Eugenol, sources

The physical and chemical characteristics of zinc oxide powders are known to affect cement formation (Smith, 1958 Norman et al., 1964 Crisp, Ambersley Wilson, 1980 Prosser Wilson, 1982). The rate of reaction depends on the source, preparation, particle size and surface moisture of the powder. Crystallinity and lattice strain have also been suggested as factors that may change the reactivity of zinc oxide powders towards eugenol (Smith, 1958). 

A chemical substance or simple mixture of substances obtained from natural sources by distillation or extraction such as citral from lemongrass oil or eugenol from clove bud. 

The main component of cinnamon leaf oil is eugenol (70 83%) [352 354b]. The oil is used as such in spicy oriental perfumes, for flavoring sweets, alcoholic beverages or as a source of high-grade eugenol. 

Isolated aroma chemicals are aroma-active substances isolated from natural sources mainly by means of crystallization, distillation, and adduct formation/decomposition. Although synthetic materials are in many cases convenient to use, isolated aroma chemicals continue to be advantageous, especially when chirality is the issue. Even if chirality is not a problem, in some cases (eg., 1,8-cineole (1), eugenol (2), and limonene (3)), isolated natural chemicals serve better than their synthetic counterpart (Table 3). 3 Isolated aroma chemicals can be useful as such for the industry, and they are also utilized as starting materials for further synthetic manipulations.34,35... 

Lord, how I ve dreaded having to write this section on eugenol. There were so many sources and multiple reports on the sources that coordinating it all into a concise, informative piece was gonna make me insane. And yes, lam now insane. 

Clove Oil Eugenia caryophyllus) The best source in the world for eugenol. No matter where it s grown the contents are the same. No matter what part of the plant is used the eugenol content is the same. The three major clove oils of commerce are the bud (that thing on your spice shelf), the leaf and the stem oils. Each one is 80-90% eugenol. T able XVI will show you what I mean [41 ]. 

Sassafras Oil This is a little squirrelly for me. Until I did the research for this book I was relying on one source for the info on the contents of sassafras oil [Guenther]. I guess a lot of people used his reference to allude that North American sassafras (Sassafras albidum) had a eugenol content of around 10%. Guenthertookhis research from the 1930-40 s or earlier. Their methods of analysis back then were rather crude when compared to today. Yet I have seen the analysis results of essential oil components from very recent articles using NMR, GC and MS get thoroughly trashed by someone with a more sophisticated instrument. 

Isoeugenol methyl ether was prepared from eugenol methyl ether by mixing eugenol methyl ether (150 parts) with potassium hydroxide (1.5 parts) and absolute ethyl alcohol (3.2 parts) at 160 to 165°C with stirring. The temperature of the mixture rose rapidly to 190 to 195° C and after 30 minutes the heat was turned off, by which time the temperature had fallen to 170°C. When the mixture reached room temperature, water was added. The oily layer was separated off, dried and vacuum distilled. The distillate (130 parts) was substantially all cis and tran.s isoeugenol methyl other. Source Bush 1968... 

The constants of clove oil are as follows specific gravity 1.047 to 1.065, refractive index 1.528 to 1.540, optical rotation 0 to—15°, eugenol by absorption with alkali 82 to 92 per cent. Source Finnemore 1926... 

Vanillin has been known as a flavouring substance since about 1816, and by 1858 the pure chemical had been obtained from ethanolic extracts of vanilla beans. It was not until 1872 that Carles established its correct formulation and in 1874, Tiemann and Haarmann reported it as 3-methoxy-4-hydroxy-benzaldehyde (Fig. 3.60). Finally, Reimer synthesized vanillin from guaiacol and thus proved its chemical structure. For many years, the most important source of vanillin was eugenol, from which it was obtained by oxidation. Today, the major portion of commercial vanillin is obtained by processing waste sulfite liquors, the rest through fully synthetic processes starting from guaiacol [21 ]. 

Eugenia ccayopyllata that is known to be the natural source of eugenol - phenolic compound that might be an inhibitor of chain radical reactions. Different samples of caryopl ene could differ in the content of the phenolic microimpurity (eugenol) and, therefore, posses different activity. All these facts have lead us to the suggestion that the epoxidation process in 02/IBA/CoNaY system has chain radical nature, and negligible impurities can dramatically influence on the reaction rate. 

In a non-optimized biotransformation using growing cells in an aqueous mineral salts medium containing gluconate as a source of carbon and energy and 6.5 mM eugenol, vanillin accumulated up to a concentration of 2.9 mM, corresponding to a... 

Eugenol. 2-Methoxy-4-(2-propenyi)phenol 4-at-lyl-2-methoxyphenol altylguaiacol eugenic acid caryophyl-lic acid. C H, 0, mol wt 164.20. C 73,14%, H 7,37%, O 19.49%. Obtained from many natural sources Beilstein voi. 6, 961, Prepn Claisen, Ann. 418, 113 (1919) from oil o cloves Waterman, Priester, f ec, Trav. Chim. 48, 1272... 

Eugenol is a phenylpropanoid with a free hydroxyl group. It is widely distributed in plants, one of the main sources being clove oil from flower buds of Syzygium aromaticum (Myrtaceae). It is a major constituent of bay leaf, nutmeg and allspice. 

The Australian myrtle leaf (Backhousia myrtifolia) is a rich source of phenylpropanoid essential oils, particularly elemicin and methyl eugenol (Brophy et al. 1995). 

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