Sabinene Chemotype of Essential Oil of Seeds of Daucus carota L. ssp. carota Growing Wild in Lithuania, The

Abstract

The composition of the essential oil of Daucus carota L. ssp. carota seeds (fruits) collected from ecologically clean localities and in polluted areas near the roads was analyzed by GC and GC/MS. The oils from all samples were of the sabinene (28.2-37.5%) chemotype. The other major constituents were [alpha]-pinene (16.0-24.5%), terpinen-4-ol (4.6-7.5%), [gamma]-terpinene (2.9-6.0%) and limonene (2.3-4.0%). The oils consisted of 83.4-95.1% monoterpenoids (monoterpene hydrocarbons made up 60.5-74.8%) and 3.4-10.5% sesquiterpenoids. The ratio of sesquiterpenoids and monoterpenoids from clean localities and from the areas near the roads was found to be different (probably due to pollution). Identified compounds made up 92.1-99.5% of the oil.

Key Word Index

Daucus carota ssp. carota, Umbelliferae, wild carrot, essential oil composition, sabinene, [alpha]-pinene.

Introduction

The essential oil of the seeds (fruits) of Daucus carota L. collected in various countries belongs to different chemotypes (1-11). The main chemotypes are: carotol (

Carrot seed oil is widely used as an aromatic and fragrance component in the formulation of numerous alcoholic liquors (7) and in most major food categories (12). Species-specific combinations of volatile terpenes have been identified as an essential host recognition cue for pests (13). The sesquiterpenes found in D. carota show allelopathic activity, and some (carotol, [beta]-caryophyllene and caryophylene oxide) exhibited herbicidal or fungicidal activity (14).

Carrot seed oil has been used in therapy and aromatherapy because of its anthelmetic, antiseptic, diuretic, hepatic, stimulant, tonic, smooth muscle relaxant and other properties (12). In China, carrot seeds have been used to treat dysentery and to expel worms. The antibacterial effect of carrot seed oil depends on its composition. The oils of D. carota L. ssp. sativa, which were found to contain neryl acetate (ca. 25%) showed a weak antibacterial effect as compared with the oil of D. carota L. ssp. carota (15).

We hope that the determination of the chemical composition of D. carota L. ssp. carota growing wild in Lithuania will provide the users and investigators with more precise literature data.

Materials and Methods

The seeds of D. carota ssp. carota were collected from two habitats farfrom the roads in Jeruzale (A, 1996) and Sapiegine (B, 1995-2000) and near the roads in Santariskes (C, 1995, 1997), Rokantiskes(D, 1995-1997) and Sapiegine (E, 1995-1998,2000). Voucher specimens have been deposited in the Herbarium of the Institute of Botany (BILAS), Vilnius, Lithuania (numbers: A-59504, B-59505, C-59508, D-59506, E-59507). The oils (0.5-0.7 %) were prepared by hydrodistillation of 100 g of air-dried seeds.

Gas chromatography (GC) analyses were carried out on a Hewlett Packard 5890 gas Chromatograph equipped with flame ionization detector. The separation was performed on a silica capillary column, CP-SiI 8CB (50 m × 0.32 mm, film thickness 0.25 µm). The GC oven temperature was programmed as follows: from 60°C (isothermal for 1 min) increased to 160°C at a rate of 5°C/min and to 250°C at a rate of 10°C/min and the final temperature was kept for 3 min. The temperatures of the injector and the detector were 250°C and 280°C, respectively. The flow rate of carrier gas (helium) was 1 mL/min.

The same capillary column and temperature program as in the GC analysis was used in GC/MS. Mass spectra in electron mode were generated at 70 eV. Qualitative analysis was based on comparison with mass spectral libraries and retention index (16-18). The percentage composition of the oil was computed from GC peak areas without using correction factors.

Results and Discussion

Oaucus carota ssp. carafe is the only species growing wild in Lithuania (19). Seven samples of D. carota ssp. carota seeds (fruits) were collected from ecologically clean habitats (A, B) far from the roads (Table I) and 10 samples were collected from polluted localities (C, D, E) near the roads (Table II) in Vilnius district. The oils of all 17 samples of seeds were found to belong to the sabinene chemotype containing 28.2-37.5% of sabinene. The second major constituent was [alpha]-pinene (16.0-24.5%) (Tables I and II). The two main constituents comprise more than the half of the oil composition of D. carota ssp. carota from Lithuania. According to Lawrence (2,3,6 and references therein), some of the oils of D. carota from various countries also belong to the sabinene chemotype. all investigated samples of the oils with the large amount of sabinene contained marked quantities of [alpha]-pinene.

The other main constituents of oils from the Vilnius district were terpinen-4-ol (4.6-7.5%), [gamma]-terpinene (2.9-6.0%) and limonene (2.3-4.0%). [beta]-Pinene, [alpha]-terpinene, linalool and frens-verbenol (each about 2-3%) and other monoterpenoids (each

A majority of the oil consisted of monoterpenoids (83.4-95.1%) (Tables I and II) of which 60.5-74.8% were monoterpene hydrocarbons.