Comparative HPLC Analyses of Alkamides within the Achillea millefolium Group

Abstract

Petrol/Et₂O extractable alkamides from the subterranean parts of different members of the Achillea millefolium group were separated and compared by reversed phase HPLC. Apart from different retention times, each peak could be characterized by its typical UV spectrum obtained by on-line photodiode array detection. Based on previously isolated and identified alkamides, a library search program of UV spectra and corresponding retention times was prepared which greatly facilitated a general comparison of the different HPLC profiles. Apart from the dominating deca-2E,4E,6Z-trienoic piperideide in the European representatives (A. millefolium, A. pannonica, A. collina, A. aspleniifolia, A. setacea), the different cytotypes may be characterized by various accumulation tendencies, mainly towards two isomeric decatetraenoic piperideides and (+)-sesamin. The amide patterns of the Asian and North American members (A. asiatica, A. lanulosa) clearly deviate; the characteristic decatrienoic and decatetraenoic piperideides are replaced here by a preponderance of decadienoic acid-derived isobutylamide and piperideide. Since there are no diploid members known from North America, the striking chemical similarities with the diploid Asian members strongly suggest an Asian origin.

Key words

Achillea millefolium group - Asteraceae-Anthemideae - cytotypes - geographical distribution - alkamides - HPLC-comparison