Curcumin: An effective inhibitor of interleukin-6

Curcumin is apolyphenolic compound found in the dietary spice turmeric. Anti-inflammatory effects of turmeric have been known for centuries and extensive studies over the last two to three decades revealed that curcumin is a key component in the anti-inflammatory effects of turmeric. Chronic inflammation is involved in the various pathologic states and curcumin demonstrated therapeutic effects in different inflammation-related diseases in various in vivo, in vitro and human based studies through regulation of different signaling molecules including transcription factors, chemokines, cytokines, tumor suppressor genes, adhesion molecules and microRNAs. Interleukin-6 (IL-6) plays important roles in various events during inflammation including regulation of antibody (and autoantibody) production, activation of T cells, differentiation of B cells, increased production of acute-phase proteins, hematopoiesis and angiogenesis, vascular permeability, and osteoclast differentiation. IL-6 is also involved in pathogenesis of different inflammatory diseases. There are numerous studies demonstrating association of down-regulation of IL-6 and/or inhibition of IL-6 signaling with therapeutic effects of curcumin suggesting a role for modulation of IL-6 in anti-inflammatory effects of curcumin. Moreover, curcumin can be considered as potential therapy against IL-6 involved pathologic stats. In this narrative review, the in vitro, experimental and clinical studies that report association of IL-6 inhibition and therapeutic effects of curcumin are discussed.