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Astragalus

What Is Astragalus Used for Today? | What Is the Scientific Evidence for Astragalus? | Dosage | Safety Issues | References

Astragalus membranaceus


Principal Proposed Uses
  • Strengthen Immunity (Against Colds, Flus, and Other Illnesses)
Other Proposed Uses
  • AIDS; Atherosclerosis; Chemotherapy Side Effects; Chronic Active Hepatitis; Diabetes; Genital Herpes; Hypertension (High Blood Pressure); Hyperthyroidism; Insomnia
 

 


Dried and sliced thin, the root of the astragalus plant is a common component of Chinese herbal formulas. According to tradition, astragalus "strengthens the spleen, blood, and Qi; raises the yang Qi of the spleen and stomach; and stabilizes the exterior."1  Don't worry if you didn't understand what you just read, because without many months of training in traditional Chinese herbal medicine, there's no way you could have. Suffice it to say that the traditional understanding of the way astragalus works is different from the way it tends to be presented today.

 


What Is Astragalus Used for Today?

In the United States, astragalus has been presented as an immune stimulant useful for treating colds and flus. Many people have come to believe that they should take astragalus, like echinacea, at the first sign of a cold.

The belief that astragalus can strengthen immunity has a partial basis in traditional Chinese medicine. The expression noted above, "stabilize the exterior," means helping to create a "defensive shield" against infection. However, according to tradition, astragalus formulas should not be taken during the early stage of infections. To do so is said to resemble "locking the chicken-coop with the fox inside," causing the infection to be "driven deeper." Rather, astragalus is supposedly appropriate only for use while you're healthy, for the purpose of preventing future illnesses.

 


What Is the Scientific Evidence for Astragalus?

Although Chinese herbal tradition suggests that astragalus should generally be used in combination with other herbs, modern Chinese investigators have found various intriguing effects when astragalus is taken by itself. Extracts of astragalus have been found to stimulate parts of the immune system in mice and humans, and to increase the survival time of mice infected with various diseases.2,3  Astragalus has also been shown to enhance diuresis (urine output) by encouraging the kidneys to release more sodium into the urine.12  Other highly preliminary research suggests that astragalus might be useful in treating atherosclerosis, hyperthyroidism, hypertension, insomnia, diabetes, chronic active hepatitis, genital herpes, AIDS, and increase the efficacy and/or reduce the side effects of cancer chemotherapy.4-9, 11  However, none of these possibilities can be regarded as proven.

 


Dosage

A typical daily dosage of astragalus involves boiling 9 to 30 g of dried root to make tea. Newer products use an alcohol-and-water extraction method to produce an extract standardized to astragaloside content, although there is no consensus on the proper percentage.

 


Safety Issues

Astragalus appears to be relatively nontoxic. High one-time doses, as well as long-term administration, have not caused significant harmful effects.10  Side effects are rare and generally limited to the usual mild gastrointestinal distress or allergic reactions. However, some Chinese herb manuals suggest that astragalus at 15 g or lower per day can raise blood pressure, while doses above 30 g may lower blood pressure.

As mentioned above, traditional Chinese medicine warns against using astragalus in cases of acute infections. Other traditional contraindications include "deficient yin patterns with heat signs" and "exterior excess heat patterns." Because understanding what these mean would require an extensive education in traditional Chinese herbal medicine, we recommend using astragalus only under the supervision of a qualified Chinese herbalist.

Safety in young children, pregnant or nursing women, or those with severe liver or kidney disease has not been established.


References[ - ]

1. Bensky D, Gamble A, Kaptchuk TJ. Chinese Herbal Medicine: Materia Medica. Seattle, Wash: Eastland Press; 1986:457-459.

2. Hou YD, Ma GL, Wu SH, et al. Effect of Radix Astragali seu Hedysari on the interferon system. Chin Med J (Engl). 1981;94:35-40.

3. Sun Y, Hersh EM, Talpaz M, et al. Immune restoration and/or augmentation of local graft versus host reaction by traditional Chinese medicinal herbs. Cancer. 1983;52:70-73.

4. Bensky D, Gamble A, Kaptchuk TJ. Chinese Herbal Medicine: Materia Medica. Seattle, WA: Eastland Press; 1986:457-459.

5. Liang R. Clinical study on braincalming tablets in treating 450 cases of atherosclerosis. J North Chin Med. 1985;1:63-65.

6. Xia SN, Xu ZZ, Zhang ZH, et al. Hyperthyroidism treated with "yiqiyangyin" decoction. J Tradit Chin Med. 1986;6:79-82.

7. Zhang YD, Wang YL, Shen JP, et al. Effects on blood pressure and inflammation of astragalus saponin 1, a principle isolated from Astragalus membranaceus BGE [in Chinese, English abstract]. Acta Pharm Sin. 1984;19:333-337.

8. Zhang H. Treatment of adult diabetes with jiangtangjia tablets. J Trad Chin Med. 1986;7:37-39.

9. Zhou MX. Therapeutic effect of astragalus in treating chronic active hepatitis and the changes in immune function [in Chinese]. J Chin People's Liberation Army. 1982;7:242-244.

10. Bensky D, Gamble A, Kaptchuk TJ. Chinese Herbal Medicine: Materia Medica. Seattle, WA: Eastland Press; 1986:457-459.

11. McCulloch M, See C, Shu XJ, et al. Astragalus-based Chinese herbs and platinum-based chemotherapy for advanced non-small-cell lung cancer: meta-analysis of randomized trials. J Clin Oncol. 2006;24:419-30.

12. Ai P, Yong G, Dingkun G, et al. Aqueous extract of Astragali Radix induces human natriuresis through enhancement of renal response to atrial natriuretic peptide. J Ethnopharmacol. 2007 Dec 23.



Astragalus

Overview:

Astragalus (Astragalus membranaceus) has been used in Traditional Chinese Medicine (TCM) for thousands of years. It was often combined with other herbs to strengthen the body against disease. Astragaus is called an adaptogen, meaning it is thought to help protect the body against various stresses, including physical, mental, or emotional stress.

Astragalus may help protect the body from diseases such as cancer and diabetes. It contains antioxidants, which protect cells against damage caused by free radicals, byproducts of cellular energy. Astragalus is used to protect and support the immune system, for preventing colds and upper respiratory infections, to lower blood pressure, to treat diabetes, and to protect the liver.

Astragalus has antibacterial and anti-inflammatory properties. It is sometimes used on the skin for wounds. In addition, studies have shown that astragalus has antiviral properties and stimulates the immune system, suggesting that it may help prevent colds.

In the United States, researchers have looked at astragalus as a possible treatment for people whose immune systems have been weakened by chemotherapy or radiation. In these studies, astragalus supplements seem to help people recover faster and live longer. Research on using astragalus for people with AIDS has produced mixed results.

Recent research in China suggests that, because astragalus is an antioxidant, it may help people with severe forms of heart disease, relieving symptoms and improving heart function. At low-to-moderate doses, astragalus has few side effects. However, it does interact with a number of other herbs and prescription medications. Astragalus may also be a mild diuretic, meaning it helps the body get rid of excess fluid.

Plant Description:

Astragalus is a perennial plant, about 16 - 36 inches tall, that is native to the northern and eastern parts of China as well as Mongolia and Korea. It has hairy stems with leaves made up of 12 - 18 pairs of leaflets. The root is the medicinal part, and is usually harvested from 4-year-old plants.

Parts Used:

The dried root is used medicinally.

Medicinal Uses and Indications:

Astragalus has been used for the following:

  • Adaptogen -- protects the body from stress and disease
  • Anemia -- One early study suggested astragalus may improve blood counts in people with aplastic anemia. But the study was poorly designed, so more research is needed.
  • Colds and influenza -- In TCM, astragalus is used as part of an herbal combination to prevent or treat colds, although TCM theory holds that, in some cases, it may make colds worse. Evidence in animal and laboratory tests suggests that it may act against viruses like the ones that cause colds.
  • Diabetes -- Astragalus appears to lower blood sugar. More studies are needed to know whether it can actually help treat diabetes.
  • Fatigue or lack of appetite from chemotherapy -- Some studies suggest astragalus may help reduce side effects from chemotherapy. The studies have not been well designed, however. More research is needed.
  • Heart disease -- Several studies suggest that astragalus may act as an antioxidant and help treat heart disease. However, most of the studies were not well designed, so more research is needed.
  • Hepatitis -- A few studies have used a combination of herbs containing astragalus to treat hepatitis. Results have been mixed.
  • Kidney disease -- Astragalus may help protect the kidneys and may help treat kidney disease, although the research is preliminary. More studies are needed.
  • Seasonal allergies -- One study found that astragalus may help reduce symptoms in people who have allergic rhinitis or hayfever.

Available Forms:

Astragalus root may be available in a variety of forms:

  • Tincture (liquid alcohol extract)
  • Capsules and tablets, standardized and non-standardized
  • Injectable forms for use in hospital or clinical settings in Asian countries
  • Topically for the skin

How to Take It:

Pediatric

There is not a lot of scientific evidence about giving astragalus to children, so ask your doctor first. According to Traditional Chinese Medicine, you should not give astragalus to a child with fever because the herb may make the fever last longer or grow stronger. Any dosage should be determined by your doctor.

Adult

Doses from 1 - 25 g per day are sometimes used. Higher doses may suppress the immune system. For best results, it is recommended to use a standardized astragalus supplement. Recommended doses are as follows:

  • Standardized extract: 250 - 500 mg, three to four times a day standardized to 0.4% 4-hydroxy-3-methoxy isoflavone 7-sug.
  • Decoction (strong boiled tea): 3 - 6 g of dried root per 12 oz water, three times per day
  • Fluid extract (1:1) in 25% ethanol: 2 - 4 mL, three times a day
  • Powdered root: 500 - 1,000 mg, three or four times per day
  • Ointment: 10% astragalus applied to surface of wound. Do not apply to open wound without your doctor's supervision.
  • Tincture (1:5) in 30% ethanol: 3 - 5 mL, three times a day

Precautions:

At recommended doses, astragalus has no serious side effects and can generally be used safely. It does interact with other herbs and medications (see Possible Interactions section).

There is not much evidence about whether astragalus is safe for women who are breastfeeding or nursing. Talk to your doctor before taking any medication, including herbs.

Possible Interactions:

If you take any of the following medications, you should not use astragalus without first asking your doctor:

Drugs that suppress the immune system -- Astragalus may interfere with how these drugs act. If you have an autoimmune disease such as rheumatoid arthritis or lupus, or take cyclophosphamide, a medication used to reduce the chances of rejection in transplant recipients, or corticosteroids, do not take astragalus.

Lithium -- Astragalus can make it harder for the body to get rid of lithium, so dangerously high levels of the drug could build up.

Alternative Names:

Astragalus membranaceus; Astragalus mongholicus; Huang-qi; Milk-vetch root

  • Reviewed last on: 10/12/2010
  • Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.

Supporting Research

Chen KT, Su CH, Hsin LH, et al. Reducing fatigue of athletes following oral administration of huangqi jianzhong tang. Acta Pharmacol Sin. 2002;23(8):757-761.

Duan P, Wang ZM. [Clinical study on effect of Astragalus in efficacy enhancing and toxicity reducing of chemotherapy in patients of malignant tumor]. Zhongguo Zhong Xi Yi Jie He Za Zhi.2002;22(7):515-517.

Hao Y, Qiu QY, Wu J. [Effect of Astragalus polysaccharides in promoting neutrophil-vascular endothelial cell adhesion and expression of related adhesive molecules]. Zhongguo Zhong Xi Yi Jie He Za Zhi. 2004;24(5):427-430.

Hei ZQ, Zhang JJ, Lin SQ, et al. [Effects of Astragalus membranaceus injection on nitric oxide and endothelin concentration of intestinal mucosa after hemorrhage shock-reperfusion in rats]. Zhongguo Zhong Yao Za Zhi. 2004;29(5):444-447.

Kim SH, Lee SE, Oh H, et al. The radioprotective effects of bu-zhong-yi-qi-tang: a prescription of traditional Chinesemedicine astragalus. J Chin Med. 2002;30(1):127-137.

Mao SP, Cheng KL, Zhou YF. [Modulatory effect of Astragalus membranaceus on Th1/Th2 cytokine in patients with herpes simplex keratitis]. Zhongguo Zhong Xi Yi Jie He Za Zhi. 2004;24(2):121-123.

Matkovic Z, Zivkovic V, Korica M, et al. Efficacy and safety of Astragalus membranaceus in the treatment of patients with seasonal allergic rhinitis. Phytother Res. 2010;24:175-81.

Shao BM, Xu W, Dai H, et al. A study on the immune receptors for polysaccharides from the roots of Astragalus membranaceus, a Chinese medicinal herb. Biochem Biophys Res Commun. 2004;320(4):1103-1111.

Shi FS, Yang ZG, Di GP. [Effect of Astragalus saponin on vascular endothelial cell and its function in burn patients]. Zhongguo Zhong Xi Yi Jie He Za Zhi. 2001;21(10):750-751.

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