Echinacea: anatomy, phytochemical pattern, and germination of the achene.

The achenes (fruits) of the therapeutically used Echinacea species E. purpurea, E. angustifolia, and E. pallida can be differentiated structurally (shape, anatomy) as well as phytochemically (essential oil components, alkamides). During germination in all three species dodeca-2E, 4E, 8Z, 10E(10Z)-tetraenoic acid isobutylamide (8/9) is mainly formed. Besides this a number of alkamides typical for the root of E. purpurea are synthesized in moderate amounts. Also, alkene derivatives of isovalerianic acid are produced. It is an interesting fact that neither 2-monoene alkalmides nor polyacetylenes could be detected during achene germination.