One Tangerine/Grapefruit Hybrid (Tangelo) Contains Trace Amounts of Furanocoumarins at a Level Too Low To Be Associated with Grapefruit/Drug Interactions

Tangelos are citrus hybrids with grapefruit and tangerine parentage and are a significant crop in Florida, marketed as specialty fruit. Because tangelos contain genetic material from grapefruit, there is the question of whether or not they contain furanocoumarins and exhibit an interaction with the drugs that have been associated with the grapefruit-drug interaction. Authentic samples of 13 tangerine-grapefruit hybrids (tangelos), 1 tangerine-orange hybrid, and 1 mandarin tangerine from Florida were obtained and screened for furanocoumarin monomer and dimer contents. None of the tangerine or tangerine hybrids were found to contain any furanocoumarins except for the KEarly variety, which contained trace amounts of 6,7-dihydroxybergamottin (0.028 ppm 0.0034), bergapten (0.011 ppm 0.005), and bergamottin (0.025 ppm 0.011). These amounts are low and insignificant in that they are not at levels that would significantly inhibit CYP3A4 enzyme and affect absorption of drugs metabolized by this enzyme. This information presents strong evidence that the commercial tangerine and tangelo varieties grown in Florida are unlikely to cause any interaction with the drugs affected by grapefruit.