Turmeric has been used for centuries in Ayurvedic medicine as a treatment for inflammatory disorders including arthritis. Based on this traditional usage, dietary supplements containing turmeric rhizome and turmeric extracts are also being used in the western world for arthritis treatment and prevention. However, to our knowledge, no data are available regarding anti-arthritic efficacy of complex turmeric extracts similar in composition to those available for use as dietary supplements. Therefore, the studies described here were undertaken to determine the in vivo efficacy of well characterized curcuminoid-containing turmeric extracts in the prevention or treatment of arthritis using streptococcal cell wall (SCW) induced arthritis, a well-described animal model of rheumatoid arthritis (RA). Arthritic index, a clinical measure of joint swelling, was used as the primary endpoint for assessing the effect of extracts on joint inflammation. An essential oil-depleted turmeric fraction containing 41% of the three major curcuminoids was efficacious in preventing joint inflammation when treatment was started before, but not after, the onset of joint inflammation. A commercial sample containing 94% of the three major curcuminoids was more potent in preventing arthritis than the essential oil-depleted turmeric fraction when compared by total curcuminoid dose per body weight. In conclusion, these data (1) document the in vivo anti-arthritic efficacy of an essential oil-depleted turmeric fraction and (2) suggest that the three major curcuminoids are responsible for this anti-arthritic effect, while the remaining compounds in the crude turmeric extract may inhibit this protective effect.
Turmeric (Curcuma longa L. [Zingiberaceae]) is a perennial native to Asia where its rhizome is used as a spice (being responsible for the yellow color of curry), a pigment dye for textiles or for skin in religious ceremonies, and a traditional medicine, primarily used for the treatment of inflammatory disorders.1 Typical dietary intake of turmeric is estimated to be as high as 2.5 g/d (approximately 100 mg curcumin/d) in some countries,2 while up to 8 g/d of curcumin, one of the three major curcuminoids (curcumin [1], demethoxycurcumin [2] and bis-demethoxycurcumin [3], see Figure 1) that constitute 3% of the total rhizome, is without evidence of side effects in Phase I clinical trials.3