The spice for joint inflammation: anti-inflammatory role of curcumin in treating osteoarthritis

Abstract

Osteoarthritis is a degenerative disease of the joint affecting aging populations worldwide. It has an underlying inflammatory cause, which contributes to the loss of chondrocytes, leading to diminished cartilage layer at the affected joints. Compounds with anti-inflammatory properties are potential treatment agents for osteoarthritis. Curcumin derived from Curcuma species is an anti-inflammatory compound as such. This review aims to summarize the antiosteoarthritic effects of curcumin derived from clinical and preclinical studies. Many clinical trials have been conducted to determine the effectiveness of curcumin in osteoarthritic patients. Extracts of Curcuma species, curcuminoids and enhanced curcumin, were used in these studies. Patients with osteoarthritis showed improvement in pain, physical function, and quality of life after taking curcumin. They also reported reduced concomitant usage of analgesics and side effects during treatment. In vitro studies demonstrated that curcumin could prevent the apoptosis of chondrocytes, suppress the release of proteoglycans and metal metalloproteases and expression of cyclooxygenase, prostaglandin E-2, and inflammatory cytokines in chondrocytes. These were achieved by blocking the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) system in the chondrocytes, by preventing the activation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha, phosphorylation, and translocation of the p65 subunit of NF-κB complexes into the nucleus. In conclusion, curcumin is a potential candidate for the treatment of osteoarthritis. More well-planned randomized control trials and enhanced curcumin formulation are required to justify the use of curcumin in treating osteoarthritis.

Alternative Therapeutic Approach for Cartilage Repair

“…When stimulated by interleukins IL-1β and TNF-α, there is activation of I kappa beta kinase (IKK), which promotes the phosphorylation of IKB-α. Thus, IKB-α is degraded by ubiquitination, and the dimers compounded by p50 and p65 reach the nucleus and can stimulate the expression of more than 400 genes, of which some are proinflammatory and pro-apoptotic genes [8,18]. Therefore, there is production of various interleukins, including IL-1, IL-6, IL-8, and IL-10 [8, 15,16].…”

“…longa, or turmeric or saffron, is native to Asia and India and belongs to the Zingiberaceae family, and its rhizome has been used as a seasoning and in the traditional medicine since ancient times [18,25].…”

“…The three most important compounds originated from this rhizome are curcumin (diferuloylmethane), bisdemethoxycurcumin, and demethoxycurcumin, which are present, respectively, in concentrations of 77, 17, and 3%. Curcumin gives the typical yellowish coloration of the rhizome, and this part of the plant is the most widely studied [18,26,27].…”

“…By inhibiting the phosphorylation of this kinase, curcumin prevents the activation of NF-kB. Consequently, it inhibits the expression of pro-apoptotic genes in chondrocytes (caspase-3) and the formation of inflammatory mediators [18]. Thus, it is responsible for the downregulation of lipoxygenases, COX-2, phospholipase A2, prostaglandin E2 (PGE2), IL-1β, IL-6, and IL-8 [19,30].…”

“…Therefore, curcumin acts on the NF-kB system, in addition to the stimulation of the production of type II collagen and glycosaminoglycan resulting in a protective and anti-inflammatory action of cartilage and bones, reducing pain and improving the quality of life of patients with degenerative diseases [18].…”