Calvatia nipponica is an extremely rare mushroom with a limited number of studies on its chemical components and biological activities published. Here we report the isolation of a novel sterol, calvatianone (1), possessing a 6/5/6/5-fused ring system with a contracted tetrahydrofuran B-ring, and four known steroids (2–5) from the fruiting bodies of C. nipponica. The structure of calvatianone including its absolute configuration was determined by NMR spectroscopic analyses, HR-ESIMS, gauge-including atomic orbital NMR chemical shift calculations, and ECD calculations. Ergosterol peroxide (3) and cyathisterol (4) suppressed the cell viability increase induced by 17β-estradiol in MCF-7 breast cancer cell lines, suggesting a possible approach for these compounds to serve as ERα antagonists.

中文翻译：

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Calvatianone，一种具有 6/5/6/5-稠环系统和收缩的四氢呋喃 B 环的甾醇，来自 Calvatia nipponica 的子实体。

Calvatia nipponica是一种极其稀有的蘑菇，发表的关于其化学成分和生物活性的研究数量有限。在这里，我们报告了一种新的甾醇，calvatianone ( 1 )，它具有一个6/5/6/5稠环系统和一个收缩的四氢呋喃 B 环，以及四种已知的类固醇 ( 2 - 5 )。C. nipponica。通过 NMR 光谱分析、HR-ESIMS、包括原子轨道 NMR 化学位移计算和 ECD 计算的规范，确定了卡尔瓦酮的结构，包括其绝对构型。过氧化麦角甾醇 ( 3 ) 和氰甾醇( 4 )) 抑制了 17β-雌二醇在 MCF-7 乳腺癌细胞系中诱导的细胞活力增加，表明这些化合物作为 ERα 拮抗剂的可能方法。