Sesquiterpenes from the inner bark of the silver birch and the paper birch.

The compositions of the mixtures of sesquiterpenoids, largely hydrocarbons that were found in the inner bark of the silver birch, Betula pendula Roth and the paper birch, Betulapapyrifera Marshall, grown in New Zealand were analyzed by SPME-GCMS. The major components of the volatile oil from the inner bark of B. pendula were trans alpha-bergamotene (31%) and alpha-santalene (19%). This composition was quite different from that of the oil from the branches, buds and leaves of the same species from Turkey, but was very similar to that of the oil from the bark of B. pubescens from Russia. The major components of the oil from the inner bark of B. papyrifera were trans alpha-bergamotene (18%), ar-curcumene (12%), E-beta-farnesene (12%), Z-beta-farnesene (10%) and cis-alpha-bergamotene (8%).