Suppressive Effects of Quercetin on Ovalbumin‐induced Airway Hyperresponsiveness

TL;DRAbstract

Quercetin potently inhibits PDE3 and PDE4. The aim of this investigation is to determine whether it possesses anti‐asthmatic effect. Female BALB/c mice were sensitized by intraperitoneal injections of ovalbumin (OVA), then challenged by 1% OVA nebulization two times. The airway hyperresponsiveness was measured using a whole‐body plethysmograph, and nebulized methacholin (MCh, 5~50 mg/ml). Quercetin (30~100 μmol/kg, i.p.) dose‐dependently attenuated the enhanced pause (Penh) value induced by MCh (25~50 mg/ml). Quercetin (10~100 μmol/kg, i.p.) also significantly inhibited total inflammatory cells, neutrophils, eosinophils, lymphocytes and macrophages, in BALF. It also significantly attenuated the release of IL‐2, IL‐4, IL‐5, IFN‐γ and TNF‐α with an exception that at 10 μmol/kg it did not significantly inhibit the release of IL‐5. Quercetin (10~100 μM) significantly inhibited cumulative OVA (1~100 μg/ml)‐induced contractions of isolated sensitized guinea pig trachealis. By Lineweaver‐Burk

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