The aerial part of Montanoa leucantha subsp. leucantha, afforded in ad
dition to known compounds, seven new sesquiterpene lactones, four mont
ahibisciolides, a new skeletal-type of sesquiterpene lactones, as well
as three 9-keto-melampolides, all being 6,12-cis-lactones. The struct
ures and stereochemistries of the new compounds were established based
on H-1 NMR spectral studies.