Genome mining guided identification of new furo[3,2-c]pyridones phaeopyridones A–C from the endophytic fungus Phaeobotryon negundinis 12020

Three pairs of new furo[3,2-c]pyridone derivative racemates, named (±)-phaeopyridones A-C (1-3), together with two new compounds, berkeleyamide E (4), and phaeopyranone (5), were isolated from the endophytic fungus Phaeobotryon negundinis 12020, along with three known compounds, (8S,9S)-dihydroisoflavipucine (6), (8S,9R)-dihydroisoflavipucine (7), and sapinopyridione (8), guided by bioinformatics and feature-based molecular networking and fragment-based LC-MS/MS analysis. The chemical structures of these compounds were elucidated by comprehensive spectroscopic analyses and single-crystal X-ray diffraction. Furthermore, a biosynthetic pathway for compounds 1-3 was proposed, indicating the unique furo[3,2-c]pyridone moiety may be generated by a non-enzymatic intermolecular hemiketal formation reaction. Our research expands the known range of flavipucine alkaloids and highlights the unexplored biosynthetic potential of natural products derived from endophytic fungi.