Oroxylin A is a flavonoid that has been found in S. radix and has diverse biological activities.^1,2,3 It inhibits decreases in cell viability and increases in nitric oxide (NO) production induced by polyinosinic-polycytidylic acid (poly(I:C)) in RAW 264.7 macrophages when used at concentrations ranging from 5 to 25 μM.² Oroxylin A (10-50 μM) also inhibits poly(I:C)-induced increases in IL-1α, IL-1β, GM-CSF, IL-6, IL-10, monocyte chemoattractant protein-1 (MCP-1), and TNF-α production in RAW 264.7 cells. Oroxylin A (10 and 20 μM) inhibits hypoxia-induced migration and invasion of MCF-7, DU145, and HepG2 cells in wound healing and cell invasion assays, respectively.³ It is an inhibitor of the UDP-glucuronosyltransferase (UGT) isoform UGT1A1 (IC50 = 9.14 μM) and P-glycoprotein (IC50 = 78.3 μM).^4,5 Oroxylin A increases the cytotoxicity of the P-glycoprotein substrate paraquat in MDR1-MDCKII cells and paclitaxel in MX-1 and MX-1/T cells.⁵