Eight New Myrochromanol Derivatives From a Marine Fungal-Bacterial Symbiont.

Eight new myrochromanol derivatives (1-5, 7-9), together with two known analogues (6, 10), were isolated from the marine-derived fungal-bacterial symbiont Albifimbria verrucaria/Burkholderia territorii GXIMD 14478. Their structures with absolute configurations were determined through extensive spectroscopic data, circular dichroism (CD) spectroscopy, quantum chemical calculations, and chemical modifications. Notably, compounds 1-2 possessed rare 6/6/6 and 6/6/5 tricyclic benzopyran skeletons, respectively. In bioassays, compound 6 exhibited cytotoxicity against RAW264.7 macrophages (83.3% inhibition of cell viability at 20 µM), while other compounds showed no notable cytotoxic effects. Compounds 8 and 9 inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages. This study expands the structural diversity of myrochromanols from marine fungal-bacterial symbionts and underscores their potential for bioactive metabolite discovery.