Use of Innovative (Micro)Extraction Techniques to Characterise Harpagophytum procumbens Root and its Commercial Food Supplements

IntroductionFor the determination of harpagoside and the wide phenolic pattern in Harpagophytum procumbens root and its commercial food supplements, dispersive liquid-liquid microextraction (DLLME), ultrasound-assisted DLLME (UA-DLLME), and sugaring-out liquid-liquid extraction (SULLE) were tested and compared. ObjectivesIn order to optimise the extraction efficiency, DLLME and UA-DLLME were performed in different solvents (water and aqueous solutions of glucose, -cyclodextrin, (2-hydroxypropyl)--cyclodextrin, sodium chloride, natural deep eutectic solvent, and ionic liquid). Material and MethodsThe plant material was ground and sieved to obtain a uniform granulometry before extraction. Commercial food supplements, containing H. procumbens are commercially available in Italy. ResultsThe most effective sodium chloride-aided-DLLME was then optimised and applied for analyses followed by HPLC-PDA. For comparison, microwave-assisted extraction was performed using the same solvents and the best results were obtained using 1% of -cyclodextrin or 15% of sodium chloride. ConclusionAll commercial samples respected the European Pharmacopoeia monograph for this plant material, showing a harpagoside content1.2%. Copyright (c) 2017 John Wiley & Sons, Ltd.