MUC5AC and bronchitis: A Korean study by Seok JH et al. compared the effects of P. grandiflorum de Candolle (APG), platycodin D(3) and deapi-platycodin against airway mucin hypersecretion in PMA-stimulated NCI-H292 cells and sulfur dioxide-stimulated rat bronchitis pulmonary mucin hypersecretion in vivo.