The recent isolation and structural elucidation of balanol (1, Figure l),'an unusual metabolite produced by the fungus Verticillium balanoides, represents a significant new development in the quest for effective inhibitors of protein kinase C (PKC). Z PKC-mediated signal transduction is known to lead to a variety of cellular responses, including gene expression and cell proliferation, 2J and activated PKC has been implicated in conditions as diverse ...