One novel bisabolane‐derived sesquiterpenoid retrobisabolane A (1), featuring a methyl group location at the C‐4 position instead of C‐3 in the bisabolanes, and a known ester‐substituted eremophilane‐type sesquiterpenoid cryptosphaerolide (2), along with three known indole alkaloids (3‒5) were discovered from the fermented cultures of a deep‐sea‐derived fungus Retroconis fusiformis MCCC 3A00792. The planar structure of new compound 1 was determined by extensive analysis of the NMR and HRESIMS spectra. The relative and absolute configurations of 1 were resolved by the coupling constant (J), calculation of ECD and NMR spectra, and the DP4+ probability analysis of the 1H and 13C NMR data. Interestingly, retrobisabolane A was the new subclass of bisabolanes bearing a methyl group linkage at C‐4 instead of C‐3 position. Three human cancer cell lines (Hela, AGS, and BIU‐87) were subjected to evaluate the cytotoxic activities of compounds 1‒5. As a result, compound 2 exhibited significant inhibitory activities against three cell lines with IC50 values ranging from 9.95 to 18.77 μM.

中文翻译：

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后红没药烷 A，一种从深海衍生真菌 Retroconis fusiformis MCCC 中分离出来的新型红没药烷衍生倍半萜类化合物 MCCC 3A00792

一种新型红没药烷衍生的倍半萜类反没药烷 A (1)，其特征是甲基位于红没药烷的 C-4 位，而不是红没药烷中的 C-3，以及一种已知的酯取代的 eremophilane 型倍半萜类隐球内酯 (2)，以及三种已知的吲哚生物碱 (3-5) 是从深海来源的真菌 Retroconis fusiformis MCCC 3A00792 的发酵培养物中发现的。新化合物 1 的平面结构通过对 NMR 和 HRESIMS 光谱的广泛分析确定。 1的相对构型和绝对构型通过耦合常数(J)、ECD和NMR谱的计算以及1H和13C NMR数据的DP4+概率分析来解析。有趣的是，逆红没药烷 A 是红没药烷的新亚类，在 C-4 位而不是 C-3 位上带有甲基键。使用三种人类癌细胞系（Hela、AGS 和 BIU-87）评估化合物 1-5 的细胞毒活性。结果，化合物2对三种细胞系表现出显着的抑制活性，IC50值范围为9.95至18.77 μM。