Sesquiterpene Lactones from Achillea

The species of genus Achillea, particularly those belonging to the Achillea millefolium group have received a lot of attention so far, due to their use in traditional medicine. Among the numerous chemical compounds isolated from the A. millefolium species, the sesquiterpene lactones are usually one of the major constituents (Seaman, 1982). Continuing our chemotaxonomic examination of Bulgarian Achillea taxa, we have undertaken an investigation of the chloroform extract of Achillea collina Becker, a tetraploid species of the A. millefolium group. Previous chemical studies on this species revealed the presence of lactones belonging to the guaiane type only. The main lactones were reported to be artabsin derivatives (VerzarPetri et al., 1980; Kastner et al.,1991a; Kastner et al., 1991b; Kubelka et al., 1999), although a matricin derivative (Verzar-Petri et al., 1980) and a matricarin derivative (Glasl et al., 1994) were also isolated. In contrast, we could not detect any other lactones but germacranolides and eudesmanolides. In the present paper, we wish to report the isolation of three new sesquiterpene lactones, 2, 4 and 5, in addition to the known lactones 1, 3, 6, 7 and 8.