The chemical is called parthenolide. It's the active ingredient of the feverfew plant -- also called bachelor's button --- and is common in North America. The feverfew plant has been used for centuries as an herbal medicine for migraine and rheumatoid arthritis, write the researchers, who included Monica Guzman, PhD, of the University of Rochester Medical School.
So far, parthenolide has shown promise in lab tests on human cells. Guzman and colleagues found that 18 hours of exposure to parthenolide killed leukemia stem cells -- which give rise to leukemia cancer cells -- without harming normal, healthy blood cells.
"Thus, not only is parthenolide a potent anti-leukemia agent, it has no significant toxicity to normal cells at the concentrations tested," write the researchers in the online edition of the journal Blood.
Parthenolide was also compared to a chemotherapy drug commonly used for leukemia. The drug, called cytarabine, didn't match parthenolide's results. Cytarabine showed "modest toxicity" to the leukemia cells and "relatively high toxicity" to normal cells, write the researchers.
"The data suggest that parthenolide has intriguing potential as an anti-leukemia agent," they write.
Parthenolide is the first single agent known to act on leukemia stem cells, according to a University of Rochester news release. Other leukemia treatments are like "pulling the weed without getting to the root," says the University of Rochester's Craig Jordan, PhD, in the news release. Jordan also worked on the parthenolide study.
But don't head to your herbal pharmacy just yet. Someone with leukemia should not take feverfew or any other herbal supplement without talking to his or her doctor. And feverfew and other supplements are no substitute for well-tested, proven leukemia treatments.
"A person with leukemia would not be able to take enough of the herbal remedy to halt the disease," says the news release.
Parthenolide may need some chemical modification for use, write the researchers in the journal. They say such modifications appear to retain the cancer-fighting properties, but that's being tested in living animals.
They say the next step would be to show that the compound works to halt leukemia in human cases rather than just within cells in a lab. They also want to demonstrate that treatment of leukemia with this chemical can target just stem cells.
The National Cancer Institute has put parthenolide on its rapid access program -- the fast track to take experimental drugs from the lab to human studies, says the news release. It's important to keep in mind that many drugs and herbs that appear to work in the laboratory are found to be ineffective once tested in the human body.