Eucalyptus

Summary and Pharmaceutical Comment

Eucalyptus is characterised by its volatile oil components. Antiseptic and expectorant properties have been attributed to the oil, in particular to the principal component eucalyptol. The undiluted oil is toxic if taken internally. Essential oils should not be applied to the skin unless they are diluted with a carrier vegetable oil.

Species (Family)

Eucalyptus globulus Labill. (Myrtaceae)

Synonym(s)

E. maidenii subsp. globulus (Labill.) Kirkp., Fevertree, Gum Tree, Tasmanian Bluegum

Part(s) Used

Leaf

Pharmacopoeial and Other Monographs

BHP 1996(G9)

BP 2007(G84)

Complete German Commission E(G3)

Martindale 35th edition(G85)

Ph Eur 2007(G81)

Legal Category (Licensed Products)

GSL(G37)

Constituents

The following is compiled from several sources, including General References G2 and G75.

Flavonoids Eucalyptrin, hyperoside, quercetin, quercitrin and rutin.

Volatile oils 0.5–3.5%. Eucalyptol (cineole) 70–85%. Others include monoterpenes (e.g. a-pinene, b-pinene, d-limonene, p- cymene, a-phellandrene, camphene, g-terpinene) and sesquiterpenes (e.g. aromadendrene, alloaromadendrene, globulol, epiglobulol, ledol, viridiflorol), aldehydes (e.g. myrtenal) and ketones (e.g. carvone, pinocarvone).

Figure 1 Selected constituents of eucalyptus.

Other constituents Tannins and associated acids (e.g. gallic acid, protocatechuic acid), caffeic acid, ferulic acids, gentisic acid, resins and waxes.

E

Food Use

Eucalyptus is listed by the Council of Europe as a natural source of food flavouring (leaves, flowers and preparations: category N4, with limits on eucalyptol) (see Appendix 3).(G17) Both eucalyptus

and eucalyptol (cineole) are used as flavouring agents in many food products.(G41) Previously in the USA, eucalyptus was

approved for food use and eucalyptol was listed as a synthetic flavouring agent.(G41)

Herbal Use

Eucalyptus leaves and oil have been used as an antiseptic, febrifuge and expectorant.(G2, G41, G64)

Figure 2 Eucalyptus (Eucalyptus globulus).

Figure 3 Eucalyptus – dried drug substance (leaf).

248 Eucalyptus

Dosage

Dosages for oral (unless otherwise stated) administration (adults) for traditional uses recommended in older standard reference texts are given below.

Eucalyptol (cineole BPC 1973) 0.05–0.2 mL.

Eucalyptus Oil (BPC 1973) 0.05–0.2 mL.

Fluid extract 2–4 g.

Oil for local application 30 mL oil to 500 mL lukewarm water.

E

Pharmacological Actions

In vitro and animal studies

Hypoglycaemic activity in rabbits has been documented for a crude leaf extract rich in phenolic glycosides. Purification of the extract resulted in a loss of activity.(G41) Expectorant and antibacterial activities have been reported for eucalyptus oil and for eucalyptol.(G41) Various Eucalyptus species have been shown to possess antibacterial activity against both Gram-positive and Gram-negative organisms. Gram-positive organisms were found to be the most sensitive, particularly Bacillus subtilis and

Micrococcus glutamious.(1)

In vitro antiviral activity against influenza type A has been documented for quercitrin and hyperoside.(G41)

Clinical studies

There is a lack of clinical research assessing the effects of eucalyptus and rigorous randomised controlled clinical trials are required.

Eucalyptus oil has been taken orally for catarrh, used as an inhalation and applied as a rubefacient.(G45) A plant preparation

containing tinctures of various herbs including eucalyptus has been used in the treatment of chronic suppurative otitis.(2)

Side-effects, Toxicity

Externally, eucalyptus oil is stated to be generally non-toxic, nonsensitising and non-phototoxic.(G58) Undiluted eucalyptus oil is toxic and should not be taken internally. A dose of 3.5 mL has proved fatal.(G45) Symptoms of poisoning with eucalyptus oil include epigastric burning, nausea and vomiting, dizziness, muscular weakness, miosis, a feeling of suffocation, cyanosis, delirium and convulsions.

Contra-indications, Warnings

Eucalyptus oil should be diluted before internal or external use.

Drug interactions None documented. However, the potential for preparations of eucalyptus to interact with other medicines administered concurrently, particularly those with similar or opposing effects, should be considered. There is limited evidence from preclinical studies that constituents of eucalyptus have hypoglycaemic activity.

Pregnancy and lactation Eucalyptus oil should not be taken internally during pregnancy or lactation.

References

1Kumar A et al. Antibacterial properties of some Eucalpytus oils. Fitoterapia 1988; 59: 141–144.

2Shaparenko BA et al. On use of medicinal plants for treatment of patients with chronic suppurative otitis. Zh Ushn Gorl Bolezn 1979; 39: 48–51.

Summary and Pharmaceutical Comment

There is little published information concerning euphorbia, although documented actions observed in animals support the traditional herbal uses. There is a lack of information concerning toxicity and excessive or prolonged ingestion should be avoided.

Species (Family)

Chamaesyce hirta (L.) Millsp. (Euphorbiaceae)

Synonym(s)

Euphorbia capitata Lam., E. hirta L., Pillbearing Spurge, Snakeweed

Part(s) Used

Herb

Pharmacopoeial and Other Monographs

BHP 1983(G7)

Martindale 35th edition(G85)

Legal Category (Licensed Products)

GSL(G37)

Constituents

The following is compiled from several sources, including General References G41 and G48.

Flavonoids Leucocyanidin, quercetin, quercitrin and xanthorhamnin.

Terpenoids a- and b-Amyrin, taraxerol and esters, friedelin; campesterol, sitosterol and stigmasterol (sterols).

Other constituents Choline, alkanes, inositol, phenolic acids (e.g. ellagic, gallic, shikimic), sugars and resins.

Food Use

Euphorbia is not used in foods.

Herbal Use

Euphorbia is stated to be used for respiratory disorders, such as

asthma, bronchitis, catarrh and laryngeal spasm. It has also been used for intestinal amoebiasis.(G7, G64)

Dosage

Dosages for oral administration (adults) for traditional uses recommended in older standard reference texts are given below.

Herb 120–300 mg as an infusion.(G7)

Liquid Extract of Euphorbia (BPC 1949) 0.12–0.3 mL.

Euphorbia Tincture (BPC 1923) 0.6–2.0 mL.

Pharmacological Actions

Figure 1 Selected constituents of euphorbia.

Figure 2 Euphorbia (Chamaesyce hirta).

250 Euphorbia

E

Figure 3 Euphorbia – dried drug substance (herb).

and contracting activities have been exhibited by euphorbia in vitro (guinea-pig ileum) and have been attributed to shikimic acid and to choline, respectively.(1)

In vivo antitumour activities have been documented for euphorbia.(G41)

Antibacterial activity in vitro versus both Gram-positive and Gram-negative bacteria has been documented for euphorbia.(2) Stem extracts were slightly more active than leaf extracts. In vitro amoebicidal activity versus Entamoeba histolytica has been reported for a euphorbia decoction.(3)

Clinical studies

There is a lack of clinical research assessing the effects of euphorbia and rigorous randomised controlled clinical trials are required.

Side-effects, Toxicity

None documented. However, there is a lack of clinical safety and toxicity data for euphorbia and further investigation of these aspects is required. Carcinogenic properties in mice have been

reported for shikimic acid, although no mutagenic activity was observed in the Ames assay.(G41)

Contra-indications, Warnings

None documented.

Drug interactions None documented. However, the potential for preparations of euphorbia to interact with other medicines administered concurrently, particularly those with similar or opposing effects, should be considered.

Pregnancy and lactation The safety of euphorbia has not been established. Euphorbia has been reported to cause both contraction and relaxation of smooth muscle. In view of the lack of pharmacological and toxicity data, the use of euphorbia during pregnancy and lactation should be avoided.

Preparations

Proprietary single-ingredient preparations

India: Thankgod.

Proprietary multi-ingredient preparations

Australia: Asa Tones; Euphorbia Complex; Procold; Sambucus Complex. Canada: Sirop Cocillana Codeine. Hong Kong: Cocillana Christo; Cocillana Compound; Cocillana Compound; Cocillana Compound; Mefedra-N. UK: Antibron.

References

1 El-Naggar L et al. A note on the isolation and identification of two pharmacologically active constituents of Euphorbia pilulifera. Lloydia 1978; 41: 73–75.

2 Ajao AO et al. Antibacterial activity of Euphorbia hirta. Fitoterapia 1985; 56: 165–167.

3Basit N et al. In vitro effect of extracts of Euphorbia hirta Linn. on

Entamoeba histolytica. Riv Parasitol 1977; 38: 259–262.