Expand Document  |  Expand Chapter  |  Full TOC  |  Printable HTML version
WHO Monographs on Selected Medicinal Plants - Volume 1
(1999; 295 pages) View the PDF document
Table of Contents
View the documentAcknowledgements
View the documentIntroduction
View the documentBulbus Allii Cepae
View the documentBulbus Allii Sativi
View the documentAloe
View the documentAloe Vera Gel
View the documentRadix Astragali
View the documentFructus Bruceae
View the documentRadix Bupleuri
View the documentHerba Centellae
View the documentFlos Chamomillae
View the documentCortex Cinnamomi
View the documentRhizoma Coptidis
View the documentRhizoma Curcumae Longae
View the documentRadix Echinaceae
View the documentHerba Echinaceae Purpureae
View the documentHerba Ephedrae
View the documentFolium Ginkgo
View the documentRadix Ginseng
View the documentRadix Glycyrrhizae
View the documentRadix Paeoniae
View the documentSemen Plantaginis
View the documentRadix Platycodi
View the documentRadix Rauwolfiae
View the documentRhizoma Rhei
View the documentFolium Sennae
View the documentFructus Sennae
View the documentHerba Thymi
View the documentRadix Valerianae
View the documentRhizoma Zingiberis
View the documentAnnex. Participants in the WHO Consultation on Selected Medicinal Plants
 

Herba Ephedrae

Definition

Herba Ephedrae consists of the dried stem or aerial part of Ephedra sinica Stapf or other ephedrine-containing Ephedra species (Ephedraceae) (1–5).

Synonyms

None.

Selected vernacular names

Amsania, budshur, chewa, Chinese ephedra, ephédra, horsetail, hum, huma, joint fir, khama, ma hoàng, ma huang, máhuáng, mao, maoh, maou, mao-kon, môc tac ma hoàng, mu-tsei-ma-huang, phok, san-ma-huang, shrubby, soma, song tuê ma hoàng, trung aa hoàng, tsao-ma-huang, tutgantha (4–10).

Description

Erect or prostrate, green, almost leafless shrub, 20–90 cm high. Branches erect, short, glaucous green, somewhat flat, 1.0–1.5 mm in diameter, with small sparse longitudinal striae, fasciated at the nodes; nodes reddish brown; internode 2.5– 5.5 cm long × 2 mm in diameter. Small triangular leaves opposite, reduced to scales, barely 2mm. Flowers in summer, unisexual, dioecious; male flowers pedunculate or nearly sessile, grouped in catkins composed of 4 to 8 pairs of flowers with about 8 anthers; female flowers biflorous, pedunculate with 3 or 4 pairs of bracts, the naked ovule surrounded by an urn-shaped perianth sheath, fruiting with often fleshy red succulent bracts, 2-seeded (4, 7, 11).

Plant material of interest: stem or aerial part

General appearance

Macroscopically, Herba Ephedrae occurs as thin cylindrical or ellipsoidal cylinder, 1–2 mm in diameter; 3.5–5.5cm in length of internode; light green to yellow-green; numerous parallel vertical furrows on the surface; scaly leaves at the node portion; leaves, 2–4 mm in length, light brown to brown in colour, usually opposite at every node, adhering at the base to form a tubular sheath around the stem. Under a magnifying glass, the transverse section of the stem appears as circle and ellipse, the outer portion greyish green to yellow-green in colour, and the centre filled with a red-purple substance or hollow. When fractured at an internode, the outer part is fibrous and easily split vertically (1).

Organoleptic properties

Odour, slight; taste, slightly bitter and astringent, giving a slight sensation of numbness on the tongue (1).

Microscopic characteristics

The epidermal cells of the stem are covered with a moderately thick granular cuticle; the cells are polygonal or subrectangular, axially elongated, having straight anticlinal walls. The stomata are few and are of the ranunculaceous type with lignified appendages. The epidermis of the scaly leaf is covered with smooth (upper) or warty (lower) cuticle and consists of subrectangular to polygonal cells, having straight or sometimes slightly beaded anticlinal walls; few stomata are present resembling those of stem. The epidermis of the apical and marginal regions of the scaly leaf shows short papillae-like outgrowths. Chlorenchymatous palisade-like cells form the outer zone of the cortex; rounded ordinary parenchymatous cells form the inner zone of the cortex. Cortical parenchyma and pith cells contain an amorphous reddish brown substance. Non-lignified or lignified hypodermal and pericyclic fibres, which have thick walls, bear slit-like pits and blunt, slightly tapering, occasionally forked ends. The vessels of the secondary xylem of the stem are lignified with bordered pits, having rounded or oval apertures. The vessel segments have much inclined end walls, bearing foraminate perforation plates. The tracheids and fibrous tracheids of secondary xylem of the stem are lignified with bordered pits having oval or slit-like apertures. The fibres of the scaly leaf are lignified, usually irregular or nearly straight, having moderately thick walls and blunt or sometimes forked ends. Few, small, rounded, simple and compound starch granules with indistinct hilum are present in cortical parenchyma, pith, and medullary ray cells. Few, small prisms of calcium oxalate are present in the cortical parenchyma (4).

Powdered plant material

Powdered Herba Ephedrae is greyish green. Numerous thick fragments of cutinized outer walls of epidermis vary from colourless to varying shades of brown or red; numerous fragments of sclerenchyma fibres with extremely thickened, non-lignified to lignified walls, narrow, frequently indistinct lumina and sharp pointed ends; fragments of vascular tissue showing tracheids with bordered pores and occasional spiral and pitted tracheae; numerous chlorenchyma cells; starch grains simple, spheroidal to occasionally ovate, averaging up to 1.2µm but occasionally up to 20µm; fragments of epidermis with rectangular cells and granular contents, some with sunken elliptical stomata; fragments of lignified or non-lignified pith parenchyma, some of the cells showing mucilage sacs; papillae; granules of calcium oxalate (4, 6).

Geographical distribution

Ephedra species are found in Afghanistan, Central America, China, India, regions of the Mediterranean, Mongolia, and North America (4, 612).

General identity tests

Macroscopic and microscopic examinations and microchemical tests for the presence of alkaloids with Mayer's reagent (15, 7).

Purity tests

Microbiology

The test for Salmonella spp. in Herba Ephedrae products should be negative. The maximum acceptable limits for other microorganisms are as follows (1315). For preparation of decoction: aerobic bacteria-not more than 107/g; fungi-not more than 105/g; Escherichia coli-not more than 102/g. Preparations for internal use: aerobic bacteria-not more than 105/g or ml; fungi-not more than 104/g or ml; enterobacteria and certain Gram-negative bacteria-not more than 103/g or ml; Escherichia coli-0/g or ml.

Foreign organic matter

Woody stems, not more than 5% (1). Does not contain stems of Equisetaceae or Gramineae plants, nor any other foreign matter (1).

Total ash

Not more than 9% (3).

Acid-insoluble ash

Not more than 2% (1).

Moisture

Not more than 9% (3).

Pesticide residues

To be established in accordance with national requirements. Normally, the maximum residue limit of aldrin and dieldrin for Herba Ephedrae is not more than 0.05 mg/kg (15). For other pesticides, see WHO guidelines on quality control methods for medicinal plants (13) and guidelines for predicting dietary intake of pesticide residues (16).

Heavy metals

Recommended lead and cadmium levels are no more than 10 and 0.3mg/kg, respectively, in the final dosage form of the plant material (13).

Radioactive residues

For analysis of strontium-90, iodine-131, caesium-134, caesium-137, and plutonium-239, see WHO guidelines on quality control methods for medicinal plants (13).

Other purity tests

Chemical, dilute ethanol-soluble extractive, and water-soluble extractive tests to be established in accordance with national requirements.

Chemical assays

Contains not less than 0.7% total alkaloids, calculated as ephedrine by highperformance liquid chromatography in the Japanese pharmacopoeia; or not less than 0.8% of total alkaloids, calculated as ephedrine in the Chinese pharmacopoeia (1, 2).

Thin-layer (17), gas–liquid (18) or high-performance liquid (19) chromatographic analysis for ephedrine and related alkaloids are available.

Major chemical constituents

The major active principle found in Herba Ephedrae is (-)-ephedrine in concentrations of 40–90% of the total alkaloid fraction, accompanied by (+)-pseudoephedrine. Other trace alkaloids in the alkaloid complex include (-)-norephedrine, (+)-norpseudoephedrine, (-)-methylephedrine and (+)- methylpseudoephedrine. The total alkaloid content can exceed 2% depending on the species (20). Not all Ephedra species contain ephedrine or alkaloids.

Dosage forms

Powdered plant material; extracts and other galenicals. Store in well closed, light-resistant containers.

Medicinal uses

Uses supported by clinical data

Herba Ephedrae preparations are used in the treatment of nasal congestion due to hay fever, allergic rhinitis, acute coryza, common cold, and sinusitis. The drug is further used as a bronchodilator in the treatment of bronchial asthma (4, 8, 10, 2123).

Uses described in pharmacopoeias and in traditional systems of medicine

Herba Ephedrae has been used for the treatment of urticaria, enuresis, narcolepsy, myasthenia gravis, and chronic postural hypotension (4, 8, 22, 23).

Uses described in folk medicine, not supported by experimental or clinical data

Other medical uses claimed for Herba Ephedrae preparations include its use as an analgesic, an antiviral agent, an antitussive and expectorant, an antibacterial, and an immune stimulant (10, 24, 25).

Clinical pharmacology

Two of the main active constituents of Herba Ephedrae, ephedrine and pseudoephedrine, are potent sympathomimetic drugs that stimulate α-, β1- and β2- adrenoceptors (22, 23). Pseudoephedrine's activity is similar to ephedrine, but its hypertensive effects and stimulation of the central nervous system are somewhat weaker. Part of ephedrine's peripheral action is due to the release of norepinephrine, but the drug also directly affects receptors. Tachyphylaxis develops to its peripheral actions, and rapidly repeated doses become less effective owing to the depletion of norepinephrine stores (22).

Cardiovascular actions

Like epinephrine (adrenaline), ephedrine excites the sympathetic nervous system, causing vasoconstriction and cardiac stimulation. Ephedrine differs from epinephrine in that it is orally active, has a much longer duration of action, and has more pronounced activity in the central nervous system, but is much less potent (22, 23). The drug stimulates the heart rate, as well as cardiac output, and increases peripheral resistance, thereby producing a lasting rise in blood pressure. The cardiovascular effects of ephedrine persist up to ten times as long as those of epinephrine (22). Ephedrine elevates both the systolic and diastolic pressures and pulse pressure. Renal and splanchnic blood flows are decreased, while coronary, cerebral, and muscle blood flows are increased (22, 23).

Bronchodilator and nasal decongestant

Ephedrine, like epinephrine, relaxes bronchial muscles and is a potent bronchodilator owing to its activation of the β-adrenoceptors in the lungs (22, 23). Bronchial muscle relaxation is less pronounced but more sustained with ephedrine than with epinephrine. As a consequence, ephedrine should be used only in patients with mild cases of acute asthma and in chronic cases that require maintenance medication. Ephedrine, like other sympathomimetics with α-receptor activity, causes vasoconstriction and blanching when applied topically to nasal and pharyngeal mucosal surfaces (22, 23). Continued, prolonged use of these preparations (>3 days) may cause rebound congestion and chronic rhinitis (26). Both ephedrine and pseudoephedrine are useful orally as nasal decongestants in cases of allergic rhinitis, but they may not be very effective for the treatment of nasal congestion due to colds.

Central nervous system

Mydriasis occurs after local application of ephedrine (3–5%) to the eye, but the effect lasts for only a few hours (22). Ephedrine is of little value as a mydriatic in the presence of inflammation. The activity of the smooth muscles of the uterus is usually reduced by ephedrine; consequently, the drug has been used to relieve the pain of dysmenorrhoea (22).

Ephedrine is a potent stimulator of the central nervous system. The effects of the drug may last for several hours after oral administration (23). Thus, preparations containing Herba Ephedrae have been promoted for use in weight reduction and thermogenesis (fat burning) (27, 28). The safety and effectiveness of these preparations is currently an issue of debate and requires further investigation (29).

Ephedrine stimulates the α-adrenoceptors of the smooth muscle cells of the bladder base, which increases the resistance to the outflow of urine (23). Thus Herba Ephedrae has been used in the treatment of urinary incontinence and nocturnal enuresis.

Contraindications

Herba Ephedrae should not be administered to patients with coronary thrombosis, diabetes, glaucoma, heart disease, hypertension, thyroid disease, impaired circulation of the cerebrum, phaeochromocytoma, or enlarged prostate (10, 21, 23). Co-administration of Herba Ephedrae preparations with monoamine oxidase inhibitors is contraindicated as the combination may cause severe, possibly fatal, hypertension (23).

Warnings

Dosage should be reduced or treatment discontinued if nervousness, tremor, sleeplessness, loss of appetite or nausea occurs. Not for children under 6 years of age. Keep out of the reach of children (30). Continued, prolonged use may cause dependency.

Precautions

General

Insomnia may occur with continued use of Herba Ephedrae preparations (23).

Drug interactions

In combination with cardiac glycosides or halothane, may cause heart rhythm disturbances (21); with guanethidine, may cause an enhancement of sympathomimetic effect (21); with monoamine oxidase inhibitors, can cause severe, possibly fatal, hypertension (26); with ergot alkaloid derivatives or oxytocin, may increase risk of high blood pressure (21).

Carcinogenesis, mutagenesis, impairment of fertility

Extracts of Ephedra sinica are not mutagenic in the Salmonella/microsome reversion assay (31).

Pregnancy: teratogenic effects

Ephedra sinica did not have any teratogenic effects in vivo (32).

Pregnancy: nonteratogenic effects

Ephedra sinica is not abortifacient in rats (32). Clinical studies in humans are not available; therefore, use of the drug during pregnancy is not generally recommended.

Nursing mothers

There are no reliable studies on this subject. Therefore, nursing mothers should not take Herba Ephedrae without consulting a physician.

Paediatric use

Herba Ephedrae should not be administered to children under 6 years of age.

Other precautions

No information available concerning drug and laboratory test interactions.

Adverse reactions

In large doses Herba Ephedrae products can cause nervousness, headaches, insomnia, dizziness, palpitations, skin flushing and tingling, and vomiting (21). The principal adverse effects of ephedrine and Herba Ephedrae are stimulation of the central nervous system, nausea, tremors, tachycardia, and urine retention (24). Continued, prolonged use (>3 days) of topical preparations containing Herba Ephedrae, for the treatment of nasal congestion, may cause rebound congestion and chronic rhinitis (26). Continued prolonged use of oral preparations may cause dependency (21).

Posology

Crude plant material: 1–6g for decoction daily (8, 21). Liquid extract (1:1 in 45% alcohol): 1–3ml daily (21). Tincture (1:4 in 45% alcohol): 6–8ml daily (21).

References

1. The pharmacopoeia of Japan XII. Tokyo, The Society of Japanese Pharmacopoeia, 1991.

2. Pharmacopoeia of the People's Republic of China (English ed.). Guangzhou, Guangdong Science and Technology Press, 1992.

3. Deutsches Arzneibuch 1996. Stuttgart, Deutscher Apotheker Verlag, 1996.

4. African pharmacopoeia, 1st ed. Lagos, Organization of African Unity, Scientific, Technical & Research Commission, 1985.

5. Vietnam materia medica. Hanoi, Ministry of Health, 1972.

6. Hsu HY. Oriental materia medica, a concise guide. Long Beach, CA, Oriental Healing Arts Institute, 1986.

7. Youngken HW. Textbook of pharmacognosy, 6th ed. Philadelphia, Blakiston, 1950.

8. Medicinal plants in China. Manila, World Health Organization, 1989 (WHO Regional Publications, Western Pacific Series, No. 2).

9. The Indian pharmaceutical codex. Vol. I. Indigenous drugs. New Delhi, Council of Scientific & Industrial Research, 1953.

10. Farnsworth NR, ed. NAPRALERT database. Chicago, University of Illinois at Chicago, IL, March 15, 1995 production (an on-line database available directly through the University of Illinois at Chicago or through the Scientific and Technical Network (STN) of Chemical Abstracts Services).

11. Tyler VE, Brady LR, Robbers JE, eds. Pharmacognosy, 9th ed. Philadelphia, Lea & Febiger, 1988.

12. Morton JF. Major medicinal plants: botany, culture and use. Springfield, IL, Charles C Thomas, 1977.

13. Quality control methods for medicinal plant materials. Geneva, World Health Organization, 1998.

14. Deutsches Arzneibuch 1996. Vol. 2. Methoden der Biologie. Stuttgart, Deutscher Apotheker Verlag, 1996.

15. European pharmacopoeia, 3rd ed. Strasbourg, Council of Europe, 1997.

16. Guidelines for predicting dietary intake of pesticide residues, 2nd rev. ed. Geneva, World Health Organization, 1997 (unpublished document WHO/FSF/FOS/97.7; available from Food Safety, WHO, 1211 Geneva 27, Switzerland).

17. Zhang JS, Tian Z, Lou ZC. Detection and identification of the alkaloids in Herba Ephedra (Ma huang) by chemical tests and HPTLC. Yaowu fenxi zazhi, 1992, 12:38– 41.

18. Cui JF et al. Analysis of alkaloids in Chinese Ephedra species by gas chromatographic methods. Phytochemical analysis, 1991, 2:116–119.

19. Zhang JS, Tian Z, Lou ZC. Simultaneous determination of six alkaloids in Ephedra Herba by high performance liquid chromatography. Planta medica, 1988, 54:69–70.

20. Bruneton J. Pharmacognosy, phytochemistry, medicinal plants. Paris, Lavoisier, 1995.

21. German Commission E Monograph, Ephedrae herba. Bundesanzeiger, 1991, 11:17 January.

22. Goodman and Gilman's the pharmacological basis of therapeutics, 6th ed. New York, MacMillan, 1985:169–170.

23. Goodman LS et al. Goodman and Gilman's the pharmacological basis of therapeutics, 8th ed. New York, MacMillan, 1993:213–214.

24. Kim TH, Yang KS, Hwang EZ, Park SB. Effect of Ephedrae Herba on the immune response in mice. Korean journal of pharmacognosy, 1991, 22:183–191.

25. Konno C et al. Ephedroxane, anti-inflammatory principal of Ephedra herbs. Phytochemistry, 1979, 18:697–698.

26. Handbook of non-prescription drugs, 8th ed. Washington, DC, American Pharmaceutical Association, 1986.

27. Daley PA et al. Ephedrine, caffeine and aspirin: safety and efficacy for the treatment of human obesity. International journal of obesity, 1993, 17(Suppl. 1):S73–S78.

28. Pardoe AU, Gorecki DKJ, Jones D. Ephedrine alkaloid patterns in herbal products based on Ma Huang (Ephedra sinica). International journal of obesity, 1993, 17(Suppl. 1):S82.

29. Adverse events with Ephedra and other botanical dietary supplements. FDA medical bulletin, 1994, 24:3.

30. Policy Statement on Ephedra sinica (Ma huang). Austin, TX, American Herbal Products Association 1994.

31. Morimoto I et al. Mutagenicity screening of crude drugs with Bacillus subtilis recassay and Salmonella/microsome reversion assay. Mutation research, 1982, 97:81–102.

32. Lee EB. Teratogenicity of the extracts of crude drugs. Korean journal of pharmacognosy, 1982, 13:116–121.

 

to previous section
to next section
 
 
The WHO Essential Medicines and Health Products Information Portal was designed and is maintained by Human Info NGO. Last updated: November 5, 2014