Bisacremines E–G, Three Polycyclic Dimeric Acremines Produced by Acremonium persicinum SC0105

Three dimeric acremines, bisacremines E–G (1–3), with an unusual carbon skeleton were isolated from cultures of the soil-derived fungus Acremonium persicinum SC0105. Their structures were elucidated by spectroscopic analysis, X-ray diffraction, and ECD/TDDFT computations. Compound 3 exhibited inhibitory effects on the production of TNF-α, IL-6, and NO in LPS-stimulated macrophages. A biogenetic pathway with a [4 + 2] cycloaddition as the key reaction is proposed for 1–3.