- LONDON (Agence France Presse) - A Chinese traditional remedy derived
from plants, which has shown itself to be effective in treating certain
forms of leukemia, has revealed its secrets to French molecular biologists,
according to a report in the May issue of the monthly Nature Cell Biology.
- The scientists found that indirubin,
which is a component of the ancient Chinese remedy, blocks the multiplication
or the division of the cancerous cells.
- Chinese herbal remedies, in use for centuries,
are generally a mixture of several plants and it is often difficult to
isolate the active ingredients and determine how they work.
- In their study of the remedy Danggui
Longhui Wan, which is a mixture of 11 plants, the team of Laurent Meijer
of the CNRS cellular cycle laboratory in Roscoff, Brittany, used the resources
of molecular biology.
- Indirubin, which is the red relative
of indigo blue, the first dye used by man, had been regarded for some
time as the active ingredient of the Danggui Longhui Wan potion, which
is used to treat chronic myeloid leukemia.
- The French team, working in collaborating
with British and German scientists, found that indirubin interacted with
a class of proteins called cyclin dependent kinases (CDK). These enzymes
play a role in the process which commands cell division, the report said.
- "When indirubin binds to these kinases,
it blocks their activity and hence halts cell division," the report
- "Meijer's group have also determined
the molecular structure of a complex molecule comprised of CDKs bound to
indirubin. This structure sheds light on how exactly indirubin is able
to specifically impede the function of these enzymes but not others like
- "It is hoped that these insights
into the way indirubin - and indeed Danggui Longhui Wan - works may feed
into the search for better anti-cancer drugs," the report said.
- Future development of "powerful
and selective inhibitors" of CDK enzymes "offers hope for future
application in the treatment of various diseases," the scientists
said in a complementary report published in the Franco-Quebec review Medicine-Sciences.