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Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of cajuput oil obtained from fresh leaves of Melaleuca cajuputi Maton & Sm. ex R. Powell and Melaleuca leucadendra (L.) L., when used as a sensory additive for all animal species. The FEEDAP Panel concluded that cajuput oil is safe up to the maximum proposed use levels in complete feed of 30 mg/kg for sows and dogs, 50 mg/kg for horses and ornamental fish, 40 mg/kg for salmon and 5 mg/kg for cats. For the other species, the calculated safe concentrations were 18 mg/kg for chickens for fattening, 26 mg/kg for laying hens, 23 mg/kg for turkeys for fattening, 37 mg/kg for pigs for fattening, 31 mg/kg for piglets, 78 mg/kg for veal calves (milk replacer), 69 mg/kg for cattle for fattening and sheep/goats, 45 mg/kg for dairy cows and 28 mg/kg for rabbits. These conclusions were extrapolated to other physiologically related species. For any other species, the additive is safe at 5 mg/kg complete feed. The use of cajuput oil in water for drinking was considered safe provided that the total daily intake does not exceed the daily amount considered safe when consumed via feed. No concerns for consumers and the environment were identified following the use of the additive up to the highest safe use level in feed. The essential oil under assessment should be considered as an irritant to skin and eyes, and as a dermal and respiratory sensitiser. Since cajuput oil was recognised to flavour food and their function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary., Competing Interests: If you wish to access the declaration of interests of any expert contributing to an EFSA scientific assessment, please contact interestmanagement@efsa.europa.eu., (© 2024 European Food Safety Authority. EFSA Journal published by Wiley‐VCH GmbH on behalf of European Food Safety Authority.)

Three new β-triketone flavanone hybrids, cajuputones A-C were obtained from Melaleuca cajuputi (the Australian 'tea tree'). The structures of cajuputones A-C were elucidated by 1D/2D NMR spectroscopy and HR-ESI-MS analyses; and their absolute configurations were established by electric circular dichroism (ECD) calculations using TDDFT method. Structurally, cajuputones A-C feature a rare 6/6/6/6 oxatetracyclic ring system fused between an acylphloroglucinol-derived β-triketone and a pinocembrin or strobopinin moiety via an angle-type pyran-like motif. DFT-based conformational optimization in chloroform explained the similarity of the 1D NMR data of cajuputones B and C (C-2 epimers)., (© 2020 Wiley-VHCA AG, Zurich, Switzerland.)

Melaleuca cajuputi subsp. cajuputi is one of the Australian Melaleuca species commonly found in Pulau Buru (Maluku, Indonesia). Its oil, the M. cajuputi essential oil (MCEO), has been utilized as the main flavor of the Indonesian functional food, Cajuputs Candy. However, the availability of MCEO is becoming limited. On the other hand, Indonesia has many other potential MCEO sources which can be developed as flavor ingredient. Thus, it is noteworthy to explore these new MCEO sources by studying their sensory characteristics and metabolite profiles. This study was conducted to identify potential metabolites that are correlated to sensory attributes of MCEO by using the metabolomics approach. The metabolite profiles of thirteen MCEOs from different origins were analyzed by gas chromatography-mass spectrometry while sensory analyses on Cajuputs Candy were conducted by difference-from-control and rate-all-that-apply tests. Sixty metabolites from the MCEO were annotated that includes 1,8-cineole, α-terpineol, caryophyllene, α-pinene, and γ-terpinene. Sensory analysis revealed cooling aftertaste and sweet taste as favorable attributes. Further analysis using Orthogonal Partial Least Square indicated that 1,8-cineole and γ-terpinene were correlated with cooling aftertaste, while 1,8-cineole and caryophyllene were also correlated with sweet taste. In contrast, linalool and nerolidol were associated with the feature of the most characteristic manufacturer's products which have unfavorable attributes such as floral, iodophor-like, metallic, and soapy attributes. The identification of these metabolites will be useful for the selection of MCEOs that can potentially be used as flavor., (Copyright © 2019 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

We evaluated the activity of methanolic extracts of Melaleuca cajuputi flowers against the filarial worm Brugia pahangi and its bacterial endosymbiont Wolbachia. Anti-Wolbachia activity was measured in worms and in Aedes albopictus Aa23 cells by PCR, electron microscopy, and other biological assays. In particular, microfilarial release, worm motility, and viability were determined. M. cajuputi flower extracts were found to significantly reduce Wolbachia endosymbionts in Aa23 cells, Wolbachia surface protein, and microfilarial release, as well as the viability and motility of adult worms. Anti-Wolbachia activity was further confirmed by observation of degraded and phagocytized Wolbachia in worms treated with the flower extracts. The data provided in vitro and in vivo evidence that M. cajuputi flower extracts inhibit Wolbachia, an activity that may be exploited as an alternative strategy to treat human lymphatic filariasis.

Background: Melaleuca cajuputi essential oil in aerosol spray was evaluated against the dengue vectors Aedes aegypti and Ae. albopictus at low cost housing flats in Section 10, Setapak, Kuala Lumpur, Malaysia., Methods: ESSENTIAL OIL IN AEROSOL VIZ: 5% and 10% of concentrations were sprayed for 5 seconds each towards hung mosquitoes in 5 cylindrical net cages. Aerosol weights were recorded before and after spraying to determine discharge rates. Knockdown and mortality number were observed and compared to MS standard aerosol which contain 0.07% prallethrin and 0.05% d-phenothrin as positive control and aerosol contain 40% kerosene and 60% LPG was used as negative control., Results: High knockdown and mortality was observed in both species of mosquitoes towards MS standard aerosol. There was a significant difference (P< 0.05) of mortality and knockdown between 5% and 10% of essential oil aerosol and 5% and 10% essential oil between MS standard. For 5% essential oil, mean percentage (%) of knockdown and mortality of Ae. aegypti displayed slightly higher compared to Ae. albopictus. Spraying with 5% M. cajuputi essential oil aerosol indicated a knockdown of Ae. aegypti 5.60±1.18 and mortality of 22.90±4.22 while Ae. albopictus showed 4.60±0.89 knockdown and 20.00±2.85 mortality. The 10% essential oil concentration gave 23.60±1.68 knockdown and 48.05±0.37 mortality for Ae. aegypti. Ae. albopictus gave 23.00±3.16 knockdown and 44.20 ± 2.10 mortality respectively., Conclusions: Extracts of essential oils does possessed an adulticidal effects and could be considered and utilized for future dengue vectors control.