Nigella sativa L. (NS) seeds, known as black seed, is a spice and a traditional herbal medicine used in various diseases including bronchial asthma. This review aimed to assess the studies supporting the medicinal use of NS in asthma and to highlight future research priorities. Various medical databases were searched for the effects of NS and its active secondary metabolites in asthma inflammation and outcomes. There were fourteen preclinical studies describing multiple effects of NS in animal or cellular models of asthma including bronchodilation, anti-histaminic, anti-inflammatory, anti-leukotrienes and immunomodulatory effects. Furthermore, seven clinical studies showed improvements in different asthma outcomes including symptoms, pulmonary function and laboratory parameters. However, often these studies are small and used ill-defined preparations. In conclusion, NS could be therapeutically beneficial in alleviating airway inflammation and the control of asthma symptoms, but the evidence remains scanty and is often based on poorly characterised preparations. Accordingly, well-designed large clinical studies using chemically well characterised NS preparation are required.
Keywords: ACT, Asthma Control Test; Asthma; Black seed; Clinical studies; FEV1, forced expiratory volume in one second; FeNO, fractional exhaled nitric oxide; GINA, Global Initiative for Asthma; IL, Interleukin; IgE, Immunoglobulin E; NS, Nigella sativa L.; Nigella sativa; RDBCT, Randomised Double-Blinded Clinical Trial; RDBPCT, Randomised Double-Blinded Placebo-Controlled Clinical Trial; RSBPCT, Randomised Single-Blinded Placebo-Controlled Clinical Trial; Th1, Type 1 T helper (Th1) cells; Th2, Type 2 T helper (Th2) cells; Traditional medicine.