The impact of drying on the composition of volatile constituents of Bosnian Pine (Pinus heldreichii Christ. var. leucodermis)

Bosnian pine (Pinus heldreichii Christ. var. leucodermis) is a plant endemic to the Balkan Peninsula and Southern Italy. The free volatile constituents of this plant have been studied in the context of biosystematic investigations related to the environment [1, 2]. Essential oils are dominated by monoterpene hydrocarbons such as limonene, pinenes and terpinenes, followed by sesquiterpenes germacrene, Δ -cadinene, α -humulene, and caryophyllene. The aim of this study was to determine the impact of drying on the chemical composition of Bosnian pine essential oil. Samples of plant material (pine needles) were collected in central Herzegovina near Mostar (Bosnia and Herzegovina) in January 2007. Each sample was collected in triplicate, pooled and then divided in two parts: one was investigated as fresh plant material (100 g) and other (500 g) was dried in shaded place at room temperature and submitted consecutively to five investigations within air-drying period for 30 days. The essential oil was isolated by hydrodistillation in Clevenger type apparatus for 2 h. The yields of essential oils were determined by gravimetric method and expressed as a mean value. Volatile constituents were analyzed using a Hewlett-Packard GC-MS system (GC 5890 series II, MSD 5971A). The comparative analysis of oils isolated from fresh and dried plant material showed a minor increase in essential oil yield and no significant qualitative differences in oil composition after drying. On the other hand, some quantitative differences were found, especially in major components limonene and germacrene. The oil obtained form dried plant material showed remarkable increase in abundance of limonene (22.7% - 42.8%), α -pinene (1.0%-14.2%) and β -pinene (0.6%-5.26%). However, a substantial decrease was noted for germacrene (52.5% - 21.9%).