(+)-Epogymnolactam, a novel autophagy inducer from mycelial culture of Gymnopus sp.

Abstract Mushrooms, including Ganoderma lucidum , have been used as a potential source of therapeutic compounds, and an autophagy inducer would be useful for treatment of diverse diseases in human. Reported here is a full account of screening, isolation, structural determination, and biological activity of an autophagy inducer, (+)-epogymnolactam ( 1 ) from a mycelial culture of a Gymnopus sp. strain. Its structure was elucidated by HR-ESI-MS, NMR, and its plus sign by specific rotation. It exists as a tautomeric mixture of 1a and 1b in MeOH. The major tautomer of 1 is (1 R ,5 S )-4-butyl-4-hydroxy-3-aza-6-oxa-bicyclo[3.1.0]hexan-2-one ( 1a ), and the minor tautomeric form is (2 R ,3 S )-3-pentanoyloxirane-2-carboxamide ( 1b ).