Experimental and clinical reports on anti‐inflammatory, antioxidant, and immunomodulatory effects of Curcuma longa and curcumin, an updated and comprehensive review

Abstract Curcuma longa ( C. longa ) or turmeric is a plant with a long history of use in traditional medicine, especially for treating inflammatory conditions C. longa and its main constituent, curcumin (CUR), showed various pharmacological effects such as antioxidant and anti‐microbial properties. The updated knowledge of anti‐inflammatory, antioxidant, and immunomodulatory effects of C. longa and CUR is provided in this review article. Pharmacological effects of C. longa , and CUR, including anti‐inflammatory, antioxidant, and immunomodulatory properties, were searched using various databases and appropriate keywords until September 2020. Various studies showed anti‐inflammatory effects of C. longa and CUR, including decreased white blood cell, neutrophil, and eosinophil numbers, and its protective effects on serum levels of inflammatory mediators such as phospholipase A2 and total protein in different inflammatory disorders. The antioxidant effects of C. longa and CUR were also reported in several studies. The plant extracts and CUR decreased malondialdehyde and nitric oxide levels but increased thiol, superoxide dismutase, and catalase levels in oxidative stress conditions. Treatment with C. longa and CUR also improved immunoglobulin E (Ig)E, pro‐inflammatory cytokine interleukin 4 (IL)‐4, transforming growth factor‐beta, IL‐17, interferon‐gamma levels, and type 1/type 2 helper cells (Th1)/(Th2) ratio in conditions with disturbance in the immune system. Therefore C. longa and CUR showed anti‐inflammatory, antioxidant, and immunomodulatory effects, indicating a potential therapeutic effect of the plant and its constituent, CUR, for treating of inflammatory, oxidative, and immune dysregulation disorders.