Furanocoumarins are a group of organic compounds produced by certain plants as a defence mechanism to protect themselves from external organisms. The importance of furanocoumarins is their interactions with metabolism of some medications. They induce enzyme inhibition, which means they block the liver enzyme cytochrome P450, interfering with the metabolism of some medications.
Subtypes are bergamottin, dihydroxybergamottin, bergapten, isobergapten, angelicin, and psoralen.
Fruits: grapefruit (bergamottin and dihydroxybergamottin), Seville oranges (bergamottin and dihydroxybergamottin), pomelo (bergamottin and dihydroxybergamottin), and fig (psoralen).
Vegetables: celery (bergapten and psoralen), parsnips (isobergapten and psoralen), fennel seeds (psoralen), parsley (psoralen), and wild carrot (psoralen).