Synthesis of Furanocoumarin, Benzofuran and Coumarin Derivatives Possessing an Inhibitory Effect on Human CYP, and Elucidation of the Inhibitory Mechanism.

Grapefruit juice (GFJ) consumption has been shown to increase the bioavailability of certain orally administered drugs. The furanocoumarin derivatives Paradisin A and bergamottin, which are present in GFJ, are potent mechanism-based inhibitors of CYP3A4. The primary aim of this work was to synthesize a series of furanocoumarin derivatives with a view to determining the relationship between the structure of the inhibitors and their inhibitory CYP3A4 activity. Furanocoumarin derivatives that were more stable and accessible than the furanocoumarin derivatives in GFJ were prepared, and their ability to inhibit CYP3A4 was examined. Synthesized furanocoumarin monomers showed strong mechanism-based inhibition of CYP3A4. The furanocoumarin dimers are also mechanism-based inhibitors of CYP3A4. These monomers and dimers are more potent inhibitors of CYP3A4 than bergamottin and Paradisin A, respectively.