Effects of Nigella sativa oil extract on inflammatory cytokine response and oxidative stress status in patients with rheumatoid arthritis: a randomized, double-blind, placebo-controlled clinical trial

Objective: Nigella sativa is a medicinal plant that has long been used in traditional medicine for treating various conditions. Numerous animal studies provided evidences that the seed may elicit a broad anti-inflammatory/anti-oxidant activity. The aim of the present clinical trial was to evaluate anti-inflammatory and antioxidant properties of Nigella sativa oil in patients with rheumatoid arthritis (RA). Materials and Methods: Forty-two patients with RA were assigned into two groups in this randomized, double blind, placebo-controlled clinical trial. Subjects in intervention group received two capsules, 500 mg each, of Nigella sativa oil, each day for 8 weeks. The other group consumed two capsules as placebo per day for the same period of time. Serum TNF-alpha, IL-10, and whole blood levels of oxidative stress parameters were measured at baseline and end of the trial. Results: The serum level of IL-10 was increased in the Nigella sativa group (p< 0.01). Moreover, treatment with Nigella sativa led to significant reduction of serum MDA and NO compared with baseline (p< 0.05). There were no significant differences in the TNF-a, SOD, catalase, and TAS values between or within the groups, before and after the intervention (p> 0.05). Conclusion: This study indicates that Nigella sativa could improve inflammation and reduce oxidative stress in patients with RA. It is suggested that Nigella sativa may be a beneficial adjunct therapy in this population of patients.