CAM InteractionsHerbals

Potential drug interactions with ethnic herbals

An international group of researchers report on the ability of 3 herbal products commonly used in Cuba and Mexico to inhibit the action of the CYP450 system of drug metabolizing enzymes.

It’s relevant considering the millions of illegal aliens who have entered the US and bring their folk medicines with them.

First, the details.

  • Experiments were conducted using human liver microsomes — tiny granules in liver cells where protein synthesis takes place.
  • Changes in the activities of CYP1A1/2, CYP2D6, and CYP3A4 were measured using specific probe substrates.
    • Among the 57 CYP450 genes identified, those named CYP1, CYP2, and CYP3 contribute to the metabolism of drugs.
    • The subfamilies called CYP1A1/2, CYP2D6, and CYP3A4 were studied here.
  • Extracts of the following medicinal plants were tested.
    • Heliopsis longipes (Compositae): a Mexican plant used in juices, smoothies, ice cream, fruit bars, raspados, aguas frescas, pies, and sweet chili sauce, or mixed with chamoy — a sweet and spicy chili paste.
    • Mangifera indica L. (mango): a common ingredient in new functional foods often called superfruits.
    • Thalassia testudinum (turtle grass): considered to have liver protective activity.

And, the results.

  • H. longipes inhibited the activity of each of the 3 enzymes, with higher concentration exerting greater inhibition.
  • Similar effects were produced by affinin (a metabolite of H. longipes).
  • M. indica L. and T. testudinum diminished CYP1A1/2 and 3A4 activities, but not CYP2D6 activity.

The bottom line?
The authors concluded, “These results suggest that these herbs inhibit the major human CYP450 enzymes involved in drug metabolism and could induce potential herbal-drug interactions.”

I found no reports of drug interactions involving these plants. But awareness of a potential problem might increase the chances of recognizing an interaction in the absence of other diagnoses.

A detailed review of CYP450 enzymes with lists of drugs that might be affected by changes in enzyme activity can be found here.

10/14/08 16:25 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.