Multivariate statistical analysis of the essential oil composition of Thymus praecox Opiz ssp polytrichus (Kern. ex Borb,) Ronn. collected in the Tyrolean Alps

The essential oils of 141 individual plants of Thymus praecox Opiz ssp. pol ytrichus (Kern, ex Borb.) Ronn., emend. Jalas, collected at 16 localities i n the Austrian and Italian Alps (Tyrol and South Tyrol), were investigated concerning their composition and the variations therein. In total, 60 compo nents, almost exclusively monoterpenes and sesquiterpenes. were identified by GC and CC-MS. The patterns of the oils were processed by means of multiv ariate statistical analysis (MSA) including factor analysis (FA), cluster a nalysis (CA) and discriminant analysis (DA). The most plausible result, rev ealing 12 clusters, was obtained by a modified CA method based on the avera ge linkage method with the Pearson correlation. Considering all other stati stical results obtained, 12 oil types became evident with the following typ e-characterising compounds: thymol, geraniol/geranyl acetate, trans-sabinen e hydrate/terpinen-4-ol, alpha -terpineol, linalol, linalol/linalyl acetate , borneol, trans-nerolidol, hedycaryol, T-cadinol, germacra-1(10),5-dien-4- ol, and germacra-1(10),4-dien-6-ol. All these oil types have been found bef ore in other Thymus species. The thymol type, found for 46 samples, represe nted the most dominant oil type. The chemical similarity with Mediterranean and North Atlantic Thymus, species indicates a mixing of southern and nort hern elements in the Alps, which is also reflected in the overlapping morph ological characters of T. praecox ssp. polytrichus . Copyright (C) 2000 Joh n Wiley & Sons, Ltd.