Session: Analytical Division Poster:

The purpose of this research was to quantitate two furanocoumarins, bergamottin and 6’,7’-dihydroxybergamottin, found in the over-the-counter dietary supplements, Nutribiotic Maximum Strength Defense Plus and Chewable Acerola Vitamin C Complex. Bergamottin and 6’,7’-dihydroxybergamottin are two compounds responsible for the “grapefruit effect”, which results in increased levels of over 80 drugs when taken with grapefruit due to inhibition of CYP enzymes.
Methanol was used to extract the furanocoumarins which were then quantitated using high-performance liquid chromatography with diode array detection. Initial results showed 52.66 ng DHB/tablet and 209.34 ng BGT/tablet in the Acerola supplements and 1.256 µg DHB/tablet and 2.270 BGT µg/tablet in the Nutribiotic supplements.
This amount is considerably less than the amount researchers have measured in an 8-ounce serving of grapefruit juice (0.2 – 2.9 mg BGT and 0.02 - 7.4 mg DHB). Consuming 8 ounces of grapefruit juice with certain drugs is enough to cause the “grapefruit effect”. These levels could be obtained, however, if taking more than one pill or even by taking the pills with grapefruit juice and/or other supplements that have the same effect. Without labeling, the consumer is unaware of the potential for dangerous drug-drug interactions. Our results indicate the need for warning labels on these supplements.

Miriam Bregman

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