Agarwood oil Chemical compositions
Here are over 60 chemical compounds found in agarwood oil depending on the species, the testing method, and the origin of the samples. The most common constituents are:
- 3 phenyl 2 butanone
- α – cubebene
- β – agarofuran
- 10-epi- γ eudismol
- β – eudismol
- Jinkoh – eremol
- Jinkohol II
The components that cause the aroma are agarospirol, jinkohol-eremol, and jinkohol. 3-phenyl- 2-butanone and alpha-cubebene are producing the waxy and herbal odor with a medium strength.
In most cases the major compounds of the agarwood oil are sesquiterpenes. They are what causes the agarwood oil to smell as it does. The variety of the sesquiterpene is endless. They are known to have menthol, cinnamon, citrus, eucalyptus, and other scents that are usually found in oud oil.
Other aromatic compounds make up about 30 % of the chemical composition of the oud oil. They are guai-1(10)-en-11-ol, 2(3H)-naphthalenone, 4,4a,5,6,7,8-hexahydro-4a,5-dimethyl-3-(1-methylethylidene)-, (4ar-cis)- , α-copaen-11-ol (10.84%), 1,3,5-trimethyl-2-(2,2,2-trifluoro-ethoxy)-benzene and baimuxinal
The composition of the chemical compounds determines the quality of the agarwood oil from the highest to the lowest. The classification of the agarwood oil is usually based on the properties of the wood: the time the aroma lasts when burning, the color, the content of the resin, the fixative properties, and human perceptions. However, there is also classification based on the chemical compounds of peak area percentage
High quality oud oil must contain α-guaiene with the peak area less than 0.05%. However, if the wood doesn’t contain α-guaiene at all, it’s considered to be low quality.
Only the highest quality agarwood oil has the following compounds which are sesquiterpenes and chromone derivatives.
Different chemical compound combinations can be found in different samples from the same tree. At least 30 % of the agarwood oil chemical compounds are responsible for the special aroma the tree is famous for.
The chemical composition of the agarwood tree oil depends on the following factors
- Age and quality of the fungal infection of the tree.
- The age of the tree itself.
- The species of the tree (there are over 20 different Aquilaria species).
- Environmental conditions.
- Geographical location of the tree.
- The age of the oil.
- The amount of the exposure to the air.
- Type of distillation used.
- Purity of the oil.
- Method of inoculation that helps stimulate the resin production.
- Method of extraction .
There is a difference in the composition of the oil extracted from the naturally infected trees and the trees that were artificially inoculated. However, the difference is so slight that even a chemical analysis might miss it. Accordingly, it is possible to produce high-quality agarwood oil from artificially inoculated trees.
There are chemical compounds that can be added to the oil in order to make its composition appear close to the agarwood oil. It’s easy to cheat the olfactory senses.
- 3-n-propyl-phenol – Creates exception synergies of the various undertones. Makes up an animal aspect and develops composition warmness.
- 3-ethylphenol –Increases the animal aspect of the amberis notes. Creates a warm undertone, and improves the natural scent of the oil.
- 3-i-butyl-phenol – Increases the warm undertones and the animal aspect. The warmness effect is stronger. Improves the natural closeness to the real scent.
- 3-n-butyl-phenol –Increase the warm undertones and the animal aspect. The overall effect is similar to 3-n-propyl-phenol but is slightly weaker.
There are also compounds used for oil preparation called co-ingredients. They are used as a base for creating a faux agarwood oil. There are many such compounds but some of them are castoreum, benzylacetone, pentanoic acid, 2,6,6-trimethyl-l,Safranal, 4-(4-methoxyphenyl)-2-butanone, 3,3- dimethyl-5-(2,2,3-trimethyl-3-cyclopenten-l-yl)-4-penten-2-ol, β-santalol, santal oil.
source : oud-selection