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Essential Oil Composition of Species in the Genus Achillea

Abstract Based on the present knowledge of essential oil composition of species belonging to the genus Achillea the factors, which may infuence the composition with regard to plant biology, production and application are discussed. According to studies from the last 15 years, a mean of 54 compounds have been identifed in samples of different species. Among them, the largest number of components (149 compounds) were found in the oils of A. millefolium, A. pannonica and A. collina. The monoterpenes, 1,8-cineole, camphor, borneol, α- and β-pinenes are among the fve most abundant components. Beside chamazulene, the most frequently identifed sesquiterpenes are β-caryophyllene and its oxide. The presence of chamazulene seems to remain a characteristic, but it is not ubiquitous to the members of the Millefolium group. The heritance mechanism of sesquiterpenes, especially chamazulene, seems to be established, while we know relatively less about the genetic regulation of the monoterpene compounds. During ontogenesis, major differences could be found between the stages before and after fower development. The phenological phase assuring the highest level of azulenes seems to be during fowering. Composition and compositional changes of an essential oil within the Achillea genus in different plant organs seems to depend on the species. In several cases a dominance of sesquiterpene components above the monoterpenes was found in the vegetative organs. The most important differ-ence seems to be the lack or low amount of chamazulene as artefact in the extracts compared to the distillates.