Mansonones A and C to G, sesquiterpene quinones possessing antifungal properties, were isolated from the elm
Ulmus americana infected with
Ceratocystis ulmi. Scopoletin and
-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 of
C. ulmi induced in
U. americana by a non-aggressive strain of the fungus remains to be determined.
We thank P. Giguère, R. Cormier, B. Roze, and D.J. Kelly for technical assistance. M.T.D. is indebted to the Natural Sciences and Engineering Research Council of Canada for financial support. The authors are indebted to L. Calhoun (Univ. New Brunswick) for recording 200 MHz NMR-spectra, and to Professor J.C. Overeem (Utrecht) and Professor G.B. Marini-Bettolo (Rome) for kindly providing some reference spectra and helpful information.