Ganotheaecolin A, a Neurotrophic Conjugated Ergosterol with a Naphtho[1,8-ef]azulene Scaffold from Ganoderma theaecolum

Ganotheaecolin A (1), a novel ergosterol with a rare naphtho[1,8-ef]azulene ring system, was isolated from the fruiting bodies of Ganoderma theaecolum. Its structure was determined by spectroscopic data and computational methods. Compound 1 represents a 6/6/7/5-fused carbon skeletal ergosterol typically formed by Wagner-Meerwein rearrangement, whose plausible biosynthetic pathway was briefly discussed. Finally, the neurotrophic activity of 1 was examined using PC12 cells.