Safety and efficacy of curcumin in the treatment of ulcerative colitis: An updated systematic review and meta-analysis of randomized controlled trials

Objective: This study aims to systematically evaluate the safety and efficacy of curcumin as an adjunctive treatment for patients with ulcerative colitis (UC) and to assess the methodological quality of the published studies. Methods: A comprehensive search was conducted in PubMed, Embase, and CENTRAL databases for randomized controlled trials published up to August 18, 2023. Two independent reviewers screened studies based on predefined criteria. Meta-analysis was performed using a random-effects model with RevMan 5.4. Heterogeneity was assessed using Cochran's Q test and I2 statistic. Results: Eight randomized controlled trials involving 482 patients were included. Seven studies reported clinical remission, and three reported endoscopic remission. Compared to the placebo group, adjunctive curcumin therapy significantly improved clinical remission (RR=2.33, 95 % CI: 1.25 to 4.34; P = 0.008; I2=80 %). Although endoscopic remission showed an increasing trend, it was not statistically significant (RR=4.17, 95 % CI: 0.63 to 27.71; P = 0.14; I2=80 %). Significant improvements were also observed in clinical improvement (RR=1.93, 95 % CI: 1.10 to 3.36; P = 0.02; I2=56 %) and endoscopic improvement (RR=1.76, 95 % CI: 1.12 to 2.77; P = 0.01; I2=62 %) in the curcumin group. No serious adverse events were reported. Subgroup analysis indicated a positive correlation between treatment efficacy and dosage, with no significant impact of administration method or follow-up duration on the pooled results or heterogeneity. Conclusion: Curcumin as an adjunctive treatment shows promise in improving clinical and endoscopic outcomes in UC patients without significant adverse effects. However, due to the limited number of studies and substantial heterogeneity, further large-scale randomized controlled trials are necessary to confirm these findings.