By Fatemeh Askari and Fatemeh Sefidkon

Abstract: Abstract: Essential oils were isolated by hydrodistillation from the stems/leaves, inflorescences and seeds of Pimpinella tragioides (Boiss.) Benth. et Hook. The oil yields of stems/leaves, inflorescence and seed oils were 0.15%, 0.79% and 2.49% w/w, respectively. Thirteen constituents in the stem plus the leaf oil, 13 constituents in the inflorescence oil and 15 constituents in the seed oil were identified. The major constituent in the stem/leaf oil and inflorescence oil was trans-α-bergamotene (77.1% and 70.3%, respectively), whereas the major constituent of the seed oil was pregeijerene (87.0%). Nonadecane (8.6%) and isoacarone (15.1%) were the other major constituents in the stem/leaf and inflorescence oils, respectively. Only two trace compounds of P. tragioides (β-caryophyllene and bicyclogermacrene) were common between the stem/leaf, inflorescence and seed oils. Key Word Index: Pimpinella tragioides, Umbelliferae, essential oil composition, trans-α-bergamotene, pregeijerene, isoacarone.

Introduction
Pimpinella tragioides (Boiss.) Benth. et Hook. (syn. Reutera tragioides Boiss.) is one of the endemic plants of Iran distributed in west, northwest and center of Iran. Pimpinella tragioides is perennial plant of 30–65 cm length, numerous umbels, yellow inflorescence and ellipsoid fruit (1,2).

To the best of our knowledge, there is no previous work concerning the volatile constituents of P. tragioides. We have previously reported the oil composition of P. aurea and P. anisum, which grow wild in Iran. The yields of the stem/leaf, inflorescence and seed oils of P. aurea were 0.4%, 1.5%, and 2.0% w/w, respectively. Major constituents of the stem/leaf oil were found to be 1,8-cineole and limonene (21.4%), viridiflorol (12.8%), α-pinene (11.5%) and kessane (10.5%). Major constituents of the flower oil were viridiflorol (32.5%) and β-bisabolene (29.5%), while the main constituents of the seed oil were β-bisabolene (50.8%) and viridiflorol (37.0%) (3). The seed oil of P. anisum was obtained at 3.3% w/w yield by steam distillation and consisted of 11 compounds, with (E)-anethole (more than 90%) as the main component (4). The aim of this study was to determine the quantity and quality of the oils from different plant parts of P. tragioides.