Synthesis of lantadene analogs with marked in vitro inhibition of lung adenocarcinoma and TNF-α induced nuclear factor-kappa B (NF-κB) activation

The new series of pentacyclic triterpenoids reduced lantadene A (3), B (4), and 22 beta-hydroxy-3-oxo-olean-12-en-28-oic acid (5) analogs were synthesized and tested in vitro for their NF-kappa B and IKK beta inhibitory potencies and cytotoxicity against A549 lung cancer cells. The lead analog (11) showed sub-micromolar activity against TNF-alpha induced activation of NF-kappa B and exhibited inhibition of IKK beta in a single-digit micromolar dose. At the same time, 11 showed promising cytotoxicity against A549 lung cancer cells with IC50 of 0.98 mu M. The Western blot analysis further showed that the suppression of NF-kappa B activity by the lead analog 11 was due to the inhibition of I kappa B alpha degradation, a natural inhibitor of NF-kappa B. The physicochemical evaluation demonstrated that the lead analog 11 was stable in the simulated gastric fluid of pH 2, while hydrolyzed at a relatively higher rate in the human blood plasma to release the active parent moieties. Molecular docking analysis showed that 11 was hydrogen bonded with the Arg-31 and Gln-110 residues of the IKK beta. (C) 2014 Elsevier Ltd. All rights reserved.