Circumdatin G, a new alkaloid from the fungus Aspergillus ochraceus.

The crude extract of the broth of Aspergillus ochraceus was found to inhibit the final stage of polyprotein processing during hepatitis C virus replication. Bioassay-guided fractionation led to the isolation of the known compound mellein as the active component of the extract. Also isolated were circumdatin F and a new alkaloid, circumdatin G. The structure of circumdatin G was determined by spectroscopic analysis.