A selective and irreversible inhibitor of NF-κB activation that blocks TNF-α-induced phosphorylation of IκB-α without affecting constitutive IκB-α phosphorylation; inhibits the TNFα-induced surface expression of adhesion molecules ICAM-1, VCAM-1, and E-selectin in human endothelial cells (IC50 = 5-10 µM).