Effect of Needle Age and Location on the Volatile Composition of Essential Oils from Juniperus communis L.: A Chemometric Study

Profiles of the volatile organic compound (VOC) content of essential oils (EOs) extracted from young and old Juniperus communis L. needles were generated via gas chromatography combined with mass spectrometry (GC-MS) and flame ionization detection (GC-FID) and subsequently processed using multivariate statistical methods. These were then used to differentiate the EOs according to needle age and geographical origin. From a total 49 of VOCs identified, statistically significant differences (p<0.05) between young- and old-needle EOs were found for 21 VOCs. Most of the EOs from the young needles showed higher (p<0.05) contents of alpha- and beta-pinene and sesquiterpenes (beta- and gamma-elemene, germacrene D and B, alpha-muurolene, and delta-cadinene) and their oxygenated derivatives (alpha- and tau-cadinol), while most of the monoterpenes (alpha-thujene, sabinene, terpinolene, beta-myrcene, beta-phellandrene, and p-cymene) were present in higher quantities (p<0.05) in the EOs from the old needles. The volatiles germacrene D, alpha- and beta-pinene, alpha-cadinol, and sabinene were identified via stepwise and canonical discriminant analysis as the most valuable for EO discrimination according to needle age and geographical origin. Recognition and prediction ability tests of the EOs achieved 100 % accuracy in EO classification according to the above mentioned criterion.