Utilization of supercritical carbon dioxide, in essential oil extraction from agarwood aquilaria subintegra

Abstract

The supercritical carbon dioxide extraction (SC-carbon dioxide) of agarwood Aquilaria subintegra was studied. Extraction of agarwood in fine-milled form with 35 mesh size gave 4 times higher the extraction yield than cut dry agarwood. Various extraction conditions; temperature 40-70℃, pressure 12-25 MPa, and carbon dioxide flow rate 1-4 g/min, were investigated. The chemical compositions were analyzed by gas chromatography (GC) and gas chromatography with mass spectrometry (GC/MS). The results were compared with the commercial products. It was found that the optimal condition for extraction was 65℃, 12 MPa, and carbon dioxide flow rate of 3 g/min. Considering the extract contained sesquiterpenoid compounds as also found in the commercial ones. Three different co-solvents: methanol, ethanol, and ethyl acetate, were used in SC-carbon dioxide extraction and the additional volume was varied 5-10%v/v. Although the extraction gave higher yield, their GC chromatogram showed few sesquiterpenoid derivatives whereas many chromone derivatives were obtained. In addition, the extraction by the steam distillation and soxhlet extraction of agarwood were investigated. Although the soxhlet extraction gave the highest yield among all methods, the chemical compositions consisted of long chain carboxylic acid and chromone derivatives.