A new azaphilone from the entomopathogenic fungus Hypocrella sp.

This report describes the isolation of a new azaphilone, designated hypocrellone A (2), together with five known compounds (1, 3-6) from a submerged culture of the entomopathogenic fungus Hypocrella sp. (isolate WYTY-21). The absolute stereostructures of the two compounds (1 and 2) were elucidated based on 1D and 2D NMR spectroscopic and mass spectrometric data combined with the data from various chemical transformations. Hypocrellone A (2) and three (3-6) of the five known compounds were cytotoxic to hepatoma cells (cell line BEL-7404); IC50 values ranged from 6.2 to 17.4 mu M. At 200 mu M, none of the six compounds was toxic to normal human liver cells (cell line HL-7702) or to normal human kidney epithelial cells (cell line HEK-293T).