Abstract: Only one trial (89 patients) fulfilled the inclusion criteria. This trial randomized 45 patients to curcumin and 44 patients to placebo. All patients received treatment with sulfasalazine or mesalamine. The study was rated as low risk of bias. Curcumin was administered orally in a dose of 2 g/day for six months. Fewer patients relapsed in the curcumin group than the placebo group at six months. Four per cent of patients in the curcumin group relapsed at six months compared to 18% of patients in the placebo group (RR 0.24, 95% CI 0.05 to 1.09; P = 0.06). There was no statistically significant difference in relapse rates at 12 months. Twenty-two per cent of curcumin patients relapsed at 12 months compared to 32% of placebo patients (RR 0.70, 95% CI 0.35 to 1.40; P = 0.31). A total of nine adverse events were reported in seven patients. These adverse events included sensation of abdominal bulging, nausea, transient hypertension, and transient increase in the number of stools. The authors did not report which treatment group the patients who experienced adverse events belonged to. The clinical activity index (CAI) at six months was significantly lower in the curcumin group compared to the placebo group (1.0 + 2.0 versus 2.2 + 2.3; MD -1.20, 95% CI -2.14 to -0.26). The endoscopic index (EI) at six months was significantly lower in the curcumin group than in the placebo group (0.8 + 0.6 versus 1.6 + 1.6; MD -0.80, 95% CI -1.33 to -0.27). Curcumin may be a safe and effective therapy for maintenance of remission in quiescent UC when given as adjunctive therapy along with mesalamine or sulfasalazine. However, further research in the form of a large scale methodologically rigorous randomized controlled trial is needed to confirm any possible benefit of curcumin in quiescent UC.

Plain-language summary: The purpose of this systematic review was to examine the effectiveness and safety of curcumin therapy for the maintenance of remission in patients with ulcerative colitis (UC), a chronic inflammatory condition of the colon. Currently available agents for the management of this condition have been reported to result side effects, particularly when used for prolonged periods. This review includes one randomized trial with a total of 89 participants. All patients received treatment with sulfasalazine or mesalamine (drugs containing 5-aminosalicylic acid). Fewer patients in the curcumin group relapsed at six months compared to patients who received placebo (e.g. fake drug). However, this result was not statistically significant. Patients in the curcumin group had significantly lower disease activity index and endoscopic index scores at six months than patients in the placebo group. No serious side effects were reported. A total of nine mild side effects were reported in seven patients. These side effects included a sensation of abdominal bulging, nausea, a brief increase in blood pressure, and a brief increase in the number of stools. The results of this systematic review suggest that curcumin may be a safe and effective therapy for maintenance of remission in ulcerative colitis when given as additional therapy with mesalamine or sulfasalazine. Further research is needed to confirm any possible benefit of curcumin for maintenance therapy in ulcerative colitis.