Eucalyptus species

P.J. Dunlop, C.M. Bignell, J.F. Jackson, D.B. Hibbert, Chemometric analysis of gas chromatographic data of oils from Eucalyptus species. Chemom. Intell. Lab. Systems 30 (1995) 59-67. K. Varmuza, F. Stangl, H. Lohninger and W. Werther, Automatic recognition of substance classes from data obtained by gas chromatography, mass spectrometry. Lab. Automation Inf. Manage., 31 (1996) 221-224. 

Is there coevolution between mammals and their food plants Herbivorous mammals usually consume many different plant species, and a plant typically is food to more than one herbivore species. Any patterns of coevolution would be diluted, resulting in diffuse rather than narrow coevolution. Even the diets of the koala (eucalyptus) and giant panda (bamboo) are more varied than commonly assumed. The koala feeds on several Eucalyptus species and did not thrive in zoos when fed only one species. The giant panda even includes animals in its diet. Nevertheless, Lindroth (1988) saw coevolution as an attractive hypothesis for some mammals. 

Many Eucalyptus species are economically important for their timber, their essential oil content, or their contribution to reafforestation in tropical and subtropical countries. Monoterpenoids, which have been linked with allelopathy by several workers, including Muller ( ) and Lovett (M), are common... 

Table 17.3 Monoterpene compounds from Melaleuca and Eucalyptus species [45]...

Terpineol is mainly isolated from plants of the Eucalyptus species and is a mixture of a-terpineol, P-terpineol, 4-terpineol, and 1,4- and 1,8-terpindiols. Both enantiomers of a-terpineol are commercially produced through hydration of a-pinenes.37... 

There are a number of allelochemicals among the mono-, sesqui-, and diterpenoids. In particular, plants in arid and semiarid regions produce diverse volatile terpenoids with allelopathic activity.5 Among the volatile monoterpenes, 1,8-cineole (4) and camphor (5) exhibit strong growth inhibitory effects on plants and are considered to be involved in plant competition. 1,4-Cineole (6), a minor isomer of 1,8-cineole, is a potent inhibitor of asparagine synthetase.6 -Menthane-3,8-diols (fir 7 and frw .r8), -menth-2-en-l-ols (cis 9 and trans 10), thymol (11), carvacrol (12), 1,8-cineole, cr-pinene (13), and /3-pinene (14) were isolated as allelopathic monoterpenes from Eucalyptus species.7 Eucalyptus trees also produce allelopathic sesquiterpenes including spathulenol (15), and a-, (3-, and 7-eudesmols (16-18).7... 

Myristica fragrans (nutmeg) Eucalyptus species (eucalyptus) Melaleuca alternifolia (tea tree) Oenothera biennis (evening primrose)... 

Aioe Aloe capensis Eucaiyptus Eucalyptus species... 

It was mentioned earlier that charcoal makers are well aware that woods from different tree species yield charcoals of differing quality. These differences can be linked to differences in wood anatomy and composition. There are well known and well-characterised anatomical and chemical differences between softwoods and hardwoods, for example [13], and softwood charcoal is widely regarded as inferior to that from hardwoods. Significant differences can also exist between the charcoals and charcoal yields from superficially similar species of the same genus. This has been shown in the case of Eucalyptus species [14][15]. There can even be differences in charcoals made from trees of the same species when these come from regions with dissimilar climates or soil types. 

Eucalyptus citriodora Hook f (Lemon gum) The oil of the fresh leaves of E. citriodora (2.2-8.3%), a tree introduced into Kenya from Australia (68), has been well researched in Kenya. Results indicate that there are two chemical varieties that were introduced. The chief essential oil constituents of one variety are citronellal (65-88%), citronellol (2-25%) and isopulegol (2-19%). In constrast, the second variety has as its major essential oil consitutents citronellol (32-52%), citronellal (38-59%) and 1,8-cineole (2-19%) (68,69). The essential oil is regarded as a perfumery oil. This plant is the second most commercially important Eucalyptus species in the essential oil trade and is only second to E. smithii Baker (69). The aromatic oil is used in soaps, creams and lotions due to its desirable odor properties, and as with many other essential oils is also used extensively in many technical preparations to mask other industrial malodors. A highly active mosquito repellent compound, p-menthane 3,8-diol has been isolated from the waste water of distillation of E. citriodora. There are now many commercial mosquito repellents based on this waste water (70-73). 

Elsewhere in the world eucalypts are planted. It is worth repeating the observation, that although Australia is the home of almost all eucalyptus species, the 3.1 million m of sawlog production comes almost entirely from native forests. This roughly matches the estimated 2.9 million m coming from plantations worldwide (with 37% from Brazil alone). Indeed in Australia the plantation area is only about 15% of that in Brazil, which has c. 3 million hectares (Donnelly et al, 2003). 

EUCALYPTUS OIL Eucalypti aetheroleum is obtained by steam distillation of fresh leaves (in practice whole twigs) of Eucalyptus /lobulus Labill. and other Eucalyptus species, such as E. fructicetorum F. von Muller (=E. polybractea RF. Baker), family Myrtaceae. The genus Eucalyptus belongs to the Australian flora, but now has a global distribution by... 

P. anthracophilus found on a Eucalyptus species were established at the same time. The work on eburicoic acid was carried out by Robertson in Liverpool. The elucidation of the structure of polyporenic acid A (5.161) benefited from experience gained in studies on the structure of lanosterol and on the penta-cyclic triterpenes. The identification of some structural features also showed the developing role of UV and IR spectroscopic methods in the 1950s. However, the purification of these compounds was impeded by the difficulty of separating the 8(9)-enes from the 7(8),9(ll)-dienes that often accompanied them. Initial studies on polyporenic acid A revealed the presence of a carboxylic acid, two hydroxyl groups and two double bonds, each of differing reactivity. One double bond was a terminal methylene since formaldehyde was obtained on ozonolysis whilst the other was more hindered. Typical of the tetracyclic triterpenes. 

Xie, Y. M. (2004) Difference of condensed lignin strnctnres in eucalyptus species. Nordic Pulp Paper Res. J. 19(f), f8-21. 

C,oH180, Mr 154.25, bpm3kP 212°C, bp0.5kPa, 73.5°C, d20 0.9315, n20 1.4799, occurs as (+)-, (-)-, and racemic l-terpinen-4-ol in many essential oils, e.g., from Pitt us and Eucalyptus species, and in lavender oil. It is a colorless liquid with a spicy, nutmeg-like, woody-earthy, and also lilac-like odor. 

The different Eucalyptus species of importance to the perfumery industry contain different ter-penes as their major components. The terpenes of each are related to the following major components E. citriodora, citronellal E. dives, piperitone E. globulus, cineole E. staigeriana, citral. TThe oil and absolute are known as cistus. 

The leaf tissue of mature plants of some eucalyptus species, eg E. grandis, produce amounts (up to 7.5 mg/g dry wt) of three plant growth regulators, the G-inhibitors (55-57), which are characterised by the presence of an epidioxy functionality. Since these compounds lacked optical activity, the possibility that they were artefacts was considered. In fact, the (3-triketone (58) (Scheme 2) rapidly formed the epidioxide (57) on exposure to air. However, isolation of the inhibitors in the presence of 1802 did not result in incorporation of isotopic oxygen. It has been suggested that (55-57) arise from the corresponding Mannich bases which are con-... 

In 1970, Hillis and Seikel isolated an ellagitannin from a Eucalyptus species, and tentatively suggested it to be a dimer composed of two... 

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