Astragalus Membranaceous and White Blood Cell Function


Traditional Chinese medicine as practiced today had its theoretical and philosophical tenets first outlined in the Yellow Emperor's Inner Classic, written between 200 and 100 BCE. The Inner Classic promotes the use of herbs, acupuncture, dietary management and exercise as therapeutic modalities (Bensky, Gamble).

Centuries of careful observation and empirical study have resulted in an extremely detailed and refined system of herbal use according to traditional Chinese medical theory (TCM). However, very little is known about the mechanism of action or the physiological effects of most Chinese herbs in terms of modern Western medical thought. Recently, research has been conducted, mostly in China, in an attempt to elucidate these areas.

Radix Astragali, the root of Astragalus membranaceous (Huang Ch'i), is a popular tonic herb first described in the Divine Husbandman's Classic of the Materia Medica, a text reconstructed and edited from several earlier works by Tao Hong-Jing in the 6th century CE (Bensky et al). According to TCM, Radix Astragali affects the Spleen, Lung and Triple Warmer meridians. It specifically tonifies the exterior, or protective energy (Wei Chi), which is understood to be the body's first defense against the external disease factors (ie., Wind, Cold, Damp, Heat, Dryness). Huang Ch'i also tonifies Chi, especially the Yang Chi of the Spleen and Stomach. It tonifies Blood and regulated fluid metabolism (Bensky et al; Teeguarden).

Modern research has revealed several effects of Radix Astragali.

Of primary interest to the author is the herb's reputed stimulatory effect on the immune system. Teeguarden reports on Chinese studies which have shown Astragalus to have in-vitro anti-bacterial effects, as well as an inhibitory effect on T-suppressor cells. He also cites clinical trials on cancer patients which suggest that Astragalus enhances bone marrow activity and adrenal cortical function which had been depleted by chemotherapy and/or radiation treatment. (The original papers were not available for perusal.)

One study found that Radix Astragali significantly enhanced interferon production in mice, in human cell cultures and in-vitro leucocyte samples (Hou, Ma, Wu, Li, Li). These workers also describe a clinical trial showing that a combination of human interferon and Astragalus was more effective in preventing common cold symptoms than either interferon alone or a flu vaccine. In one of the few Western studies conducted, Astragalus was found to restore T-cell function in cancer patients with an impaired immune response, and to augment T-cell function in normal donors (Sun, Hersh, Talpaz, Lee, Wong, Loo, Mavligit).

This paper will report on the effect of Radix Astragali on white blood cell (WBC) status in human volunteers as reflected by WBC differential count and by "Liv Cell" analysis.


The effect of a decoction of the Chinese tonic herb Astragalus membranaceous on certain aspects of white blood cell (WBC) status was studied in seven healthy volunteers. After a one week course of treatment with Astragalus decoction at a dosage equivalent to 1.5g of dried root t.i.d. per os, the relative number of leucocytes was significantly increased (p s 0.01). Furthermore, this effect was sustained (p s 0.05) one week after treatment had been discontinued. A WBC differential count showed significant changes in the proportions of individual categories of leucocytes (p s 0.05), such that high or low percentages of leucocytes were brought into normal range, with the exception of basophils, which remained high. This effect was also sustained one week after treatment had been discontinued (p s 0.05). A 'Liv Cell' analysis did not yield significant (p s 0.05), but this may have been a function of the criteria chosen to measure WBC status. This study suggests that Astragalus membranaceous may have a regulatory effect on WBC status and therefore may be a useful treatment in conditions of the deficient and excess (or disproportionate) WBC levels.

Materials and Methods

Herbal Preparation:
454 grams of grade 'A' quality dried Astragalus root was obtained from Nam Pek Hong, a reputable Chinese herb store in Toronto's Chinatown. The root was placed in 9.09 l. distilled water, brought to a boil, and then simmered to half the original volume of water, The extractive was poured off and saved. An additional 6.82 l. distilled water was added to the herb, brought to the boil and similarly simmered to half the original volume. This extractive was added to the first and white vinegar was also added to 4.5% of the final solution as a preservative. The final decoction yielded unit doses of 42.6 ml., equivalent to 1.5 g. of dried root.

The placebo solution was prepared by boiling potato with onion skins in distilled water to obtain the required color, and adding white vinegar in 4.5% of the final solution.

Twelve healthy volunteers were recruited and randomly divided into two groups of eight and four subjects, treatment and placebo groups respectively. Subjects were asked to refrain from using any other treatment modalities or making any dietary or lifestyle changes during the test period.

Experimental Design and Procedure:
A double blind format was used. Blood samples were obtained by finger prick on days 1, 8, and 15. The herbal decoction or placebo was taken for 6 days, from day 2 to 8 inclusive. The dosage was 42.6 ml. three times a day. A WBC differential count and 'Liv Cell' analysis (product information) were performed on the blood samples by a technician blind to the experimental conditions.

For the 'Liv Cell' analysis, 25 WBC's were examined for each subject. Five categories were used to indicate WBC status, namely, the number of WBC's showing:

  1. phagocytized material
  2. streaming of cytoplasm/chemotaxis
  3. irregular borders
  4. spilling of contents/degeneration
  5. no apparent activity

Categories 1 and 2 were considered indicative of positive WBC function and given a score of +1 for each cell in either of these categories. Categories 3, 4 and 5 were chosen as negative parameters of WBC status and cells appearing in them were given a score of -1 each. Overlap between categories was allowed; thus a cell showing characteristics of more than one category would be entered under each. Therefore the maximum score possible for optimal WBC function would by 50 (ie. 25 in each of categories 1 and 2, and 0 in categories 3, 4 and 5). The final score was used as an index of WBC status and comparisons were made between all possible pairs of scores.

Statistical Analysis:
The number of fields examined to yield a count of 100 WBC's was taken as an indication of the relative numbers of WBC's per sample. Statistical analysis of the changes in the number of fields between pretreatment with Astragalus and post treatment samples taken at one and two weeks respectively, was performed using a right-tailed Student's t-test for paired data at p s 0.05 level of significance. Similarly, the same test was used to analyze the change in the proportion of individual types of leucocytes, except that a two tailed test was used. Student's t- test (right-tailed) was also used to analyze the difference between the WBC index score obtained from the 'Liv Cell' analysis.


All but one treatment subject showed a decrease in the number of fields needed to locate 100 WBC's in the differential count, indicative of a relative increase in the total number of WBC's after treatment with Astragalus. The one subject who showed a slight increase in the number of fields had the lowest number of fields initially (100 as compared to the mean of 410 fields). The mean difference in numbers of fields studied was 183.9 and the difference was significant at p s 0.01. Furthermore, the change was maintained in sample number 3 taken one week after discontinuing the Astragalus (p s 0.05).

Each of the five types of leucocytes showed a significant change in their proportions of the total count immediately after treatment at p s 0.05 level of significance. The changes appeared to be regulatory, such that relatively low proportions were increased while high proportions were decreased. In most cases, except for the basophils, the differential count was brought more in line with the expected normal frequencies for adults (ie. neutrophils, 50-70%; lymphocytes, 20-40%; monocytes, 2-10%; eosinophils, 1-4%; basophils s 0.5%).

The "immune index" scores obtained using 'Liv Cell' analysis did not show an effect at the p s 0.05 level of significance. However, the mean difference (4.71) was only 0.40 units below the upper limit of acceptance for the null hypothesis (5.11). Furthermore, a significant negative change in the immune index score was shown by only one subject, and if this subject is omitted from the statistical analysis of results, the mean change in scores increases significantly at the p s 0.05 level.

It was not possible to statistically compare the treatment group with the placebo group, as only one subject in the placebo group completed the study.


Radix Astragali has long been used in traditional Chinese medicine as an important tonic herb. More recently, it has come under scrutiny regarding its physiological actions as understood in Western Medical theory. Among these is the herb's reputed positive effect on the immune system. This study has attempted to determine the effect of Astragalus decoction on certain parameters of WBC activity.

Astragalus was seen to have a stimulatory effect on the relative numbers of leucocytes at the p s 0.01 level of significance. The relative proportions of individual categories of leucocytes were also significantly affected by treatment with Astragalus (p s 0.05), such that high proportions were lowered and low proportions were raised. This effect applied to both the variance between sample means and the variance within samples. Specifically, four subjects had above normal baseline proportions of monocytes and/or eosinophils, while three subjects had below normal proportions. In each case, treatment with Astragalus brought the proportions within normal ranges. Thus Astragalus appears to have a regulatory or amphoteric effect on individual classes of leucocytes in the WBC differential count. Furthermore, these effects seem to be sustained over time as the results obtained one week after discontinuing treatment indicate. This finding corroborates observations made by Hou et al.

In addition to the WBC differential, a 'Liv Cell' analysis was used in an attempt to support findings. The Liv Cell technique allows observation of living, unstained blood corpuscles and their activity. However, criteria for standard assessment is not well established for this method. An attempt was made to choose and weight parameters visible by Liv Cell analysis which would provide a measure of immune status. The parameters chosen yielded results that were just below the p s 0.05 level of significance and that lend support to the findings obtained using the WBC differential, namely, that Astragalus appears to have an enhancing effect on leucocyte function. The Liv Cell affords valuable and unique information about the dynamic state of the blood, but more work needs to be done in setting definite criteria for both quantitative and qualitative analysis.

Although the sample size in this study was small, the results would seem to warrant further investigation into the area of enhancement of the immune system by Astragalus. Specifically, a larger sample size with a placebo control group would be in order. In addition to WBC differential count, a total WBC count should be performed. It would also be interesting to screen subjects to recruit those with both high and low baseline differentials for specific categories of leucocytes to test the hypothesized regulatory effect of Astragalus suggested by this study. Furthermore, a longer treatment time with follow-up samples taken over several months (see Hou et al) would provide more information about the long term effects.

If Astragalus is consistently found to regulate leucocyte activity, it may be a valuable adjunct in the treatment of both immune deficient conditions and conditions of aberrant leucocytosis, such as leukemia.

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