Astragalus: and Immune Support

James Meschino DC, MS, ROHP

General Features
Astragalus has been used for at least 2000 years in China and continues to be widely used as a herb that is known to enhance function of the immune system and facilitates an increase in energy production within the heart muscle, in cases where certain forms of heart disease exist.^1,2,3,4,5  It is one of the most widely used herbs in Fu-zheng therapy − the use of herbs to augment the host defense mechanisms.^1,2,3,6 Astragalus is a herbaceous perennial with the root of the plant used for medicinal purposes.⁷

Active Constituents
These primarily include:

1. Triterpene glycosides (saponins): astragalosides, etc.
2. Polysaccharides: astragalans
3. Flavonoids^7,8,9,10,11

Clinical Application and Mechanism of Action

1. Immune Function (The common cold and minimizing the effects of chemotherapy and radiation treatment)

Astragalus is used as an immune stimulant to treat and help prevent the common cold.^4,8 It has also been used to reduce the side effects of chemotherapy and radiation treatment in human studies. A large clinical study of 572 cancer patients demonstrated that Astragalus supplementation was able to protect adrenal cortical function during radiation and chemotherapy treatment. It also helped to greatly minimize bone marrow depression and gastrointestinal side effects, such as nausea, vomiting and intestinal tract ulcerations in these patients.⁶

In patients with very low white blood cell counts, as a side effect of drugs, radiation or chemotherapy, Astragalus supplementation has been shown to help significantly increase the number of circulating white blood cells, helping to restore normal function of the immune system in these severely immune-compromised patients.¹²

The biological activity that can account for these outcomes is related the active constituents in Astragalus, primarily its triperpene glycosides and polysaccharide content, which have been shown to significantly increase the proliferation of lymphocytes,^3,12 enhance interferon and  interleukin-2 production and activity- two powerful signalling agents that enhance the effectiveness of immune cells,^13,14,15,16 activate T cell blastogenesis,¹⁷ increase T cell cytotoxicity,^2,17 enhance the secretion of the immune  modifying chemical known as tumor necrosis factor (TNF),⁹ enhance phagocytosis by immune cells,¹⁸ increase natural killer cell cytotoxicity – the ability of these white blood cells to destroy developing cancer cells, viruses and other pathogens,^17,19 increase the activity of peritoneal macrophages,¹⁸ and provide direct anti-viral effects.^20,21,22,23

2. Congestive Heart Failure and Angina Pectoris

The active constituents of Astragalus appear to provide an inotropic effect on the heart muscle, in a similar manner to hawthorn. An inotropic effect implies that these active ingredients in some way enhance the ability of the heart muscle to synthesize ATP energy, which is required for heart muscle contraction. In congestive heart failure the heart muscle becomes weak, partly due to insufficient ATP production, and preliminary evidence suggests that Astragalus may help to improve these cases. Thus far, two small clinical trials have shown that patients with congestive heart failure demonstrate improvement in chest distress, dyspnea (shortness of breath), exercise tolerance and other parameters of cardiac function, when given Astragalus intravenously.^10,24

Astragalus has also been used effectively in patients suffering from ischemic heart disease ²⁵ and it has been shown to increase cardiac output in 20 patients with angina pectoris.²⁶

3. Anti-Cancer Effects

The immune- enhancing effects of Astragalus make this herb an interesting compound in terms of its potential in cancer treatment. A clinical study of 54 patients with small cell lung cancer were treated with regular medical interventions plus Traditional Chinese Medicine (including Astragalus). Increased survival was noted in comparison to the average survival statistics of conventional medicine alone.²⁷

Animal studies demonstrate quite strongly that Astragalus has the potential to prevent some cancers and has curative potential in others (e.g., renal cell carcinome model in mice).^28,29  Intensive research continues in an attempt to establish the true anti-tumor potential of Astragalus.

4. Male Fertility

Astragalus has been shown to significantly increase the motility of human sperm in vitro.³⁰ This may be of value in the treatment of male infertility where poor sperm motility is a suspected factor. Note that L-carnitine and zinc supplementation have demonstrated similar capabilities (see details in this document under their individual headings.)

Dosage and Standardized Grade (2:1 powdered extract )

1. Common Cold – For general prevention consider 100-200 mg per day.

During the preliminary stages of a cold consider up to 500 mg, three times daily if used as single agent.³¹

1. Radiation Treatment, Chemotherapy – Consider up to 500 mg, three times per day if taken as a single agent. (Consider combining Astragalus with reishi mushroom extract to minimize side effects of these treatments.) (Requires attending physician’s approval)
2. Congestive Heart Failure, Angina Pectoris and Ischemic Heart Disease – No oral dose values have been established.
3. Decreased Sperm Motility Causing Infertilty – Dosage  not established, however taking up to 500 mg, three times daily is considered to be safe.

Toxicity and Adverse Side Effects
There are no reported side effects or toxicity associated with the use of Astragalus at recommended doses.³¹

Drug-Nutrient Interactions
Immunosuppressive Medications – As Astragalus has been shown to enhance immune function, it may counter the efficacy of immnosuppressive drugs.^32,33

References:

1. Foster S, ChongxlY. Herbal Emissaries. Bringing Chinese Herbs to the West. Rochester, VT; Healing Arts Press, 1992:p356
2. Zhao KS, Manoinin C, Doria G. Enhancement of the immune response in mice by Astragalus membranaceous extracts. Immunopharmacology. 1990:20(3):225-233
3. Sun, Y, et al. Preliminary observations on the effects of the Chinese medicinal herbs Astragalus membranaceous and Ligustrum lucid on lymphocyte blastogenic responses. Journal of Biological Response Modifiers. 1983;2:227-237
4. Geng CS, et al. Advances in Immuno-pharmacological Studies on Astragalus membranaceous. Chung, Hsi i Chieh Ho Tsa Chih. 1986;6(1):62-64
5. Chen, LX, Liao, JX., Guo, WQ. Effects of Astragalus membranaceous on left Ventribular Function and Oxygen Free Radical in Acute Myocardial Infarction Patients and Mechanism of its Cardiotonic Action. Chung Kuo, Chung Hsi, I Chieh Ho Tsa Chih. Mar 1995;15 (3):141-3
6. Sun Y, Change YH, Uy Gq, et al. Effect of Fu-zheng therapy in the management of malignant diseases. Chinese Med Journal, 1981;61:97-101
7. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics. 2^nd Toronto/New York: John Wiley and Sons Inc;1996:p649
8. Chevallier A. The Encyclopedia of Medicnal Plants. London: Readers Digest;1996:p336
9. Zhao, K W, Kong, HY. Effect of Astragalan on secretion of tumour necrosis factor in human peripheral blood monomuclear cells. Chung-Kuo Chung Hsi i Chieh, Ho Tsa Chih. 1993
10. Luo HM, Dai RH, Li Y. Nuclear cardiology study on effective ingredients of Astragalus membranaceous in treating heart failure. Chung-Kuo Chung His i Chieh, Ho Tsa Chih. 1995; 15(12):709-9
11. Hirotani M, Zhou Y, Rui H, Furuya T. Cycloartane triterpene glycosides from the hairy root cultures of Astragalus membranaceous. Phytochemistry. 1994;37(5):1403-7
12. Weng XS. Treatment of leucopenia with pure Astragalus preparation – an analysis of 115 leucopenic cases 9Chinese). Chung-Kuo Chung Hsi i Chieh, Ho Tsa Chih. 1995;15(8):462-4
13. Chu, DT et al. 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
14. Chen YC. Experimental studies on the effects of danggui buxue decoction on IL-2 production of blood-deficient mice (Chinese). Chung-Kuo Chung Hsi i Chieh. 1994; 19(12): p739-41,p763
15. Liang H, Zhang Y, Geng B. The effect of Astragalus polysaccharides (APS) on cell medicated immunity (GMI) in burned mice. Chung-Hua Cheng Hsing Shao Shang Wai Ko Tsa Chih.
16. Hou YD, Ma GL, Wu SH, Li HT. Effect of radix Astrageli seu Hedysari on the interferon system. Chinese Medical Journal. 1981;94:35-40
17. Jin R, Wan LL, Mitsuishi T. Effects of shi-ka-ron and Chinese herbs in mice treated with anti-tumor agent mito mycin C (Chinese). Chung-Kuo Chung Hsi i Chieh, Ho Tsa Chih. 1995;15(2):101-3
18. Sugiura H, Nishida H, Indaba R, Iwata H. Effects of exercise in the growing stage in mice and of Astragalus membranaceous on immune functions (Japanese). Nippon Eiseigaku Zasshi – Japanese Journal of hygiene, 1993;47(6):1021-31
19. Yang YZ, Jin PY, Guo Q, et al. Effect of Astragalus membranaceous on natural killer cell activity and induction of a- and g- interferon in patients with coxsackie B viral myocarditis. Chinese Medical Journal 1990;103(4):304-307
20. Yang YZ, Guo Q, Jin PY, et al. Effect of Astragalus membranaceous injection on Coxsackie B-2 virus infected rat beating heart cell culture. Chinese Medical Journal. 1987;100-595
21. Hou YD. Study on the biological active ingredients of Astragalus membranaceous. Chung His i Chieh Ho Tsa Chih. 1984;4:p420
22. Zhang Xq, et al. Studies of Astragalus membranaceous on antiinfluenza virus activity, interferon induction and immunostimulation in mice. Chinese Journal of Microbiology and Immunology. 1984;4:p92
23. Research Group of Common Cold and Bronchitis. Investigation into Astragalus membranaceous. II. A research on some of its mechanism of reinforcing the Qi (vital energy.) Journal of Traditional Chinese Medicine. 1980;3:p67
24. Shi HM, Dai RH, Fan WH. Intervention of lidocaine and Astragalus membranaceous on ventricular late potentials (Chinese). Chung-Kuo Chung Hsi i Chieh, Ho Tsa Chih. 1994;14 (10):598-600
25. Li SQ, Yuan RX, Gao H. Clinical observation of the treatment of ischemic heart disease with Astragalus membranaceous (Chinese). Chung-Kuo Chung Hsi i Chieh, Ho Tsa Chih. 1995;15(2):77-80
26. Lei ZY, Qin H, Liao JZ. Action of Astragalus membranaceous on left ventricular function of antina pectoris (Chinese). Chung-Kuo Chung Hsi I Chieh, Ho Tsa Chih. 1994;14(4):199-202
27. Cha RJ, Zeng DW, Chang QS. Non-surgical treatment of small cell lung cancer with chemo-radio-immunotherapy and traditional Chinese medicine (Chinese). Chung-Hua Nei Ko Tsa Chih – Chinese Journal of Internal medicine. 1994;33(7):462-6
28. Lau BH, Ruckle HC, Botolazzo T, Lui, PD. Chinese medicinal herbs inhibit growth of murine renal cell carcinoma. Cancer Biotherapy. 1994;9(2):153-61
29. Chu DT, Lin JR, Wong W. The in vitro potentiation of LAK cell cytotoxidicty in cancer and AIDS patients induced by F3 – a fractionated extract of Astragalus membranaceous (Chinese). Chung-Hun Chung Liu Tsa Chih – Chinese Journal of Oncology. 1994;16(3):167-71
30. Hong C, Ku J, et al. Astragalus membranaceous stimulates human sperm motility in vitro. American journal of Chinese Medicine. 1992;20:289-94
31. Murray The Healing Power of Herbs. Rocklin, CA: Prima Publishing;1992:p246
32. Zhao KS, et al. Enhancement of the Immune Response in Mice by Astragalus membranaceous Extracts. Immunopharmacology. 1990;20(3):225-33
33. Chu, DT, et al. Immune Resoration of Local Xenogeneic Graft-versus-host Reaction in Cancer Patients in In-vitro and Reversal of Cyclophosphamide-induced Immune suppression in the Rat in Vivo by Fractionated Astragalus membranaceous. Chung Hsi i Chieh Ho Tsa Chih. Jun 1989;9:351-54.