Conducted by researchers at Baqiyatallah University of Medical Sciences in Tehran, Iran, the study looked at various measures of knee discomfort. The study used a curcumin ingredient supplied by Sabinsa Corp. that was also combined with piperine (an extract of black pepper) to boost bioavailability of this notoriously hard-to-absorb compound. Sabinsa markets these ingredients under the brand names of Curcumin C3 Complex (a mixture of three curcuminoids) and Bioperine, respectively. The company also offered a decolorized Curcumin C3 Reduct version of the ingredient.
The randomized, placebo-controlled trial enrolled 40 subjects with mild to moderate knee osteoarthritis. The 19-member curcuminoids group received 1500 mg of the curcuminoids/piperine treatment in three daily doses, while the 21-member control group got a matched placebo. Measures of OA impairment used in the study were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analogue scale (VAS) and Lequesne's pain functional index (LPFI). The test group showed statistically significant improvement in all scores, with the exception of the stiffness portion of the WOMAC score. No adverse effects were observed among the curcumin group.
“Curcuminoids represent an effective and safe alternative treatment for OA,” the authors concluded.
Mode of action
In a separate paper generated from the same trial, researchers looked at the systemic antioxidant effects of curcuminoids. They concluded these effects, which have been well established in other studies, could not account for the positive effects on knee osteoarthritis observed in this study. So how did the curcuminoid treatment improve the measures for the test group?
“The primary efficacy measures in osteoarthritis trials is reduction of disease symptoms and improvement of quality of life. We have shown that by assessing WOMAC, LPFI and VAS. This clearly supports the efficacy of curcuminoids,” said Amir Hosein Sahebkar, one of the study’s authors. “there are several factors in the pathophysiology of osteoarthritis. And we just looked at systemic inflammation.”
Sahebkar noted that parsing out how curcuminoids have their effects is a complex undertaking, as these molecules interact with more than 400 molecular targets. in another paper that awaits peer review, the authors looked at the oxidative stress markers in these groups, and found that the curcuminoid/piperine combo reduced these biomarkers compared to placebo, which could account for the overall positive effects on knee osteoarthritis, Sahebkar said.
“There also other putative mechanisms: One is that curcuminoids may exert their anti-osteoarthritis effects through local anti-inflammatory properties rather than systemic effects. Hence, it would be nice to measure the biomarkers in the synovial fluid rather than in plasma. Another effect may be modulation of the immune system, as immune system deregulations may play a role in the pathogenesis of osteoarthritis. There are different potential mechanisms for the protetic effects of curcuminoids in osteoarthritis. We have looked at systemic inflammation and oxidative stress so far, and the second one has give positive results,” Sahebkar said.
Source: Phyotherapy Research
2014 May 22. doi: 10.1002/ptr.5174. [Epub ahead of print]
"Curcuminoid Treatement for Knee Osteoarthritis: A Randomized, Placebo-Controlled Trial"
Authors: Panahi Y, Rahimnia AR, Sharafi M, Alishiri G, Saburi A, Sahebkar A.