Effects of baicalin and wogonin on mucin release from cultured airway epithelial cells.

Scutellaria baicalensis Georgi has been used for the treatment of diverse chronic inflammatory diseases including respiratory disease in oriental medicine and its major components - baicalin, baicalein and wogonin - were reported to have various biological effects. This study investigated whether baicalin, baicalein and wogonin affect basal and ATP-induced mucin release 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 release. The results were as follows: (1) Baicalein did not affect both basal and ATP-induced mucin release significantly. (2) Baicalin and wogonin increased basal mucin release at the highest concentrations (10(-3) m). (3) However, baicalin and wogonin significantly inhibited ATP-induced mucin release. It is concluded that baicalin and wogonin can slightly increase basal mucin release whereas they can inhibit ATP-induced mucin release, by directly acting on airway mucin-secreting cells. It is suggested that baicalin and wogonin be further investigated for the possible use as mucoregulators during the treatment of chronic airway diseases.