Effect of some soybean and bean phytoalexins and related isoflavonoids on growth of Candida albicans.

The influence of a series of related isoflavonoids on growth of the zoopathogenic yeast, Candida albicans, in liquid media was studied. The order of effectiveness was identical with that previously found for a range of phytopathogenic fungi. Minimum inhibitory concentration of phaseollinisoflavan, the most active test compound, was 250 microM for 3 days after inoculation. However, C. albicans resumed growth thereafter. Phaseollinisoflavan, 500 microM, did not inhibit but only delayed growth of the yeast. Tolerance of C. albicans to phaseollin and phaseollinisoflavan was based on nondegradative mechanism(s), while tolerance to glyceollin appeared to be based on detoxification.