title: Optimization of supercritical carbon dioxide extraction of essential oil from Dracocephalum kotschyi Boiss: An endangered medicinal plant in Iran.
abstract: Extraction of the essential oil from a medicinal plant called Dracocephalum kotschyi Boiss was performed by green technology of supercritical carbon dioxide (SC-CO2) extraction. A Taguchi orthogonal array design with an OA16 (4(5)) matrix was used to evaluate the effects of five extraction variables: pressure of 150-310bar, temperature of 40-60°C, average particle size of 250-1000μm, CO2 flow rate of 2-10ml/s and dynamic extraction time of 30-100min. The optimal conditions to obtain the maximum extraction yield were at 240bar, 60°C, 500μm, 10ml/s and 100min. The extraction yield under the above conditions was 2.72% (w/w) which is more than two times the maximum extraction yield that has been reported for this plant in the literature using traditional extraction techniques. Results from analysis of variance (ANOVA) indicated that the CO2 flow rate and the extraction time were the most significant factors on the extraction yield by percentage contribution of 44.27 and 28.86, respectively. Finally, the chemical composition of the essential oil was evaluated by using gas chromatography-mass spectroscopy (GC-MS). Citral, p-mentha-1,3,8-triene, D-3-carene and methyl geranate were the major components identified.
authors.affiliation: Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Nejad-Sadeghi
authors.affiliation: Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Taji
authors.affiliation: Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran. Electronic address: igoodarznia@yahoo.com.
authors.forename: Iraj
authors.initials: I
authors.lastname: Goodarznia
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D025924:Chromatography, Supercritical Fluid; D056727:Endangered Species; D008401:Gas Chromatography-Mass Spectrometry; D007492:Iran; D019686:Lamiaceae / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification*; D010946:Plants, Medicinal / Q000737:chemistry*; D011312:Pressure; D013696:Temperature
chemical_list: D009822:Oils, Volatile; D002245:Carbon Dioxide
keywords: Dracocephalum kotschyi; Essential oil; Gas chromatography; Supercritical fluid extraction; Taguchi design