Alpha-Thujene (α-Thujene), sometimes referred to as 3-Thujene, is a natural flavouring compound derived from Eucalyptus. While α-Thujene is the most commonly referenced isomer, a less prevalent chemically related double-bond isomer is known as β-Thujene (or 2-Thujene). Another distinct double-bond isomer of Thujene is Sabinene. Thujene may also be encountered under alternative names such as 3-Thujene or Thujiene.
As two primary double-bond isomers of Thujene, α-Thujene and β-Thujene exhibit subtle differences in their chemical structures, which in turn affect their volatility and interactions within biological systems.
- Natural Abundance: Beta-Thujene is often found in higher concentrations in certain plants (e.g., Cinnamomum species, up to approximately 2.82%) compared to Alpha-Thujene (around 0.22%).
- Aroma Profile: Both isomers are considered important volatile compounds contributing to woody aromas. Research indicates that samples with a higher relative concentration of Beta-Thujene may present a more pronounced woody flavour, akin to that of crushed wood chips. In contrast, Alpha-Thujene tends to contribute more earthy and woody notes, commonly found in frankincense and thyme oils.