Variability of essential oil of different populations of Teucrium montanum L. (Lamiaceae) from Balkan peninsula

Abstract

Teucrium montanum L. is widely distributed in the Balkan Peninsula, extending from the sea coast to altitudes of over 2100 m a. s. l. with the highest number of occurrences in the zone between 500 and 1000 m. The aim of the study was to investigate the chemical composition of essential oil of aerial parts of T. montanum from 14 different populations from Balkan Peninsula, ten from Serbia (SR-Trešnjica canyon, SR-Brdjanska gorge, SR-Goč, SR-Gornjak gorge, SR-Grza canyon, SR-Jelašnica, SR-Kopaonik, SR-Maglič, SR-Rtanj, SR-Sićevačka gorge), two from Greece (GR-Olimp, GR-Ossa) and two from Albania (AL-Deja, AL-Skadar). The essential oils were obtained by hydrodistillation and qualitative and quantitative analysis was performed by GC-FID and GC-MS. The aerial parts of T. montanum contained only small amounts of oil (traces-0.7%), predominantly composed by sesquiterpene compounds (58.0-99.0%). One population from Albania (Deja), two from Greece (Olimp, Ossa) and two from Serbia (Sićevačka gorge, Trešnjica canyon) contained more than 90% of sesquiterpenes. The composition of essential oils was quite variable and the main compounds in almost all oils were germacrene D (trace-45.5%), sabinene (trace-23.1%), α-pinene (trace-20.7%), limonene (trace-20.4%), (E)-caryophyllene (2.9-14.5%), γ-cadinene (trace-13.8%) and δ-cadinene (trace-12.0%). The cluster analysis revealed the separation of investigated essential oils to five clusters. The first cluster (AL-Skadar, SR-Brdjanska gorge, SR-Gornjak gorge, SR-Grza canyon, SR-Goč) is characterized by high germacrene D content (17.6-45.5%), the second (SR-Maglič, SR-Kopaonik, SR-Sićevačka gorge) by high sesquiterpene alcohol shyobunol content (14.6-55.2%), the third (AL-Deja, SR-Jelašnica) by high α-bisabolol content (31.2%-43.7%) and shyobunol (3.2%) in population AL-Deja, the fourth (SR-Rtanj) by high cis-sesquisabinene hydrate content (42.4%) and the fifth (GR-Olimp, GR-Ossa, SR-Trešnjica canyon) by high germecrene D-4-ol (5.96%-61.9%), and β-eudesmol (14.9%) and epi-α-cadinol (10.2%) content in GR-Olimp population. Such a high variability needs more research to define relationships among populations.