ALKAMIDE LEVELS IN ECHINACEA-PURPUREA - A RAPID ANALYTICAL METHOD REVEALING DIFFERENCES AMONG ROOTS, RHIZOMES, STEMS, LEAVES AND FLOWERS

A rapid extraction, clean-up, and RPLC procedure suitable for routine quantitative analyses of alkamide levels in Echinacea purpurea extract s is described. The C-13-NMR spectra of the main diene-diyne alkamides in E. purpurea are reported. Alkamide levels differed significantly a mong roots, rhizomes, stems, leaves, and flowers of E. purpurea. Roots were distinguished from other plant parts by higher levels of the C-1 2 diene-diyne alkamides, whereas levels of the C-12 tetraene alkamides and C-11 diene-diynes were highest in vegetative stems. The ratio of the two stereoisomeric C-12 tetraene alkamides differed between flower s and all other E. purpurea parts. These results are important for sta ndardisation of medicinal preparations of E. purpurea.