EYEBRIGHT Euphrasia officinalis L. (Scrophulariaceae)

HERBAL

MEDICINE

PLANT

EYEBRIGHT

Euphrasia officinalis L. (Scrophulariaceae)

by

RETTODWIKART THENU

EYEBRIGHT

Euphrasia officinalis L. (Scrophulariaceae)

SUMMARY AND PHARMACEUTICAL COMMENT

Limited information is available regarding the constituents of eyebright and it is unclear which Euphrasia species is most commonly utilised. In addition, eyebright is also used as a common name for plants other than Euphrasia species. Little scientific information was found to justify the reputed herbal uses, although tannin constituents would provide an astringent effect. The use of home-made preparations for ophthalmic purposes should be avoided. Little is known regarding the toxicity of eyebright and, in view of the reported presence of unidentified alkaloids, it should be used with caution and excessive doses and prolonged treatment should be avoided.

SPECIES (FAMILY)

Euphrasia officinalis L. (Scrophulariaceae)

Other Euphrasia species, including E. rostkoviana Hayne, are used and these may differ in their chemical constituents. The genus Euphrasia consists of around 450 Euphrasia species and their wild hybrids and these are difficult to identify botanically.

SYNONYM(S)

Euphrasia

PRODUCT AVAILABILITY

Internal: Fresh herb, infusion, tablets, tincture; topical: infusion, fl uid extract, fresh herb, lotion, poultice

Plant Part Used: Flowering plant

PHARMACOPOEIAL AND OTHER MONOGRAPHS

BHP 1983(G7)

Martindale 35th edition(G85)

LEGAL CATEGORY (LICENSED PRODUCTS)

Eyebright is not included in the GSL.(G37)

CONSTITUENTS

The following is compiled from several sources, including General References G2, G40 and G75. Unless otherwise stated, constituents listed are for E. officinalis.

Acids Caffeic acid, ferulic acid.(1)

Alkaloids Unidentified tertiary alkaloids, choline, steam volatile bases.(1)

Amino acids Glycine, leucine and valine.

Flavonoids Four compounds (unidentified). Quercetin and rutin stated to be absent.(1) Quercetin, quercitrin and rutin have been documented for E. rostkoviana.

Iridoids Aucubin 0.05%. Additional glycosides have been reported for related Euphrasia species including catalpol, euphroside, eurostoside, geniposide, ixoroside and mussaenoside for E. rostkoviana.(2–5)

Phenethyl glycosides Dehydroconiferyl alcohol-4-b-D-glucoside( 3) and eukovoside (3,4-dihydroxy-4 phenethyl-O-a-L-rhamnoside( 13)-4-O-isoferuoyl-b-D- glucoside)(4) from E. rostkoviana.

Tannins About 12%. Condensed and hydrolysable; gallic acid is among the hydrolysis products.(1)

Volatile oils About 0.2%. Seven major and numerous minor components, mainly unidentified; four of the major compounds are thought to be aldehydes or ketones.(1)

Other constituents Bitter principle, b-carotene, phytosterols (e.g. b-sitosterol, stigmasterol),(1) resin, carbohydrates (e.g. arabinose, glucose, galactose) and vitamin C.

USES

FOOD USE

Eyebright is listed by the Council of Europe as a natural source of food flavouring (category N3). This category indicates that eyebright can be added to foodstuffs in the traditionally accepted manner, although there is insufficient information available for an adequate assessment of potential toxicity.(G16)

HERBAL USE

Eyebright is stated to possess anticatarrhal, astringent and antiinflammatory properties. Traditionally it has been used for nasal catarrh, sinusitis and specifically for conjunctivitis when applied locally as an eye lotion.(G2, G7, G64)

Figure 1.  Eyebright (Euphrasia officinalis).

DOSAGE

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

·         Dried herb 2–4 g as an infusion three times daily.(G7)

·         Liquid extract 2–4mL (1 : 1 in 25% alcohol) three times daily.(G7)

·         Tincture 2–6 mL (1 : 5 in 45% alcohol) three times daily.(G7)

Dosages

Ophthalmic

·         Adult topical decoction: 5-10 drops (2%) in eye to cleanse, tid-qid

·         Adult topical infusion: soak a towelette in infusion and apply over eye area prn

Other

·         Adult PO dried herb: 2-4 g tid as an infusion (Mills, Bone, 2000)

·         Adult PO fl uid extract: 2-4 ml (1:2 dilution) tid (Mills, Bone, 2000)

·         Adult PO tea: cover 2-3 g fi nely cut herb with boiling water and let stand 10-15 min, strain, drink

·         Adult PO tincture: 2-6 ml (1:5 dilution) tid (Mills, Bone, 2000)

PHARMACOLOGICAL ACTIONS

In Vitro And Animal Studies

None documented for eyebright. Caffeic acid is bacteriostatic,(1) and a purgative action in mice has been documented for iridoid glycosides.(6) The purgative action of aucubin is approximately 0.05 times the potency of sennosides, with onset of diarrhoea stated to occur more than six hours after aucubin administration.( 6) Tannins are known to possess astringent properties.

Clinical Studies

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

SIDE-EFFECTS, TOXICITY

There is a lack of clinical safety and toxicity data for eyebright and further investigation of these aspects is required. Information in older literature states that doses of as little as 10–60 drops of eyebright tincture could lead to adverse effects, including mental confusion,(G22) although this requires confirmation.

SIDE EFFECTS/ADVERSE REACTIONS

CNS: Confusion, headache, weakness, fatigue

EENT: Nasal congestion, blurred vision, photophobia, lid swelling, sneezing

INTEG: Hypersensitivity reactions

Interactions

Drug

Antidiabetics: May increase the effects of antidiabetics (theoretical) when Euphrasia offi cinalis is taken internally.

Iron salts: Eyebright tea may interfere with the absorption of iron salts; separate by at least 2 hours.

Figure 2. Eyebright – dried drug substance (herb).

CONTRA-INDICATIONS, WARNINGS

The use of eyebright for ophthalmic application has been discouraged.(G60)

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

Pregnancy and lactation The safety of eyebright has not been established. In view of the lack of pharmacological and toxicity data, the use of eyebright during pregnancy and lactation should be avoided.

CONTRAINDICATIONS

Pregnancy category is 3; breastfeeding category is 2A.

Eyebright should not be used by persons with hypersensitivity to this herb.

CLIENT CONSIDERATIONS

Assess

·         Assess the reason the client is using eyebright.

·         Assess for hypersensitivity reactions. If present, discontinue use of eyebright and administer an antihistamine or other appropriate therapy.

·         Assess the eye for swelling, lacrimation, redness, and exudate.

Administer

·         Instruct the client to apply eyebright externally as a compress or drops.

·         Instruct the client to store eyebright products in a cool, dry place, away from heat and moisture.

TEACH CLIENT/FAMILY

·         Inform the client that pregnancy is category 3 and breastfeeding is category 2A.

·         If an eye infection is present, instruct the client to wash hands frequently and not to share towels with others.

·         Instruct the client on the correct method for washing the eye with solution.

PREPARATIONS

Proprietary single-ingredient preparations

UK: Snore Calm.

Proprietary multi-ingredient preparations

Australia: Euphrasia Complex; Euphrasia Compound; Eye Health Herbal Plus Formula 4; Lifesystem Herbal Plus Formula 5 Eye Relief; Sambucus Complex. Italy: Eulux; Iridil. Malaysia: Eyebright Plus. Switzerland: Collypan; Oculosan; Tendro. UK: Se-Power; Summertime Tea Blend; Vital Eyes. USA: Eye Support Formula Herbal Blend. 

REFERENCE

 Barnes, J., Anderson, L. A., and Phillipson, J. D. 2007. Herbal Medicines Third Edition. Pharmaceutical Press. Auckland and London.

Duke, J. A. with Mary Jo Bogenschutz-Godwin, Judi duCellier, Peggy-Ann K. Duke. 2002. Handbook of Medicinal Herbs 2nd Ed. CRC Press LLC. USA.

Linda S-Roth. 2010. Mosby’s Handbook Of Herbs & Natural Supplements, Fourth Edition. Mosby Elsevier. USA.