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WHO Monographs on Selected Medicinal Plants - Volume 1
(1999; 295 pages) Voir le document au format PDF
Table des matières
Afficher le documentAcknowledgements
Afficher le documentIntroduction
Afficher le documentBulbus Allii Cepae
Afficher le documentBulbus Allii Sativi
Afficher le documentAloe
Afficher le documentAloe Vera Gel
Afficher le documentRadix Astragali
Afficher le documentFructus Bruceae
Afficher le documentRadix Bupleuri
Afficher le documentHerba Centellae
Afficher le documentFlos Chamomillae
Afficher le documentCortex Cinnamomi
Afficher le documentRhizoma Coptidis
Afficher le documentRhizoma Curcumae Longae
Afficher le documentRadix Echinaceae
Afficher le documentHerba Echinaceae Purpureae
Afficher le documentHerba Ephedrae
Afficher le documentFolium Ginkgo
Afficher le documentRadix Ginseng
Afficher le documentRadix Glycyrrhizae
Afficher le documentRadix Paeoniae
Afficher le documentSemen Plantaginis
Afficher le documentRadix Platycodi
Afficher le documentRadix Rauwolfiae
Afficher le documentRhizoma Rhei
Afficher le documentFolium Sennae
Afficher le documentFructus Sennae
Afficher le documentHerba Thymi
Afficher le documentRadix Valerianae
Afficher le documentRhizoma Zingiberis
Afficher le documentAnnex. Participants in the WHO Consultation on Selected Medicinal Plants
 

Radix Platycodi

Definition

Radix Platycodi is the root of Platycodon grandiflorum (Jacq.) A. DC. (Campanulaceae) (1, 2).

Synonyms

Platycodon chinensis Lindl, P. autumnalis Decne., P. sinensis Lem., P. stellatum, Campanula grandiflora Jacq., Campanula glauca Thunb., Campanula gentianoides Lam. (3, 4).

Selected vernacular names

Balloon-flower, chieh keng, Chinese bell flower, gil gyeong, Japanese bell- flower, jiegeng, jieseng, kikiyou, kikyo, kikyokon, kikyou, platycodon radix (38).

Description

Perennial herb wholly glabrous, slightly glaucescent; root white, fleshy, radishshaped, finger-thick, with abundant milky juice; stems ascending from base or straight, simple, 40–50 cm, herbaceous, glabrous or smooth, longitudinally striate in lower part; radical leaves alternate or sometimes nearly opposite, arranged along the lower half of stem or even higher, ovate-lanceolate, sessile, tapering at base, 2.5–3.4 cm long, 2–3 cm wide, rather large-toothed, pale beneath, glaucescent, upper leaves reduced. Flowers usually 1, sometimes 2, large, lengthily pedunculate, broadly campanulate or deeply saucer-shaped; calyx in 5 segments; corolla 5-lobed, violet-blue, 4 cm long; stamens 5; ovary many-celled. Fruit an ovoid capsule dehiscent at the top; seeds ovoid, compressed, obtuse, first violet then brown; albumen fleshy (3, 9).

Plant material of interest: dried root

General appearance

The root is irregular, somewhat thin and long fusiform, tapering, conical, often branched; externally greyish brown, light brown, or white; main root 10–15cm in length, 1–3 cm in diameter at the upper end, with dented scars of removed stems, fine lateral wrinkles and longitudinal furrows, and slightly constricted; the remaining part of the root, except the crown, covered with coarse longitudinal wrinkles, lateral furrows and lenticel-like lateral lines; hard in texture, but brittle; fractured surface not fibrous, often with cracks. Under a magnifying glass, a transverse section reveals cambium and its neighbourhood often brown in colour; cortex slightly thinner than xylem, almost white and with scattered cracks; xylem white to light brown and the tissue slightly denser than cortex (2).

Organoleptic properties

Odour, odourless; taste, tasteless at first, later bittersweet and pungent; colour, greyish brown (1, 2).

Microscopic characteristics

In transverse section of whole peeled root, cork cells occasionally remain; unpeeled roots show cork layers. Cork cells contain calcium oxalate prisms. Cortex narrow, often with clefts. Phloem scattered with laticiferous tube groups, walls somewhat thickened; contains yellowish brown granules. Cambium in a ring. Xylem vessels singly scattered or aggregated in groups arranged radially. Parenchymatous cells contain inulin (1).

Powdered plant material

Light greyish yellow to light greyish brown powder containing numerous fragments of colourless parenchyma cells; fragments of reticulate vessels and scalariform vessels; fragments of sieve tubes and lactiferous tubes; fragments of cork layer are sometimes observed. Starch grains are not usually observed, but very rarely simple grains are present, ellipsoid to irregular spheroid, 12–25 µm in diameter (2).

Geographical distribution

Northern Asia, China, the Democratic People's Republic of Korea, Japan, the Republic of Korea, the Russian Federation (east Siberia) (3, 7, 9).

General identity tests

Macroscopic and microscopic examinations; microchemical tests for saponins (1, 2), thin-layer chromatographic analysis for characteristic saponin profile (10).

Purity tests

Microbiology

The test for Salmonella spp. in Radix Platycodi should be negative. The maximum acceptable limits of other microorganisms are as follows (11–13). 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 4.0% (2).

Acid-insoluble ash

Not more than 1.0% (2).

Alcohol-soluble extractive

Not less than 25% (2).

Pesticide residues

To be established in accordance with national requirements. Normally, the maximum residue limit of aldrin and dieldrin in Radix Platycodi is not more than 0.05 mg/kg (13). For other pesticides, see WHO guidelines on quality control methods for medicinal plants (11) and guidelines for predicting dietary intake of pesticide residues (14).

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 (11).

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 (11).

Other purity tests

Chemical, foreign organic matter, moisture, and water-soluble extractive tests to be established in accordance with national requirements.

Chemical assays

Triterpene saponins, not less than 2% (6). Saponin content of the root can be evaluated by thin-layer chromatography–densitometry (10).

Major chemical constituents

The major chemical constituents of Radix Platycodi root are triterpene saponins based on the sapogenins platycodigenin and polygalacic acid; examples are platycodins A–I and polygalacins D and D2 (6, 15).

 

R1

R2

R3

R4

platycodin A

H

CH2OH

H

CO-CH3

platycodin C

H

CH2OH

CO-CH3

H

platycodin D

H

CH2OH

H

H

platycodin D2

glc *

CH2OH

H

H

polygalacin D

H

CH3

H

H

polygalacin D2

glc *

CH3

H

H

* glc = β-D-glucopyranosyl

Dosage forms

Dried roots, extracts, and other preparations.

Medicinal uses

Uses supported by clinical data

None.

Uses described in pharmacopoeias and in traditional systems of medicine

As an expectorant and antitussive (1, 3–5) used to treat coughs, colds, upper respiratory infections, sore throats, tonsillitis, and chest congestion (1, 7). In Chinese traditional medicine, Radix Platycodi has been used to treat cough with sputum, tonsillitis, pertussis, and asthma (16). Also used to treat stomatitis, peptic ulcers, and chronic inflammatory diseases (17, 18).

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

Other medical uses for Radix Platycodi include the treatment of viral infections and high blood pressure (6).

Pharmacology

Experimental pharmacology

Anti-inflammatory activity

The anti-inflammatory activity of Radix Platycodi has been attributed to the platycodins (17, 19, 20). In vivo studies have shown that intragastric administration of the drug antagonized carrageenin- and acetic acid-induced swelling of rat paws, and oral administration markedly inhibited cotton pledget-induced granulation in rats (21). Platycodins also effectively inhibited adjuvant-induced arthritis in rats (22). Researchers investigating some Japanese Kampo medicines concluded that Radix Platycodi was at least partly responsible for the antiinflammatory activity of these preparations (17).

Expectorant and antitussive activity

Radix Platycodi has both antitussive and expectorant activities (18, 20). The expectorant effects include the promotion of salivary and bronchial secretions (6). Oral administration of a decoction of the drug (1 g/kg) to anaesthetized dogs increased mucus secretions in the respiratory tract with a potency similar to that of ammonium chloride (23). A similar response was observed in cats (24). The platycodins are believed to be the active components. Oral doses of platycodins irritated the pharyngeal and gastric mucosa, increasing mucosal secretions in the respiratory tract and diluting sputum for easy expectoration (25).

In vivo studies have demonstrated the effectiveness of platycodins as an antitussive drug. When administered to guinea-pigs, platycodins reduced the frequency of coughing; the median effective dose was 6.4 mg/kg given intraperitoneally (5, 26). A 20% decoction of Radix Platycodi was also effective in treating coughing induced by ammonia in mice (6).

Antipeptic ulcer activity

Platycodins have been reported to inhibit gastric secretion and prevent peptic ulcer in rats (5). A dose of 100 mg/kg inhibited gastric secretion in rats induced by ligation of the pylorus and stress ulceration (18).

Antihypercholesterolaemic and antihyperlipidaemic activity

An effect of Radix Platycodi on serum and liver lipid concentrations has been demonstrated. Rats with diet-induced hyperlipidaemia were fed diets containing 5% and 10% Radix Platycodi. The rats fed with the 5% diet had signifi- cantly lower concentrations of total cholesterol and triglycerides in serum and of liver lipids than did controls (27).

Toxicity

The median lethal dose of a decoction of Radix Platycodi given orally was 24 g/kg in mice (5). The median lethal doses of platycodins in mice and rats were 420 and 800mg/kg (oral), or 22.3 and 14.1 mg/kg (intraperitoneal), respectively (5). Crude platycodins have been reported to have sedative side-effects in mice, such as inhibition of movement and a decrease in respiration after both intraperitoneal and oral administration (18). These side-effects were less pronounced after oral administration, suggesting that platycodins are poorly absorbed through the gastrointestinal tract (18).

Crude platycodins have a highly haemolytic effect in mice, of which the haemolytic index is 1.2 times that of a commercial reagent-grade saponin used as a reference (5, 18). Radix Platycodi preparations should therefore be given only orally, after which the drug loses its haemolytic effect owing to decomposition in the alimentary tract (18).

Clinical pharmacology

Crude powdered drug or decoctions of Radix Platycodi have been used to treat the symptoms of lung abscesses, lobar pneumonia, and pharyngitis with reported success (5). However, the details of these clinical studies were not available.

Contraindications

No information available.

Warnings

Playtcodon extracts have a very pronounced haemolytic effect, and therefore the drug should not be administered by injection (5).

Precautions

General

Radix Platycodi reportedly depresses central nervous system (CNS) activity (5). Patients should avoid using alcohol or other CNS depressants in conjunction with this drug. Patients should be cautioned that the combination of the drug and alcohol may impair their ability to drive a motor vehicle or operate hazardous machinery.

Drug interactions

Because of the CNS depressant activity (5), Radix Platycodi may act synergistically with other CNS depressants such as alcohol, tranquillizers, and sleeping medications. Radix Platycodon is also reported to be incompatible with Gentiana scabra and Bletilla hyacinthina (5).

Carcinogenesis, mutagenesis, impairment of fertility

To date, no genotoxic effects have been reported. Platycodon root extracts were not mutagenic in the Bacillus subtilis rec-assay or the Salmonella/microsome reversion assay (28). Nor were they mutagenic in the SOS chromotest (E. coli PQ37) and in the SOS umu test (S. typhimurium TA 1535/pSK 1002) (29).

Pregnancy: teratogenic effects

Platycodon extracts are not teratogenic in vivo (30).

Pregnancy: non-teratogenic effects

No data available; therefore Radix Platycodi 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 on drug and laboratory test interactions or on paediatric use.

Adverse reactions

No information available.

Posology

The usual dose range is 2–9g daily (1, 3, 6).

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. Keys JD. Chinese herbs, their botany, chemistry and pharmacodynamics. Rutland, VT, CE Tuttle, 1976.

4. Bailey LH, Lawrence GHM. The garden of bellflowers in North America. New York, MacMillan, 1953.

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

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

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

8. Farnsworth NR, ed. NAPRALERT database. 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).

9. Shishkin BK, ed. Flora of the USSR, Vol. XXIV. Dipsacaceae, Cucurbitaceae, Campanulaceae. Jerusalem, Israel Program for Scientific Translation, 1972 (published for the Smithsonian Institution and the National Science Foundation, Washington, DC).

10. Hosoda K et al. Studies on the cultivation and preparation of Platycodon root. III. Effect of picking flower and fruit on the quality of skin peeled root. Chemical and pharmaceutical bulletin, 1992, 40:1946–1947.

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

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

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

14. 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).

15. Tada A et al. Studies on the saponins of the root of Platycodon grandiflorum A. De Candolle. I. Isolation and the structure of platycodin-D. Chemical and pharmaceutical bulletin, 1975, 23:2965–2972.

16. Lee EB. Pharmacological studies on Platycodi radix. Korean journal of pharmacognosy, 1974, 5:49–60.

17. Ozaki Y. Studies of antiinflammatory effect of Japanese oriental medicines (Kampo medicines) used to treat inflammatory diseases. Biological and pharmaceutical bulletin, 1995, 18:559–562.

18. Lee EB. Pharmacological activities of crude platycodin. In: Woo ES, ed. Terpenoids Symposium proceedings. Seoul, Natural Products Research Institute, Seoul National University, 1975:52–64.

19. Kakimoto M et al. Anti-inflammatory and anti-allergic effects of a preparation of crude drugs, a remedy for nasal disease (fujibitol). Pharmacometrics, 1984, 28:555–565.

20. Shibata S. Medicinal chemistry of triterpenoid saponins and sapogenins. In: Proceedings of the 4th Asian Symposium on Medicinal Plants and Spices. Bangkok, 1981.

21. Takagi T. Metabolism and disease. In: Foreign references on Chinese Materia Medica. Hunan, Hunan Institute of Medical and Pharmaceutical Industry, 1975, 10:474.

22. Takagi K, Lee EB. Pharmacological studies on Platycodon grandiflorum A.DC. II. Anti-inflammatory activity of crude platycodin, its activities on isolated organs and other pharmacological activities. Journal of the Pharmaceutical Society of Japan (Tokyo), 1972, 92:961–968.

23. Tang RY et al. Chinese medical journal, 1952, 38:4–5.

24. Gao YD et al. Chinese medical journal, 1954, 46:331.

25. Zhu Y. Pharmacology and applications of Chinese medicinal materials. Beijing, China, People's Medical Publishing House, 1958.

26. Takagi KJ, Lee EB. Pharmacological studies on Platycodon grandiflorum A.DC. III. Activities of crude platycodin, on respiratory and circulatory systems and other pharmacological activities. Pharmaceutical Society of Japan (Tokyo), 1972, 92:969–973.

27. Kim K et al. Effects of Platycodon grandiflorum feeding on serum and liver lipid concentrations in rats with diet-induced hyperlipidemia. Journal of nutritional science and vitaminology, 1995, 41:485–491.

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

29. Chang IM et al. Assay of potential mutagenicity and antimutagenicity of Chinese herbal drugs by using SOS Chromotest (E. coli PQ37) and SOS UMU test (S. typhimurium TA 1535/pSK 1002). Proceedings of the first Korea–Japan Toxicology Symposium, Safety and Assessment of Chemicals in Vitro. The Korean Society of Toxicology, 1989.

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

 

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