Eugenyl Acetate, 498,

The main component of all clove oils is eugenol (up to 80%, sometimes more), which is responsible for their odor and antiseptic properties. Other major constituents are eugenyl acetate and caryophyllene [442-449]. Clove bud oil has a higher acetate content and a more delicate odor than the other oils, therefore it is much more expensive. Leaf oil is produced and used in the largest quantities. The composition of clove stem oil resembles that of bud oil but with a lower content of eugenyl acetate. 

Clove Syzygium aromaticum (Eugenia caryophyllus) (Myrtaceae) dried flower buds 15-20 eugenol (75-90) eugenyl acetate (10-15) P-caryophyllene (3) flavour, aromatherapy, antiseptic... 

The minor constituents like methyl amyl ketone, methylsalicylate, etc., are responsible for the characteristic pleasant odour of cloves. The oil is dominated by eugenol (70-85%), eugenyl acetate (15%) and /Tcaryophyllene (5-12%), which together make up 99% of the oil. /3-Caryophyllene, which was earlier thought of as an artefact of distillation, was first reported as a constituent of the bud oil by Walter (1972). 

The oils from the leaves and bark of C. zeylanicum from Madagascar contained cinnamaldehyde and camphor as the major components (Chalchat and Valade, 2000). The leaf oil from Little Andaman Island contained 47 constituents, representing 99.96% of the oil. The main constituents were eugenol (76.60%), linalool (8.5%), piperitone (3.31%), eugenyl acetate (2.74%) and cinnamyl acetate (2.59%) (Raina et al., 2001). 

The leaves harvested in summer gave the highest oil recovery (1.84%) and eugenol content (83%), whereas in the rainy season, the concentration of esters, namely, eugenyl acetate and benzyl benzoate, were comparatively higher (Kaul et al., 1996). Cinnamon leaves affected by leaf spot disease yielded less oil (1.2%), but the eugenol content was unaffected (Kaul et al., 1998). Rao et al. (2006) reported that the essential oil content (1.9-2.2%) and the chemical composition of C. verum leaves were not affected by storage up to a period of 15 months. 

Pino et al. (2001) identified 36 compounds of the volatile oil of clove buds. The major components of the bud oil were eugenol (69.8%), (3-caryophyllene (13%) and eugenyl acetate (16.1%) (Pino et al., 2001). The chief components of clove oil from various regions are listed in Table 8.5, which indicates quantitative variations of the individual components of the oil from different regions. Zachariah et al. (2005) reported that clove buds from India contained 12.9-18.5% oil, of which 44-55% was eugenol, whereas the pedicels contained 3.0-7.7% oil with 60.0-72.4% eugenol. 

The essential oil content during the different stages of leaf growth revealed that the eugenol content in the leaves increased from 38.3 to 95.2% with maturity, while the contents of eugenyl acetate (51.2 to 1.5%) and caryophyllene (6.3 to 0.2%) decreased (Gopalakrishnan and Narayanan, 1988). Clove bud and leaf oil contain various classes of compounds, e.g. monoterpenes, sesquiterpenes, aldehydes and ketones (Vernin et al., 1994), which are indicated in Table 8.8. 

Clove Eugenia caryophyllata Eugenol, (-)-caryophyllene (87), eugenyl acetate (88) 95,101... 

SYNS ACETEUGENOL 1-ACETOXY-2-METHOXY-4-ALLYLBENZENE ACETYLEUGENOL 4-ALLYL-2-METHOXYPHENOL ACETATE 1,3,4-EUGENOL ACETATE EUGENYL ACETATE FEMA No. 2469... 

Composition 75-85% eugenol, 8-15% eugenyl acetate and 2-7% caryophyllene (ISO [66]). Further constituents are humulene, a-copaene and a-cubebene. Heptanol-2, nonanol-2 and the corresponding ketones are trace components which are responsible for the fruity note (especially strong in oleoresins). The content of eugenyl acetate is responsible for the quality of the oil when compared to leaf and stem oil. Its content in oleoresins is even higher and these, therefore, represent the sensory qualities of the drug better than the oil [67], For further constituents see [68, 69, 70]. 

Composition 1,8-Cineole (app. 50%), a-terpineol (5%), camphor (1%), as well as mono- and sesquiterpene hydrocarbons [106]. The essential oil of Alpinia galanga has been analysed by Scheffer et al. [107], and 1,8-cineole (47%), terpinene-4-ol (6%), and a-terpineol (6%) were found to be the main constiments. Furthermore, De Footer et al. identified methyl eugenol, eugenyl acetate, chavicol and, for the first time in nature, chavicyl acetate as important components [108]. For the latest literature see [109]. 

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