Alkamides and a neolignan from Echinacea purpurea roots and the interaction of alkamides with G-protein-coupled cannabinoid receptors

► Four natural products, three alkamides and one neolignan, were identified in the roots of Echinacea purpurea. ► Four further known alkamides and one sesquiterpene were detected for the first time in this species. ► Ten known E. purpurea alkamides were isolated. ► Their cannabinoid receptor activity in [35S]GTPγS-binding assay were investigated on rat brain membrane preparations. ► Both partial and inverse agonist compounds were identified.