Cembrene Diterpenoids: Conformational Studies and Molecular Docking to Tubulin

A conformational analysis of the cembrene diterpenoids cembrene, cembrene A, (3Z)-cembrene A, isocembrene, casbene, and incensole, has been carried out using density functional theory at the B3LYP/6-31G* level of theory.  A molecular docking analysis of these cembrenoids with tubulin has also been performed in order to assess the potential of tubulin binding of these cytotoxic agents.  The macrocyclic cembrenoids are conformationally mobile and numerous low-energy conformations were found.  Molecular docking reveals that the cembrenoids dock into the colchicine binding site of tubulin with comparable docking energies to colchicine.