Archive for category Eucalyptus'

Cultivation and production of eucalypts in South America

FAO country estimates for the areas of plantation eucalypts in 1990 show that Brazil had the second largest area after India, 3.6 million ha (). The most recent estimate, also from FAO sources, puts the figure at 3.1 million ha (). Although this massive resource is designed to meet the raw material needs of Brazil’s forest-based industries such as timber, pulp and charcoal, it has, nevertheless, indirectly influenced the development of the eucalyptus oil industry in the country, at least in the early days. Apart from China, Brazil has been the only other significant producer and exporter of Eucalyptus citriodora oil and this aros from the widespread availability of ‘waste’ leaf from Eucalyptus citriodora planted primarily for charcoal production. Charcoal is used for fuelling the furnaces in the iron and steel industries and in the manufacture of cement and Eucalyptus citriodora has played an important role in the Brazilian economy (). In addition to Eucalyptus citriodora oil, oils from Eucalyptus globulus and E. staigeriana are produced in Brazil Production of eucalyptus oil elsewhere in South America is small compared to that in Brazil and although brief mention is made later in this chapter to Chile, Bolivia, Read more […]

Eucalyptus oil products: Formulations and legislation

Eucalyptus oils are being used with increasing frequency in a variety of products found in the supermarket or pharmacy. ‘With extract of Eucalyptus’ or ‘With Eucalyptus essential oil’ claims are becoming more common on the labels of modern consumer products such as cosmetics, toiletries and household products due to the ever-increasing interest in natural or botanical ingredients. Eucalyptus oil may be used as an active ingredient to provide scientifically provable benefits – such as nasal decongestion or antibacterial effects – or at much lower dosages to impart more esoteric or folkloric connotations to the product concerned. Eucalyptus oils are also used as components of perfumes to provide a medicinal-type note to the fragrance. Eucalyptus globulus, or Blue Gum, oil was a traditional Australian aboriginal remedy for infections and fevers. It is now used all over the world for relieving coughs and colds, sore throats and other infections. Its main constituent, 1,8-cineole, is mucolytic (i.e. it thins out and relaxes the flow of mucus) and is excreted through the lung surface. Eucalyptus radiata oil is sometimes preferred by aromatherapists for its more pleasant smell while Eucalyptus smithii oil is Read more […]

The use of eucalyptus oils in consumer products

Insect repellents As noted in the introduction, Eucalyptus citriodora oil has been used as a ‘natural’ insect repellent. Depending on the product formulation it is used in, Lemon Eucalyptus (known as Quwenling in China) is up to four or five times more effective and longer-lasting than citronella oil (from Cymbopogon nardus), one of the best known natural insect repellents. p-Menthane-3,8-diol is the main active component of Quwenling and this can be isolated and used as a highly effective insect repellent. Eucalyptus citriodora oil contains up to 80–90 per cent citronellal, along with geraniol, both of which are known to have insect repellent activity but tend to dilute the much higher activity of the p-menthane-3,8-diol. The Mosi-guard Natural insect repellent spray produced by MASTA in the UK contains ‘Extract of Lemon Eucalyptus’ and claims on the label: Approved and recommended by the London School of Hygiene and Tropical Medicine. Field trials have shown effective protection for 6 h after a single application in mosquito infected areas. Also protects against many other biting insects. Mosi-guard Natural is made from a natural and renewable resource. It is kind to your skin and has no adverse effects Read more […]

Antimicrobial activity of eucalyptus oils

The preservative properties of the volatile oils and extracts of aromatic and medicinal plants have been recognised since Biblical times, while attempts to characterise these properties in the laboratory date back to the early 1900s (e.g. Hoffman and Evans 1911). Martindale (1910) included ‘Eucalyptus amygdalina’ (probably the phellandrene variant of Eucalyptus dives) and Eucalyptus globulus oils, as well as eucalyptol (1,8-cineole), in his study of the antiseptic powers of essential oils and although the ‘carbolic coefficients’ of eucalyptus oils were not as great as those for oils containing large amounts of phenolics – such as origanum (carvacrol), cinnamon leaf (eugenol) and thyme (thymol) – they did, nevertheless, give some quantitative measure of the antiseptic properties of eucalyptus leaf oils. Many volatile oils – particularly those of herbs and spices, but including those from Eucalyptus – have been used to extend the shelf-life of foods, beverages and pharmaceutical and cosmetic products; their antimicrobial and antioxidant properties have also pointed to a role in plant protection. Such a wide variety of applications, actual or potential, has meant that the antimicrobial properties of Read more […]

Antibacterial activity of eucalyptus oils

The antibacterial properties of plant volatile oils have been recognised since antiquity and have been rediscovered in more recent times. Eucalyptus leaf oils have received attention in a number of studies. Deans and Ritchie () examined the antibacterial effects of fifty volatile oils purchased from a commercial supplier, including eucalyptus, on twenty-five different bacterial genera. The culture collection consisted of food spoilage, food poisoning, human, animal and plant disease types, along with indicators of faecal pollution and secondary opportunist pathogens. Eucalyptus oil was most effective against Elavobacterium suaveolens and the dairy organism Leuconostoc cremoris. However, it was not amongst the ten most inhibitory oils (thyme, cinnamon, bay, clove, bitter almond, lovage, pimento, marjoram, angelica and nutmeg). Leaf oils from eight Brazilian-grown eucalypts were tested against Mycobacterium avium by Leite et al. (): E. botryoides, E. camaldulensis, Eucalyptus citriodora, E. deglupta, Eucalyptus globulus, E. grandis, E. maculata and E. tereticornis. M. avium was sensitive to all the oils at 10mg/ml but only four of them at 5 mg/ml: Eucalyptus citriodora, E. maculata, E. camaldulensis and E. tereticornis. Read more […]

Antifungal activity of eucalyptus oils

Human pathogens The volatile oil from Eucalyptus camaldulensis (syn. E. rostrata) has been the subject of several studies where the target organisms were dermatophytic fungi. Singh et al. () tested the oil against four human pathogens, Trichophyton mentagrophytes, Epidermophyton floccosum, Microsporum cants and M. gypseum, as well as two storage fungi, Aspergillus nidulans and A. terreus. At concentrations of 10,000 ppm (1 per cent) the oil showed fungicidal activity towards all the test organisms. In a second study (), a combination of oils from E. camaldulensis and Juniperus communis was found to be more effective than either single oil against Epidermophyton floccosum, M. gypseum and Paecilomyces variotii. The minimum inhibitory concentration (MIC) and time taken to inhibit mycelial growth were less with the mixture than with the individual oils, suggesting that there were synergistic interactions between the components present in the two oils. In a wide-ranging study Pattnaik et al. () tested ten essential oils, one of them from Eucalyptus citriodora, against twelve test fungi (mostly human pathogens, with a few plant pathogens): Alternaria citrii, Aspergillus fumigatus, A. oryzae, Candida albicans, Cryptococcus Read more […]