Obtusifolin, isolated from the seeds of Cassia obtusifolia, regulates the gene expression and production of MUC5AC mucin in airway epithelial cells via inhibiting NF-kB pathway. Obtusifolin suppresses phthalate esters-induced breast cancer bone metastasis by targeting parathyroid hormone-related protein[2].In Vitro: Obtusifolin (1, 10, 100 μM) inhibits MUC5AC gene expression induced by EGF, PMA, or TNF-α in NCI-H292 cells.