Carbenoxolone and triterpenoids inhibited mucin secretion from airway epithelial cells.

This study investigated whether carbenoxolone, oleanolic acid and ursolic acid affect ATP-induced mucin secretion from cultured airway epithelial cells. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled using (3)H-glucosamine for 24 h and chased for 30 min in the presence of varying concentrations of each agent to assess the effects on (3)H-mucin secretion. The possible cytotoxicity of each agent was investigated with a lactate dehydrogenase assay. The results were as follows: (1) carbenoxolone, oleanolic acid and ursolic acid significantly inhibited the secretion of airway mucin induced by ATP; (2) none of the compounds showed significant cytotoxicity at any concentration. This result suggests that carbenoxolone, oleanolic acid and ursolic acid can regulate 'mucin secretion induced by ATP'--phenomenon simulating mucus overproduction from inflamed airway epithelial cells--y directly acting on airway mucin-secreting cells.