Essential Oil Composition of the Spice Plant Echinophora tenuifolia L. Subsp. sibthorpiana Tutin from Turkey

Abstract

sibthorpiana were found to be 0.2 and 0.23% in plants collected during rosette phenological period and dried room temperature conditions in the research. Essential oil yield was 0.4% in plants collected at pre-flowering period. Plant ontogeny is one of the most important factors affecting essential oil accumulation in essential oil plants [4]. Because the leaf content of plants decreases after pre-flowering periods and they have no economic value as spice and herbal tea after the periods, the plants were collected from rosette phenological periods to pre-flowering periods. Therefore, we examined the essential oil composition of the two phenological periods. From previous research, the essential oil content of Echinophora tenuifolia L. subsp. sibthorpiana in Turkey was between 1.01 and 1.73% [2]. The composition and relative percentages of the essential oil of Echinophora tenuifolia L. subsp. sibthorpiana were elucidated by the aid of GC-MS analysis (Table 1). Components were grouped according to similarity of their chemical structure. The essential oil components identified in the research were 15 monoterpenes; three of them are oxygenated monoterpenes, six aldehydes, five aromatic components, three sesquiterpenes, and 15 other components. It was determined that methyl eugenol, an aromatic compound, was the most abundant component in both samples, making up 52.4 and 62.9% of the total area in sample I and II, respectively. Another important component was 1-phellandrene with 30.4% in sample I, while p-cymene (7.8–9.1%) and δ-3-carene (3.3–5.7) were other dominant components following methyl eugenol in sample II. Literature review showed variation among the essential oil compositions of different Echinophora spp. species oil [2]. The essential oil compositions of Echinophora tenuifolia subsp. sibthorpiana growing in Manisa, Aegean region of Turkey, were characterized by a high percentage of α-phellandrene (51.0%), methyl eugenol (24.7%), δ-3-carene (5.7%), β-phellandrene (5.0%), and p-cymene (4.3%) [3]. However, Baser et al. [2] identified the essential oil composition of the same species growing in Van (East Turkey), having methyl eugenol (58.7%) as the main component with other components such as α-phellandrene (15.5%) and p-cymene (11.0%). Although our results were similar to Baser et al. [2] since the main component was methyl eugenol, the essential oil composition of Echinophora tenuifolia subsp. sibthorpiana shows chemical variability within the same subspecies, and it seems to depend on the genetic structure of the plants and on climatic conditions [5]. Identification of oil components was accomplished based on their mass spectral fragmentation patterns (WILEY and NIST database/ChemStation data system). The quantification of the components was made on the basis of their peak areas in total ion chromatograms.