Effect of Nigella sativa supplementation on lung function and inflammatory mediators in partly controlled asthma: a randomized controlled trial

BACKGROUND: Nigella sativa and its derivatives have been reported to have anti-inflammatory and bronchodilator effects, but the effects have been evaluated in only a few clinical studies. OBJECTIVES: To determine the effect of N sativa supplementation on inflammation of the airways and limitation of airflow in partly controlled asthma patients. DESIGN: Single-blind, placebo-controlled, randomized study. SETTING: Asthma and allergy clinic of a university hospital in eastern Saudi Arabia. PATIENTS AND METHODS: Patients were divided into three groups. A control group (n=24) received the placebo, while NS-1 and NS-2 groups (n=26 each) received 1 and 2 g/day of N sativa, respectively, for 3 months along with maintenance inhaled therapy. MAIN OUTCOME MEASURE(S): Asthma control test (ACT) score, fractional exhaled nitric oxide (FeNO), peak expiratory flow (PEF) variability and other pulmonary function tests, IgE, serum cytokines, and frequency of exacerbations. RESULTS: FEF25-75% and FEV1 (% predicted) increased significantly (P<.05) at both 6 and 12 weeks in the NS-2 group. PEF variability significantly improved in both NS-1 and NS-2 groups at 6 and 12 weeks as compared with the controls (P<.05). FeNO and serum IgE decreased significantly after 12 weeks in both the NS-1 and NS-2 groups vs baseline (P<.05). Both doses of N sativa produced a significant increase in the serum IFN-γ at 12 weeks vs baseline (P<.05) as well as a significant improvement in the ACT score at 6 and 12 weeks vs baseline (P<.001, <.01). Significantly fewer patients had exacerbations in the NS-1 group (P<.05). CONCLUSION: N sativa supplementation with inhaled maintenance therapy improves some measures of pulmonary function and inflammation in partly controlled asthma. LIMITATIONS: No bronchoalveolar lavage or sputum samples taken for measurement of asthma markers.