Acremonidin B

Acremonidins A to approximately E (1 to approximately 5) were produced by fermentation of Acremonium sp., LL-Cyan 416, in heterogeneous phases. The structures of these compounds, containing a bridging keto group, were determined by spectroscopic analysis. Acremonidins A and B showed moderate activity against Gram-positive bacteria, including the methicillin-resistant staphylococci and vancomycin-resistant enterococci. Selective acylations of acremonidin B afforded ester derivatives 6 to approximately 9 that exhibited improved antibacterial activity.

Two new xanthone-anthraquinone heterodimers, acremoxanthone C (5) and acremoxanthone D (2), have been isolated from an extract of an unidentified fungus of the order Hypocreales (MSX 17022) by bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi. Two known related compounds, acremonidin A (4) and acremonidin C (3) were also isolated, as was a known benzophenone, moniliphenone (1). The structures of these isolates were determined via extensive use of spectroscopic and spectrometric tools in conjunction with comparisons to the literature. All compounds (1-5) were evaluated against a suite of biological assays, including those for cytotoxicity, inhibition of the 20S proteasome, mitochondrial transmembrane potential and nuclear factor-κB.