Comparative Analysis of Essential Oil Quality and Composition from Tissue Culture Seedlings of Thymus vulgaris L. Using Different Extraction Methods

The essential oils of Thymus vulgaris were extracted by steam distillation, organic solvent extraction and supercritical CO₂ extraction.The amounts,compositions and relative contents of the essential oils extracted from the three methods were compared.The results showed that the amount of essential oils extracted by steam distillation was 0.21%,the main chemical components were thymol(36.53%), benzene,1-methyl-3-(1-methylethyl)-(14.13%),1,4-cyclohexadiene,1-methyl-4-(1-methylethyl)(8.09%), and caryophyllene(4.14%);the amount of essential oils extracted by organic solvent extraction was 0.19%,the main components were 1,2-benzenedicarboxylic acid,mono(2-ethylhexyl)ester(55.23%),thymol(8.73%),and 1,4-cyclohexadiene,1-methyl-4-(1-methylethyl)(5.23%);and the amount of essential oils extracted by supercritical CO₂ extraction was 0.27%,the main components were thymol(26.68%),2-propenoic acid,3-phenyl-,methyl ester(21.55%), and benzene,1-methyl-3-(1-methylethyl)(9.69%).Based on the quality,major chemical compositions and extraction amount of essential oils,the steam distillation was the best method to extract essential oils from Thymus vulgaris.