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Research Highlights
Popular Herb 'Goldenseal' Lowers Cholesterol in Lab Tests
September 21, 2006
This article was taken from VA Research Currents, September 2006.
Animal and cell-culture tests by a team at the VA Palo Alto Health Care System have shown that goldenseal root, a popular North American herb used mainly to fight upper respiratory infections, may also be an effective cholesterol-lowering agent. The findings appeared online last month in the Journal of Lipid Research and are scheduled to appear in print next month.
According to senior investigator Jingwen Liu, PhD, this would be a heretofore unreported application for goldenseal, one of the five top-selling herbs in the U.S. "The cholesterol-lowering effect of goldenseal has never been reported in the literature," said Liu, a molecular biologist.
Previous research by Liu and colleagues found that berberine, an alkaloid found in goldenseal and other herbs, could lower lipids. In a small clinical trial published in 2004 in Nature Medicine, a group of Liu's collaborators in China treated 32 hyperlipidemic patients with berberine isolated from the traditional Chinese herb huang lian, or coptis chinensis—used, like goldenseal, mainly as an antimicrobial. On average, the patients' cholesterol and triglyceride levels dropped by about a third.
In the new research, conducted solely
in Liu's VA lab, goldenseal root proved
more powerful than berberine by itself as
an agent against high cholesterol. Based
on the evidence from her cell-culture and
hamster experiments, Liu believes that other
compounds in goldenseal, in addition to
berberine, work in concert to keep lipids
in check. Her team identified one of these
compounds as canadine. They are working
to purify and characterize two others.
The study showed that the compounds
boost the production of a protein known as
LDLR (liver low-density lipoprotein receptor).
Anchored to the surface of liver cells,
LDLR grabs particles of LDL, or "bad,"
cholesterol from the blood and draws them
inside the cell. This lowers cholesterol in
the bloodstream.
Statin drugs—used by millions of Americans
to lower cholesterol—accomplish the
same job, but they do so by blocking an
enzyme that enables natural production of
cholesterol in the liver. When the liver is
low in cholesterol, this activates LDLR and
liver cells take in more harmful lipids from
the bloodstream. Statins have been studied
for other possible cardiovascular and antiinflammatory
benefits, but their side effects
could include liver and muscle damage.
"Because the bioactive components in
goldenseal lower cholesterol by a mechanism
different from [that of] statins, goldenseal
could be used in combination therapy"
with statins to improve their efficacy, said
Liu. "In addition, for those patients who do
not tolerate statins due to muscle pain, goldenseal could be an alternative." She emphasized
that the herb's safety and efficacy for
this purpose would need to be evaluated in
clinical testing.
Liu's VA collaborators included Parveen
Abidi, PhD; Wei Chen, MD; Fredric B. Kraemer,
MD; and Hai Li, PhD. Their work was
supported by VA and the National Center for
Complementary and Alternative Medicine.
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