Essential oils with high antimicrobial activity for therapeutic use

Abstract

After a comparison of the antimicrobial activity of the essential oils of Australian tea tree oil, Australian lavender, New Zealand manuka, lemongrass oil, and eucalyptus oil it was found that the relative antimicrobial activity varied depending upon the microorganism under test. Lavender has useful antimicrobial properties and a product was formulated containing a combination of tea tree oil and lavender for the treatment of burns. A selected New Zealand manuka oil had strong antimicrobial activity against Staphylococcus aureus. The use of tea tree oil and combinations of tea tree oil and manuka are being investigated for therapeutic use against Methicillin Resistant Staphylococcus aureus (MRSA) and other antibiotic resistant bacteria such as Enterococci (VRE) which is resistant to Vancomycin. For therapeutic use as an antimicrobial active in formulated products the essential oil must have a broad spectrum of activity with the additional properties of being stable and non irritant to sensitive or damaged skin. Overall tea tree oil had the best combination of useful properties including strong antimicrobial activity. Australian Tea Tree Management Limited has assisted in the selection and breeding of superior plants of Melaleuca alternifolia and M. linariifolia which provide a tea tree oil high in terpinen-4-ol. By the end of 1997 over 2 million clones of these selections will have been planted. The use of tea tree oil in pharmaceutical products will be boosted by the production of commercial quantities of highly active oil with a broad spectrum of antimicrobial activity suitable for use in formulations for vaginal thrush, tinea, acne and dandruff.