A New Taraxastane-Type Triterpene from Vitex trifolia var. simplicifolia

3-Oxotaraxer-14-en-30-al (1), a new taraxastane-type triterpene, together with 14 known compounds, taraxerone (2), 3-epiursolic acid (3), 2,3-dihydroxyurs-12-en-28-oic acid (4), lupeol (5), betulinic acid (6), casticin (7), artemetin (8), luteolin (9), 4-hydroxybenzoic acid (10), docosanoic acid (11), tetracosanoic acid (12), cerotic acid (13), -sitosterol (14), and -daucosterol (15), was isolated from the leaves and twigs of Vitex trifolia var. simplicifolia . Compounds 2-6 were found for the first time in this plant. Their structures were established by spectroscopic analysis, including 2D-NMR techniques. Cytotoxic activities of compounds 3, and 5-10 were tested on the three cancer cell lines, PANC-1, K562, and BxPC-3. Results revealed that 7 exhibited cytotoxicity against PANC-1, K562, and BxPC-3, with IC50 values of 4.67, 0.72, and 4.01 g/ml, respectively, whereas 8 was inactive against these cancer cell lines. The structureactivity relationship of compound 7 and 8 indicated that the 3-OH group in polymethoxyflavonoids is essential for antitumor activity.