In addition to known eudesmanolide and germacranolide sesquiterpene la
ctones a new eudesmanolide, lpha,6alpha-trihydroxyeudesm-11-en-8alpha,
12-olide was isolated from the aerial parts of Tanacetum densum subsp.
amani. The structure of the new compound was established by spectral
data; it showed weak antimicrobial activity.