The peeling white bark of the common birch tree (Betula alba) has inspired
poets as one of the most beautiful sights, especially in northern climbs.
The Russians consider the birch their most beautiful tree. It also intrigues
scientists, since it is an ancient tree, whose fossil forms go back to the
upper Cretaceous period.
The white birch remains abundant from the Arctic Circle to Florida and Texas.
A good old tree can reach a height of 45 to 50 feet.
American Indians tapped the birch for its sap, for a beverage and as a syrup.
Oil of wintergreen can be distilled from its inner bark and twigs. Traditionally,
it has been used for treatment of diarrhea, dysentery, cholera, and all diseases
of the alimentary tract. It is said to be a good "blood cleanser." It has
been an approved medication in Russia since 1834.
Traditionally, a teaspoon of the leaves or bark are infused in a cup of boiling
water for 15 minutes. A person drinks three to five cups per day. It is said
to mix well with other herbal teas.
Externally applied, it is a traditional treatment for "eczema and cutaneous
diseases," according to Alma R. Hutchens, A Handbook of Native American Herbs).
So it should be little surprise that the white birch may be a source of potent
chemicals useful in the fight against melanoma and other kinds of cancer.
In 1994, scientists at the University of North Carolina at Chapel Hill reported
that compounds found in white birch bark (in this case isolated from the
leaves of an evergreen tree, Syzigium claviforum) were potent inhibitors
of the HIV virus, the putative cause of AIDS (J Nat Prod 1994;57:243-247).
In August of that year, French drug company scientists reported at the
International Conference on AIDS (abs. PA0316) that different compounds found
in birch bark were "very potent anti-HIV-1 agents acting by a novel mode
of action."
Then in March, 1995, John Pezzuto of the University of Illinois, Chicago
reported that one of these compounds, calledbetulinic acid, was able to kill
human melanoma cells transplanted into mice.
Dr. Pezzuto extracted betulin from birches found in an old woodpile near
his Chicago laboratory (Cancer Biotech Weekly, 4/3/95) and converted this
into betulinic acid. According to the scientist, betulinic acid "worked better
than the drug most commonly used in people to treat melanoma."
Unlike conventional chemotherapy, this compound caused no apparent side effects
and, for obvious reasons, is potentially very inexpensive. According to Dr.
Pezzuto, about 50 pounds of bark provides enough betulinic acid for 100 doses
of betulinic acid for people (8 oz. of bark per dose). Pezzuto, who is head
of medicinal chemistry at the university's Pharmacy School, said he hopes
human testing will begin within a year or so.
In the Chicago experiment, researchers transplanted melanoma cells into
mice's legs. Once these cells had formed tumors large enough to feel, the
animals received six injections of betulinic acid, one dose every three days.
The scientist told a major cancer meeting in Toronto that in one group of
five mice, the betulinic acid treatment shrank tumors by 70 percent in two
of the animals and 40 percent in two others. In four out of five mice who
received a different strain of melanoma, the tumors virtually disappeared.
In another kind of mouse which received betulinic acid at the same time that
melanoma cells were injected, these cells refused to form tumors.
Dr. Antonio Buzaid of the University of Texas's M.D. Anderson Cancer Center
in Houston is strongly in favor of testing the substance. "History has taught
us to be cautiously optimistic," he said, about an anti-cancer substance
that works well in animals. And Matt Suffness, of the National Cancer Institute
(NCI), said the Illinois data "looks good." This compound "has the potential
for being a reasonably nontoxic treatment for certain types of melanoma,"
Suffness has said.
Dr. Pezzuto cautions that nobody knows yet whether the substance will actually
help melanoma patients. He has also been quoted as saying that people should
not try to concoct home remedies out of birch bark—although people have
been doing just that for hundreds, possibly thousands of years.... Purified
betulinic acid may turn out to be active against not just melanoma but some
other kinds of cancer as well. Obviously, this topic is crying out for further,
vigorous testing. Dr. Klausner [DIRECTOR OF NCI, ED.]—are you listening?
