Molecule of the Week

α-Thujone

June 16, 2008

The monoterpene α-thujone [(+)-3-thujone], and its diastereomer, β-thujone, occur in several plants, such as arborvitae (genus Thuja), mugwort, common sage, wormwood, and some junipers. α-Thujone, and to a lesser extent the β-isomer, is a γ-aminobutyric acid (GABA) antagonist and can cause brain neurons to fire easily, causing muscle spasms and convulsions. It has been implicated in unusual behaviors attributed to the wormwood oil–flavored liqueur absinthe, but recent studies have shown that the thujone concentration in absinthe is too small to cause toxic effects.