Abstract
The present study investigated the anti-asthmatic activity of quercetin glycosides in neonatal asthmatic rats. Rats were divided into four groups: sham (non-asthmatic), asthmatic control, quercetin (25 mg/kg), and quercetin (50 mg/kg). Inflammatory cells in bronchoalveolar lavage fluid (BALF), inflammatory markers, apoptosis, fibrinogen level, prothrombin time, thrombin time, activated partial thromboplastin time, coagulation factor activity, and histopathology were monitored. Quercetin significantly reduced total leukocytes, eosinophils, tumor necrosis factor-α (TNF-α), interleukin (IL-6), nitric oxide (NO), and apoptosis. It also considerably reduced blood coagulation time and coagulation factor activity compared to the controls. The mRNA expression levels of TNF-α, IL-6, and inducible nitric oxide synthase (iNOS) were elevated in asthmatic rats by 1.3-, 1.04-, and 1.1-fold, respectively. However, treatment with 50 mg/kg quercetin glycosides significantly reduced the mRNA expression of TNF-α, IL-6, and iNOS by more than 40%. Quercetin considerably reduced the protein expression of iNOS. Airway and blood vessel narrowing, as well as the accumulation of eosinophils in the lungs were observed in neonatal asthmatic rats. However, treatment with quercetin glycosides significantly reduced inflammation and eosinophil infiltration. In summary, quercetin glycosides significantly attenuated levels of inflammatory markers, demonstrating its protective effects against neonatal asthma in rats.