Amphichoterpenoids A–C, unprecedented picoline-derived meroterpenoids from the ascidian-derived fungus Amphichorda felina SYSU-MS7908

Unprecedented picoline-derived meroterpenoids, amphichoterpenoids A–C, possessing a pyrano[3,2-c]pyridinyl-γ-pyranone skeleton, were characterized from the ascidian-derived fungus Amphichorda felina (A. felina) using a modified encapsulated nanodroplet crystallization method to afford the crystals. [Display omitted] Amphichoterpenoids A–C (1–3), unprecedented picoline-derived meroterpenoids possessing a pyrano[3,2-c]pyridinyl-γ-pyranone scaffold, were characterized from the ascidian-derived fungus Amphichorda felina SYSU-MS7908. Their structures were elucidated by spectroscopic methods, X-ray diffraction and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway was proposed. The isolated compounds displayed moderate inhibitory activity against acetylcholinesterase with 50% inhibiting concentration (IC50) values of 18.8–53.2 μmol/L.