Submitted to: Subtropical Technology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2004
Publication Date: 10/21/2004
Citation: Widmer, W.W., Stinson, W., Dou, H., Haun, C. 2004. Furanocoumarin variation in four grapefruit varieties with respect to maturity. Subtropical Technology Conference Proceedings. 55:26-27. Interpretive Summary:
Technical Abstract: Grapefruit juice, when consumed with some orally administered medications, has been shown to increase their bioavilability. After more than a decade of research, it has been shown the interaction occurs because a number of grapefruit components cause inhibition of the intestinal enzyme cytochrome P-450 3A4. Naringin was initially thought to be the active CYP3A inhibitor in grapefruit juice, and while naringin does have some inhibitory effect in-vitro, it has little or no effect in-vivo. It is now fairly well accepted that components completely or largely responsible for the CYP3A4 inhibition are naturally occurring furanocoumarin monomers (bergamottin, 6,7-dihydroxybergamottin) and dimer compounds. The dimer compounds identified are composed of two furanocoumarins either linked by joining the terpene sidechains (tail to tail), or by linking the terpene sidechain to the ketone oxygen on the aromatic ring (head to tail). Furanocoumarins were monitored in four varieties of grapefruit (Marsh White, Ruby Red, Flame, Rio Red) over two seasons and the results of this study will be discussed.