Development of a non-alcoholic extraction method for alkylamides in Echinacea purpurea

Introduction: Alkylamides are recognized as the main active constituents of Echinacea purpurea . Owing to their lipophilic nature, they are conventionally extracted using ethanol-based solvents. Ethanol-free preparations, including Echinacea glycerites and glycetracts, have emerged as alternatives; however, their alkylamides content has not been rigorously verified and is assumed to be low. The lack of ethanol-free extracts capable of preserving alkylamides potency presents a major challenge for product development. Method: E. purpurea were subjected to ultrasonic-assisted extraction using propylene glycol (PG) as the extraction solvent. Comparative analyses were conducted with E. purpurea glycerite, glycetract and hydroethanolic extracts. Results: Organoleptic evaluation indicated that PG-based extracts retained the characteristic tingling properties observed in hydroethanolic extracts. Quantitative HPLC analysis demonstrated that glycerite and glycetract preparations contained approximately 44 % of the alkylamides concentration measured in hydroethanolic extracts. In contrast, PG-based ultrasonic extracts achieved 83 % of the alkylamides yield of the hydroethanolic extract. Furthermore, alkylamides were not detected in the aerial parts extract. Conclusion: PG extract offers a viable ethanol-free E. purpurea alternative, while maintaining a high alkylamides content.