Apigenin-d₅is an internal standard for the quantificaiton of apigenin by GC- or LC-MS. Apigenin is a flavonoid compound found in many fruits and vegetables that selectively inhibits casein kinase 2 (CK2). Apigenin inhibits CK2 activity in the renal cortex with an IC50 value of 30 µM to improve renal function in a rat model of glomerulonephritis.¹CK2 inhibition by 20 µM apigenin decreases the degradation of IκBα and down-regulates NF-κB levels in WEHI-231 cells.²Apigenin, at 5 µM, is a potent inhibitor of the synthesis of the inflammatory mediators nitric oxide and prostaglandin E₂, reducing inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression by 56% and 64%, respectively, in the macrophage cell line J774A.1.³

1.Yamada, M., Katsuma, S., Adachi, T., et al.Inhibition of protein kinase CK2 prevents the progression of glomerulonephritisProceedings of the National Academy of Sciences of the United States of America102(21)7736-7741(2005) 2.Shen, J., Channavajhala, P., Seldin, D.C., et al.Phosphorylation by the protein kinase CK2 promotes calpain-mediated degradation of IκBα1Journal of Immunology1679)4919-4925(2001) 3.Raso, G.M., Meli, R., Di Carlo, G., et al.Inhibition of inducible nitric oxide synthase and cyclooxygenase-2 expression by flavonoids in macrophage J774A.1Life Sciences68(8)921-931(2001)