Research Area: Respiratory Diseases Biological Activity: Fudosteine is a novel mucoactive agent and a MUC5AC mucin hypersecretion inhibitor. MUC5AC mucin synthesis and the expression of the MUC5AC gene were increased by LPS in rats or TNF-α in NCI-H292 cells; these effects were inhibited by fudosteine treatment. Fudosteine inhibits MUC5AC mucin hypersecretion by reducing MUC5AC gene expression and the effects of fudosteine are associated with the inhibition of extracellular signal-related kinase and p38 mitogen-activated protein kinase in vivo and extracellular signal-related kinase in vitro. [1]