Fungi are important resources for drug development, as they have a diversity of genes, that can produce novel secondary metabolites with effective bioactivities. Here, five depsidone-based analogs were isolated from the rice media of Chaetomium brasiliense SD-596. Their structures were elucidated using NMR and mass spectrometry analysis. Five compounds, including three new depsidone analogs, mollicellin S (1), mollicellin T (2), and mollicellin U (3), and two known compounds, mollicellin D (4) and mollicellin H (5), exhibited significant inhibition against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA), with MIC values ranging from 6.25 to 12.5 μg ml⁻¹. Herein, we identified the predicted plausible biosynthetic cluster of the compounds and discussed the structure-activity relationship. Finally, we found that the introduction of aldehyde and methoxyl groups provide marked improvement for the inhibition against MRSA.

真菌是药物开发的重要资源，因为它们具有多样性的基因，可以产生具有有效生物活性的新型次级代谢产物。在这里，从Chaetomium brasiliense SD-596的水稻培养基中分离出五种基于地塞酮的类似物。使用核磁共振和质谱分析阐明了它们的结构。五种化合物，包括三种新的地塞酮类似物 mollicellin S ( 1 )、mollicellin T ( 2 ) 和 mollicellin U ( 3 )，以及两种已知化合物 mollicellin D ( 4 ) 和 mollicellin H ( 5 )，对葡萄球菌表现出显着的抑制作用金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌(MRSA)，MIC 值范围为 6.25 至 12.5 μg ml ^-1。在此，我们确定了化合物的预测合理生物合成簇并讨论了构效关系。最后，我们发现醛基和甲氧基的引入显着改善了对 MRSA 的抑制作用。