Talarophilone, a ring-opened azaphilone from the endophytic fungus Talaromyces sp. YUD18002

Talarophilone (1), a novel ring-opened azaphilone, along with two known analogues were obtained from the culture of the Gastrodia elata-derived endophytic fungus Talaromyces sp. YUD18002. The structure of the new compound was elucidated using spectroscopic methods and its absolute configuration was confirmed by a single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD) analysis aided by TDDFT-ECD calculations. Talarophilone represented the first ring-opened azaphilone featuring ester group at C-6′ functionality. A putative biosynthetic pathways for compounds 1–3 were proposed. The in vitro cytotoxic activities of the new compound were also investigated.