Isolation and identification of six mansonones fromUlmus americana infected withCeratocystis ulmi

Mansonones A and C to G, sesquiterpene quinones possessing antifungal properties, were isolated from the elmUlmus americana infected withCeratocystis ulmi. Scopoletin and β-sitosterol were also present in the extracts. The mansonones were not detected on chromatographic analysis of extracts from healthy elm tissue. The extent to which these antifungal compounds may contribute to resistance to an aggressive strain ofC. ulmi induced inU. americana by a non-aggressive strain of the fungus remains to be determined.