Eucalyptol: One of the two most important monoterpene oxides, the other is Ascaridole, Eucalyptol, more widely known as Cineol is one of the most widely distributed constituents amongst plants as an oxidised product of monoterpenes.

Eucalyptol is a expectorant widely used in commercial cough lozenges. It has a reputation as a skin irritant amongst many practitioners but recent tests have failed to confirm this.

Cineole: One of the two most important Monoterpene Oxides, the other is Ascaridole, Cineole is one of the most widely distributed constituents amongst plants as an oxidised product of monoterpenes. Cineole is often also called Eucalyptol, named so because it is the major component of Eucalyptus oil.

Cineole is a expectorant widely used in commercial cough lozenges. It has a reputation as a skin irritant amongst many practitioners but recent tests have failed to confirm this.

PubChem CID: 2758

Chemical Names: Eucalyptol; Cineole; 1,8-Cineole; Cajeputol; 1,8-Epoxy-p-menthane; 1,8-Cineol; More...

Molecular Formula: C10H18O

Molecular Weight: 154.24932 g/mol



Safety Summary: Laboratory Chemical Safety Summary (LCSS)

Eucalyptol is a natural organic compound which is a colorless liquid. It is a cyclic ether and a monoterpenoid. Eucalyptol is an ingredient in many brands of mouthwash and cough suppressant. It controls airway mucus hypersecretion and asthma via anti-inflammatory cytokine inhibition. Eucalyptol is an effective treatment for nonpurulent rhinosinusitis. Eucalyptol reduces inflammation and pain when applied topically. It kills leukaemia cells in vitro. (from DrugBank)

PHYSICAL DESCRIPTION: Colorless liquid with a camphor-like odor. Spicy cooling taste. (NTP, 1992)

Eucalyptol - Eucalyptol is widely distributed in plants. In the list the main sources are: Achillea millefolium, Alpinia galanga, Artemisia abrotanum, Artemisia absinthium, Artemisia vallesiaca, Artemisia vulgaris, Crocus sativus, Cuminum cyminum, Cupressus sempervirens, Curcuma longa, Cymbopogon citratus, Cymbopogon flexuosus, Cymbopogon laniger, Cymbopogon martini, Cymbopogon nardus, Cymbopogon schoenanthus, Cymbopogon winterianus, Elettaria cardamomum, Eucalyptus citriodora, Eucalyptus globulus, Eucalyptus

odorata, Eucalyptus smithii, Hyptis suaveolens, Laurus nobilis, Melissa officinalis, Mentha piperita, Myristica fragrans, Rosmarinus officinalis, Satureja montana, Thymus serpillum, Thymus vulgaris.

In some plants eucalyptol is the primary constituent of essential oil (Eucalyptus, Rosmarinus, Elettaria) and is also present in considerable quantities in others too. Eucalyptol can be hazardous via ingestion, skin contact or inhalation, and it can have acute health effects on behaviour, respiratory tract and nervous system.

The available toxicological studies relating to eucalyptol are limited and inadequate to derive a TMDI: eucalyptol has been classified as a class II activeprinciple. The estimated daily intake of eucalyptolfrom foods and beverages of approximately 4.5 mg per person is a factor of 1000 below the lowest exposure of eucalyptol by ingestion of eucalyptus oil reported to result in severe intoxications or death inhumans (2.45-6.25 g eucalyptol per person) [16].

For a more precise risk characterisation to set an MDI, further data on exposure and toxicity would be needed.

The general limit in food and beverages is 10 mg/kg with some exceptions [17].

16. Council of Europe, Committee of Experts on Flavouring Substances - Active principles (constituents of toxicologicalconcern) contained in natural sources of flavourings. Health Protection of the Consumer Series, Strasbourg: Council of

Eur ope Press; October 2005. Available from: t/e/social_cohesion/soc sp/public_health/flavouring_substances/Active%20principles.pdf.

17. Council of Europe, Committee of Experts on FlavouringSubstances. Natural sources of flavourings. Report No. 3. Belgium: Council of Europe Publishing; 2008.

Respir Med. 2003 Mar;97(3):250-6.

Anti-inflammatory activity of 1.8-cineol (eucalyptol) in bronchial asthma: a double-blind placebo-controlled trial.

Juergens UR1, Dethlefsen U, Steinkamp G, Gillissen A, Repges R, Vetter H.

Airway hypersecretion is mediated by increased release of inflammatory mediators and can be improved by inhibition of mediator production. We have recently reported that 1.8-cineol (eucalyptol) which is known as the major monoterpene of eucalyptus oil suppressed arachidonic acid metabolism and cytokine production in human monocytes. Therefore, the aim of this study was to evaluate the anti-inflammatory efficacy of 1.8-cineol by determining its prednisolone equivalent potency in patients with severe asthma. Thirty-two patients with steroid-dependent bronchial asthma were enrolled in a double-blind, placebo-controlled trial. After determining the effective oral steroid dosage during a 2 month run-in phase, subjects were randomly allocated to receive either 200 mg 1.8-cineol t. i.d. or placebo in small gut soluble capsules for 12 weeks. Oral glucocorticosteroids were reduced by 2.5 mg increments every 3 weeks. The primary end point of this investigation was to establish the oral glucocorticosteroid-sparing capacity of 1.8-cineol in severe asthma. Reductions in daily prednisolone dosage of 36% with active treatment (range 2.5-10 mg, mean: 3.75 mg) vs. a decrease of only 7% (2.5-5 mg, mean: 0.91 mg) in the placebo group (P = 0.006) were tolerated. Twelve of 16 cineol vs. four out of 16 placebo patients achieved a reduction of oral steroids (P = 0.012). Long-term systemic therapy with 1.8-cineol has asignificant steroid-saving effect in steroid-depending asthma. This is the first evidence suggesting an anti-inflammatory activity of the monoterpene 1.8-cineol in asthma and a new rational for its use as mucolytic agent in upper and lower airway diseases.

Acta Pharmacologica Sinica (2007) 28, 908–912; doi:10.1111/j.1745-7254.2007.00555.x Immunopharmacology

Inhibitory effect of 1,8-cineol (eucalyptol) on Egr-1 expression in lipopolysaccharide-stimulated THP-1 cells

Project supported by the National Natural Science Foundation of China (No 30670930), and the Science and Technology Department of Zhejiang Province, China (No 2004C23011).

Aim: To study the effects of 1,8-cineol (eucalyptol) on the expression of early growth response factor-1 (Egr-1) and NF-kappaB in the human monocyte THP-1 cell line stimulated by lipopolysaccharide (LPS).

Methods: The THP-1 cells were incubated with serial doses of 1,8-cineol (1, 10, and 100 mg/L, 30 min) before being stimulated with LPS (1 mg/L, 30 min). The localization of Egr-1 in the THP-1 cells was detected by immunofluorescence and a laser scanning confocal microscope. The expression of Egr-1 in the nuclei and whole cell, and NF-kappaB in the nuclei, were measured by Western blot analysis.

Results: When stimulated by LPS, the FITC-labeled Egr-1 was detected mainly in the nuclei. Moreover, the expression of Egr-1 in the whole cell increased markedly compared with the control cells. 1,8-Cineol pretreatment decreased the expression of Egr-1 in both the nuclei and whole cell of the LPS-stimulated THP-1 cells, and this effect was concentration-dependent, but there was no reaction on the expression of NF-kappaB in the nuclei protein in the LPS-stimulated THP-1 cells.

Conclusion: In a concentration-dependent manner, 1,8-Cineol reduces LPS-induced Egr-1 expression in nuclei and in whole cell of THP-1 cells, but shows no effect on NF-kappaB expression.