Global Challenges/Chemistry Solutions

Making grapefruit juice safer for people who take certain prescription drugs

February 10, 2009

Credit: The Florida Department of Citrus
(Click here to download a high resolution
version of this image


Today’s topic is research on making foods safer.
This discovery could make grapefruit and certain
other citrus juices a lot safer for millions of
people taking certain prescription medicines.
Scientists report that adding an edible fungus to
grapefruit juice may help to reduce so-called
“grapefruit/drug” interactions.

“A key compound in grapefruit blocks a key enzyme that
metabolizes certain medications. The inhibition of the
enzyme by this compound can lead to a potential overdose
and side effects.”

That was Dr. Kyung Myung. He led a team of scientists in Florida who reported a possible solution in the ACS’ bi-weekly Journal of Agricultural and Food Chemistry. Dr. Myung is with the U. S. Department of Agriculture’s Agricultural Research Service.

In the study, Dr. Myung and colleagues focused on furanocoumarins (FCs). These chemicals found in grapefruit and some other citrus block a key enzyme in the human body. That enzyme is critical for metabolizing, or breaking down, certain prescription medications. FCs are responsible for “grapefruit/drug” interactions — sometimes called the “grapefruit effect.” It can turn normal drug doses into toxic overdoses.

Almost 50 medications carry the risk of grapefruit-induced drug-overdose interactions. As a result, some prescription drugs now carry warning labels against taking grapefruit juice or fresh grapefruit during drug consumption. Researchers have tried to remove FCs using chemical, physical and microbiological methods.

Dr. Myung’s group, for example, previously discovered that an inedible fungus can remove most of the FCs from grapefruit juice. Their new solution: Adding an edible mushroom-like fungus to grapefruit juice may help to reduce those side effects.

Now they have shown, in lab experiments, that the fungus removes most of the furanocoumarins from grapefruit juice. Called Morchella esculenta, the fungus reduced grapefruit juice’s inhibition of the enzyme by 60 percent. Dried Morchella also worked. As a result, the researchers suggest that the fungus could help remove furanocoumarins from commercial grapefruit juice. It also could help them identify the specific components in the fungi that bind to furanocoumarins.

“The consumption of grapefruit by U. S. consumers has
been decreased mainly due to the grapefruit drug
interaction caused by this key compound. The removal of
this compound by a certain method may be required to
reduce this grapefruit drug interaction. This may boost the
grapefruit industry in the future.”

Well said, Dr. Myung. This discovery could help allow millions of people to once again enjoy the nutritional bonanza in grapefruit and other fruit juices, without affecting their medication.

Smart chemists/Innovative Thinking

Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st Century. Please check our full-length podcast on safe food. Today’s podcast was written by Michael Woods. I’m Adam Dylewski at the American Chemical Society in Washington.

New Sources and Resources on the “Grapefruit Effect”

“Removal of Furanocoumarins in Grapefruit Juice by Edible Fungi”
ACS Journal of Agricultural and Food Chemistry

Dr. Kyung Myung, John A. Manthey and Jan A. Narciso, co-authors of the study. Credit: U.S. Department of Agriculture (Click here to download a high resolution version of this image)