Skullcapflavone II inhibits ovalbumin-induced airway inflammation in a mouse model of asthma.

Skullcapflavone II is a flavonoid derived from Scutellaria baicalensis, a widely used herbal medicine in anti-inflammatory and anticancer therapy in Korea. Skullcapflavone II antagonized the bradykinin receptor more potently than any of the other flavonoids derived from this plant. Here, we were investigated its therapeutic effects in a mouse model of ovalbumin (OVA)-induced allergic asthma. Administration of skullcapflavone II significantly reduced airway hyperresponsiveness (AHR), airway eosinophilia, Th2 cytokine production, and increased transforming growth factor-β1 (TGF-β1) levels in bronchoalveolarlavage (BAL) fluids and lungs from OVA-sensitized and -challenged mice. Skullcapflavone II administration also significantly suppressed subepithelial collagen deposition and goblet cell hyperplasia, elevated Smad7 expression and suppressed pSmad2/3 levels. Collectively, these findings indicate that skullcapflavone II, a potential bradykinin antagonist, reduced the major pathophysiological features of allergic asthma, at least in part by acting on TGF-β1/Smad signaling pathways. Thus, skullcapflavone II may have therapeutic potential for the treatment of allergic asthma.