Which extraction technique is the best for LC × LC analysis of bioactive compounds from European medicinal plants: Conventional or sustainable extraction techniques?

Abstract

The growing interest in medicinal plants calls for further information about the extraction and chemical composition of potential bioactive compounds. Extraction is the most essential part of generating highly bioactive herbal remedies by isolating and preconcentrating bioactive compounds while, nowadays, the greenness of the method needs to be considered and improved. In this approach, different plant parts such as flowers, berries, and barks from Sambucus nigra L., a plant that has been studied for two decades for its promising hepatoprotective activity were investigated. Conventional and sustainable extraction techniques (infusion, magnetic-assisted extraction, ultrasound assisted extraction, and microwave-assisted extraction) were optimized for the recovery of bioactive compounds from these plant parts considering the greenness of the method as well as the total phenolic content, the antioxidant activity and the extraction yield. The parameters solvent-to-plant ratio, time, temperature, water-ethanol ratio as solvent and microwave power were optimized by an experimental design according to the extraction technique. The profile of the bioactive compounds of each plant part and extraction method was evaluated by LC × LC and hyphenated to tandem mass spectrometry for identification purposes. Compared to previously reported green extraction techniques, all four optimized methods were able to obtain similar results by being less time consuming, yielding good greenness values and were suited for high-throughput analysis. MAE proved to be the best of the investigated methods in terms of greenness and efficient extraction of bioactive compounds and will therefore play a significant role in future research applications.