Potent Kv1.3 inhibitors from correolide-modification of the C18 position.

Kv1.3, the voltage-gated potassium channel in human T cells, represents a new target for treating immunosuppression and autoimmune diseases. Correolide (1), a pentacyclic natural product, is a potent and selective Kv1.3 channel blocker. Simplification of correolide via removal of its E-ring generates enone 4, whose modification produced a new series of tetracyclic Kv1.3 blockers. The structure-activity relationship for this class of compounds in two functional assays, Rb_Kv and human T cell proliferation, is presented herein. The most potent analog 43 is 15-fold more potent than correolide as inhibitor of human T cell proliferation.