The steam volatile oil of Wollemia nobilis and its comparison with other members of the Araucariaceae (Agathis and Araucaria)

The leaf essential oil of Wollemia nobilis (Wollemi Pine) has been investigated and compared with other members of the family Araucariaceae. All araucaroids examined yielded steam volatile oils in low yields. The oil from Wollemia nobilis was composed mainly of (+)-16-kaurene (60%), together with alpha-pinene (9%) and germacrene-D (8%). Oils from Agathis species endemic to Australia were high in monoterpenes, in contrast to those isolated from extra-Australian species. The major constituents of A. atropurpurea oil were phyllocladene (13%) and 16-kaurene (19%), followed by alpha-pinene (8%) and delta-cadinene (9%). A. microstachya yielded oil in which alpha-pinene (18%) was the major component; the only other components in excess of 5% were myrcene (7%), bicyclogermacrene (6%) and delta-cadinene (6%). A. robusta oil contained spathulenol (37%) and rimuene (6%). Approximately 40% of the oil was unidentified sesquiterpenes. A. australis oil contained 16-kaurene (37%), sclarene (5%) and an unidentified oxygenated diterpene K (12%) as major components; the only other compound in excess of 5% was germacrene-D (9%). 5,15-Rosadiene (60%), and 16-kaurene (7%) were the major constituents of A. macrophylla oil. A. moorei oil was rich in sesquiterpenes, but the only compounds in excess of 5% were allo-aromadendrene (6%), germacrene-D, delta-cadinene (10%), an unidentified sesquiterpene (12%) and 16-kaurene (6%). In A. ovata oil the most significant compounds were caryophyllene oxide (15%) and phyllocladene (39%). Araucaria angustifolia contained germacrene-D (9%) and the diterpenes hibaene (30%) and phyllocladene (20%) as major components of its essential oil. Oils of A. bidwillii, A. columnaris and A. cunninghamii were all low in mono- and sesquiterpenes and high in diterpenes. In the first, hibaene (76%) was the major constituent; the second contained hibaene (9%), sclarene (6%), luxuriadiene (13-epi-dolabradiene)(23%) and two unidentified diterpene hydrocarbons (B) (33%) and (E) (10%). In the last, 16-kaurene (53%) was the most significant component followed by hibaene (29%). A. heterophylla was unusual in that over half the oil was made up of the monoterpenoid alpha-pinene (52%), with phyllocladene (32%) being the only other compound of significance. alpha-Pinene (18%) was a significant component of A. hunsteinii oil; sclarene (11%) and germacrene-D (5%) were the only other compounds present in concentrations of more than 5%. A. luxurians oil was composed of 5,15-rosadiene (20%) and luxuriadiene (13-epi-dolabradiene) (66%), previously unreported from natural sources. The major components of A. montana were phyllocladene (61%) and 16-kaurene (23%). Sclarene (20%), luxuriadiene (19%) and the unidentified diterpene hydrocarbons (B) (25%) and (E) (10%) were the most important constituents of A. muelleri oil. A. scopulorum contained large amounts of 16-alpha-phyllocladanol (41%) as well as luxuridiene (10%) and delta-cadinene and alpha-copaene, both at 6%.