Effects of Lupenone, Lupeol, and Taraxerol Derived from Adenophora triphylla on the Gene Expression and Production of Airway MUC5AC Mucin

BACKGROUND: Adenophora triphylla var. japonica is empirically used for controlling airway inflammatory diseases in folk medicine. We evaluated the gene expression and production of mucin from airway epithelial cells in response to lupenone, lupeol and taraxerol derived from Adenophora triphylla var. japonica. METHODS: Confluent NCI-H292 cells were pretreated with lupenone, lupeol or taraxerol for 30 minutes and then stimulated with tumor necrosis factor α (TNF-α) for 24 hours. The MUC5AC mucin gene expression and production were measured by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Additionally, we examined whether lupenone, lupeol or taraxerol affects MUC5AC mucin production induced by epidermal growth factor (EGF) and phorbol 12-myristate 13-acetate (PMA), the other 2 stimulators of airway mucin production. RESULTS: Lupenone, lupeol, and taraxerol inhibited the gene expression and production of MUC5AC mucin induced by TNF-α from NCI-H292 cells, respectively. The 3 compounds inhibited the EGF or PMA-induced production of MUC5AC mucin in NCI-H292 cells. CONCLUSION: These results indicated that lupenone, lupeol and taraxerol derived from Adenophora triphylla var. japonica regulates the production and gene expression of mucin, by directly acting on airway epithelial cells. In addition, the results partly explain the mechanism of of Adenophora triphylla var. japonica as a traditional remedy for diverse inflammatory pulmonary diseases.