Recovery evaluation of lipophilic markers from Echinacea purpurea roots applying microwave‐assisted solvent extraction versus conventional methods

Abstract

AbstractIn the present study the recovery from roots of lipophilic markers (mainly alkamides) of Echinacea purpurea (L.) Moench for analysis by GC/MS was evaluated by applying microwave‐assisted solvent extraction (MASE), as a new extraction approach, versus two other conventional methods (Soxhlet and ultrasonic extraction). A preliminary screening of the three methods, using the best‐reported parameters (solvent and extraction time) for Soxhlet (as a reference method) and ultrasonic extraction, showed MASE and ultrasonic extraction (using 70% methanol as the solvent system in both) to be superior methods to Soxhlet extraction in two solvent systems. Both methods, MASE and ultrasound, were further evaluated applying different ratios of methanol‐water (60 to 100% methanol) as the solvent system. In these investigations, MASE showed significantly higher recoveries than the ultrasonic technique over the 70–100% methanol range while comparable values were obtained at 60% methanol. The best recovery of the individual alkamides and the whole lipophilic fraction was obtained at 70% methanol. The MASE method could serve as good alternative procedure for the preparation of more chemically potent samples and/or crude extracts from Echinacea species.