中文摘要：

报道南海湛江硇洲岛软珊瑚Dendronephthya sp．中两种具有细胞毒性的四羟基甾醇化合物：23-降-24-亚甲基-麦角甾-3β，5α，6β,7β四醇（1）和24-亚甲基-麦角甾-3β，6β,9α，19β-四醇（2），其结构通过波谱和化学方法确定，其中化合物1为新化合物，化合物2首次从该属珊瑚中获得．化合物1对肿瘤细胞BEL-7402，MCG，MCF，LOVO和HepG-2具有抑制作用，其IC50值分别为32．2，20．5，2．0，5．5和18．6μg／mL；化合物2对肿瘤细胞MCG和LOVO作用的IC50值分别为22．0和和13．8μg／mL．

英文摘要：

Two cytotoxic activity sterols 23-nor-ergost-24（28）-ene-3β,5α,6β,7β-tetrol （1） and ergost-24（28）-ene-3β,6β,9α,19β-tetrol （2） from Dendronephthya sp. collected from Naozhou Islands of the South China Sea have been reported. Their structures were defined by spectroscopic and chemical methods. Sterol 1 is a new compound, which exhibited cytotoxicity against BEL-7402, MCG, MCF, LOVO and HepG-2 cells （IC50 32.2, 20.5, 2.0, 5.5 and 18.6 μg/mL, respectively）. Sterol 2 also showed significant cytotoxicity against MCG and LOVO cells （IC50 22.0 and 13.8 μg/mL, respectively）.