Abstract
The present study was designed to find pharmacologically active compound against airway inflammation from the roots of Asparagus cochinchinensis. The 70% ethanol extract of the roots of A. cochinchinensis (ACE) was found to inhibit IL-6 production from IL-1β-treated lung epithelial cells (A549) and the major constituent, methyl protodioscin (MP), also strongly inhibited the production of IL-6, IL-8, and tumor necrosis factor- (TNF-) α from A549 cells at 10-100 μM. This downregulating effect of proinflammatory cytokine production was found to be mediated, at least in part, via inhibition of c-Jun N-terminal kinase (JNK) and c-Jun activation pathway. When examined on an in vivo model of airway inflammation in mice, lipopolysaccharide- (LPS-) induced acute lung injury, ACE, and MP significantly inhibited cell infiltration in the bronchoalveolar lavage fluid by the oral treatment at doses of 100-400 mg/kg and 30-60 mg/kg, respectively. MP also inhibited the production of proinflammatory cytokines such as IL-6, TNF-α, and IL-1β in lung tissue. All of these findings provide scientific evidence supporting the role of A. cochinchinensis as a herbal remedy in treating airway inflammation and also suggest a therapeutic value of MP on airway inflammatory disorders.