Extraction of Essential Oil from Nepeta pratti Levl.Based on CO2 Supercritical Extraction Technology

[Objective]The research aimed to establish the best extraction technology of essential oil from Nepeta pratti Levl based on CO2 supercritical extract technology (CD2-SFE). [Method] The orthogonal experiment was used to optimize the extract technology. And the gas chromatography-mass spectrum(GC-MS) technology was used to analyze the main components and their contents of N. pratti Levl volatile oil, then compare them to that of volatile oils extracted by the steam distillation method and the solvent extraction method. [Result] The results showed that the main components of volatile oil extracted by CO2 supercritical extract technology were pulegone, menthone, caryophyllene, D-limonene, transcarveol, germacrene D, (2R-cis)-5-methyl-2-(1-methylethyl)-Cyclohexanone, isopulegone, limonene, 1-octen-3-ol, 2-cyclopentylcyclopen-tanone, caryophyllene oxide, dactylol, β-myrcene, and their content was respectively 45.21%, 19.90%, 1.89%, 1.80%, 1.49%, 1.07%,0 .81%, 0.78%, 0.65%, 0.51%, 0.51%, 0.50%, 0.47%, 0.40%, 0.21%. The terpenes content was the highest, up to 76.20%. Compared with the steam distillation method and the solvent extraction method, the main components from N. pratti Levl extracted by CO2 supercritical extract technology were the highest, and the kinds of extracted components were relatively more. [Conclusion] Supercritical extraction method is simple and feasible, with the characteristics of quick mass transfer speed, strong penetrability, high selectivity and extractive efficiency, low operating temperature and so on.