Ashley Dowell

Tea tree oil (TTO) is the essential oil of tea tree (Melaleuca alternifolia or M. linariifolia, Myrtaceae). Adulteration of TTO has become more apparent in recent years. Adulteration occurs with single essential oil components (e.g., sabinene from pine oil), waste products derived from other essential oils such as pine (Pinus spp., Pinaceae), eucalyptus (Eucalyptus globulus and other Eucalyptus spp., Myrtaceae), and camphor (Cinnamomum camphora, Lauraceae) oils, or with essential oils from other Melaleuca species and the closely related genus Leptospermum. This Laboratory Guidance Document presents a review of the various analytical technologies used to differentiate between authentic tea tree oil and essential oils containing adulterating materials. This document can be used in conjunction with the Tea Tree Oil Botanical Adulterants Bulletin published by the ABC-AHP-NCNPR Botanical Adulterants Prevention Program in 2017.

Essential oils are derived from not-fatty parts of plants and are mostly used in aromatherapy, as well as cosmetics and perfume production. The essential oils market is growing rapidly due to their claimed health benefits. However, because only therapeutic grade oil is required in the medicinal sector, there is a substantial low-value waste stream of essential oils that can be used in the transportation and agricultural sectors. This study investigated the influence of orange, eucalyptus, and tea tree oil on engine performance and combustion characteristics of a multi-cylinder compression ignition engine. Orange, eucalyptus, and tea tree oil were blended with diesel at 10% by volume. For benchmarking, neat diesel and 10% waste cooking biodiesel-diesel blend were also tested. The selected fuels were used to conduct engine test runs with a constant engine speed (1500 RPM (revolutions per minute)) at four loads. As the load increased, frictional power losses decreased for all of the fuel samples and thus mechanical efficiency increased. At higher loads (75% and 100%), only orange oil-diesel blends produced comparable power to diesel and waste cooking biodiesel-diesel blends. Fuel consumption (brake and indicated) for the essential oil-diesel blends was higher when compared to base diesel and waste cooking biodiesel-diesel blends. Thermal efficiency for the essential oil-diesel blends was comparable to base diesel and waste cooking biodiesel-diesel blends. At higher loads, blow-by was lower for essential oil blends as compared to base diesel and waste cooking biodiesel-diesel blends. At 50% and 100% load, peak pressure was lower for all of the essential oil-diesel blends when compared to base diesel and waste cooking biodiesel-diesel blends. From the heat release rate curve, the essential oil-diesel blends ignition delay times were longer because the oils have lower cetane values. Overall, the low-value streams of these essential oils were found to be suitable for use in diesel engines at 10% blends by agricultural producers of these oils.

Turban snails (family Turbinidae) are gastropod molluscs that are harvested for human consumption yet little is known about the nutritional properties of these snails, particularly from Australian waters. This study compares the proximate composition (ash, moisture, protein, and lipid content), fatty acid profiles, mineral, and trace element content of three species of turbinid snails; Turbo militaris, Lunella undulata, and Lunella torquata from northern New South Wales, Australia. They were all found to have relatively high protein in their flesh (16.0% to 18.5% of the fresh weight). L. torquata had a significantly higher lipid content (8.5% w/w) than L. undulata (5.2% w/w), whereas T. militaris (5.6% w/w) was not significantly different to either. Analysis with gas chromatography showed there was no significant difference in monounsaturated fatty acid (MUFA) content, with an average of approximately 14% of the total fatty acids in all three species. However, saturated fatty acids (SFA) were significantly higher in T. militaris (41%), whereas polyunsaturated fatty acids (PUFA) were significantly higher in L. undulata (46%). The ratio of n−3/n−6 fatty acids ranged from 1.1 in T. militaris to 1.4 in L. torquata, which is good for human health and comparable to other high value gastropods. The results indicate that T. militaris, L. undulata, and L. torquata provide a good source of essential elements such as zinc, selenium, and iron. At the location studied, toxic metals and metalloids were below safe recommended standards for human consumption. Overall, this study confirms the suitability of turban snails as a nutritional food for human consumption.

Ocean warming and acidification are current global environmental challenges impacting aquatic organisms. A shift in conditions outside the optimal environmental range for marine species is likely to generate stress that could impact metabolic activity, with consequences for the biosynthesis of marine lipids. The aim of this study was to investigate differences in the lipid content of Dicathais orbita exposed to current and predicted future climate change scenarios. The whelks were exposed to a combination of temperature and CO₂-induced acidification treatments in controlled flowthrough seawater mesocosms for 35 days. Under current conditions, D. orbita foot tissue has an average of 6 mg lipid/g tissue, but at predicted future ocean temperatures, the total lipid content dropped significantly, to almost half. The fatty acid composition is dominated by polyunsaturated fatty acids (PUFA 52%) with an n-3:6 fatty acid ratio of almost 2, which remains unchanged under future ocean conditions. However, we detected an interactive effect of temperature and pCO₂ on the % PUFAs and n-3 and n-6 fatty acids were significantly reduced by elevated water temperature, while both the saturated and monounsaturated fatty acids were significantly reduced under increased pCO₂ acidifying conditions. The present study indicates the potential for relatively small predicted changes in ocean conditions to reduce lipid reserves and alter the fatty acid composition of a predatory marine mollusc. This has potential implications for the growth and survivorship of whelks under future conditions, but only minimal implications for human consumption of D. orbita as nutritional seafood are predicted.

Brahmi (Bacopa monnieri) has been used by Ayurvedic medical practitioners in India for almost 3000 years. The pharmacological properties ofBacopa monnieriwere studied extensively and the activities were attributed mainly due to the presence of characteristic saponins called “bacosides.” Bacosides are complex mixture of structurally closely related compounds, glycosides of either jujubogenin or pseudojujubogenin. The popularity of herbal medicines and increasing clinical evidence to support associated health claims require standardisation of the phytochemical actives contained in these products. However, unlike allopathic medicines which typically contain a single active compound, herbal medicines are typically complex mixtures of various phytochemicals. The assay for bacosides in the British Pharmacopoeia monograph forBacopa monnieriexemplifies that only a subset of bacosides present are included in the calculation of total bacosides. These results in calculated bacoside values are significantly lower than those attained for the same material using more inclusive techniques such as UV spectroscopy. This study illustrates some of the problems encountered when applying chemical analysis for standardisation of herbal medicines, particularly in relation to the new method development and validation of bacosides from KeenMind.