Twelve new lanostane triterpenoids, sterenoids A-L (1-12) have been isolated from fruiting bodies of the basidiomycete Stereum sp. Compounds 1-12 are rare 14(13→︀12)abeo-lanostane triterpenoids featuring remarkable 13R configurations that discriminate from the previously covered counterparts. Their structures and absolute configurations are assigned on the basis of in-depth one- and two-dimensional NMR spectroscopic analysis, as well as unbiased quantum chemical NMR and electronic CD calculations. All isolates are evaluated for their in vitro cytotoxicity against five human tumor cell lines. Compound 5 exhibits potent cytotoxic activities against tumor cell lines HL-60 and SMMC-7721 with IC₅₀ values of 4.7 and 7.6 μM, respectively.

中文翻译：

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拟南芥Stereum sp。的子实体中的羊毛脂三萜类化合物，结构和生物活性。

从担子菌Stereum sp。的子实体中分离出十二种新的羊毛甾烷三萜，类固醇AL（1-12）。化合物1-12是稀有的14（13→︀12）阿拉伯羊毛甾烷三萜类化合物，具有非凡的13R构型，与以前涵盖的对应物区分开。它们的结构和绝对构型是根据深入的一维和二维NMR光谱分析以及无偏量子化学NMR和电子CD计算指定的。评价所有分离株对五种人类肿瘤细胞系的体外细胞毒性。化合物5对肿瘤细胞系HL-60和SMMC-7721表现出强力的细胞毒活性，IC ₅₀值分别为4.7和7.6μM。