Sour makes you he althy
If a sick person takes their medicine with grapefruit juice, the effect can sometimes be increased. This effect has been known for some time. It has now been possible to isolate two substances in grapefruit juice that lead to better absorption of certain drugs in the human body. Previous studies have shown that the effects of some drugs can be improved if patients take them with grapefruit juice. The key to how grapefruit juice increases drug absorption lies in the interaction between the juice and an enzyme found in the small intestine.
Now the director of the General Clinical Research Center at the University of Michigan, Dr.medical Paul B. Watkins and his colleagues isolated two substances in grapefruit juice (furanocoumarins) that are responsible for the so-called "grapefruit effect". The new findings are published in the November issue of the journal Drug Metabolism and Disposition.
According to Watkins, the two components of fruit juice bind to an enzyme in the small intestine known as CYP3A4, destroying its ability to interfere with drug absorption. The enzyme normally acts as a kind of gatekeeper to certain drugs, such as those prescribed for high blood pressure, heart disease, allergies, AIDS and organ transplants. Unlike most other drugs, these drugs are not effectively absorbed in the gut because most of them are broken down by CYP3A4 found in the gut walls. According to Watkins, people typically have varying amounts of the enzyme in their intestines. This seems to explain why some individuals absorb more of an administered medicine than others.
Watkins also explains that the two furanocoumarins have different properties. The main active compound in grapefruit juice is called 6',7'-dihydroxybergamottin (DHB), while the researchers called the other compound FC726. Their difference is that DHB appears to have multiple effects, while FC726 appears to act specifically at the CYP3A4 enzyme.
These findings, Watkins says, could have important implications for future drug manufacturing. The researchers believe that adding one of the furanocoumarins found in grapefruit juice to certain orally administered drugs can significantly improve their reliability and safety. The discovery allows for the development of improved oral drugs, not only for existing drugs but also, more importantly, for drugs that have not previously been effectively taken orally, says Watkins. By putting DHB or FC726 directly into a pill, the drug is reliably absorbed.
The study also found that the concentration of active ingredients varies greatly between different grapefruit juices, even within the same product line. This is most likely due to the growing conditions in different regions and the fact that producers tend to source their grapefruit from different areas. For this reason, says Watkins, it is better to add the active ingredient directly to the pill rather than simply taking the drug with grapefruit products.
Watkins believes there are likely other compounds in grapefruit that affect drug absorption. We are now looking further to find exactly the substance that does what we want – without interfering with other processes. We think that grapefruit has all sorts of components that can be useful in the manufacture of different types of medicines.
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