Solvent-free microwave extraction of essential oils from Laurus nobilis and Melissa officinalis: comparison with conventional hydro-distillation and ultrasound extraction.

Solvent-free microwave extraction (SFME) has been applied to the extraction of essential oils from Melissa officinalis L. and Laurus nobilis L. The results of SFME were compared with those obtained by hydro-distillation (HD) and ultrasound-assisted extraction (USE) of essential oils from dried plant materials. The compositions of the essential oils were identified by GC-MS. The essential oil obtained with SFME contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than the oils obtained by conventional methods. The three different extraction methods used showed differences in the compositions and contents of the essential oils.