A Comparative Study of the Essential Oils of Wild and Cultivated Satureja hortensis L.

Journal of Essential Oil Research: JEOR, Sep/Oct 2004 by Baser, K H C, �zek, T, Kirimer, N, T�men, G

Abstract

The essential oils from 20 samples of wild and cultivated collections of Satureja hortensis L. were investigated by GC and GC/MS. The oils from cultivated forms contained carvacrol (42-63%) as the major constituent. Thymol (29-43%) was the main component in the wild forms of S. hortensis.

Key Word Index

Satureja hortensis, Labiatae, essential oil composition, carvacrol, thymol.

Introduction

The flora of Turkey is well documented with around 10,000 species, which is nearly 2,000 less than the number of species growing in the entire European continent (1,2). About 1,000 species are medicinally used in folk preparations and an estimated 1/3 of the flora consists of aromatic plants. Most aromatic plants that belong to the family Labiatae such as Salvia, Sideritis, Thymus, Thymbra, Satureja, Origanum, Micromeria, etc. are used as herbal teas.

The genus Satureja is represented in Turkey by 14 species (1). Most of the Satureja species growing in Turkey are aromatic plants that are often used as an herbal tea, a condiment or in folk medicine.

Satureja hortensis L. is known with the following local names: �ipriska, �ibrika, Yer Kekigi, �am Kekigi, Karanfil �ayi, Dag Anugu, Ebem Kekigi, �ay Otu, �ay Kekigi and Kekik, and is used as condiment and herbal tea for stomachaches, as antidiabetic and as a depressant.

It is a native plant of Turkey, which grows naturally in the eastern parts and is cultivated in Edirne, Bursa, Balikesir, Izmir, Denizli, Eskisehir, Konya and Kayseri provinces. According to Baytop, the cultivated form of S. hortensis in Turkey is of Bulgarian origin (3).

Previous Work

A literature survey of the previous work on the oil of this species has been conducted. Akg�l et al. reported that cultivated S. hortensis of Erzurum origin contained 2.9% oil with 30.6% carvacrol, while the oil of the wild form contained 2.7% oil with thymol (49.7%) as major constituent. These results are in line with our findings (4).

Oils from four different geographic regions were analyzed and found to contain carvacrol (Italy - 52%, Yugoslavia - 44%, Hungary - 45%, South America - 31%) and [gamma]-terpinene (Italy - 25%, Yugoslavia- 32%, Hungary - 30%, South America - 6%). Thymol (18%) was the second main component in the South American oil. Highest oil yield was obtained with the Yugoslavian material (2.7%) while the Italian material gave the lowest yield (0.6%) (5).

Satureja hortensis oils from Italy were reported to contain [gamma]-terpinene (38-53%) and carvacrol (24-37%) as main constituents (6). In a separate study, an Italian oil sample with strong antibacterial activity and no DNA-damaging effect was reported to contain [gamma]-terpinene (38%) and carvacrol (37%) as main constituents (7).

The oil from S. hortensis of Russian origin was reported to contain p-cymene (35.8%), carvacrol (12.8%) and thymol (8.6%) as main constituents (8).

Oils of S. hortensis grown in four consecutive seasons in Scotland were shown to contain carvacrol (40-49%) and [gamma]-terpinene (36-45%) (9). Carvacrol (47%) and [gamma]-terpinene (35%) were also reported as main constituents in a separate study from Scotland. The oil was reported to possess strong antibacterial activity (10).

[gamma]-Terpinene (40.9%) and carvacrol (39.3%) were the main constituents in a hybrid of S. hortensis named 'Saturn' in Poland (11).

Carvacrol (58% and 73%) and p-cymene (21% and 14%) were identified as main components in the oil samples of Crimean origin (12).

The lowest oil yields were reported by Lawrence as 0.3-0.5% with carvacrol (18.2-50.4%), [gamma]-terpinene (34.1-60.3%) and p-cymene (4.5-11.8%) (13).

Experimental

Plant material: Aerial parts of the plants were collected from different regions in Turkey (Table I). Voucher specimens are kept at the Herbarium of the Faculty of Pharmacy (ESSE).

Distillation: Air-dried herbal materials were hydrodistilled for 3 h using a Clevenger-type apparatus. The percentage yields of the oils based on moisture free basis are shown in Table I.

GC: The GC analysis was carried out using Shimadzu GC-9A with CR4-A integrator. Thermon 600 T fused silica capillary column (50 m x 0.25 mm, with 0.25 �m film thickness). Carrier gas was nitrogen. Oven temperature was kept at 70�C for 10 min and programmed to 180�C at a rate of 2�C/min, then kept at 180�C for 30 min. Injector and detector (FID) temps were 250�C. Relative percentage amounts were calculated by the computerized integrator.

GC/MS: The GC/MS analysis was carried out with Shimadzu GC/MSQP 200OA system. Thermon 600T fused silica capillary column, as described above, was used under the same conditions with helium as carrier gas. MS were taken at 70 eV. Scanning speed was 2 scans/s from m/z 10 to 400.

Library search was carried out using LS S-30 Library Search Software from the NBS/NIH/EPA Library, The Wiley/NBS Registiy of Mass Spectral Data and BASER Library of Essential Oil Constituents. The MS were also compared with reference compounds and confirmed with the aid of retention indices from published sources (14-18).