Immunosuppressive effects of fisetin in ovalbumin-induced asthma through inhibition of NF-κB activity.

Fisetin, a flavonoid compound commonly present in fruits and vegetables, can exert anti-inflammation activities via inhibition of the NF-κB-signaling pathway. This study aims to evaluate the antiasthma activity of fisetin and investigate its possible molecular mechanisms. We found that fisetin attenuated lung inflammation, goblet cell hyperplasia, and airway hyperresponsiveness in ovalbumin-induced asthma and decreased eosinophils and lymphocytes in bronchoalveolar lavage fluid. Fisetin treatment reduced expression of the key initiators of allergic airway inflammation (eotaxin-1 and TSLP), Th2-associated cytokines (IL-4, IL-5, and IL-13) in lungs, and Th2-predominant transcription factor GATA-3 and cytokines in thoracic lymph node cells and splenocytes. Notably, fisetin treatment impaired NF-κB activation in OVA-stimulated lung tissues and TNF-α-stimulated bronchial epithelial cells. Collectively, this study demonstrated the beneficial effect of fisetin in the amelioration of asthmatic phenotypes. The antiasthma activity of fisetin is associated with reduction of Th2 responses as well as suppression of NF-κB and its downstream chemokines.