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

Journal of Essential Oil Research: JEOR, Sep/Oct 2004 by Brophy, Joseph J, Goldsack, Robert J, Forster, Paul I

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 [alpha]-eudesmol (9-5%), [beta]-eudesmol (7-11%), [beta]-caryophyllene (10-16%), bicyclogermacrene (1-9%) and [alpha]-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%), [beta]-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 [beta]-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)-[beta]-ocimene (6-8%) and (E)-[beta]-ocimene (2-5%) as principal components and a significant number of mono- and sesquiterpenes in small amounts.

Key Word Index

Melodorum sp. (Font Hills G.Sankowsky 380), Melodorum sp. (Stone Crossing L.W.Jessup 814), Melodorum sp. (Topaz G.Sankowsky 244), Melodorum sp. (Claudie River B.P.Hyland 21171V), Melodorum uhrii, Melodorum leichhardtii, Annonaceae, essential oil composition, bicyclogermacrene, germacrene D, spathulenol, [beta]-caryophyllene, [alpha]-pinene, [alpha]-eudesmol, [beta]-eudesmol, benzyl benzoate.

Introduction

The genus Melodorum Lour, comprises about 16 species that are widely distributed through Indo-China, Malesia and Australia (1,2). Melodorum includes the genus Rauwenhoffia Scheff. in synonymy (1,2), although because of a misapplication some authors have kept the two genera separate (3,4). The different species of Melodorum are invariably woody lianas or scandent shrubs and often form large parts of the canopy in the wide range of rainforest communities where they occur. Whilst the phylogeny of the Annonaceae remains to be satisfactorily resolved, Melodorum (as the synonym Rauwenhoffia) is thought to be allied to the genera Anomianthus Zoll., Cyathostemma Griff, Ellipeia Hook.f. et Thomson and Ettipeiopsis R.E.Fries (3,4).

Seven species of Melodorum are known to be present in Australia (2). One of these is endemic to the Northern Territory and is not considered further here because it was unavailable to us. The other six species occur in Queensland, with one species [M. leichhardtii (F.Muell.) Benth.] extending to New Guinea and northeastern New South Wales. Apart from M. leichhardtii and M. uhrii F.Muell., the other four species are as yet undescribed.

Melodorum leichhardtii (Zig Zag Vine) is widespread, occurring in southern New Guinea, the Torres Strait and south through eastern Australia to near Dorrigo in northeastern New South Wales. Plants grow in a wide range of rainforest communities but are very common in deciduous vine thickets, araucarian microphyll and notophyll vineforests, semideciduous mesophyll and notophyll vineforests on a range of substrates from near sea level up to 1000 m altitude. The fruit is edible but not particularly palatable.

Melodorum uhrii is endemic to the wet tropics of northeastern Queensland from Gap Creek in the north to near Wallaman Falls west of Ingham in the south. Plants grow in evergreen notophyll and mesophyll vineforests on a variety of substrates including granite and metamorphics at altitudes between 200 and 1100 m.

Melodorum sp. (Claudie River B.P.Hyland 21171V) is endemic to far north Queensland where it is known from Moa Island in Torres Strait in the north to the Mcllwraith Range in the south. Plants grow in deciduous and semideciduous vine thickets and microphyll vineforests on substrates derived from granite or deep sands at altitudes from near sea level up to 300 m.

Melodorum sp. (Font Hills G.Sankowsky 380) is widespread in northern Queensland from near Coen in the north to west of Mackay in the south. Plants grow in deciduous vine thickets amongst granite outcrops at altitudes between 100 and 400 m.

Melodorum sp. (Stone Crossing L.W.Jessup814) is endemic to far north Cape York Peninsula in Queensland from the Lockerbie Scrub near Bamaga in the north to the Archer River in the south. Plants grow in semideciduous mesophyll or notophyll vine forest on alluvium or at altitudes from near sea level to 300 m.

Melodorum sp. (Topaz G.Sankowsky 244) is endemic to the wet tropics of northeastern Queensland with a relatively restricted range from Topaz to the Francis Range on the Atherton Tableland. Plants grow in evergreen mesophyll vine forest on substrates derived from basalt at altitudes between 600 and 1100 m.