Friday March 14 2008
Traditional Chinese medicine is based on herbal treatments
Traditional Chinese herbal remedies could combat eczema, reports the Daily Mail. A “pentaherb formulation”, a combination of five herbs, “reduced sufferers' need for conventional medicines and improved the quality of life for those being treated for atopic eczema,” the newspaper says.
The findings that the report is based on follow a study carried out last year by the same researchers. The 2007 study found that the pentaherb formulation improved “quality of life” and reduced steroid use in children compared with placebo. However, the herbs were no better than placebo at reducing the symptoms of eczema. The news reports have mixed up the methods of these two different studies.
This latest study, which was carried out in the laboratory and in 28 Chinese patients with eczema, found that the herbs had no effect on steroid use. The results of this study and the earlier one are not conclusive. Herbal medicines, if they are being suggested as treatments for skin conditions, should have their safety and efficacy tested in the same way as other medicines. More randomised controlled trials are needed in this area, particularly studies that compare tested treatments (such as steroid creams and emollients) with herbal medicines.
Where did the story come from?
Dr Tin Fan Leung and colleagues from the Department of Paediatrics and Chemical Pathology and the Institute of Chinese Medicine at the Chinese University of Hong Kong carried out this study. The research was funded by the Health, Welfare and Food Bureau and by the Chinese University. It was published in the British Journal of Dermatology, a peer-reviewed medical journal.
What kind of scientific study was this?
Researchers created capsules of a “pentaherbs formulation”, a common traditional Chinese mixture of five herbs. The capsules contained Japanese honeysuckle, root bark of tree peony, peppermint, the underground stem of the atractylodes herb and bark from an Amur cork tree. This herbal formulation was tested in two ways.
First, the researchers carried out a laboratory study. They isolated peripheral blood mononuclear cells (which are part of the immune system and are known to have abnormal responses in people with eczema) from anonymous blood samples sourced through the Hong Kong Red Cross Blood Transfusion Service. These human immune cells were exposed in the laboratory to a steroid used to treat eczema (dexamethasone) or to the pentaherbs formulation. The researchers compared the effects on cell growth and the production of inflammatory mediators (chemicals released by the cells as part of their immune response). They determined how toxic the chemicals were to the cells.
In the second part of their experiment, 28 Chinese patients with moderate to severe atopic dermatitis (i.e. eczema) who were aged five to 21 years were given three capsules of the pentaherb formulation twice a day for three months. Blood samples were taken at the beginning of this period and at the end so that researchers could determine the response of the immune system and perform other tests to show how safe the formulation was.
What were the results of the study?
The researchers looked at the effects of the herbs on the human immune cells in the laboratory. They found that the steroid treatment suppressed the release of all the inflammatory chemicals from these cells. The herbal concoction reduced only some of these chemicals, and the concentration of the immune activating chemical ENA-78 was increased.
In their study of 28 Chinese patients, most of who were already being treated with a steroid (mometasone furoate), they found no change in the amount of steroid used over the three months. They also found that levels of two chemicals involved in inflammation (BDNF and TARC) reduced over the three months.
What interpretations did the researchers draw from these results?
The researchers conclude that their laboratory studies suggest that the pentaherbs formulation has some “immunomodulatory” properties (i.e. that it has an effect on the complex reactions that occur when immune cells respond).
The effects of the herbs on inflammatory agents that have been linked to eczema suggest that the herbs may have value in treatment. The researchers call for more research into the effects of ENA-78, to help understand why the herbs apparently increased circulating levels.
What does the NHS Knowledge Service make of this study?
- The authors acknowledge that “there are many limitations to this study”. They remind us that the randomised controlled trial conducted in 2007, which compared the effects of the herbs with placebo in children with eczema, did not find any effects on severity of symptoms. However, it did find that the herbs improved “quality of life” and reduced the use of steroids.
- In this particular study, the test on live patients was not randomised and there was no comparison with other treatments. This type of design is a weak one to test the effects of a treatment. This study found that the use of the herb had no effect on steroid use.
There is limited evidence overall that herbal treatments are effective in treating eczema. The herbal medicine industry is a controversial one because it is largely unregulated. Various herbs are used to “treat” eczema, but there is little evidence to prove how safe or effective they are. Randomised controlled trials are the only way properly to explore whether these herbal treatments work or not. Until there is a consistent body of knowledge and evidence about herbal treatments, it would be premature to recommend their use.
For now, people with eczema should continue to use conventional treatments, such as steroids and emollients, for which there is strong supporting evidence.