Extraction optimisation using water/glycerol for the efficient recovery of polyphenolic antioxidants from two Artemisia species

A step-by-step optimisation of an extraction process was carried out, with the aim of establishing an eco-friendly methodology for polyphenol recovery from two endemic Cretan Artemisia species. The extraction medium composed of water and glycerol, and the optimisation included factors that were critical to the process, such as glycerol concentration (C-gl) and liquid-to-solid ratio (R-L/S). Maximum polyphenol yield was 48.45 and 59.91 mg GAE g(-1) dw, for Artemisia arborescens and Artemisia inculta Delile, respectively, and it was achieved with C-gl = 90% (w/v) glycerol and R-L/S = 100 mL g(-1) for both botanical species. These conditions were used to further examine the extraction behaviour of water/glycerol mixtures with regard to temperature, employing kinetics. The extractions of both species were shown to display similar kinetic attributes, with the activation energy (E-a) being 37.64 and 33.59 kJ mol(-1), for A. arborescens and A. inculta, respectively. The outcome concerning the effect of temperature on the antioxidant properties of the extracts was in concurrence of those findings. The liquid chromatography-diode array-mass spectrometry analysis revealed that extracts from both plants were dominated by several chlorogenates, accompanied mainly by flavone C-glycosides. (C) 2015 Elsevier B.V. All rights reserved.