Antimicrobial Dolabellanes and Atranones from a Marine-Derived Strain of the Toxigenic Fungus Stachybotrys chartarum

Three new dolabellane-type diterpenoids
(1–3) and three new atranones (4–6) were isolated
and identified from a marine-derived strain of the toxigenic fungus Stachybotrys chartarum. The planar and relative structures
of 1–6 were elucidated using extensive
spectroscopic methods, and their absolute configurations were fully
confirmed via single-crystal X-ray diffraction analysis. Structurally,
compounds 2 and 3 have a 1,14-seco dolabellane-type diterpenoid skeleton; compound 4 is
the first C23 atranone featuring a propan-2-one motif linked
to a dolabellane-type diterpenoid by a carbon–carbon bond;
compound 5 represents the first example of a C24 atranone with a 2-methyltetrahydrofuran-3-carboxylate motif fused
to a dolabellane-type diterpenoid at C-5–C-6. In an in vitro
antimicrobial activity assay, compound 2 was active against Acinetobacter baumannii and Enterococcus faecalis with MIC values of 16 and 32 μg/mL, respectively, while compound 4 exhibited significant inhibitory activities against Candida albicans, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA) with MIC values of 8, 16, and 32 μg/mL, respectively.

从一株有毒真菌 Stachybotrys chartarum 的海洋来源菌株中成功分离并鉴定出三种新的 dolabellane 型二萜化合物（1-3）和三种新的 atranones（4-6）。通过广泛应用的波谱学方法，阐明了1-6的平面和相对结构，并通过单晶X射线衍射分析完全确定了其绝对构型。在结构上，化合物2和3具有1,14-去甲基dolabellane型二萜骨架；化合物4是首个具有丙酮基团并通过碳-碳键连接到dolabellane型二萜的C23 atranone；化合物5是首个在C-5-C-6位置将2-甲基四氢呋喃-3-羧酸酯基团与dolabellane型二萜融合的C24 atranone。在体外抗菌活性测试中，化合物2对鲍曼不动杆菌和粪肠球菌表现出活性，其最低抑菌浓度（MIC）分别为16和32 μg/mL；而化合物4对白色念珠菌、粪肠球菌和耐甲氧西林金黄色葡萄球菌（MRSA）显示出显著的抑制作用，其MIC值分别为8、16和32 μg/mL。