Rhizovagine A, an unusual dibenzo-α-pyrone alkaloid from the endophytic fungus Nitaf22.

Rhizovagine A (1), a novel dibenzo-α-pyrone alkaloid with an unprecedented 5/5/6/6/6 fused pentacyclic skeleton, was isolated from the endophytic fungus Nitaf22. The structure was elucidated by comprehensive spectroscopic analysis, in combination with quantum chemical C NMR and electronic circular dichroism (ECD) calculations for configurational assignment. A plausible biosynthetic pathway for 1 was proposed. Compound 1 displayed acetylcholinesterase inhibitory activity.