Comparative Analysis of Essential Oil Quality and Composition from Tissue Culture Seedlings ofThymus vulgarisL. Using Different Extraction Methods

The essential oils of Thymus vulgaris were extracted by steam distillationꎬ organic solvent extraction and supercritical CO2 extraction. The amountsꎬ 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%ꎬ the main chemical components were thymol(36􀆰 53%)ꎬ benzeneꎬ 1 ̄methyl ̄3 ̄(1 ̄methylethyl) ̄(14􀆰 13%)ꎬ 1ꎬ4 ̄cyclohexadieneꎬ 1 ̄methyl ̄4 ̄(1 ̄methylethyl) (8􀆰 09%)ꎬ and caryophyllene (4􀆰 14%)ꎻ the amount of essential oils extracted by organic solvent extraction was 0􀆰 19%ꎬ the main components were 1ꎬ2 ̄benzenedicarboxylic acidꎬ mono(2 ̄ethylhexyl)ester(55􀆰 23%)ꎬ thymol (8􀆰 73%)ꎬ and 1ꎬ4 ̄cyclohexadieneꎬ 1 ̄methyl ̄4 ̄(1 ̄methylethyl)(5􀆰 23%)ꎻ and the amount of essential oils extracted by supercritical CO2 extraction was 0􀆰 27%ꎬ the main components were thymol(26􀆰 68%)ꎬ 2 ̄propenoic acidꎬ 3 ̄phenyl ̄ꎬ methyl ester(21􀆰 55%)ꎬ and benzeneꎬ 1 ̄ methyl ̄3 ̄(1 ̄methylethyl) (9􀆰 69%) . Based on the qualityꎬ major chemical compositions and extraction amount of essential oilsꎬ the steam distillation was the best method to extract essential oils from Thymus vulgaris.