Sesquiterpenes and flavonoid aglycones from a Hungarian taxon of the Achillea millefolium group

The investigation of a dichloromethane extract of flower heads of a Hungarian taxon of the Achillea millefolium group led to the isolation of three flavonoid aglycones, one triterpene, one germacranolide and five guaianolides. Their structures were elucidated by UV-VIS, EI- and CI-MS, 1H NMR and 13C NMR spectroscopic methods as well as by 2D-NMR studies and by selective 1D-NOE experiments. Besides apigenin, luteolin and centaureidin, beta-sitosterol, 3beta-hydroxy-11alpha,13-dihydro-costunolide, desacetylmatricarin, leucodin, achillin, 8alpha-angeloxy-leucodin and 8alpha-angeloxy-achillin were isolated. Both latter substances are reported here for the first time. Their NMR data were compared with those of the other guaianolides. The stereochemistry of 3beta-hydroxy-11alpha,13-dihydro-costunolide was discussed and compared with data of the literature.