文摘
Two new clerodane diterpenoids (<b>1b> and <b>2b>) and the known compound caseanigrescen D (<b>3b>) were isolated from the leaves of Casearia grewiifolia by bioassay-guided fractionation. Their structures were determined by analyses of MS and 2D NMR data. The absolute configurations of <b>1b> and <b>3b> were established by analysis of X-ray diffraction data. Compounds <b>1b>鈥?b>3b> were evaluated for their cytotoxicity against four cancer cell lines, KB (mouth epidermal carcinoma cells), HepG-2 (human liver hepatocellular carcinoma cells), LU-1 (human lung adenocarcinoma cells), and MCF-7 (human breast cancer cells). Caseagrewifolin B (<b>2b>) had inhibitory activity against KB and HepG-2 cell lines with ICb>50b> values of 6.2 to 7.0 渭M, respectively. When tested against the normal cells (NIH/3T3), caseagrewifolin B (<b>2b>) exhibited a significant selective inhibition against cancer cells in comparison with the normal cells. Caseanigrescen D (<b>3b>) was cytotoxic against four cancer cell lines; however it had no selective inhibition compared with normal cells.