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Pharmacol Res. 2016 May;107:234-242. doi: 10.1016/j.phrs.2016.03.026. Epub 2016 Mar 26.

Curcumin downregulates human tumor necrosis factor-α levels: A systematic review and meta-analysis ofrandomized controlled trials.

Author information

Biotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Metabolic Research Centre, Royal Perth Hospital, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.
Medicine and Surgery Sciences Dept.,University of Bologna, Italy. Electronic address:
Biomedical Research Unit, Mexican Social Security Institute, Durango, Mexico.
Cytokine Research Laboratory, Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX USA.
Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, India.



Tumor necrosis factor-α (TNF-α) is a key inflammatory mediator and its reduction is a therapeutic target in several inflammatory diseases. Curcumin, a bioactive polyphenol from turmeric, has been shown in several preclinical studies to block TNF-α effectively. However, clinical evidence has not been fully conclusive.


The aim of the present meta-analysis was to evaluate the efficacy of curcumin supplementation on circulating levels of TNF-α in randomized controlled trials (RCTs).


The search included PubMed-Medline, Scopus, Web of Science and Google Scholar databases by up to September 21, 2015, to identify RCTs investigating the impact of curcumin on circulating TNF-α concentration. Quantitative data synthesis was performed using a random-effects model, with weighed mean difference (WMD) and 95% confidence interval (CI) as summary statistics. Meta-regression and leave-one-out sensitivity analyses were performed to assess the modifiers of treatment response.


Eight RCTs comprising nine treatment arms were finally selected for the meta-analysis. There was a significant reduction of circulating TNF-α concentrations following curcumin supplementation (WMD: -4.69pg/mL, 95% CI: -7.10, -2.28, p<0.001). This effect size was robust in sensitivity analysis. Meta-regression did not suggest any significant association between the circulating TNF-α-lowering effects of curcumin with either dose or duration (slope: 0.197; 95% CI: -1.73, 2.12; p=0.841) of treatment.


This meta-analysis of RCTs suggested a significant effect of curcumin in lowering circulating TNF-α concentration.


Curcuma longa; Curcumin; Inflammation; Meta-analysis; Randomized controlled trial; TNF-α

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