Turmeric Prevents Experimental Rheumatoid

Arthritis, Bone Loss

An
ancient spice, long used in traditional Asian medicine, may hold
promise for the prevention of both rheumatoid arthritis and
osteoporosis, according to a recently completed study at The University
of Arizona College of Medicine.

Turmeric, the spice that flavors and gives its
yellow color to many curries and other foods, has been used for
centuries by practitioners of Ayurvedic medicine to treat inflammatory
disorders. Turmeric extract containing the ingredient curcumin is
marketed widely in the Western world as a dietary supplement for the
treatment and prevention of a variety of disorders, including arthritis.

At
the UA College of Medicine, Janet L. Funk, MD, working with Barbara N.
Timmermann, PhD, then-director of the National Institutes of Health
(NIH)-funded Arizona Center for Phytomedicine Research at the UA, set
out to determine whether (and how) turmeric works as an anti-arthritic.
They began by preparing their own extracts from the rhizome, or root,
of the plant, providing themselves with well-characterized materials to
test and to compare with commercially available products. (Dr.
Timmermann since has joined the faculty of the University of Kansas,
Lawrence, Kan.)

Dr. Funk and her colleagues then tested in animal
models a whole extract of turmeric root, only the essential oils, and
an oil-depleted extract containing the three major curcuminoids found
in the rhizome. Of the three extracts, the one containing the major
curcuminoids was most similar in chemical composition to commercially
available turmeric dietary supplements. It also was the most effective,
completely inhibiting the onset of rheumatoid arthritis.

Dr.
Funk, an endocrinologist in the UA Department of Medicine, says this
study provides several noteworthy “firsts.” Completed with the
researchers’ own prepared, well-defined extracts, the study represents
the first documentation of the chemical composition of a
curcumin-containing extract tested in a living organism, in vivo, for
anti-arthritic efficacy. It also provides the first evidence of
anti-arthritic efficacy of a complex turmeric extract that is analogous
in composition to turmeric dietary supplements.

The
significance, she explains, is that translating the results of trials
such as these to clinical use depends on accurate information about the
chemical content and biological activity of the botanical supplements
available for use. This work paves the way for the preclinical and
clinical trials needed before turmeric supplements can be recommended
for medicinal use in preventing or suppressing rheumatoid arthritis.

This
study also provides the first in vivo documentation of a mechanism of
action — how curcumin-containing extracts protect against arthritis.
The researchers found that the curcuminoid extract inhibits a
transcription factor called NF-KB from being activated in the joint. A
transcription factor is a protein that controls when genes are switched
on or off. Once the transcription factor NF-KB is activated, or turned
on, it binds to genes and enhances production of inflammatory proteins,
destructive to the joint. The finding that curcuminoid extract inhibits
activation of NF-KB suggests that turmeric dietary supplements share
the same mechanism of action as anti-arthritic pharmaceuticals under
development that target NF-KB. It also suggests that turmeric may have
a use in other inflammatory disorders, such as asthma, multiple
sclerosis and inflammatory bowel disease.

In addition to
preventing joint inflammation, Dr. Funk’s study shows that the
curcuminoid extract blocked the pathway that affects bone resorption.
Noting that bone loss associated with osteoporosis in women typically
begins before the onset of menopause, she has begun work on another
NIH-funded study to determine whether turmeric taken as a dietary
supplement during perimenopause can prevent bone loss and osteoporosis.
Both of the studies are supported by the National Center for
Complementary and Alternative Medicine (NCCAM) and the Office of
Dietary Supplements (ODS), both of the NIH.

An initial
publication of the rheumatoid arthritis study results in the Journal of
Natural Products, which was among the most-accessed articles from
April-June 2006 in this prestigious American Chemical Society journal,
is being followed by more detailed study results, which will appear in
the November 2006 issue of the American College of Rheumatology
flagship journal, Arthritis and Rheumatism. The article, “Efficacy and
Mechanism of Action of Turmeric Supplements in the Treatment of
Experimental Arthritis,” is scheduled to appear in the online issue of
Arthritis and Rheumatism Monday, Oct. 30, 2006.

Contributors to
the study include Janet L. Funk, MD; Jennifer B. Frye; Janice N.
Oyarzo, MS; Nesrin Kuscuoglu, PhD; Jonathan Wilson; Gwen McCaffrey,
PhD; Gregory Stafford; Guanjie Chen, MD; R. Clark Lantz, PhD; Shivanand
D. Jolad, PhD; Aniko M. Soìlyom, PhD; Pawel R. Kiela, DVM, PhD; and
Barbara N. Timmermann, PhD.