Effect of curcumin on nasal symptoms and airflow in patients with perennial allergic rhinitis.

BACKGROUND: Allergic rhinitis (AR) is a common disorder that can significantly affect patient quality of life. Previous studies have found that curcumin had anti-inflammatory and antioxidant effects and clinical benefits in cancer and asthma. OBJECTIVE: To determine the efficacy of curcumin in the treatment of AR and to explore the molecular mechanisms involved. METHODS: In a randomized, double-blind study, 241 patients with AR received either placebo or oral curcumin for 2 months. The therapeutic effects of curcumin were evaluated by nasal symptoms and nasal airflow resistance. In addition, the production of interferon γ, interleukin (IL) 4, IL-10, and tumor necrosis factor α from mononuclear cells and IL-8, soluble intercellular adhesion molecule, polyethylene glycol 2, and leukotriene C4 from polymorphonuclear neutrophils were compared before and after curcumin treatment. RESULTS: Curcumin alleviated nasal symptoms (sneezing and rhinorrhea) and nasal congestion through reduction of nasal airflow resistance. Curcumin was found to exert diverse immunomodulatory effects, including suppression of IL-4, IL-8, and tumor necrosis factor α and increased production of IL-10 and soluble intercellular adhesion molecule. However, curcumin did not affect the release of prostaglandin E2 and leukotriene C4 from polymorphonuclear neutrophils. CONCLUSION: This pilot study provides the first evidence of the capability of curcumin of improving nasal airflow and modulating immune response in patients with AR.