California Lomatiums, Part VI. Composition of the Essential Oils of Lomatium foeniculaceum ssp. fimbriatu

Journal of Essential Oil Research: JEOR, Nov/Dec 2006 by Beauchamp, Philip S, Dev, Barbara C, Dev, Vasu

Abstract

The fruit essential oil of Lomatium foeniculaceum ssp. fimbriatum collected from the Inyo National Forest in California contained myrcene (24.5%), β-phellandrene/limonene (12.9%), germacrene D (13.9%), (E)-β-ocimene (10.4%), and (Z)-ligustilide (9.8%) as the major components. Germ acrene D and (Z)-ligustilide also constituted the major components of the stem and leaf oil. (Z)-Falcarinol (38.1%) was the major component of the root essential oil.

Key Word Index

Lomatium foeniculaceum ssp. fimbriatum, Apiaceae, essential oil composition, myrcene, β-phellandrene, limonene, (E)-β-ocimene, germacrene D, (Z)-ligustilide, (Z)-falcarinol.

Introduction

In earlier communications, mention has been made of the importance of the genus Lomatium. Raf. to California natives (1,2). In continuation of our work on the essential oils of several species of this genus endemic to California, we wish to report the composition of the essential oils of Lomatium foeniculaceum (Nutt.) J. Coulter et Rose ssp. fimbriatum (Theob).

Experimental

Plant material: Lomantium foeniculaceum ssp. fimbriatum was collected in its mature fruiting stage on the north side of Highway168 about four miles south of Westgaard Pass in the Inyo National Forest. GPS location at 7250 ft elevation, N 37° 15.762", W 118°09.524'. Plant identification was confirmed by the staff at Rancho Santa Ana Botanic Gardens, Claremont, CA, where Herbarium sample has been deposited (accession # RSA703277).

Isolation of oils: The three parts of the plant (fruits, stems and leaves, roots) were separately subjected to hydrodistillation. The oils were obtained from the hydrodistillates by procedures described earlier (2). Fifty-one g of fruits gave 0.127g (0.25%) of oil while 119 g of stems and leaves, and 60 g roots gave 0.093 g (0.078%) and 0.196 g (0.33%) of respective oils. Dilute solutions of the oils in 50:50 hexanerether were analyzed by GC and GC/MS. The oil compositions and the retention indices (RI values) were determined from the GC data.

Analyses: A Hewlett Packard 6890GC fitted with FID and a HP-5MS capillary column (30 m x 0.25 mm, film thickness 0.25 µm) was used for gas chromatography. The oven temperature was programmed at 50°C for 10 min and then at 3°C/min to 250°C, after which it was maintained at this temperature for 5 min. The GC/MS analyses were carried out with AGILENT 5973 Network Mass Selective Detector interfaced with an AGILENT 6950 GC system fitted with a capillary column matching the one used with the HP 6890GC. It was programmed at 50°C for 10 min, followed by 3°C/min to 230°C and then isothermal at 230°C for 10 min. The mass spectra were recorded under EI conditions at 70 eV.

Results and Discussion

The identification of components in the oils was done by comparing their respective RI values and their mass spectra with those available from other sources as indicated in Table I. Identification of several compounds was further confirmed by matching their GC/MS retention times, as well as the mass spectra of authentic samples. The GC composition data were taken from the computer area percent data without the use of correction factors and rounded off to the first decimal place (Table I). Compounds representing less than 0.05% were labeled as trace components (t).

The gas chromatograms of the fruit as well as the stem and leaf oils were rather uncomplicated. A comparison of the observed RI values and the mass spectra with those available from other sources allowed the identification of the components in the two oils (Table I). The identified components accounted for ~98% and ~96% of the respective oils. The GC of the root oil showed a rather complicated chromatogram consisting of at least 112 peaks. Of these, 65 accounted for only 3.3% of the oil, most of them amounting to 0.02-0.05% each of the oil. Table 1 shows that while (Z)-falcarinol was only a minor component of the fruit as well as stem and leaf oils, it accounted for 38.1% of the root oil. Interestingly, we have also observed more than 20% (Z)-falcarinol, a potent elicitor of contact dermatitis in guinea pigs, in the root oils of L. califarnicum, L. torreyi, l. dasycarpum ssp. dasycarpum, L. lucidum, L. utriculatum and L. nevadense van parishii (1,3-5). Several components of the present root oil, particularly those with RI values greater than 2000 and with higher than 1% abundance could not be identified. Attempt was not made to isolate these components for their identification by other spectral methods because of the difficulty in obtaining sufficient quantity of the scarce plant material needed for isolation work. The m/z values of the mass spectral fragments of five of the unidentified components accounting for 14.6% of the oil are provided as footnotes under Table I, in a decreasing order of their relative intensities.

Acknowledgments

The authors are greatly thankful to Lawrence M. Blakely and Ruth M. Blakely of Bishop, CA for locating, assisting in the collection of L. foeniculaceum. Thanks to Kathleen Nelson, Forest Botanist, Inyo National Forest, Bishop, CA for issuing permits to collect Lomatiums in the National Forest. Last but not least, our thanks to Floyd Howell of the Chemistry Department for his untiring technical assistance in the maintenance of the instruments.