Inflammatory injury mediated by reactive oxygen species may be prevented by the antioxidant activity of anthocyanins. Karlsen and co-workers at the University of Oslo, found anthocyanin supplementation may have a role in the prevention or treatment of chronic inflammatory diseases by inhibition of nuclear factor-kappaB transactivation and deceased plasma concentrations of pro-inflammatory chemokines, cytokines and inflammatory mediators . The transcription factor nuclear factor-kappaB is activated by oxidative stress and pro-inflammatory stimuli and controls the expression of numerous genes involved in the inflammatory response. This activation results in the expression of inflammatory genes and the secretion of chemokines and cytokines. Limiting the inflammatory response may prevent inflammatory damage. Karlsen and co-workers hypnotized that anthocyanins may inhibit nuclear factor-kappaB activation induced by lipopolysaccharides in cultured human monocytes. They also investigated the effect of anthocyanins on inflammatory mediators in adult in a randomized placebo-controlled trial. The scientists found that anthocyanins efficiently suppressed lipopolysaccharides-induced activation of nuclear factor -kappaB. Their in-vivo experiment on 120 men and women also showed lower levels of inflammatory mediators, chemokines and cytokines in the anthocyanin group.
The anthocyanin cyanidin has been shown to alleviate arthritis in animal model . Rats with adjuvant-induced arthritis showed significant less paw swelling when treated with cyanidin. The phytochemecial possibly acts by increasing glutathione and superoxide dismutase levels and total antioxidative capacity.
 Anthocyanins inhibit nuclear factor-kappaB activation in monocytes and reduce plasma concentrations of pro-inflammatory mediators in healthy adults. J Nutr. 2007 Aug;137(8):1951-4.
 He YH, Xiao C, Wang YS, Zhao LH, Zhao HY, Tong Y, Zhou J, Jia HW, Lu C, Li XM, Lu AP. " Antioxidant and anti-inflammatory effects of cyanidin from cherries on rat adjuvant-induced arthritis" Zhongguo Zhong Yao Za Zhi. 2005 Oct;30(20):1602-5.