Major furocoumarins in grapefruit juice I: Levels and urinary metabolite(s)

► Bergaptol > bergamottin > 6′,7′-DHB were the major furocoumarins in commercial grapefruit juices. ► In freshly prepared, home-made juices an inverse picture (DHB > bergamottin > bergaptol) was obtained. ► Consumption of grapefruit juice led to a urinary excretion of free plus conjugated bergaptol only. ► Other furocoumarins were not found in urine. ► The excreted amount of bergaptol exceeded the consumed one.