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Characterisation of supercritical carbon dioxide extract oils from Origanum glandulosum Desf. From two wild Tunisian populations, chemical composition and antioxidant activities

Mechergui, K., Boukhchina, S., Khouja, M.L., Coelho, J.A., Palavra, A.M., Ben Lamine, S.
Acta horticulturae 2013 no.997 pp. 83-88
Origanum, antioxidant activity, antioxidants, carbon dioxide, carvacrol, chemical composition, flowers, free radicals, gallic acid, gamma-terpinene, gas chromatography, inhibitory concentration 50, leaves, mass spectrometry, oils, oregano, p-cymene, supercritical fluid extraction, thymol
Origanum glandulosum Desf. volatile oils from flowers and leaves were obtained by supercritical fluid dioxide extraction (SFE). Two wild Tunisian populations, one from Bargou and the other from Nefza were studied. The Origanum oils were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) to characterize its components. The volatile oils from oregano collected from Bargou and Nefza were obtained in yields of 2.23 and 2.07% (v/w) respectively. The main compounds of oils obtained by using supercritical CO2 extraction at 40ºC and 90 bar were thymol (41% and 40% corresponding to Bargou and Nefza respectively), followed by p-cymene (32.3% and 36.2%), γ-terpinene (20.3% and 13.3%) and carvacrol (2.3% and 2.2%). The SFE oils were assayed for their total phenolics content, by the Folin-Ciocalteu method, and antioxidant effectiveness, using the 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging assay. The abilities to scavenge the DPPH radicals, expressed by IC50, are 44.02 and 60.31 mg L-1 and the total phenolic contents, expressed in gallic acid equivalent (GAE) g kg-1 dry weight, are 14 g kg-1 from Bargou and 12.4 g kg-1 from Nefza.