Seasonal variations in the concentrations of lipophilic compounds and phenolic acids in the roots of Echinacea purpurea and Echinacea pallida.

Roots of Echinacea purpurea and Echinacea pallida cultivated for 4 years in a North European climate were analyzed for seasonal variations in the concentrations of lipophilic constituents (alkamides, ketoalkenes, and ketoalkynes) and phenolic acids by harvesting five times during 1 year to establish the optimal time for harvest. A total of 16 alkamides, three ketoalkenes, two ketoalkynes, and four phenolic acids (echinacoside, cichoric acid, caftaric acid, and chlorogenic acid) were identified in aqueous ethanolic (70%) extracts by liquid chromatography-mass spectrometry and quantified by reverse-phase high-performance liquid chromatography. The major alkamides in the roots of E. purpurea were at their lowest concentration in the middle of autumn and early winter, and the total concentration of lipophilic compounds in E. pallida showed the same pattern. Moreover, all of the major phenolic acids in E. purpurea were at their highest concentrations in spring. The optimal harvest time in spring is in contrast to normal growing guidelines; hence, this specific information of seasonal variations in the concentrations of lipophilic and phenolic compounds in E. purpurea and E. pallida is valuable for research, farmers, and producers of medicinal preparations.