Analysis of Leaf Essential Oils from the Indigenous Five Conifers of Taiwan

Leaf essential oils of the 5 most-valuable conifers in Taiwan were collected by hydrodistillation and analyzed using GC and GC-MS to identify the ingredients and their compositions. In the leaf oil of Chamaecyparis formosensis, we identified 60 compounds, with α-pinene, δ-2-carene, β-myrcene, γ-muurolene, β-pinene and α-caryophyllene, respectively making up 71.6%, 4.6%, 4.1%, 3.1%, 2.7%, and 2.0% of the essential oil. Forty-four compounds were identified in the leaf essential oil of C. obtusa var. formosana with α-pinene (76.7%), β-myrcene (5.7%), β-pinene (3.2%), γ-muurolene (2.8%), δ-2-carene (2.1%), and β-phellandrene (2.1%) the major components. In the leaf essential oil of Calocedrus formosana, we identified 81 compounds, with α-pinene (69.8%), β-caryophyllene (4.7%), β-myrcene (4.3%), and limonene (2.0%) the major components. For the leaf essential oil of Taiwania cryptomerioides, 56 compounds were found, with limonene (44.5%), α-pinene (14.4%), caryophyllene oxide (8.5%), δ-2-carene (3.9%), α-terpineol acetate (3.6%), β-myrcene (2.6%), δ-cadinene (2.6%), and 1-epi-cubenol (2.3%) the main components. In the leaf essential oil of Cunninghamia lanceolata var. konishii, there were 68 identified compounds, with α-pinene (36.4%), α-thujene (11.4%), α-eudesmol (8.1%), elemol (5.8%), β-elemene (3.5%), γ-eudesmol (2.8%), γ-himachalene (2.7%), β-myrcene (2.4%), cis-β-guaiene (2.2%), and 4-terpineol (2.2%) the major constituents. All 5 species of conifers had monoterpene hydrocarbons as their main components. Except for Taiwania, for which limonene was the main component, α-pinene was the predominant components of all other species.