISM OF ACTION OF THE ANTIFUNGAL COMPOUND FALCARINDIOL

S ummary The mode of action of the polyacetylenic antifungal compound falcarindiol was explored. Chlamydospores of Mycocentrospora acerina removed falcarindiol from test solutions. Falcarindiol at 28 μg ml −1 burst bimolecular lipid membranes formed from lecithin or lecithin‐cholesterol and caused haemolysis in erythrocytes. At a concentration of 100 μg ml ‐1 falcarindiol caused rapid electrolyte loss from both chlamydospores of M. acerina and discs of Doucus carota. Hyphal tips of M. acerina burst, and the internal structure of chlamydospores of M. acerina was altered by concentrations of 75 μg ml ‐1 falcarindiol. The hypothesis is advanced that falcarindiol acts on the plasma membrane or affects some process needed for membrane function.