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
 

Radix Astragali

Definition

Radix Astragali is the dried root of Astragalus membranaceus (Fisch.) Bunge and Astragalus mongholicus Bunge (Fabaceae) (1, 2).

Synonyms

Fabaceae are also known as Leguminosae.

Astragalus membranaceus (Fisch.) Bunge

A. propinguus B. Schischk. (3).

Astragalus mongholicus Bunge

A. membranaceus (Fisch.) Bunge var. mongholicus (Bunge) Hsiao (3).

Selected vernacular names

Astragalus root, hoàng k´y, huang-chi, huangoi, huangqi, huángqi, hwanggi, membranous milkvetch, milkvetch, Mongolian milk-vetch, neimeng huangqi, ogi, ougi, zhongfengnaomaitong (1, 3–9).

Description

Astragalus membranaceus (Fisch.) Bunge

Perennial herb, 25–40 cm tall. Leaves 3–6 cm long; petiole obsolete; stipules free, cauline, green, triangular ovate, sparingly vested on the outside with white hair. Leaflets oblong-obovate, oval or oblong-oval. Racemes oblong-ovoid to ovoid, 4–5cm long, 10–15 flowers; bracts lanceolate. Calyx 8–9mm long, campanulate, strongly oblique, glabrous. Corolla yellowish, 18–20mm long. Ovary glabrous (4). Root cylindrical or nearly cylindrical with small bases of lateral root dispersed on the surface, and usually not branched; greyish yellow to yellowish brown epidermis and fibrous fracture (2, 5).

Astragalus mongholicus Bunge

Perennial herb, 60–150 cm tall. Leaves pinnate, leaflets broadly elliptical. Raceme axillary. Calyx tubular 5mm long. Corolla yellowish; pod ovate-oblong, glabrous, reticulate. The root is flexible and long and covered with a tough, wrinkled, yellowish brown epidermis, which has a tendency to break up into woolly fibres. The woody interior is yellowish white (6).

Plant material of interest: root

General appearance

Radix Astragali is cylindrical, some upper branches relatively thick, 30–90cm long, 1–3.5 cm in diameter. Externally pale brownish yellow or pale brown, with irregular, longitudinal wrinkles or furrows. Texture hard and tenacious, broken with difficulty, fracture highly fibrous and starchy, bark yellowish white, wood pale yellow, with radiate striations and fissures, the centre part of old root occasionally looking like rotten wood, blackish brown or hollowed (1).

Organoleptic properties

Colour, pale yellow to yellow-brown; taste, slightly sweet; odour, slight (1, 2, 4, 7).

Microscopic characteristics

The transverse section shows cork consisting of many rows of cells. Phelloderm, 3–5 rows of collenchymatous cells. Outer part of phloem rays often curved and fissured, fibres in bundles, walls thickened and lignified or slightly lignified, arranged alternately with sieve tube groups; stone cells sometimes visible near phelloderm. Cambium in a ring. Xylem vessels scattered singly or 2 or 3 aggregated in groups; wood fibres among vessel stone cells singly or 2– 4 in groups, sometimes visible in rays. Parenchymatous cells contain starch granules (1).

Powdered plant material

Yellowish white. Fibres in bundles or scattered, 8–30µm in diameter, thickwalled, with longitudinal fissures on the surface, the primary walls often separated from the secondary walls, both ends often tassel-like, or slightly truncated. Bordered-pitted vessels colourless or orange, bordered pits arranged closely. Stone cells occasionally visible, rounded, oblong or irregular, slightly thick-walled (1).

Geographical distribution

Indigenous to China, the Democratic People's Republic of Korea, Mongolia, and Siberia (5, 6). Commercially cultivated in northern China and the Democratic People's Republic of Korea (5).

General identity tests

Macroscopic and microscopic examination and thin-layer chromatographic analysis for the presence of triterpene saponins (astragaloside I as reference standard) (1).

Purity tests

Microbiology

The test for Salmonella spp. in Radix Astragali products should be negative. The maximum acceptable limits of other microorganisms are as follows (10, 11). 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.

Total ash

Not more than 5.0% (1, 2).

Acid-insoluble ash

Not more than 1.0% (1, 2).

Water-soluble extractive

Not less than 17.0% (1).

Moisture

Not more than 13.0% (2).

Pesticide residues

To be established in accordance with national requirements. Normally, the maximum residue limit of aldrin and dieldrin in Radix Astragali is not more than 0.05 mg/kg (11). For other pesticides, see WHO guidelines on quality control methods for medicinal plants (10) and WHO guidelines on predicting dietary intake of pesticide residues (12).

Heavy metals

Recommended lead and cadmium levels are not more than 10 and 0.3mg/kg, respectively, in the final dosage form of the plant material (10).

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 (10).

Other tests

Chemical tests and tests for alcohol-soluble extractive and foreign organic matter are to be established in accordance with national requirements.

Chemical assays

Determination of triterpene saponins (astragalosides I–X) by thin-layer chromatographic analysis (1). Concentration limits and quantitative methods need to be established for the triterpene saponins (e.g. astragalosides), as well as for the polysaccharides.

Major chemical constituents

Major chemical constituents are triterpene saponins (astragalosides I–X and isoastragalosides I–IV), and polysaccharides (e.g. astragalan, astraglucan AMem-P) (3, 13).

 

R1

R2

R3

R4

R5

astragaloside I

glc*

H

CH3CO

CH3 CO

H

astragaloside II

glc*

H

CH3CO

H

H

astragaloside III

H

H

glc*

H

H

astragaloside IV

glc*

H

H

H

H

astragaloside V

H

glc*

glc*

H

H

astragaloside VI

glc*

H

glc*

H

H

astragaloside VII

glc*

glc*

H

H

H

isoastragaloside I

glc*

H

CH3CO

H

CH3CO

isoastragaloside II

glc*

H

H

CH3CO

H

* glc = β-D-glucopyranosyl

Dosage forms

Crude plant material; extracts. Store in a dry environment protected from moisture and insects (1).

Medicinal uses

Uses supported by clinical data

None.

Uses described in pharmacopoeias and in traditional systems of medicine

As adjunctive therapy in the treatment of colds and influenza (1). The herb is used to enhance the immune system and to increase stamina and endurance (1).

Also in the treatment of chronic diarrhoea, oedema, abnormal uterine bleeding, and diabetes mellitus (1, 4, 14, 15), and as a cardiotonic agent (6).

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

Treatment of nephritis, chronic bronchitis, postpartum urine retention, leprosy, and the sequelae of cerebrovascular accidents (4).

Pharmacology

Experimental pharmacology

Effect on the immune system

Both in vitro and in vivo investigations have confirmed that Astragalus membranaceus enhances the immune system (14–18). In vitro studies have shown that, at concentrations of 10 mg/ml, polysaccharides isolated from the plant increased the blastization index in mixed lymphocyte cultures and the granulopexis of macrophages or polymorphonucleates (16). Using the local xenogenic graft-versus-host reaction (assessed in cyclophosphamide-treated rats) as a model assay for T-cell function, investigators found that mononuclear cells, derived from cancer patients, that were preincubated with a polysaccharide fraction from A. membranaceus had significant immunopotentiating activity, and they fully corrected in vitro T-cell function deficiency found in cancer patients (14). Further investigations of this extract established that the polysaccharide fraction enhanced interleukin-2 activity in the in vitro generation of lymphokine-activated killer cell activity (17). Intravenous injection of this polysaccharide fraction also reversed cyclophosphamide-induced immunosuppression in rats (18).

A decoction of A. membranaceus given to mice by gastric lavage, daily or on alternate days for 1–2 weeks, increased the phagocytic activity of the reticuloendothelial system (4, 5). The phagocytic index was significantly enhanced even when the rehabilitation of the mouse reticuloendothelial system was disrupted by injection of carbon particles before the A. membranaceus extract was administered (4, 5). Extracts of the crude drug enhanced antibody response to a T-dependent antigen in vivo. Intravenous administration of a crude drug extract to normal mice, or mice immunosuppressed by cyclophosphamide, radiation treatment, or ageing, induced the antibody response to a T-dependent antigen (19). Enhancement of this response is associated with an increase in Thelper cell activity in both normal and immunosuppressed mice (19). Other in vivo studies performed on cyclophosphamide-immunosuppressed mice have further suggested that A. membranaceus root extracts may modulate the immune system by activation of macrophages and splenic lymphocytes (20).

The immunostimulant activity of A. membranaceus has been associated with the polysaccharide fractions of the root extract (4, 13, 19, 21). The immuneenhancing polysaccharide molecules have relative molecular masses of approximately 25 000 (14, 18, 19). A polysaccharide fraction isolated from A. membranaceus reportedly antagonized the effect of cobra venom on the immune function of treated mice and guinea-pigs (22). The venom-treated guinea-pigs had decreased levels of complement and neutrophil phagocytotic activity, as well as increased levels of neutrophil granular substances. Treatment of the animals with the polysaccharides antagonized these changes in the venomtreated animals but had no effect in the normal group (22). Recently, a new glycan, named AMem-P, isolated from the roots of A. membranaceus, was shown by use of an in vivo carbon clearance test to significantly potentiate reticuloendothelial system activity in mice (13).

Radix Astragali is reported to have cardiovascular activity. Alcohol extracts of the drug enhanced both the contractility and contraction amplitude of isolated frog or toad hearts (4). Intraperitoneal injection of the drug to dogs did not produce any immediate effect on heart rate, but 3–4 hours after administration inverted and biphasic T waves and prolonged S–T intervals were noted (4). Intravenous administration of the drug produced hypotension in rabbits, dogs, and cats (4). Furthermore, saponins isolated from the drug were reported to exert a positive inotropic effect on isolated rat hearts (23). The saponins also decreased the resting potential of cultured rat myocardial cells, suggesting that they may exert an inotropic effect through the modulation of Na+/K+- exchanging ATPase (23).

Toxicology

No adverse effects were observed in mice after oral administration of up to 100g/kg, a dose several hundred times as high as the effective oral dose in humans (4).

Clinical pharmacology

Oral or intranasal administration of an aqueous A. membranaceus extract to 1000 human subjects decreased the incidence and shortened the course of the common cold (4). Two months of oral administration of the herb significantly increased the levels of IgA and IgG in the nasal secretions of patients susceptible to the common cold (4). Details of these studies were not available.

A hot water extract of A. membranaceus root taken by human subjects was reported to have a pronounced immunostimulant effect (24). Human adults treated with an oral dose of Astragalus root (15.6 g per person per day for 20 days) significantly increased serum IgM, IgE, and cyclic AMP concentrations (24). Extracts of A. membranaceus have been further reported to stimulate the production of interferon, a protein with antiviral activity, in both animals and humans in response to viral infections (21, 25). A hot water extract of the drug administered intramuscularly for 3–4 months to patients with coxsackievirus B myocarditis enhanced natural killer cells, a response which was mediated through interferon induction (15). Furthermore, both natural and recombinant interferons enhanced the antiviral activity of an A. membranaceus extract (26).

Contraindications

No information available.

Warnings

No information available.

Precautions

Carcinogenesis, mutagenesis, impairment of fertility

Extracts of A. membranaceus root were not mutagenic in a modified Ames test using Salmonella typhimurium TA 98 and TA 100 (27). Furthermore, an aqueous extract of A. membranaceus was reported to be antimutagenic in that it inhibited benzo[a]pyrene-induced mutagenesis in Salmonella typhimurium TA 100 (28, 29).

Pregnancy: non-teratogenic effects

No data available; therefore Radix Astragali should not be administered during pregnancy.

Nursing mothers

Excretion of the drug into breast milk and its effects on the newborn infant have not been established; therefore the use of the drug during lactation is not recommended.

Other precautions

No information available describing general precautions or precautions related to drug interactions, drug and laboratory test interactions, paediatric use, or teratogenic effects during pregnancy.

Adverse reactions

No information available.

Posology

Root: 9–30g/day for oral use (1).

References

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

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

3. Leung A, Foster S. Encyclopedia of common natural ingredients used in food, drugs, and cosmetics, 2nd ed. New York, John Wiley, 1996.

4. Chang HM, But PPH, eds. Pharmacology and applications of Chinese materia medica, Vol. 2. Singapore, World Scientific Publishing, 1987.

5. Morazzoni P, Bombardelli E. Astragalus membranaceus (Fish.) Bge. Milan, Indena, 1994.

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

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

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

9. Farnsworth NR, ed. NAPRALERT database. Chicago, University of Illinois at Chicago, IL, August 8, 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).

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

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

12. 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).

13. Tomoda M et al. A reticuloendothelial system-activating glycan from the roots of Astragalus membranaceus. Phytochemistry, 1992, 31:63–66.

14. Chu DT, Wong WL, Mavligit GM. Immunotherapy with Chinese medicinal herbs I. Immune restoration of local xenogeneic graft-versus-host reactions in cancer patients by fractionated Astragalus membranaceus in vitro. Journal of clinical laboratory immunology, 1988, 25:119–123.

15. Yang YZ et al. Effect of Astragalus membranaceus on natural killer cell activity and induction of alpha- and gamma-interferon in patients with coxsackie B viral myocarditis. Chung-hua i hseuh tsa chih (English Edition), 1990, 103:304–307.

16. Bombardelli E, Pozzi R. Polysaccharides with immunomodulating properties from Astragalus membranaceus. Europe patent, 1991, 441:278.

17. Chu DT et al. Fractionated extract of Astragalus membranaceus, a Chinese medicinal herb, potentiates LAK cell cytotoxicity generated by a low dose of recombinant interleukin-2. Journal of clinical laboratory immunology, 1988, 26:183–187.

18. Chu DT, Wong WL, Mavligit GM. Immunotherapy with Chinese medicinal herbs II. Reversal of cyclophosphamide-induced immune suppression by administration of fractionated Astragalus membranaceus in vivo. Journal of clinical laboratory immunology, 1988, 25:125–129.

19. Zhou KS, Mancini C, Doria G. Enhancement of the immune response in mice by Astragalus membranaceus extracts. Immunopharmacology, 1990, 20:225–233.

20. Jin R et al. Immunomodulative effects of Chinese herbs in mice treated with antitumor agent cyclophosphamide. Yakugaku zasshi, 1994, 114:533–538.

21. Hou YD et al. Effect of Radix Astragali seu hedysari on the interferon system. Chinese medical journal, 1981, 94:35–40.

22. Zhuang MX et al. The effects of polysaccharides of Astragalus membranaceus, Codonopsis pilosula and Panax ginseng on some immune functions in guinea-pigs. Zhongguo yaoxue zazhi, 1992, 27:653–655.

23. Wang QL et al. Inotropic action of Astragalus membranaceus Bge. saponins and its possible mechanism. Zhongguo zhongyao zazhi, 1992, 17:557–559.

24. Institute of Basic Medical Sciences, The Chinese Academy of Medical Sciences. Immunity parameters and blood cAMP changes in normal persons after ingestion of Radix Astragali. Chung hua i hsueh t'sa chih, 1979, 59:31–34.

25. Finter NB. Interferons and interferon-inducers. Amsterdam, North Holland, 1973:363.

26. Peng JZ et al. Inhibitory effects of interferon and its combination with antiviral drugs on adenovirus multiplication. Zhongguo yixue kexueyuan xuebao, 1984, 6:116–119.

27. Yamamoto H, Mizutani T, Nomura H. Studies on the mutagenicity of crude drug extracts. I. Yakugaku zasshi, 1982, 102:596–601.

28. Wong BY, Lau BH, Teel RW. Chinese medicinal herbs modulate mutagenesis, DNA binding and metabolism of benzo[a]pyrene. Phytotherapy research, 1992, 6:10–14.

29. Liu DX et al. Antimutagenicity screening of water extracts from 102 kinds of Chinese medicinal herbs. Chung-kuo chung yao tsa chi li, 1990, 15:617–620.

 

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: August 22, 2017