Resolution of Complex Sesquiterpene Hydrocarbons in Aquilaria malaccensis Volatile Oils Using Gas Chromatography Technique

Abstract

Agarwood or gaharu is resin-impregnated wood of the tree genus Aquilaria (Thymelaeaceae). In Malaysia, the main agarwood producer is Aquilaria malaccensis and oil extracted from this species is highly priced. One of the challenges in commercializing agarwood is the lack of universal standard to classify the aromatic oils. Our present knowledge places the main aromatic compounds of agarwood oil in the sesquiterpene hydrocarbon region. In this work, we extracted agarwood oil using hydrodistillation method in the laboratory and compared with a commercial-scale extraction in the factory. We analyzed the sesquiterpene hydrocarbon region using several highly sophisticated detection systems. Using GC-FID, 12 sesquiterpene hydrocarbons were identifi ed, while another eight were determined using GC-MS. Five compounds were identifi ed in both analytical techniques: aromadendrene, α-bulnesene, α-guaiene, γ-gurjunene, and β-maaliene. Advanced analysis using GC × GC/TOFMS detected 24 sesquiterpene hydrocarbons in both laboratory and pilot scale agarwood oils. Many of the sesquiterpene hydrocarbons identifi ed provide the woody aroma to the agarwood oil. Specifi cally, α-gurjunene and α-guaiene contribute to the woody balsamic aroma, while α-copaene contributes to the spicy-wood aroma. In total, 33 sesquiterpene hydrocarbons were identifi ed from A. malaccensis in the present study, with high certainty. Results from this study can be used toward establishing a universal standard for agarwood oil from the genus Aquilaria in the global market, which is presently lacking.

The Effect of Enzymatic Pre-Treatment in Agarwood Oil Extraction

“…Based on data obtained from the GC-MS analysis, Caryophyllene was identified in EP5, but the total area is too small, making it negligible. As previously mentioned, based on Terry and Heinrich [30] and Tajuddin et al [31], some of the compounds identified in the table, I provide the woody aroma to agarwood oil. Caryophyllene contributes to the spicy-wood aroma, while Gurjunene contributes to the woody balsamic aroma and Alloaromadendrene to the woody aroma.…”

Characterisation and variation of agarwood resins from Gyrinops walla

“…For centuries, it has been used as a key perfumery agent known as agar or oud in the Middle East and India. However, agarwood is now gaining popularity among western perfumery and other cosmetic industries (Tajuddin et al 2016).…”

“…The undamaged or healthy xylem tissue of agarwood tree is pale in colour. However, with the resin formation, the mass and density of the affected wood are increased and the colour changes to dark brown or black (Rahman & Basak 1980, Tajuddin et al 2016.…”

“…Sesquiterpenes can be divided into oxygenated compounds and sesquiterpene hydrocarbons; however, categorising them according to the basic sesquiterpene structures is more beneficial for qualitative and quantitative analysis. Sesquiterpene classes (types) present in agarwood are agarofuran, vetispirane, cadinane, eremophilane or valencane, eudesmane or selinane, guaiene and prezizane (Naef 2011, Tajuddin et al 2016. Geography, climate and soil conditions affect agarwood resin composition and these external factors could be more vital than inter-species differences (Gianno 1986, Soehartono & Mardiastuti 1997, Pojanagaroon & Kaewrak 2005.…”

A Novel Agarwood Resin Inducement Method Using Mycotoxins of Selected Fungal Species

“…It has also been used as a key perfumery agent, known as agar or oud, in the Middle East and India. However, agarwood has now gained popularity among Western perfumery and other cosmetic industries (Tajuddin et al, 2016).…”