Analysis of the Essential Oil of Teucrium polium ssp. capitatum from the Balkan Peninsula Violeta Mitić a , Olga Jovanović a , Vesna Stankov-Jovanović a , Bojan Zlatkovic b and Gordana Stojanovic a a Department of Chemistry, Faculty of Science and Mathematics, University of Nis, 18000 Nis, Serbia b Department of Biology and Ecology, Faculty of Science and Mathematics, University of Nis, 18000 Nis, Serbia violetamitic@yahoo.com Received: September 21 st , 2011; Accepted: November 18 th , 2011 The chemical composition of the essential oil of the aerial parts of Teucrium polium ssp. capitatum collected during the flowering period from rocky places and dry pastures, (Serbia, Niš, Kamenica), and dunes along the sea-side, (Bulgaria, Burgas, Primorsko) has been studied by GC and GC/MS. The identified compounds, 45 for the oil from Serbia and 44 for that from Bulgaria, amounted to 97.3% and 96.4% of the oils, respectively. The dominant constituents of the Serbian oil were sesquiterpenes {59.6%, the most abundant components being germacrene D (31.8%), trans-caryophyllene (8.8%) and bicyclogermacrene (6.2%)}, while monoterpenes accounted for 37.5% {the most abundant components being linalool (14.0%) and β-pinene (10.7%)}. The essential oil from Bulgaria was characterized by a high percentage of monoterpenes¸ amounting to 62.9% {the most abundant components being β-pinene (26.8%), α-pinene (9.3%) and limonene (6.4%)}, while sesquiterpenes accounted for 33.5% (the most abundant component was germacrene D 17.7%)}. Keywords: Teucrium polium L. ssp. capitatum, Lamiaceae, Essential oil composition. The Lamiaceae is one of the largest and most distinctive families of flowering plants, with about 220 genera and almost 4000 species worldwide [1a]. The genus Teucrium includes 300 species, widespread around the world. T. polium, according to the “Flora of Europe” (taken in the wide sense), is separated into five subspecies [1b], the typical subspecies polium, ssp. aureum (Schreber) Arcang., ssp. pii-fonti Palau, ssp. capitatum (L.) Arcang. and ssp. vincentinum (Rouy) D. Wood. Other literature sources recognize most of the given subspecies at the specific rank, including T. polium subsp. capitatum taken as a separate species [1b,2a]. The section Polium, which includes T. polium L. ssp. capitatum (L.) Arcangeli, (=T. capitatum) contains more than half of the Teucrium spp. and is the largest and most morphologically diverse section of the genus [2b]. T. polium is a wild-growing flowering plant abundantly distributed in the hills and deserts of Mediterranean countries in Europe, south-western Asia, and North Africa. T. capitatum is a perennial, pubescent, aromatic plant, 20–50 cm high, with green-grayish oval leaves with enrolled margins and dense heads of white flowers, which appear from June to August. T. polium possesses antipyretic [3a], antispasmodic [3b], anti- inflammatory [3c], analgesic [3c], hypoglycemic [3d], anti-ulcer [4a], hypotensive [4b], antihypertensive [4c], antibacterial [4d], antidiabetic [4e], antinociceptive [4f], calcium antagonistic [4g], and anticonvulsant [4h] activities. On the other hand, there are studies showing that after prolonged administration the plant induces fatal hepatic effects [4i] and severe acute liver failure, with marked hematological and biochemical alterations [5]. There are only a few papers about the chemical composition of the essential oil from the aerial parts of T. polium ssp. capitatum [6,7,8a], but none of them examined plants that grow in the Balkan Peninsula. In view of this, we have examined the composition of the essential oils of T. polium ssp. capitatum from two different localities on the Balkan Peninsula: from rocky places and dry pastures in Serbia (Niš, Kamenica), and from dunes along the sea-side (Bulgaria, Burgas, Primorsko). The yields of the fragrant essential oils from Serbia and Bulgaria were 0.08% and 0.14% (w/w, based on dry plant material), respectively. In total, 55 compounds were identified in both samples (Table 1). The identified compounds, 45 in the Serbian oil and 44 in that from Bulgaria, amounted to 97.3% and 96.4% of the oils, respectively. The number of common components was 33, including all seven that were most abundant in at least one oil: germacrene D 31.8% and 17.7%, β-pinene 10.7% and 26.8%, trans- caryophyllene 8.8% and 0.3%, bicyclogermacrene 6.2% and 4.0%, linalool 14.0% and 0.2%, α-pinene 3.5% and 9.3%, limonene 2.1% and 6.4%, respectively in the oils from Serbia and Bulgaria. The dominant components of T. polium ssp. capitatum essential oil from Serbia were sesquiterpenes 59.6%, {non-oxygenated components (55.1%), and oxygenated components (4.5%)}, while the monoterpene fraction accounted for 37.5% of the identified compounds. The essential oil from Bulgaria was characterized by a high percentage of monoterpenes, amounting to 62.9%, {hydrocarbons (45.7%) and oxygenated components (17.2%)}, while sesquiterpenes accounted for 33.5% of the identified compounds. The high content of monoterpenes in the oil of T. polium ssp. capitatum from Bulgaria is very similar to that of the oil from the same species from Corsica [8a] and Rabaçal, Serra do Sicó, Portugal (samples 1 and 2) [7]. In contrast, the oil from Serbia was characterized by a high content of sesquiterpenes as were the two oils from Portunhos, Portugal (samples 3 and 4), the sample from Serra DAire, Portugal (sample 5) [7], and the sample from Heraklion, Crete, Greece) [6]. Regarding the individual constituents, the essential oil composition shows variations in plants of different geographical origin: p-cymene (7.0%) was reported as one of the major components in the essential oil of T. polium ssp. capitatum from Corsica [8a]. The p-cymene content in all tested oils from Portugal [7] varied between 0.9–2.8%, but this component was not found in either the oils that were examined in this study or in the oil from Heraklion, Crete, Greece [6]. Germacrene D was not detected in the samples of oil from Corsica [8a] and Portunhos, Portugal [7], but its content in NPC Natural Product Communications 2012 Vol. 7 No. 1 83 - 86