A nontoxic pill that could be
taken on an outpatient basis to combat breast cancer or leukemia
sounds like a fantasy, but the treatment is becoming a reality
due to the investigation of a University of Washington research
team into an ancient Chinese remedy for malaria.
Two bioengineering research professors at
the University of Washington have rediscovered wormwood as
a promising potential treatment for cancer among the ancient
arts of Chinese folk medicine.
Research professor Henry Lai and assistant
research professor Narendra Singh have exploited the chemical
properties of a wormwood derivative to target breast cancer
cells with surprisingly effective results. A study in the latest
issue of the journal Life Sciences describes how the derivative
killed virtually all human breast cancer cells exposed to it
within 16 hours.
"Not only does it appear to be effective,
but it's very selective," Lai said. "It's highly
toxic to the cancer cells but has a marginal impact on normal
Environmental risk factors for cancer are
many. Lifetime exposure to the female hormone estrogen and
estrogen-mimicking chemicals such as some pesticides and herbicides
has been linked to an increase in breast cancer risk. In 1991,
the International Agency for Research on Cancer classified
the pesticide DDT as a possible human carcinogen, and the U.S.
Environmental Protection Agency (EPA) has classified DDT as
a probable human carcinogen.
The manufacture of PCBs, the oily liquids
or solids used as coolants and insulators, was stopped in the
United States in 1977 because of concerns that exposure increases
the risk of cancers, but PCBs are still found in the environment.
Most Americans are exposed every day to air
toxins emitted by motor vehicles, substances that the EPA says
have been proven to cause cancer in humans. "Benzene,
says the EPA, "is a known human carcinogen, while formaldehyde;
acetaldehyde; 1,3-butadiene; and diesel particulate matter
are probable human carcinogens." The EPA has now classified
1,3-butadiene, a gas used commercially in the production of
resins and plastics, as a known human carcinogen.
The use of the bitter herb wormwood is nothing
new. Used for centuries to rid the body of worms, it is also
an ingredient in the alcoholic beverage absinthe, now banned
in most countries.
Artemisinin, the compound that Lai and Singh
have found to fight cancers, isn't new either. It was extracted
from the plant Artemesia annua L.,
commonly known as wormwood, thousands of years ago by the Chinese,
who used it to combat the mosquito-borne disease malaria. The
treatment with artemisinin was lost over time but rediscovered
during an archaeological dig in the 1970s that unearthed recipes
for ancient medical remedies.
Now widely used in Asia and Africa to fight
malaria, artemisinin reacts with the high iron concentrations
found in the malaria parasite. When artemisinin comes into
contact with iron, a chemical reaction ensues, spawning charged
atoms that chemists call free radicals. The free radicals attack
cell membranes, breaking them apart and killing the single-cell
About seven years ago, Lai began to hypothesize
that the process might work with cancer, too.
"Cancer cells need a lot of iron to replicate
DNA when they divide," Lai explained. "As a result,
cancer cells have much higher iron concentrations than normal
cells. When we began to understand how artemisinin worked,
I started wondering if we could use that knowledge to target
Lai devised a potential method and began to
look for funding, obtaining a grant from the Breast Cancer
Fund in San Francisco. Meanwhile, the UW patented his idea.
The thrust of the idea, according to Lai and
Singh, was to pump up the cancer cells with maximum iron concentrations,
then introduce artemisinin to selectively kill the cancer.
In the current study, after eight hours, just
25 percent of the cancer cells remained. By the time 16 hours
had passed, nearly all the cells were dead.
An earlier study involving leukemia cells
yielded even more impressive results. The cancer cells were
eliminated within eight hours. A possible explanation might
be the level of iron in the leukemia cells. "They have
one of the highest iron concentrations among cancer cells," Lai
explained. "Leukemia cells can have more than 1,000 times
the concentration of iron that normal cells have."
The next step, according to Lai, is animal
testing. Limited tests have been done in that area. In an earlier
study, a dog with bone cancer so severe it couldn't walk made
a complete recovery in five days after receiving the treatment.
But more rigorous testing is needed.
If the process lives up to its early promise,
it could revolutionize the way some cancers are approached,
Lai said. The goal would be a treatment that could be taken
orally on an outpatient basis."
That would be very easy, and this could make
that possible," Lai said. "The cost is another plus:
At $2 a dose, it's very cheap. And with the millions of people
who have already taken artemisinin for malaria, we have a track
record showing that it's safe."
Whatever happens, Lai said, a portion of the
credit will have to go to unknown medical practitioners, long
gone now. "The fascinating thing is that this was something
the Chinese used thousands of years ago," he said. "We
simply found a different application."
Copyright © 2001 Environmental
News Network Inc.
Remarks on the usage of this
on wormwood as well as parasites on kitchendoctor.com