Curcuminoids are potent antioxidants and have been shown to modulate oxidative stress through various mechanisms. Curcuminoids can scavenge free radicals owing to the presence of phenolic hydroxyl groups, an effect that leads to reduced lipid peroxidation and attenuation of oxidative damage to DNA and proteins. In addition curcuminoids reduce the formation of free radicals by blocking enzymes such as COX-II, 5-lipooxygenase and inducible nitric oxide synthase, and enhance intracellular antioxidant defense through stimulation of nuclear factor-erythroid-2-related factor 2 (Nrf-2) . All these effects may account for the amelioration of joint health and pain relief following curcuminoid supplementation.