Quality assurance for tea tree oil safety investigative samples. A report for the Rural Industries Research and Development Corporation by Ian Southwell, David Leach, Robert Lowe and Aaron Pollack February 2006 RIRDC Publication No 06/026 RIRDC Project No Dan 241A © 2006 Rural Industries Research and Development Corporation. All rights reserved. ISBN 1 74151 289 1 ISSN 1440-6845 Quality assurance for tea tree oil safety investigative samples. Publication No. 06/026 Project No DAN 241A The information contained in this publication is intended for general use to assist public knowledge and discussion and to help improve the development of sustainable industries. The information should not be relied upon for the purpose of a particular matter. Specialist and/or appropriate legal advice should be obtained before any action or decision is taken on the basis of any material in this document. The Commonwealth of Australia, Rural Industries Research and Development Corporation, the authors or contributors do not assume liability of any kind whatsoever resulting from any person's use or reliance upon the content of this document. This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the Corporation is clearly acknowledged. For any other enquiries concerning reproduction, contact the Publications Manager on phone 02 6272 3186. Researcher Contact Details Dr Ian Southwell Assoc Prof David Leach, Wollongbar Agricultural Institute, Centre for Phytochemistry & Pharmacology, 1243 Bruxner Highway, Wollongbar, Southern Cross University, Military Road, Lismore, NSW, 2477 NSW 2480 Phone: 0266 261 224 Phone: 0266 223 211 Fax: 0266 283 264 Fax: 0266 223 459 Email: [email protected] Email: [email protected] In submitting this report, the researcher has agreed to RIRDC publishing this material in its edited form. RIRDC Contact Details Rural Industries Research and Development Corporation Level 2, Pharmacy Guild House 15 National Circuit BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: 02 6272 4819 Fax: 02 6272 5877 Email: [email protected]. Web : http://www.rirdc.gov.au Published in February 2006 Printed on environmentally friendly paper by Canprint ii Foreword Tea tree oil has recently received bad media coverage overseas though headlines stating: “tea tree oil – unsafe and unstable” as a result of a European SCCP (Scientific Committee on Consumer Products) opinion that concluded that insufficient data was available on the safety and stability of the oil. The industry is addressing this situation by commissioning approved tests in order to obtain a more complete safety dossier on tea tree oil. For this to be achieved, the oils tested must be well defined chemically for the dossier to be valid. This report outlines how, from eleven commercial samples screened, three oils (one fresh, one mildly oxidised and one oxidised) were chosen by peroxide index determination and thoroughly defined by GC, GCMS and physical constants as to whether they were typical oils meeting international standards before being tested for dermal penetration and other safety parameters for the dossier. Such testing will be of economic benefit as a more acceptable oil will lead to more sales and be of social benefit as the safety and stability of the oil are better defined. This project was funded from RIRDC core funds which are provided by the Australian Government. This report is an addition to RIRDC’s diverse range of over 1500 research publications. It forms part of our Tea Tree Oil R&D sub-program which aims to develop safety packages to support registration and product formulation. Most of our publications are available for viewing, downloading or purchasing online through our website: • downloads at www.rirdc.gov.au/fullreports/index.html • purchases at www.rirdc.gov.au/eshop Peter O’Brien Managing Director Rural Industries Research and Development Corporation iii Abbreviations ATTIA Australian Tea Tree Industries Association BP British Pharmacopoeia CPP Centre for Phytochemistry and Pharmacology of SCU FID Flame Ionization Detector GC Gas Chromatography GCFID Gas Chromatography – Flame Ionization Detection GCMS Gas Chromatography – Mass Spectrometry ISO International Standards Organisation NSW DPI New South Wales Department of Primary Industries Ph Eur European Pharmacopoeia SCCP Scientific Committee on Consumer Products SCU Southern Cross University TAS Technical and Safety committee of ATTIA WAI Wollongbar Agricultural Institute of NSW DPI iv Contents Foreword............................................................................................................................................... iii Abbreviations........................................................................................................................................ iv Executive Summary ............................................................................................................................. vi 1. Introduction ................................................................................................................................... 1 2. Objectives....................................................................................................................................... 1 3. Methodology .................................................................................................................................. 1 Sample Selection ................................................................................................................................. 1 Peroxide Value Determination ............................................................................................................ 1 ISO Standard Compliance................................................................................................................... 2 Gas Chromatography – Mass Spectrometry (GCMS)......................................................................... 2 4. Results ............................................................................................................................................ 2 5. Discussion....................................................................................................................................... 2 6. Conclusions, Implications and Recommendations ..................................................................... 3 7. References ...................................................................................................................................... 6 Annex 1................................................................................................................................................... 7 Annex 2................................................................................................................................................... 8 Annex 3................................................................................................................................................... 9 Gas chromatograms (GCFID) of the three selected tea tree oils. ........................................................ 9 Annex 4................................................................................................................................................. 22 Gas chromatograms (GCMS) of the three selected tea tree oils........................................................ 22 v Executive Summary Headlines in Europe recently stated: “tea tree oil – unsafe and unstable”. This undesirable media coverage overseas came as a challenge to the Australian tea tree oil industry at a time when attempts to combat low prices by better market promotion of the oil were gaining momentum. The headlines followed the release of a European SCCP (Scientific Committee on Consumer Products) opinion that concluded that insufficient data were available on the safety and stability of the oil. Consumers and the media need to know the facts about the safety and stability of tea tree oil that, along with proven efficacy, have made the oil such a popular health care product over the last 70 years. The industry is addressing this situation by commissioning approved tests in order to obtain a more complete safety dossier on tea tree oil. For this to be achieved, the oils tested must be well defined chemically for the dossier to be valid. This investigation outlines how, from eleven commercial samples screened, three oils (one fresh, one oxidised and one, blended from commercial oils, mildly oxidised) were chosen by peroxide index determination. These samples were then thoroughly defined by GC, GCMS and physical constants to determine status with respect to the ISO standard for tea tree oil before being recommended for dermal penetration and other safety parameter investigations for the dossier. The methods used were internationally accepted procedures for determining peroxide value (British or European Pharmacopoeia methods), GC profiles and physical constants (ISO Standard) and GCMS (generally accepted literature procedures). From 11 tea tree oils screened, three samples with sufficient bulk were selected for safety parameter testing. These were found to display mean peroxide values of 1.1, 11.7 and 30.5 milliequivalents of active oxygen per kg. The first of these was the only sample within the limits of the Australian and International Standards for tea tree oil. The oxidised oil failed to satisfy these standards at the following points: in the chromatographic profile, p-cymene levels were high and α- and