Sesquiterpenes
Sesquiterpenoids
C15
Also called sesquiterpenoids. They are widespread in nature, occur in a great many isomers and are widely studied as raw materials for fragrances and cosmetics.
CHEMISTRY OF SCENT
A fragrance that unfolds with fire
Agarwood consists of essential-oil components such as benzylacetone, residual components such as hydrocinnamic acid, and the compounds that make up most of the resin: sesquiterpenes and 2-(2-phenylethyl)chromones.
When agarwood is burned, its smoke carries sesquiterpenes such as karanone, agarospirol, kusunol and dihydrokaranone. Research reports that as heat oxidizes and breaks them down, each turns into different aroma compounds, and their combination creates the deep, distinctive scent of agarwood (Ishihara et al., 1993).
| Compound class | Aroma impression |
|---|---|
| Ketones · aldehydes | Floral |
| Lactones | Sweet |
| Carboxylic acids | Sharp, pungent |
Source: "A Comparative Analysis of the Volatile Components of Agarwood from Vietnam and other Regions"
SESQUITERPENES
Sesquiterpenes
Compounds of 15 carbon atoms built from three isoprene units. Heavy and slow to evaporate, they form the backbone of the scent of agarwood resin.
Agarospirol
Sesquiterpene alcohol
C15H26O
A representative sesquiterpene alcohol of agarwood, belonging to the vetispirane group. It is also detected in the smoke given off when agarwood is burned.
α-Agarofuran
Sesquiterpene
C15H24O
A compound with woody and nutty notes, found mainly in agarwood whose resin formed after fungal infection.
Jinkohol
Sesquiterpene alcohol
C15H26O
A sesquiterpene alcohol named after jinkō (沈香), the Japanese name for agarwood.
β-Selinene
Sesquiterpene hydrocarbon
C15H24
A sesquiterpene hydrocarbon found in the essential oils of many plants, including agarwood oil.
α-Bulnesene
Sesquiterpene
C15H24
A terpene made of three linked isoprene units, widely used in the perfume and cosmetics industries.
δ-Guaiene
Guaiane-type sesquiterpene
C15H24
A sesquiterpene with a guaiane skeleton, with methyl groups at positions 3 and 8 of an octahydroazulene structure.
OTHER COMPONENTS
Chromones and aromatic compounds
Agarotetrol
2-(2-Phenylethyl)chromone
C17H18O6
A compound of the 2-(2-phenylethyl)chromone group. It is characteristic of agarwood resin and is studied as a marker compound for assessing quality.
Benzylacetone
Essential-oil component
C10H12O
An essential-oil component of agarwood. With its sweet, floral scent, it is one of the main notes released when agarwood is warmed.
Hydrocinnamic acid
Residual component
C9H10O2
A component of the residual fraction of agarwood, detected together with related compounds such as p-methoxycinnamic acid.
Cucurbitacins
Bitter compounds
Bitter compounds also found in the unripe parts of gourd-family plants such as cucumbers and melons, and reported in agarwood as well. There are about 20 variants, named A through T.
· Other compounds detected in agarwood include α-santalol, cedrol, elemol, eudesmol, γ-selinene, valencene and dehydrofukinone (dihydrokaranone).
· The composition varies with origin, species, and the cause and duration of resin formation. This page introduces compound names and aroma characteristics only and does not describe any effect or benefit of products.
· Structural formulas: Korean Traditional Knowledge Portal, agarwood-related compounds