Chemical composition of the foliar essential oil of Tsuga mertensiana (Bong.) Carrière

InformationTsuga mertensiana (mountain hemlock, Pinaceae) is a species of hemlock that is native to the west coast of North America, from the Sierra Nevada Mountains of California to the Kenai Peninsula of Alaska.In this work, foliage samples of T. mertensiana were obtained from four individual trees located on Mt.Hood, Oregon.The essential oils were obtained by hydrodistillation and analyzed by gas chromatography, including enantioselective gas chromatography.The essential oils were dominated by monoterpene hydrocarbons (68.8-80.1%)and oxygenated monoterpenoids (6.4-15.3%).The major components were α-pinene (24.5 ± 3.2%, predominantly (+)-α-pinene), β-phellandrene (16.3 ± 2.1%, predominantly (+)-β-phellandrene), limonene (9.8 ± 6.2%, predominantly (-)-limonene), benzoic acid (6.4 ± 1.5%), β-pinene (5.9 ± 1.0%, predominantly (-)-β-pinene), (-)-α-phellandrene (5.8 ± 1.1%), and bornyl acetate (5.7 ± 3.5%).This is the first report on the essential oil composition, including enantiomeric distribution, of T. mertensiana collected from its natural habitat and complements our understanding of the phytochemistry of the genus.Chiral analyses of other Tsuga species would further help in chemically characterizing the genus.