Volatile oils of 'Eremophila longifolia' F. Muell. (Myoporaceae) leaves were obtained by hydrodistillation and analysed using GC–MS. A total of 33 compounds were identified in the oils examined and a high degree of intraspecific variability in chemical composition between specimens occurring in separate geographic localities was found. Multivariate statistical analysis of chemical composition of volatile oils enabled classification of three chemotypes in this species.

Essential oils from the Australian Aboriginal medicinal plant 'Eremophila longifolia' (emu bush) were characterised using GC/MS and NMR, and antimicrobial capacity investigated using disc diffusion and broth dilution. Leaves were collected from various locations within New South Wales (NSW, Australia) and hydro-distilled for volatile leaf oils. Overall yield and oil constitution differed markedly according to the geographical region from which the plants were collected. 'E. longifolia' demonstrated a variety of chemotypes not yet recognised. Four further chemotypes are now recognised within NSW, in addition to the two previously characterised from other regions of Australia; the Northern Territory (NT) and the Murchison district in Western Australia (WA). Characterisation of NSW chemotypes revealed that here 'E. longifolia' does not produce the carcinogenic volatile compound, safrole, as previously described in the leaf oil from Murchison specimens (WA). Two separate chemotypes within NSW yielded oil as high as 7% w/w and 3.5% w/w consisting mostly of iso-menthone (70-90%) and karahanaenone (≈80%) respectively; marking these as the most abundant natural sources of these compounds so far described [3,4,5]. The two remaining chemotypes had a much lower yield, 0.2 and 0.7%, and were more similar to the chemotype found in the NT; leaf oils consisting of limonene (≈20%) and borneol (20-30%) respectively. Antimicrobial assays of volatile oils from the four chemotypes revealed a moderate to high antimicrobial capacity, varying with species and chemotype. Traditional (location specific) indigenous applications of the oils are consistent with these results. The essential oil from 'E. longifolia' may thus be a likely candidate for further investigation into cosmeceutical use addressing a similar market niche to that already successfully occupied by the essential oil of 'Melaleuca alternifolia' (tea tree oil) and more recently 'Backhousia citriodora' (lemon myrtle oil). Further investigations (wound healing, anti-inflammatory and cultivar chemotype requirements) are in progress.

This paper is the first of a series which will describe the development of a synthetic plant volatile-based attracticide for noctuid moths. It discusses potential sources of volatiles attractive to the cotton bollworm, 'Helicoverpa armigera' (Hübner), and an approach to the combination of these volatiles in synthetic blends.We screened a number of known host and non-host (for larval development) plants for attractiveness to unmated male and female moths of this species, using a two-choice olfactometer system. Out of 38 plants tested, 33 were significantly attractive to both sexes. There was a strong correlation between attractiveness of plants to males and females. The Australian natives, 'Angophora floribunda' and several 'Eucalyptus' species were the most attractive plants. These plants have not been recorded either as larval or oviposition hosts of 'Helicoverpa' spp., suggesting that attraction in the olfactometer might have been as nectar foraging rather than as oviposition sources. To identify potential compounds that might be useful in developing moth attractants, especially for females, collections of volatiles were made from plants that were attractive to moths in the olfactometer. Green leaf volatiles, floral volatiles, aromatic compounds, monoterpenes and sesquiterpenes were found. We propose an approach to developing synthetic attractants, here termed 'super-blending', in which compounds from all these classes, which are in common between attractive plants, might be combined in blends which do not mimic any particular attractive plant.

'Eremophila longifolia' is a woody shrub, endemic to arid and semi-arid regions of Australia, where it is employed in traditional indigenous medicine to treat a wide variety of conditions. An early report examining 'E. longifolia' leaf essential oil composition had indicated high levels of the hepatotoxic and carcinogenic phenylpropanoid safrole, and as a result, authors have urged caution in the use of traditional preparations derived from this species. The present study was initiated after noting significant variations in morphology and odor profiles of wild 'E. longifolia' specimens in the state of New South Wales, (NSW) Australia. Leaves from several specimens were collected across a range of biogeographic regions in NSW. Essential oils were obtained by hydrodistillation and analysed using GCMS and NMR spectroscopy. Thirty-five compounds were identified with comparison of retention data and mass spectra with that of published values. Considerable variation was found among specimens in essential oil yield and composition, resulting in identification of three distinct types (here designated A, B and C). Type A specimens produced oils at relatively high yields (3.1% - 5.7 %) with major constituents isomenthone (61.1% - 86.7%), menthone (8.8% - 22.6%) and α-terpineol (8.4% - 11.0%). Type B specimens produced oils of relatively moderate yield (0.5% - 1.9% g/g) with major constituents karahanaenone (81.0% - 82.2%) and α -terpineol (4.1% - 11.7%). One specimen (designated type C) produced essential oil at relatively low yield (0.4% g/g fresh leaves) with major constituents identified as borneol (31.7%), fenchol (19.7%) and limonene (9.9%). No phenylpropanoids, including safrole, were detected in any of the specimens examined here. The relatively uncommon monoterpenoid karahanaenone is valued as a precursor in the fragrance industry and to the best of our knowledge the leaves of type B specimens described here represent the richest known natural source of this compound.

Three triticale cultivars differing in aluminium (Al) stress response, together with 1 Al-tolerant wheat cultivar (Carazinho) and 1 Al-tolerant wheat line (ET3), were used to investigate the root exudation of organic acids during Al stress. The likely relationship of organic acid exudation with Al tolerance, as assessed by root regrowth in nutrient solutions, was also examined. An enzymatic assay was used to detect malate release from both root tips and the whole root system; high performance liquid chromatography (HPLC) was also used to measure the exudation of organic acids from Al-stressed root tips. The enzymatic assay revealed some associations between Al tolerance and malate efflux from Al-stressed wheat or triticale roots, although Al-tolerant triticale cvv. Tahara and 19th ITSN 70-4 released less malate than the Al-tolerant wheat. HPLC analysis indicated that malate and citrate were not the main exudates related to the different levels of Al tolerance in these triticale cultivars. A yet to be identified organic acid in 19th ITSN 70-4 showed significant concentration differences from 2 other cultivars tested. This study highlighted the importance and necessity of elucidating the biochemical mechanisms involved in Al stress tolerance in triticale and other crops.