Gas Chromatographic Analysis and Biogenetic Relationships of Monoterpene Enantiomers in Scots Pine and Juniper Needle Oils

The enantiomeric composition of monoterpene hydrocarbons of the needle oils of Scots pine (Pinus sylvestris L.) and juniper (Juniperus communis L.) grown in Finland was investigated by gas chromatography using chiral columns. In both species, the proportions of (+)-enantiomers represented more than 50%, on the average. The (-)/(+)-ratio of alpha-pinene (0.4) was the same in low and high 3-carene chemotypes of Scots pine. 3-Carene occurred entirely as (+)-enantiomer. Multivariate analysis separated the (+)- and (-)-enantiomeric series of the major monoterpenes into distinct groups. In the (-)-series, the most close linkages were found between (-)-alpha-pinene, tricyclene and (-)-camphene, and in the (+)-series between (+)-alpha-pinene and (+)-beta-pinene. Groupings of the monoterpene enantiomers by multivariate analysis reflected well the known biogenetic linkages.