Background: The immunomodulatory properties of Nigella sativa seed, as a basis of its clinical applications by many cultures have been reviewed. Thymoquinone (TQ) is one of the major bioactive components of the volatile oil of N. sativa seeds. Methods: The review on immunomodulatory and anti- inflammatory effects of TQ was focused on published literature in the English language. The literature search was conducted in the following databases: PubMed (2004-2017), Scopus (2004-2017) and Google Scholar (2004-2017). The keywords used were the following terms: thymoquinone, immunomodulation, inflammation, autoimmune and asthma. Results: The present investigations provide a comprehensive review of the ability of TQ to modulate inflammation and immune-related disorders in the various important disease states. This finding showed that TQ has anti-inflammatory properties that prevent the biosynthesis of important mediators in inflammatory processes and asthma such as 5-LO, COX, PGD2 and LTs. TQ also reduced LPS-induced proinflammatory cytokines such as interleukins (ILs) and TNF-α. In addition, TQ showed immunomodulatory role in the cellular and humoral immunity. This study also found that TQ improves imidacloprid toxicity through reducing oxidative stress and increasing chemokinesis, chemotaxis, phagocytic activity, antibody levels and the hemagglutination of immunoglobulins as well as by reducing serum MDA levels and hepatic enzymes. Conclusion: The study indicated the beneficial effects of TQ in immune-related diseases, however, well designed clinical trials in humans are required to confirm these effects.

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