Further lupane lactones from Kokoona ochracea.

Additional new lupane lactones were isolated from the stem bark of Kokoona ochracea (Celastraceae). Their structures have been elucidated, through the application of 1D and 2D nmr spectroscopic methods, as 20,29-dihydroxy-3-oxolupan-30,21 alpha-olide (ochraceolide D) [1] and 28-hydroxy-3-oxolup-20(29)-en-30,21 alpha-olide (ochraceolide E) [2]. These compounds and the mono- and di-acetates of ochraceolide D (4 and 5, respectively) were evaluated for in vitro cytotoxic activity against P-388 murine lymphocytic leukemia cells and a panel of human cancer cell systems. Ochraceolide D [1] was significantly cytotoxic (ED50, 3.9 micrograms/ml) against human glioblastoma (U373) cells. Other compounds (4, 5, and 2) exhibited only a weak cytotoxic response in certain cancer cell lines.