Talarodride I, an Unusual Penta‐Nor‐Nonadride and Other Derivatives Characterized From the Deep‐Sea Seamount‐sourced Endozoic <i>Talaromyces scorteus</i> AS‐242

Talarodride I (1), the first representative of penta-nor-nonadride derivative having a caged bicyclo[4.3.1]deca-2,6-diene core skeleton with an aldehyde group at C-15, together with a new congener talarodride J (2) and five known secondary metabolites (3-7), were isolated and identified from the Magellan seamount-sourced sea-anemone endozoic fungus Talaromyces scorteus AS-242. Their structures were assigned by nuclear magnetic resonance and mass spectroscopic data analysis and time-dependent density functional theory electronic circular dichroism calculations. In the antibacterial assays compounds 1-5 displayed activities against a broad spectrum of human- and aquatic pathogens, with compounds 1 and 2 showing potent inhibitory effects against Escherichia coli and Aeromonas hydrophilia (minimum inhibitory concentration values 1-4 µg/mL).