Cytotoxic ent-Kaurane Diterpenoids from Salvia cavaleriei

Fifteen new ent-kaurane diterpenoids, compounds 1–15, and two known analogues, 4-epi-henryine A (16) and leukamenin E (17), were isolated from the whole plants of Salvia cavaleriei. The structures of the new compounds were established by spectroscopic methods, and their absolute configurations were determined by electronic circular dichroism and single-crystal X-ray diffraction analyses with Cu Kα radiation. Compounds 1–15 were evaluated for their cytotoxicity against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7, and SW480, as well as the noncancerous Beas-2B cell line. Compounds 1–10, 12, 14, and 15 showed broad-spectrum cytotoxicity, with compounds 1, 3, 6–10, 12, and 15 exhibiting more potent cytotoxicity than the positive control, cis-platin, with IC50 values ranging from 0.65 to 6.4 μM.从贵州鼠尾草（Salvia cavaleriei）全株中分离得到15个新的对映-贝壳杉烷二萜类化合物（ent-kaurane diterpenoids，化合物1–15）及2个已知类似物，即4-表亨利碱A（4-epi-henryine A，16）与白花鼠尾草素E（leukamenin E，17）。新化合物的结构通过波谱学方法得以确定，其绝对构型由电子圆二色谱（electronic circular dichroism）及采用Cu Kα辐射的单晶X射线衍射分析完成鉴定。对化合物1–15进行了针对5种人类癌细胞系（HL-60、SMMC-7721、A-549、MCF-7、SW480）以及非癌Beas-2B细胞系的细胞毒性评价。结果表明，化合物1–10、12、14及15均具有广谱细胞毒性，其中化合物1、3、6–10、12及15的细胞毒活性优于阳性对照顺铂（cis-platin），其半抑制浓度（IC50）值介于0.65至6.4 μM之间。