Terpene relationships among some soft and hard pine species

In this study we have reported the chemical composition of the essential oils obtained from the needles of twelve Pinus taxa, belonging to the subgenera Pinus (sections Pinus and Trifoliae) and Strobus (sect. Quinquefoliae). Monoterpenes dominated over sesquiterpenes in most of the investigated taxa of both subgenera, except in representatives of the subsection Pinaster, subgenus Pinus. α-Pinene was the most abundant terpene in eight pines, but other dominant terpenes were found in some taxa - trans-caryophyllene, germacrene D, abietadiene and β-pinene. In the subsect. Pinaster, the most dominant compounds varied from species to species. In addition, P. halepensis and P. pinaster had the highest percentage of diterpenes, while P. heldreichii was the richest in germacrene D. In the PCA and cluster analyses, three species from the subsect. Pinaster emerged as the most distant: P. halepensis, P. pinaster, and P. heldreichii. In addition, the possible taxonomic implications of the terpene profile in the analysed Pinus taxa were also discussed.