Grapefruit juice compounds and their blocking of a gut transporter in lab cells
What it found
In lab tests on dog kidney cells, several grapefruit juice compounds blocked a gut transporter that helps the body take in certain drugs.
Nobiletin was the strongest blocker among those tested.
What they found
Animal and lab studies
Strongest transporter blockers
In lab cells, nobiletin was the strongest blocker of the OATP2B1 transporter, needing less than 5 μM to cut activity in half. Four other compounds were moderate blockers, needing between 20 and 50 μM.
Weakest transporter blockers
Bergamottin and hesperidin were the weakest blockers in the lab cells. Both needed more than 300 μM to reduce transporter activity by half.
Low doses boosted uptake
At very low amounts, under 1 to 3 μM, five of the seven compounds actually increased transporter activity by up to 20% in the lab cells. Only nobiletin and bergamottin did not show this boost.
Other findings
Computer models flagged risks
Computer simulations predicted that four compounds would reach high enough levels inside human gut cells to potentially block the transporter. Two compounds, naringenin and naringin, also exceeded risk thresholds based on their amounts in grapefruit juice alone.
What the authors conclude
- They demonstrated a streamlined method for identifying which compounds in grapefruit juice are most likely to block a key gut transporter.
- Their computer models suggest that flavanones are the main blockers, but two other compounds might also matter.
- They advise further research to see if these compounds work together or compete when consumed as whole juice.
How it was done
People often drink natural products like grapefruit juice while taking prescription drugs, which can change how much medicine the body absorbs. The authors wanted a faster way to figure out which specific compounds in complex drinks are most likely to interfere with drug uptake in the gut.
They tested seven compounds found in grapefruit juice using lab-grown dog kidney cells modified to carry a human gut transporter called OATP2B1. They measured how much of each compound was needed to block half the transporter activity. They then used computer models to estimate how these compounds behave inside human gut cells after someone drinks 250 mL of juice.
What it can’t tell you
- These experiments used dog kidney cells in a dish, so they cannot directly show what happens in a person drinking grapefruit juice.
- The computer models rely on estimates rather than actual measurements from human bodies.
- Scientists do not yet know if these compounds interact with each other when consumed together in real juice.
Who paid
- Funding
- Funded by NIGMS NIH HHS; NCATS NIH HHS (from the PubMed record).
- Conflicts
- Conflict of Interest . The authors declare no conflicts of interest.
- Authors work at
- Washington State University, USA
The paper
- Title
- Prioritizing pharmacokinetic drug interaction precipitants in natural products: application to OATP inhibitors in grapefruit juice
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Johnson EJ, Won CS, Köck K, Paine MF (2017). Prioritizing pharmacokinetic drug interaction precipitants in natural products: application to OATP inhibitors in grapefruit juice. Biopharmaceutics & drug disposition. doi:10.1002/bdd.2061Free full textPubMed 28032362DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error