Structure-related fungitoxicity of isoflavonoids

A series of isoflavones, isoflavanones, pterocarpans, isofiavans and the coumestan aureol, obtained from five Phaseolus species, have been tested for fungitoxicity against Aspergillus niger and Cladosporium cucumerinum and a study made of the relationship between their structure and fungitoxicity. A high level of lipophilicity and the presence of at least one phenolic function appear important to iso-flavonoid fungitoxicity. The yield and range of structurally different isoflavonoids elicited in each of the five species in response to GuCl2 is discussed in relation to plant/fungus interactions.