Sesquiterpene constituents from the essential oil of the liverwort Plagiochila asplenioides.

The essential oil of the liverwort Plagiochila asplenioides from two different locations in Northern Germany were investigated by chromatographic and spectroscopic methods. Seven compounds were isolated by preparative gas chromatography (GC) and their structures investigated by mass spectrometry (MS), NMR techniques and chemical correlations in combination with enantioselective GC. In addition to known constituents, aromadendra-1(10),3-diene, two aromatic sesquiterpene hydrocarbons, bisabola-1,3,5,7(14)-tetraene and bisabola-1,3,5,7-tetraene, three sesquiterpene ethers, muurolan-4,7-peroxide, plagiochilines W and X, in addition to ent-4-epi-maaliol, could be identified as natural compounds for the first time.