<i>Lomatium</i> Species of the Intermountain Western United States: A Chemotaxonomic Investigation Based on Essential Oil Compositions

<i>Lomatium</i> is a genus of 98 species, widely distributed in western North America. This work presents a chemometric analysis of the essential oils of seven species of <i>Lomatium</i> (<i>L. anomalum</i>, <i>L. dissectum</i> var. <i>dissectum</i>, <i>L. multifidum</i>, <i>L. nudicaule</i>, <i>L. packardiae</i>, <i>L. papilioniferum</i>, and <i>L. triternatum</i> var. <i>triternatum</i>) from the intermountain western United States (Oregon and Idaho). The essential oils were obtained by hydrodistillation and analyzed by gas chromatographic methods. <i>Lomatium packardiae</i> essential oil can be characterized as limonene-rich, <i>L. anomalum</i> is a species rich in sabinene and α-pinene, and <i>L. multifidum</i> essential oils were rich in myrcene, while <i>L. dissectum</i> var. <i>dissectum</i> essential oils were dominated by octyl acetate and decyl acetate, <i>L. papilioniferum</i> essential oils from western Idaho had high <i>p</i>-cymene and 2-methyl-5-(1,2,2-trimethylcyclopentyl)phenol concentrations, while those from Oregon had relatively high β-phellandrene and sedanenolide levels. The essential oils of <i>L. triternatum</i> var. <i>triternatum</i> were too variable to confidently assign a chemical type. The major components in the <i>L. nudicaule</i> essential oils were β-phellandrene (16.0–45.7%), (<i>Z</i>)-ligustilide (5.6–47.1%), (<i>E</i>)-β-ocimene (3.3–9.9%), and δ-3-carene (0.2–12.6%). The enantiomeric distributions of α-pinene, camphene, sabinene, β-pinene, limonene, and linalool were also utilized to discriminate between the <i>Lomatium</i> taxa. There are not enough consistent data to properly characterize <i>L. triternatum</i> var. <i>triternatum</i> or the Oregon <i>L. papilioniferum</i> essential oils. Additional research is needed to confidently describe the chemotype(s) of these species.