シネオール

外観

無色～わずかにうすい黄色, 澄明の液体

定義

本品は、次の化学式で表されるテルペン誘導体である。

溶解性

水に難溶, エタノール, 有機溶媒に易溶。エタノール、アセトン及びクロロホルムに極めて溶けやすく、水にほとんど溶けない。

解説

シネオール，1,3,3-trimethyl-2-oxobicyclo[2.2.2]octane．C10H18O(154.25)．p-メンタン炭素骨格をもつモノテルペンオキシド．ユーカリ油など多くの植物精油中に含まれている1,8-シネオールと，ヒッチョウカPiper cubebaの果実に含まれている1,4-シネオールとがあるが，普通，前者をさす．1,8-シネオールを加水分解するとトランス形テルペンを生じる．1,8-シネオールは融点1 ℃，沸点174 ℃．n_D²⁰1.455．1,4-シネオールは沸点172 ℃．d²⁰0.9．n_D²⁰1.447．二環状モノテルペンの一つ。フトモモ科のユーカリノキの葉を水蒸気蒸留して得られる精油であるユーカリ油の主成分。ユーカリプトールeucalyptolともいう。天然に広く存在し、樟脳(しょうのう)、ハッカに似た清涼な香気を有する無色の液体。シネオールを含有する精油を分留して沸点170～180℃の留分をとり、ドライアイスなどの寒剤で冷却し、析出する結晶を分離して製品とする。人造ユーカリ油、鎮咳(ちんがい)剤、殺菌防臭剤として用いられる。

用途

香水、芳香剤

用途

香料、医薬原料、清涼剤原料、バイオマスエネルギー研究用。

化粧品の成分用途

変性剤、口腔衛生剤、皮膚保護剤、香料

効能

香料

化学的特性

1,8-Cineole occurs in many terpene-containing essential oils, sometimes as the main component. For example, eucalyptus oils contain up to 85% 1,8-cineole and laurel leaf oil contains up to 70%. It is a colorless liquid with a characteristic odor, slightly reminiscent of camphor. 1,8-Cineole is one of the few fragrance materials that is obtained exclusively by isolation from essential oils, especially eucalyptus oils. Technical-grade 1,8- cineole with a purity of 99.6–99.8% is produced in large quantities by fractional distillation of Eucalyptus globulus oil. A product essentially free from other products can be obtained by crystallization of cineole-rich eucalyptus oil fractions

天然物の起源

Its name is derived from its presence in the essential oils of Eucalyptus globulus and Melaleuca leucadendron L. (essential oil of cajeput). It was originally identified in the essential oil of Artemisia maritime and subsequently in a large number (approx. 270) of other essential oils: rosemary, laurel leaves, clary sage, myrrh, cardamom, star anise, camphor, lavender, peppermint, Litsea guatemalensis, Luvunga scadens Roxb., Achillea micrantha and Salvia triloba. The essential oil of Eucalyptus polibrac tea has been reported to contain up to 91% eucalyptol. Also reported found in citrus oils and juices, guava, papaya, cinnamon bark, root and leaf, ginger, corn mint oil, spearmint, nutmeg, pepper, Thymus zygis, cardamom, cranberry, laurel, pepper, sweet marjoram, coriander, Spanish origanum, Ocimum basilicum, curcuma, sage, laurel, sweet and bitter fennel, myrtle leaf and berry, pimento and calamus.

使用

1,8-Cineol is the chief constituent of oil of eucalyptus. Used as pharmaceutic aid (flavor).

製造方法

By fractional distillation (170 to 180°C) from those essential oils containing high levels of eucalyptol, such as Eucalyptus globulus (approx. 60%), and subsequent separation of the product by congealing the distillate.

一般的な説明

Colorless liquid with a camphor-like odor. Spicy cooling taste.

空気と水の反応

Highly flammable. Insoluble in water.

反応プロフィール

Cineole will react with acids and bases.

火災危険

Flash point data for Cineole are not available but Cineole is probably combustible.

抗がん研究

A statistically significant reduction of cell proliferation was observed compared tothe control cells when tested on RKO cells and human colon cancer cell linesHCT116 injected into the SCID mice. The 1,8-cineole induced apoptosis by inactivatingsurviving and Akt, activating p38, inducing PARP, and cleaving caspase-3(Rodd et al. 2015).

毒性学

Eucalyptol, a colourless organic compound, is a monoterpenoid and an ether. Among its various uses, eucalyptol is predominantly used as an insecticide and in fragrances (Klocke et al. 1987). The ques- tion of whether eucalyptol could potentiate toxicity has been assessed because of its widespread use in households. When Kunming mice received feed with a high dose of eucalyptol, liver and kidney tissue demonstrated vacuolar and granular degeneration (Xu et al. 2014). When the animals were fed with a subacute dose of eucalyptol, no discernible difference in body weight was observed (Xu et al. 2014). Eucalyptol’s safety profile has been assessed. Fatality after ingestion of eucalyptol oil has been reported; the approximate lethal dose of eucalyptol in the human is between 0.05 and 0.5 mL/kg of body weight (Hindle 1994). When male rats received eucalyptol, eosinophilic protein droplets accumulated in a dose- dependent fashion (Kristiansen and Madsen 1995). However, in a study of mutagenicity using CHO cells, eucalyptol did not induce mutagenicity as evidenced in the sister chromatid exchange assay (Galloway et al. 1987). Likewise, eucalyptol did not induce carcinogenicity in pathogen-free CFLP mice (Roe et al. 1979).

代謝

Eucalyptol undergoes oxidation in vivo with the formation of hydroxy cineole, which is excreted as hydroxycineoleglucuronic acid (Williams, 1959).

純化方法

Purify 1,8-cineol by dilution with an equal volume of pet ether, then saturate with dry HBr. The precipitate is filtered off, washed with small volumes of pet ether, then cineole is regenerated by stirring the crystals with H2O. It can also be purified via its o-cresol or resorcinol addition compounds. Store it over Na until required. Purify it also by fractional distillation. It is insoluble in H2O but soluble in organic solvents. [IR: Kome et al. Nippon Kagaku Zasshi [J Chem Soc Japan (Pure Chem Sect)] 80 66 1959, Chem Abstr 603 1961, Beilstein 17 II 32, 17/1 V 273.]