Germacrenes are a class of volatile organic
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...
s, specifically,
sesquiterpene
Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificatio ...
s. Germacrenes are typically produced in a number of plant species for their antimicrobial and insecticidal properties, though they also play a role as insect
pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s. Two prominent molecules are germacrene A and germacrene D.
Structures
Germacrene has five isomers.
Natural occurrences
The essential oils of red deadnettle (''
Lamium purpureum
''Lamium purpureum'', known as red dead-nettle, purple dead-nettle, or purple archangel, is an annual herbaceous flowering plant native to Europe and Asia.
Varieties:
* ''Lamium purpureum'' var. ''hybridum'' (Vill.) Vill. (synonym: ''Lamium hybr ...
'') and hedgenettles (genus ''
Stachys
''Stachys'' is a genus of plants, one of the largest in the mint family Lamiaceae.Harley, R. M., et al. 2004. "Labiatae". pages 167–275. In: Kubitzki, K. (editor) and J. W. Kadereit (volume editor). ''The Families and Genera of Vascular Plants ...
'')
are characterized by their high contents of germacrene D, as is ''
Clausena anisata
:''Should not be confused with syzygium anisatum, a tree native to eastern Australian rainforests, used as a culinary herb.''
''Clausena anisata'' (Willd.) Hook.f. ex Benth. is a deciduous shrub or small tree, belonging to the Rutaceae or Citrus ...
''. It is also a major component of
patchouli oil.
References
Further reading
General
*
Germacrene A
*
*
*
*
*
*
Germacrene D
*
*
*
*
*
*
*
{{refend
Alkene derivatives
Sesquiterpenes
Cycloalkenes
B