Leaf essential oils of the Australian species of Acronychia (Rutaceae)

The leaf oils of the 19 Australian members of the genus Acronychia have been investigated by GC and GC/MS. Oil yields were all in the range of 0.1-0.5%, with the exception of A. oblongifolia, which was 1.3-1.8%. Acronychia aberrans gave an oil which contained (Z)-ocimenone (40-55%) and (E)-ocimenone (23-28%) as principal components, while in A. acuminata the principal component was alpha-pinene (33-64%). Acronychia acidula gave oils rich in either monoterpenes or sesquiterpenes, with delta-3-carene (32-40%) and terpinolene (13-46%) the principal components of the monoterpene chemotype and alpha-santalene (2-15%), aromadendrene (2-8%) and germacrene B (0.6-18%) major components of the sesquiterpene chemotype. Spathulenol (37-52%) was the principal component of the leaf oil of A. acronychioides and alpha-pinene (65%) that of A. baeuerlenii. The leaf oil of A. chooreechillum was dominated by alpha-pinene (45-66%) while that of A. crassipetala contained up to 40% monoterpenes, the remainder being sesquiterpenes. The oil from A. eungellensis contained mostly sesquiterpenes, though alpha-pinene (21-26%) was the single largest component. The oil of A. imperforata was sesquiterpenoid, with beta-caryophyllene (13-20%) and bicyclogermacrene (21-26%) being the principal components. Acronychia laevis gave both mono- and sesquiterpenoid chemotypes, with elemol, alpha-pinene and bicyclogermacrene being the principal components of the various oils. Both A. wilcoxiana and A. littoralis gave oils in which beta-caryophyllene, pregeijerene and geijerene were principal components. Acronychia octandra gave an oil rich in (Z)-beta-ocimene (15-23%), (E)-beta-ocimene (15-23%) and limonene (4-21%), while in A. oblongifolia the principal components were alpha-pinene (34-87%), limonene (0.1-26%) and terpinolene (0.1-29%). In A. parviflora the major components were beta-caryophyllene (2-34%) and allo-aromadendrene (0.3-20%), while in A. pauciflora the principal components were alpha-pinene (14-45%) and beta-caryophyllene (10-24%). Acronychia pubescens gave a sesquiterpenicoil, with beta-caryophyllene (15-39%) as the principal component, as did Acronychia sp. (Batavia Downs, J.R.Clarkson +8511) (3-21%). Acronychia suberosa gave an oil in which (Z)-ocimenone (20-23%), (E)-ocimenone (9-13%) and beta-caryophyllene (4-10%) were the main constituents and A. vestita gave a variable oil in which alpha-pinene (40%) and beta-caryophyllene (23.5%) or limonene (67-80%) were major components.