New Antibacterial Chloro-Containing Polyketides from the Alga-Derived Fungus Asteromyces cruciatus KMM 4696

Six new polyketides acrucipentyns A-F ( - ) were isolated from the alga-derived fungus KMM 4696. Their structures were established based on spectroscopic methods. The absolute configurations of acrucipentyn A was assigned by the modified Mosher's method and ROESY data analysis. Acrucipentyns A-E were identified to be the very first examples of chlorine-containing asperpentyn-like compounds. The cytotoxic and antimicrobial activities of the isolated compounds were examined. Acrucipentyns A-F were found as antimicrobial agents, which inhibited sortase A enzyme activity, bacterial growth and biofilm formation of and decreased LDH release from human keratinocytes HaCaT in skin infection in an in vitro model.