Drugs associated with moderate (50%-80%) inhibition of 17P were fluconazole (Diflucan), itraconazole (Sporanox), diltiazem, esomeprazole (Nexium), tacrolimus, and bergamottin
Now, researchers at the University of Michigan and Parke-Davis Pharmaceutical Research, both in Ann Arbor, have identified a compound in grapefruit juice called bergamottin that could be responsible for the effect.
The finding builds on previous research, done in collaboration with scientists at Wayne State University in Detroit, that isolated a derivative of bergamottin and found that it inactivates the enzyme.
Bergamottin is "an important lead, but the jury is still out" on whether it causes the grapefruit juice effect, says David G.
They found a high concentration of bergamottin in the mix.
In contrast, orange juice extracts didn't contain bergamottin at all--in accordance with the observation that orange juice doesn't cause the same drug effects.