The researchers, from the Weifang Asthma Hospital and Weifang School of Medicine in China, and Mount Sinai School of Medicine in New York, sought to investigate alternatives to corticosteroids, the "cornerstone" of Western asthma treatment.
Since corticosteroids can cause side effects, such as greater susceptibility to infections due to immune suppression and reduced growth velocity, they said that there is a need for additional effective treatments with fewer side effects.
In China, traditional medicine is part of mainstream practice, either used alone or in conjunction with Western medications. However, little clinical research has been carried out into traditional Chinese medicine for asthma, say the researchers.
For the double-blind placebo-controlled study published in the September issue of the Journal of Allergy and Clinical Immunology (vol. 116, issue 3), they investigated the effects of a combination of three Chinese herbal extracts: Ling-Zhi (Ganoderma lucidum), Ku-Shen (Radix Sophora flavescentis) and Gan-Cao (Radix Glycyrrhiza uralensis). The combination was dubbed ASHMI - antiasthma herbal medicine intervention.
The formulation notably excluded Ma Huang, used in many herbal asthma remedies throughout the world, since it is a source of ephedrine. Ephedine has been associated with adverse effects on the cardiovascular and central nervous systems. In the United States, dietary supplements containing more than 10mg of ephedrine alkaloids are outlawed, but the ban does not extend to Ma Huang.
ASHMI was in fact developed as a simplified version of a 14-herb formula known as MSSM-002, which the same team previously found to effectively reduce the symptoms of asthma in a mouse model. Prepared by Weifang Pharmaceutical Manufacturing Factory, ASHMI was formulated on the basis of the actions of the individual herbs in MSSM-002, and according to traditional Chinese medicine formulation concepts.
The new trial involved 91 subjects with moderate to severe persistent asthma. They were admitted to hospital for the four-week duration.
Forty-six patients were randomly assigned to receive 12 ASHMI capsules per day, each one containing 0.3g of dried aqueous extract. The total daily dosage of extracts was equivalent to 20g of raw Ling-Zhi, 9g of Ku-Shen, and 3g of Gan-Cao. Patients in this group also received placebo tablets similar in appearance to prednisone, an oral administration of the hormone cortisone.
The 46 patients in the placebo group received 20mg of prednisone per day, plus placebo capsules resembling ASHMI.
The researchers measured participants' lung function, side effects and serum cortisol, cytokine and igE levels before and after treatment. The effects of prednisone and ASHMI on lung function were "slightly but significantly greater" with prednisone. However unlike prednisone, ASHMI was seen to have no adverse effects on adrenal function, and had a beneficial effect on TH1 and TH2 cytokine levels.
In addition, fewer patients receiving ASHMI experienced gastric discomfort compared to those receiving prednisone, and the prednisone patients showed significant weight gain after four weeks of treatment.
"Taken together, the findings of this study show that ASHMI is effective and well-tolerated in nonsteroid-dependent patients with moderate-severe persistent asthma," wrote the researchers.
They said that the mechanisms underlying its "remarkable" effects are largely unknown but that they are likely to be the result of synergistic or additive effects of the complex nature of its constituents.