Volatile Constituents of Three Thymus Species Grown Wild in Iran

The volatile oil of Thymus kotschyanun in Turkey [1] and Armenia [2] has been examined previously. The essential oil of T.kotschyanus is non-toxic to mice, rabbits and guinea pigs (LD₅₉ = 1000–1200 mg/kg) [3]. T.kotschyanus is used as an anthelmintic, antispasmodic, carminative, sedative, diaphoretic, usually in the form of an infusion [4] [5]. A literature survey has shown that T.pubescens and T.carmanicus were not previously investigated for essential oils. In folk medicine both species are used externally in baths to cure rheumatic and skin disease [4].

Thymus kotschyanus was collected from Dizin, 30 km north of Tehran, T.pubescens from Emarloo in Guillan and T.carmanicus from Yazd in June to July 1997. Voucher specimens (No. 7624, 7628 and 7617) were deposited in the Herbarium of the Department of Botany, Shaheed Beheshti University, Tehran. The plant material (180 g each) was dried at room temperature and subjected to hydrodistillation for 3h.

GC analysis was performed using a Packard 439 chromatograph equipped with a CP Sil 5CB column (25m × 0.25 mm i. d., film thickness 0.39µm), temperature programme 5 °C/min from 60° to 220 °C, carrier gas N₂ (0.8mL/min), split ratio 1 : 100, injector and detector temperatures were 270°C. For MS data a Varian 3700 chromatograph was used with a CP Sil 5CB column (25m × 0.25 mm i. d., film thickness 0.39µm) combined with Varian MAT 44S (70eV), temperature programmed as above, He as the carrier gas.

Constituents were identified by comparison of their mass spectra and confirmed by comparison of their retention indices with those of authentic compounds or with data in the literature [6] [7].

The oils of all 3 species ([Table 1]) are rich in monoterpene phenols, thymol (38.0 %, 37.9 % and 40.8 %) and carvacrol (14.2 %, 14.1 % and 24.8 %) both being the most representative volatiles in the genus Thymus [8]. Due to this high phenol content they can be considered as substitutes for thyme oil for medicinal purposes which demands a phenol content between 30 and 60 % [9].

Information in detail on the work-up procedure is obtainable from the author of correspondence.

Table 1 Volatile constituents of three Thymus species grown wild in Iran. Compound RRI T.kotschyanus T.pubescens T.carmanicus Yield: 0.39 % 0.30 % 0.34 % α-Thujene 924 2.2 1.6 1.0 α-Pinene 933 1.3 2.2 0.7 Camphene 946 0.3 1.3 0.8 Oct-1-en-3-ol 962 – 0.2 – Sabinene 965 – 0.2 0.7 β-Pinene 973 1.5 0.4 – Mycrene 981 – 1.5 1.1 α-Phellandrene 996 – 0.2 – p-Cymene 1013 2.2 13.1 6.7 1,8-Cineole 1022 13.2 2.2 2.3 cis-β-Ocimene 1038 – 0.8 – γ-Terpinene 1052 0.9 8.7 7.4 trans-Sabinene hydrate 1056 – 0.9 0.7 Linalool 1085 4.4 4.4 0.3 Camphor 1123 – 0.3 0.6 Borneol 1152 0.7 3.1 3.2 Terpinen-4-ol 1164 0.4 0.7 0.9 α-Terpineol 1174 – 0.3 0.4 Thymol methyl ether 1215 – 0.4 – Thymol 1275 38.0 37.9 40.8 Carvacrol 1283 14.2 14.1 24.8 β-Caryophyllene 1420 0.9 0.9 0.3 Germacrene-D 1479 0.3 0.3 – δ-Cadinene 1516 0.2 – – β-Caryophyllene oxide 1575 – 0.2 – Sum: 80.7 95.9 92.7

References

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• 2 Kasumov F Y. Khim Prir Soedin 1988 1: 134-136
• 3 Guseinov D, Kagramanova K M, Kasumov F Y, Alkhundov R A. Farmakol Toksikol (Moscow) 1987 50: 73-74
• 4 Zargari A. Medicinal Plants Tehran; Tehran Univ Press 1992 Vol. 4, 4th edn: p. 41
• 5 Amin G. Popular Medicinal Plants of Iran. Iran; Ministry of Sanitate and Health Service Publications 1991: p. 39
• 6 Adams R. P. Identification of essential oil components by Gas chromatography/Mass spectroscopy. USA; Allured Publ Corp, Carol Stream, II 1995
• 7 Eight peak index of mass spectra. Unwin Brothers LTD, Surry 1991
• 8 Stahl-Biskup E. J Ess Oil Res 1991 3: 61-82
• 9 Patakova D, Chladek M. Pharmazie 1974 29: 140-142