Retention of alkamides in dried Echinacea purpurea

Different drying methods, such as freeze-drying (FD), vacuum microwave dryi ng (VMD), and air-drying (AD), were applied to fresh roots and leaves of Ca nadian-grown Echinacea purpurea to determine the optimal method for preserv ing alkamide levels. Using HPLC, six alkamide fractions (alkamides 1, 2, 3, 6a/6, 7, 8/9) were quantitated in dried roots, whereas four alkamide fract ions (alkamides 1, 2, 3, 8/9) were measured in dried leaves. Different elut ion conditions used in HPLC for alkamide analysis did not affect the eluted fractions nor the quantitation of different alkamides. Individual alkamide concentrations in roots and leaves were affected by the drying methods use d. To preserve higher levels of total alkamides, FD was found to be the bes t method, VMD was a superior method for drying roots than AD at 70 degrees C, while AD at 50 degrees C was the preferred method for drying leaves off. purpurea.