California Lomatiums, Part IV(a): Composition of the Essential Oils of Lomatium rigidum (M.E. Jones) Jepson. Structures of Two New Funebrene Epimers and a Tridecatriene

Journal of Essential Oil Research: JEOR, Nov/Dec 2004 by Beauchamp, Philip S, Descalzo, Josette T, Dev, Barbara C, Dev, Vasu, Et al

Abstract

Oils produced from the fruits, stems and leaves and roots of Lomatium rigidum were subjected to analysis by GC, GC/MS and other spectroscopic techniques. The oils of fruits as well as the stems and leaves of L. rigidum were found to contain β-phellandrene/limonene (9.1-25.7%), δ-cadinene (7.5-12.9%), α-cadinol (16.4-18.6%), epi-α-cadinol and epi-α-muurolol (8.2-9.0%) as major components. The root oils were found to be rich in (Z)-falcarinol (10.8-14.9%), 2-epi-β-funebrene (48.2%), a new funebrene epimer, as well as the new (Z,Z,Z)-3,6,9-tridecatriene.

Key Word Index

Lomatium rigidum, Apiaceae, essential oil composition, β-phellandrene, δ-cadinene, α-cadinol, (Z)-falcarinol, 2-epi-β-funebrene, 2-epi-α-funebrene, (Z,Z,Z)-3,6,9-tridecatriene.

Introduction

The natives of California and the other Pacific states have extensively utilized the genus Lomatium for its value as food, medicinale and for community rituals (1-3). The presence of significant proportions of the centrally acting muscle relaxants, (Z)-ligustilide and related phthalides, in the essential oils of L. californicum and L. torreyi native to California has been reported (2,3). These observations and our interest in the ethnobotany and chemotaxonomy of the California Lomatiums have led us to a continuation of our studies of the essential oil composition of this genus (4).

Lomatium rigidum, also known as "prickly parsley," grows during late spring to mid-summer in rocky places among sagebrush scrub and pinon-junipers on the eastern slopes of the Sierra Nevada range at 4000-9000 ft elevation (5). This report deals with the analysis of the essential oils of this rare Lomatium species.

Experimental

Plant material: It was collected in its relatively mature fruiting stage from three different locations in the eastern Sierra Nevada mountains of California: (i) June 22,2001; west sloping hill above Four Jeffrey campground located on the south fork of Bishop Creek at an elevation of 8185 ft, N 37° 14.908', W 118° 34.109'; and again on September 18, 2001 retaining only the roots - the upper parts had pretty much dried up; (ii) June 2, 2002 along the road to Whitney Portal at 7035 ft elevation, N 36° 36.285', W 118° 12.371'; (iii) June 4, 2002 alongTaboose Canyon trail where the trail meets Taboose Creek at 6462 ft elevation, N 37° 00.138', W 118° 21.128'. Plant identification was confirmed by Steve Boyd, curator, Raucho Santa Ana Botanic Gardens, Clareinont, CA, where Herbarium specimens were deposited.

Isolation of oils: Plant materials were shaken to rid them of any dry material and separated into three portions: (a) fruits, (b) stems and leaves and (c) roots. Each portion was washed with cold DI water and patted dry with absorbent paper towels. The dried materials were separately blended along with some added water in a food blender. The pureed materials were hydrodistilled and the distillates extracted with CH^sub 2^Cl^sub 2^. The extracts were dried with anhydrous Na^sub 2^SO^sub 4^ and rotary evaporated at ~35°C at aspirator pressure. The oily residues were dried for 15 min at room temperature and at 10 torr. Collection (i): 143 g of fruit gave 0.49 g (0.34%) of pale oil, 479 g of stems and leaves gave 0.20 g (0.04%) of greenish yellow oil and 297 g of roots gave 0.21 g (0.07%) of pale yellow oil. The corresponding plants and oil weights for the remaining collections were: 380 g of roots from Sept. 18 collection at site (i) gave 0.208 g (0.055%) of oil; for combined collections (ii) and (iii) 210 g of fruits gave 0.141 g (0.067%), 623 g of stems and leaves gave 0.110 g (0.018%) and 1699 g roots gave 1.591 g (0.094%) of the respective oils.

Analyses: GC analyses were performed using a Varian 3700 GC equipped with FID and interfaced with SRI model 203 PeakSimple Chromatography data system. It was fitted with a 30 m × 0.25 mm (0.25 µm film thickness) HP-5MS capillary column with He as the carrier gas. The oven temperature was programmed at 50°C for 10 min and then 3°C/ min to 251°C, after which it was maintained isothermally at 251°C for 5 min. The GC data were rounded off to the first decimal place. GC/MS analyses were carried out with AGILENT 5973 Network Mass Selective Detector interfaced with AGILENT 6856 GC system fitted with a 30 m × 0.25 mm (0.25 µm film thickness) HP-5MS capillary column with He as the carrier gas. The oven temperature was programmed at 50°C for 10 min then 3°C/min to 230°C, after which it was maintained isotliennally at 230°C for 10 min. Mass spectra were taken under EI conditions at 70 eV. All ^sup 1^H, ^sup 13^C-NMR spectral data were obtained with a Varian iNOVA 400 Spectrometer with CDCl^sub 3^ as the solvent and its trace impurity CHCl^sub 3^ as the internal standard at δ = 7.24 ppm for ^sup 1^H-NMR spectra recorded at 400 MHz. ^sup 13^C-NMR spectra were recorded with CDCl^sub 3^ as the solvent at 100 MHz using CDCl^sub 3^ at δ = 77.0 ppm as the internal standard. Optical rotations were acquired with a Perkin-Elmer 241 Polarimeter at 589 nm with a 10 mm microcuvet.