Chinese herb may treat autoimmune diseases
Study shows herb from hydrangea root targets specific immune responses
4 June, 2009 - A medicine derived from a herb used in Chinese medicine for 2,000 years is the first to target specific cells that are overactive in rheumatoid arthritis, psoriasis and other autoimmune diseases.
The ancient herb is chang shan, from the root of the blue evergreen hydrangea. It's been used in Chinese medicine to reduce fever and fight malaria.
The herb's active compound, febrifugine, is too toxic for use as a modern medicine. In the 1960s, US Army scientists created a febrifugine derivative called halofuginone as a possible malaria medicine, but further study was soon discontinued.
More recently, halofuginone was found to reduce skin collagen and was tested as a possible treatment for scleroderma. But until now, no-one knew how the medicine worked.
That may be because the medicine’s target - a specific kind of immune cell called a Th17 cell - was identified only in 2006. But now Harvard Medical School researchers Mark S. Sundrud, PhD, Anjana Rao, PhD, and colleagues show that halofuginone does indeed inhibit Th17 cells.
That's important because Th17 cells regulate autoimmune inflammatory responses. That's the kind of immune response responsible for a wide range of diseases such as inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis, type 1 diabetes, eczema and psoriasis.
‘Halofuginone may herald a revolution in the treatment of certain types of autoimmune and inflammatory diseases’, Rao says in a news release.
Why? Current medicines for autoimmune diseases take a sledgehammer approach - they break down many different immune responses, leaving patients vulnerable to infections and cancers.
A medicine that can specifically inhibit one type of immune response would be a major breakthrough. Halofuginone may turn out to be such a medicine.
‘This is really the first description of a small molecule that interferes with autoimmune pathology but is not a general immune suppressant’, Sundrud says in the news release.
An added bonus: Halofuginone could probably be taken orally, rather than by injection.
Yet the findings by Sundrud and Rao are based only on mouse studies. They must be refined and confirmed in humans before any actual medicine is developed.
Sundrud and Rao report their findings in the 5 June issue of Science.