New Diterpenes and Norditerpenes from the Fruits of Vitex rotundifolia

A new labdane-type diterpene, vitexifolin A (1), a new clerodane-type diterpene, vitexifolin B (2), a new abeoabietane-type diterpene, vitexifolin C (3), and two new norlabdane-type diterpenes, vitexifolin D (4) and vitexifolin E (5), were isolated from the fruits of Vitex rotundifolia, along with a known halimane-type diterpene, vitetrifolin D (6), two known norlabdane-type diterpenes, trisnor-γ-lactone (7) and iso-ambreinolide (8), and three known flavonoids, casticin (9), artemetin (10), and 5,3'-dihydroxy-6,7,4'-trimethoxyflavanone (11). Their chemical structures were determined on the basis of spectroscopic data. Casticin (9) exhibited considerable growth inhibitory activity against human lung cancer cells (PC-12) and human colon cancer cells (HCT116) using the MTT assay.