Chemical Composition of the Essential Oils of Peucedanum ruthenicum (M. Bieb.) Rochel Leaves and Flowers from Kalardasht

1. Introduction

     In Iran, the genus Peucedanum (Umbelliferae) is represented by 4 species, namely P. glaucopruinosum, P. knappii, P. translucens [1] and P. ruthenicum [2], which grows wildly in different regions of Iran [3]. P. ruthenicum is a glabrous perennial plant with abundant fibres; stem terete (cylindric), striate, solid; leaves 3 (-4)-ternate, lobes 20-90 mm; rays 7-28; bracts 1-3, subulate; bracteoles several, filiform; petals pale yellow; fruit 6-7.5 mm in dry places [4]. The plant was collected for the first time from Kalardasht (Mazandaran province) at the north of Iran [2]. Some species of this genus have been used traditionally in treatment of cold [5], cough due to pathogenic wind-heat, accumulation of phlegm and heat in the lung [6] and as anti-tussive, anti-asthma and a remedy for angina [7].

     There were some reports related to the chemical analysis of volatile oil of this genus in the literature. The major components of herb and rhizome essential oil of P. ostruthium were sabinene (35.2%), 4-terpineol (26.6%), β-caryophyllene (16.1%) and α-humulene (15.8%) [8]. The major constituents of P. verticillare leaf and branch oil were sabinene and trans-anethole. β-Caryophyllene, α-Phellandrene, cis-β-farnesene and β-bisabolene were components of P. verticillare dried fruit oil, and sabinene was the constituent of P. verticillare fresh fruit oil [9].

     The component of P. ruthenicum essential oil was not reported previously and comparison of the essential oils composition of P. ruthenicum leaves, flowers and fruits will be reported and discussed in this paper.

Table 1. The percentage of the composition of the essential oils from Peucedanum rutenicum (M. Bieb.) Rochel leaves and flower.

2. Materials and methods

2.1.  Plant material and isolation procedure

     P. ruthenicum was collected during August (leaves) to October (flowers) 2003 from Kalardasht (altitude: 1700 m, average temperature: 15.8 ºC, soil: calcareous), in Mazandaran province in northern Iran and was identified by Dr. H. Akhani (Plant Sciences Department, Tehran University, Tehran, Iran) and its voucher specimen is deposited in the private herbarium of Dr. H. Akhani (hb, Salimian, 39). The plant parts were dried at ambient temperature in the shade. The leaves (80 g) or flowers (55 g) were subjected to hydro-distillation using a Clevenger-type apparatus for 4 h [10] and the oils were dried on anhydrous sodium sulfate and stored at 2-8 ºC.

2.2. Identification of the oil components

     Analysis of the essential oils was performed using a Hewlett Packard 6890 GC equipped with a HP-5MS capillary column (30 m 0.22 mm i.d., 0.25 μm film thickness) and a mass spectrometer 5973 from the same company, for GC-Mass detection with an electron ionization system (70 eV) was used.

     Helium was the carrier gas, at a flow rate of 1 ml/min., injector and detector MS transfer line temperatures were set at 250 and 290 C, respectively, column temperature was initially kept at 60 C for 5 min., then gradually increased to 220 C at the rate of 6 C/min. Retention indices were calculated by using retention times of n-alkanes that were injected after the oil at the same chro-matographic conditions. The compounds were identified by comparison of retention indices (RI, DB-5) with those reported in the literature and by comparison of their mass spectra with the Wiley library or with published mass spectra [11-13].

3. Results and discussion

     The result of GC-MS analysis essential oils of P. ruthenicum are presented in Table 1. The color of essential oils of leaves and flowers were pale green and pale yellow in the total yields of 0.3 %, and 1.5 % (v/w), respectively.

     A total of 17 components were identified in leaves oil, representing 100%, and the major constituents were thymol (57.79%) and β-bisabulene (6.10%). In the oil of flowers, 12 components were identified, representing 96.40%. Germacrene-D (45.00%) and germacrene-B (18.50%) were the main components. Comparisons of the major compounds of these two oils showed differences in some of the substances (Table 1). Particularly, the oil from leaves is characterized by high contents of thymol (57.79%) and β-bisabulene (6.1%), which does not exist in the flowers oil. In addition, germacrene-D is a major component of the flowers oil (45%) and a minor component of the leaves oil (0.35%).

     The leaves and flower oils contained 58.47% and 11.60% monoterpenes, and 38.74% and 84.80% sesquiterpenes, respectively. It is interesting that thymol is the major compound in leaves but not in flowers. Therefore, P. ruthenicum leaves is a source of thymol without carvacrol (instead of Thymus genus). This comparison will define effect of climatic condition (season of flowering stage) on production of different substances in essential oils. The major components of herb and rhizome essential oil of P. ostruthium were sabinene (35.2%), 4-terpineol (26.6%), β-caryophyllene (16.1%) and α-humulene (15.8%) [8]. The major constituents of P. verticillare leaf and branch oil were sabinene and trans-anethole. β-Caryophyllene, α-phellandrene, cis-β-farnesene and β-bisabolene were components of P. verticillare dried fruit oil and sabinene was the constituent of P. verticillare fresh fruit oil [9], but in the essential oil of P. ruthenicum thymol and β-bisabulene were the main compounds.

Acknowledgement

     This work was supported by grants from the National Research Center of Medical Sciences. The authors are grateful to Mr. Larijani for GC operation.