Sesquiterpenoids from Vitex pierreana

A new germacrane sesquiterpenoid with an epoxy moiety, pierreanin A (1), and a pair of unique cyclobutyl-containing sesquiterpenoid diastereoisomers, pierreanins B and C (2 and 3), were isolated from the branches and leaves of Vitex pierreana, together with 2 known analogues, identified as germacrone (4) and epiprocurcumenol (5). The structures of all isolates were evaluated by detailed analyses of NMR, IR, and MS data. The absolute configurations of 1-3 were determined by comparison of the experimental ECD spectra with reported data of analogues containing the same chromophore. The ability of three new compounds to inhibit the growth of DU145 prostate cancer cells was also evaluated, as well as their inhibitory effects against the production of NO in LPS-stimulated RAW264.7 cells.