Composition and seasonal variation of the essential oil from Abies sachalinensis from Hokkaido, Japan.

The composition of the steam-distilled essential oil from the leaves of Abies sachalinensis (F. Schmidt) Mast. cultivated in Hokkaido (Japan) was studied by GC-MS. The seasonal variation in the main volatile constituents was also investigated. Analysis of the essential oil resulted in the identification of 21 compounds with monoterpenes comprising 99.9% of the total. alpha-Pinene was the most abundant compound, followed by camphene, bornyl acetate, limonene, beta-pinene and beta-phellandrene. The sesquiterpene content was low, and was mainly represented by beta-caryophyllene, beta-caryophyllene, and gamma-selinene. The essential oil from the leaves, collected at eight different collection periods over more than 5 years, showed significant differences in composition. Alpha-Pinene was the predominant constituent during the collection periods, with a few exceptions. The alpha-pinene content of the oil was abundant in April-June, and decreased in November-December. Levels of bornyl acetate showed the greatest increase in December, when the temperature was very low. The enantiomeric distribution of alpha-pinene was suggested to relate to seasonal transformation. (+)-alpha-Pinene showed a tendency to increase when total precipitation, average temperature, and total duration of sunshine were high.