State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China.
State-Province Joint Engineering Laboratory of Targeted Drugs from Natural Products, Xiamen University, Xiamen 361102, China.
Molecules. 2021 Oct 28;26(21):6505. doi: 10.3390/molecules26216505.
Eight new cytochalasins - and ten known analogs - were isolated from the endophytic fungus Phomopsis sp. xz-18. The planar structures of the cytochalasins were determined by HR-ESI-MS and NMR analysis. Compounds , , and were 5/6/6/7/5-fused pentacyclic cytochalasins; compounds and had conjugated diene structures in the macrocycle; and compound had a β,γ-unsaturated ketone. The absolute configuration of 6 was confirmed for the first time by the octant rule. The acid-free purification process proved that the pentacyclic system was a natural biosynthetic product and not an acid-mediated intramolecular cyclized artifact. The new compounds did not exhibit activities against human cancer cell lines in cytotoxicity bioassays or antipathogenic fungal activity, but compounds , and showed moderate antibacterial activity in disk diffusion assays.
从内生真菌 Phomopsis sp. xz-18 中分离得到了 8 种新的细胞松弛素和 10 种已知的类似物。通过高分辨电喷雾质谱（HR-ESI-MS）和 NMR 分析确定了细胞松弛素的平面结构。化合物 、 、 和 是 5/6/6/7/5 稠合的五环细胞松弛素；化合物 和 在大环中有共轭二烯结构；化合物 有一个 β,γ-不饱和酮。化合物 6 的绝对构型首次通过八分位规则确定。无酸纯化过程证明了五环系统是天然生物合成产物，而不是酸介导的分子内环化的人为产物。新化合物在细胞毒性生物测定中对人癌细胞系没有活性，也没有抗真菌活性，但化合物 、 、 在圆盘扩散测定中表现出中等的抗菌活性。
