STRUCTURE-ACTIVITY-RELATIONSHIPS AMONG ISOFLAVONOIDS WITH REGARD TO THEIR ANTIFUNGAL PROPERTIES

In order to establish a structure-activity relationship in the class o f isoflavonoids, 16 differently substituted isoflavonoids were tested against Alternaria alternata, Cladosporium herbarum, Fusarium oxysporu m and Trichoderma harzianum. The isoflavanones, 6,7-dihydroxy-4'methox y- and 7-hydroxy-8,4'-dimethylisoflavanone showed highest antifungal a ctivity in the case of C. herbarum as test fungus. The unreduced struc ture of the isoflavones has less inhibitory effect on the growth of th e test fungi, whereas the completely reduced isoflavones, i.e. the iso flavans, showed only a very weak activity.