Optimisation of a green extraction process for the efficient recovery of polyphenolic antioxidants from two Artemisia species [Thesis (M.Sc.)]

however, in A. inculta, the major essential oil components identified are: 1,8-cineole (28.10%), cis-thujone (17.48%), trans-sabinol (12.49%), trans-thujone (11.97 %), and camphor (11.76%).

English. A step-by-step optimisation of an extraction process was carried out, with the aim of establishing a sustainable methodology for polyphenol recovery from two Artemisia species, endemic to the island of Crete. The extraction medium was composed of water and glycerol, and the optimisation included factors that were critical to the process, such as glycerol concentration (Cgl) and liquid-to-solid ratio (RL/S). Maximum polyphenol yield was achieved with Cgl = 90% (w/v) glycerol and RL/S = 100 mL g-1 for both botanical species and 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 (Ea) being 37.64 and 33.59 kJ mol-1, for A. arborescens and A. inculta, respectively. However, the outcome concerning the effect of temperature on the antioxidant properties of the extracts was contradictory. 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. The essential oil obtained by hydrodistillation of air-dried aerial parts from the two Artemisia species was analyzed by GC/MS. The main constituents of A. arborescens essential oil were found to be camphor (30.51%), trans-thujone (18.42%), and chamazulene (15.72%)