Identification of Odor-active Components of Agarwood Essential Oils from Thailand by Solid Phase Microextraction-GC/MS and GC-O

Volatile components from the essential oils of Aquilaria malaccensis, A. subintegra and A. crassna were investigated by gas chromatography (GC), gas chromatography-mass spectrometry (GC/MS), and gas chromatography-olfactometry (GC-O). A total of 31 volatile constituents were identified from the three agarwood oils. A subset of 18 out of the 31 components was identified from the essential oil of A. malaccensis with the major components being isoamyl dodecanoate, guaia-1(10),11-dien-15-ol, karanone, cyclocolorenone and jinkoheremol. Aquilaria subintegra oil yielded 28 identified compounds with the most abundant components being isoamyl dodecanoate, kusunol, jinkoh-eremol, epoxybulnesene and β-agarofuran, while 30 volatile compounds from A. crassna were identified, with isoamyl dodecanoate, β-agarofuran, kusunol, dehydrojinkoh-eremol and 9,11-eremophiladien-8-one as the main constituents. The aroma-active compounds of the three samples were analyzed by HS-SPME-GC-O. A total of 74 odor-active components were characterized by using the GC-O technique. The major components responsible for the aroma included β-agarofuran, 4-phenyl-2-butanone, furfural and benzaldehyde, while the minor aroma notes were attributed to (E)-α-bergamotene, α-humulene, α-bulnesene, α-agarofuran, nor-ketoagarofuran, epoxybulnesene, agarospirol, jinkoh-eremol, kusunol, acorenone B, selina-3,11-dien-14-al and 9,11-eremophiladien-8-one, considered to be the most important aroma impact compounds for the characteristic aroma of agarwood essential oils