The Leaf Oils of the Queensland Species of Melodorum (Annonaceae)

Abstract

The leaf oils of the six Queensland species of Melodorum, four of which have not been formally named, have been examined. Melodorum sp. (Font Hills G. Sankowsky 380) gave an oil in which the major components were α-eudesmol (9–5%), β-eudesmol (7–11%), β-caryophyllene (10–16%), bicyclogermacrene (1–9%) and α-pinene (14–15%). The major components of the leaf oil of Melodorum sp. (Stone Crossing L.W. Jessup 814) were benzyl benzoate (20%), benzyl salicylate (2.7%) and two unidentified aliphatic components (2.2% and 11.6%), with terpenic compounds, mainly sesquiterpenes, accounting for the remainder of the oil. Melodorum sp. (Topaz G.Sankowsky+ 244) leaf oil contained bicyclogermacrene (34–50%), β-caryophyllene (11–16%) and spathulenol (2–10%) as principal components. Melodorum sp. (Claudie River B.P.Hyland 21171V) gave a similar oil, with bicyclogermacrene (29.3%) and β-caryophyllene (26.7%) as principal components. The leaf oil of M. uhrii contained bicyclogermacrene (45%) and benzyl benzoate (5%) as major components, the remainder of the oil being accounted for by sesquiterpenes. Melodorum leichhardtii oil contained germacrene D (6–10%), bicyclogermacrene (15–19%), (Z)-β-ocimene (6–8%) and (E)-β-ocimene (2–5%) as principal components and a significant number of mono- and sesquiterpenes in small amounts.