Abstract

BACKGROUND: Due to their plasticity, macrophages exert critical effects on both promoting and suppressing inflammatory processes. Pathologic inflammatory conditions are frequently correlated with dynamic alterations in macrophage activation, with classically activated M1 cells associated with promoting and sustaining inflammation and M2 cells implicated in resolution or smoldering chronic inflammation. Inflammation deputes a common feature from various chronic diseases and direct involvement in the insurgence and development of these conditions. Macrophages participate in an auto-regulatory loop characterizing inflammatory process, as they produce a wide range of biologically active mediators that exert either deleterious or beneficial effects during the inflammation. Therefore, balancing the favorable ratios of M1/M2 macrophages can help to ameliorate the inflammatory landscape of pathologic conditions. Curcumin is a component of turmeric with many pharmacological properties. OBJECTIVE: Recent results from both in-vivo and in-vitro studies have indicated that curcumin can affect polarization and/or functions of macrophage subsets in the context of inflammation-related diseases. There is no comprehensive review of the impact of curcumin on cytokines involved in macrophage polarization in the context of inflammatory diseases. The present review will cover some efforts to explore the underlying molecular mechanisms by which curcumin modulates the macrophage polarization in distant pathological inflammatory conditions, such as cancer, autoimmunity, renal inflammation, stroke, and atherosclerosis, sharing macrophage-driven pathogenesis. RESULT: The accumulation of findings from in vitro and in vivo experimental studies suggest that curcumin beneficially influences M1 and M2 macrophages in a variety of inflammatory diseases with unfavorable macrophage activation. CONCLUSION: Curcumin not only enhances anti- tumor immunity (via shifting M polarization towards to M1 phenotype and/or up-regulation of M1 markers expression), but ameliorates inflammatory diseases including auto immune diseases (experimental autoimmune myocarditis and Behcet's disease), nephropathy, chronic serum sickness, stroke and atherosclerosis.