Inhibitors of the NF-κB Activation Pathway from Cryptocarya rugulosa

The nuclear factor-κB (NF-κB) signaling pathway is constitutively active in many types of cancers and is a potential therapeutic target. Using a cell-based assay for stability of inhibitor of kappa B (IκB), a critical regulator of NF-κB activity, we found that an organic solvent extract of the plant Cryptocarya rugulosa inhibited constitutive NF-κB activity in human lymphoma cell lines. The active components were identified as rugulactone, a new α-pyrone (1), and the known cryptocaryone (2). Rugulactone was the more active compound, exhibiting up to 5-fold induction of IκB at 25 μg/mL; maximal activity was observed with 10 h exposure of test cells to 1 or 2.