Supercritical CO₂ Fluid Extraction of Elsholtzia Fruticosa and GC/MS Analysis

Essential oils were extracted from Elsholtzia fruticosa with supercritical CO₂ flurd extraction. The results of experiments indicate that the optimum extraction of pressure, temperature, extraction time and CO₂ fluid are 15 MPa, 45 ℃, 1.5 h, 5 mL•min^-1, respectively，and the yield of SFECO₂ extracts is 2.87%. The chemical constituents of extracts of Elsholtzia fruticosa were determined by GC/MS. The relative contents of constitutes were determined by area normalizing method. 38 constituents are identified from 44 separated peaks, amounting to total mass fraction 96.46%. The main compounds are p-cymene(19.34%), cis-caryophyll-ene (18.23%)，β-pinene（7.10%）， carvacrol (5.63%), thymol(6.48%)， 3-octanone (5.26%), etc. Acetic acid dodecyl ester（0.29%）, 2-octene-1-ol（0.69%），pentadecanol acetate（0.86%）, hexadecanoic acid（0.70%）, 9,12-octadecadienoic acid methyl ester（1.58%）， 9-octadecenoic acid methyl ester（0.84%），9-octadecenoic acid（0.92%） are determined in essential oils of Elsholtzia fruticosa.