Once known only by traditional Chinese healers, Astragalus (Astragalus membranaceus) is now become more popularized by itís use with Western Herbalists. Known to the Orientals as Huang Qui (Yellow energy), named because of the roots yellow core, the herb, which is a member of the legume or bean family, has been a part of traditional Chinese medicine for the last 2000 years. Its roots, which are the parts used for healing, are sweet and slightly warm and said to work as a mild antibiotic, influencing the lung and the digestive tract. The herb has also been found to raise vitality, stop debilitating sweating, promote healing and tissue regeneration. The raw root has been traditionally considered to benefit the bodyís resistance, promote dieresis, reduce swelling, promote suppuration (drains pus), and regenerate tissue or promote muscle growth. Cured root is said to replenish the vital energy and used as a tonic to treat general weakness, fatigue, lack of appetite, etc. Many a person suffering from chronic fatigue have benefited from the regular use of Astragalus.
From a Western herbal perspective, the action of Astragalus is said to be adaptogenic, immune stimulating, tonic in nature, diuretic and cardio-tonic. It is very useful for regulating the immune system, increasing energy, reducing toxicity in the liver, lowering blood pressure, dilating blood vessels and increasing the endurance of the heart. It has also been found to be very useful in increasing urine flow and aiding in the recovery from bladder infection as well as helping to neutralize fevers and improve digestion.
Many constituents have been isolated from Astragalus root, but the relative importance of these constituents to oral activity in humans has not yet been clearly defined. Besides this fact, considerable evidence has been gathered identifying what is believed to be the most active constituents within the herb, though, one would be presumptuous in assuming that the activity of the herb is solely due to one isolate rather than the complex interplay of the plants whole chemistry.
The polysaccharides, especially the polysaccarrhide fraction F3, for example, show considerable immune-enhancing activity in vitro. They have been found to potentiate the immune-mediated anti-tumour activity of interleukin-2 in vitro, improve the response of lymphocytes from normal subjects and cancer patients in vitro, enhance the natural killer cells activity of normal subjects and potentiate monocyte activity in vitro.
Clinical studies have also confirmed the immune enhancing activity of the herb in vivo. In one particular Chinese study, 115 volunteers with leucopenia (low white blood cell count) where treated with whole root extracts of Astragalus membranaceus. The 115 volunteers were then divided into two randomised groups of 57 and 58. The first group of 57 where given 10grams of astragalus daily, while the second group of 58 received the equivalent of 30 grams per day.
he course of the treatment ran for 8 weeks for both groups and blood white blood cell counts were monitored. The results showed that both groups had an increase in WBC count, but the WBC count average was much higher in those taking 30 grams of Astragalus. Based on the results provided the author suggests that Astragalus not only promotes an increase in WBC count, but is also an effective treatment for leucopenia. Unfortunately the study did not include a placebo or control group.
Besides the constituents discussed, the herb also contains a reasonably broad level of trace elements. More than 20 have been isolated with, magnesium, iron, manganese, zinc, copper, rubidium, molybdenum and chromium being the major ones.
Astragalus is a highly valued Chinese herbal tonic. Like Ginseng, its pharmacological properties are varied including immunopotentiating effects, anti-bacterial and anti-viral properties, the ability to promote nucleic acid synthesis in the liver and spleen, hepatoprotective, anti-inflammatory activity, cardiovascular tonic effects such as hypotensive and vasodilatory action as well as a possible blood glucose balancing action. The herb has also been found to increase superoxide dismutase activity thus acting as a powerful anti-oxidant as well as promoting cartilage growth in vitro.
Experiments also show astragalus to be liver cell protective in laboratory induced hepatitis by preventing liver glycogen reduction caused by carbon tetrachloride exposure. In conjunction with Silybum marianum (St Marys Thistle), it would appear that astragalus, with its anti-viral and liver protective action, may contribute many benefits in the treatment of Hepatitis C.
Together with the above actions, other research has found that the herb to be very useful in the treatment of kidney disease having the ability to reduce urinary protein in chronic and acute nephritis. These effects appear to be mainly due to the saponins and polysaccharides found in the herb.
Whole root extracts have also been shown to have a profound effect on phagocytic and macrophage activity. In a variety of studies involving mice, Astragalus was shown to enhance phagocytic activity and increase super-oxide production and acid phosphatase activity of peritoneal macrophages. These benefits appear to also be passed onto the humoral immunity. Oral doses of the dried extract when given to humans were shown to increse levels of anti-bodies such as IgE and IgM. In another study, two months of oral treatment in subjects susceptible to the common cold, greatly increased levels of IgA and IgG in nasal secretions. Oral doses of Astragalus were also found to increase serum levels of IgG as well as conversion percentage of lymphocytes when given to mice.
The herb has also been observed to exert a marked antiviral action. This is most likely to be due to increased immunity and possibly the enhancement of interferon production. Together with this observation, numerous studies have shown protective effects of Astragalus with both parainfluenza virus type I and Coxsackie B virus infection of myocardial cells in vitro and vivo after injection. In vitro studies have also confirmed that the herb has anti-microbial effects against Shingella dysenteriae, Streptococcus haemolyticus, Diploccus pneumonia and Staphylococcus aureus.
Clinical studies have also confirmed the herb efficacy. Patients with low white blood cell counts responded to treatment with astragalus, maintaining 4000 cells per mL while on the preparation. In another study with 1000 subjects, prophylactic effect against the common cold was shown for oral doses and nasal sprays. There was also a decreased incidence and shortened duration of infection. Astragalus has also been found to have a cardio-tonic effect not unlike that of Hawthorn berry (Crataegus oxyacanthoides), where it was found to increase cardio output and stroke volume. From a TCM point of view, the herb is used to rebuild vital energy especially with congestive heart failure, where the disease is seen as a deficiency in vital energy. In one particular study, 20 patients with angina pectoris where treated with astragalus. All patients showed an increase in cardio output, however no improvement of left ventricular diastolic function was observed. Chinese researchers also suggest that the herb is useful in conjunction with more orthodox treatments of certain types of cancers. Patients with small lung cancer for example, were administered combined treatment of chemotherapy, radiotherapy, immunotherapy and herbal medicine consisting of Panax ginseng leaf and astragalus root. The combination of therapy resulted in an increase in survival rates, with some patients gaining 3 to 17 years of survival.
Another trial using ginseng and astragalus injections in conjunction with chemotherapy in patients with malignant tumour of the digestive tract had reduced toxic effects of the chemotherapy and increased weight. The white blood cell count did not reduce markedly in contrast to controls. Clinical trials also suggest that the herb has therapeutic benefit in assisting in the healing of peptic ulcers, especially gastric, and chronic nephritis.
Based on studies and clinical trials, astragalus may have some benefits assist recovery associated to prevention of infection and weekend immunity, bacterial or viral infections and health issues associated extended fatigue.