Vitamin C Helps Drugs Pass Blood-Brain Barrier
http://dailynews.yahoo.com/h/nm/20020115/hl/vitamin.html
By Rossella Lorenzi
FLORENCE (Reuters Health) - Vitamin C could provide a key to unlock the blood-brain
barrier, which stops many drugs from getting into the brain where they could
potentially treat diseases such as Alzheimer's or epilepsy, according to preliminary
findings from researchers in Italy.
Dr. Stefano Manfredini from the University of Ferrara and colleagues found that
drugs used to treat neurological disorders appear to slip past the blood-brain
barrier more easily when a vitamin C molecule is attached.
``Ascorbic acid works like a sort of a shuttle. Theoretically, it could transport
onto the brain any compound,'' Manfredini told Reuters Health.
Potential applications include not only drugs for diseases such as Alzheimer's,
Parkinson's and epilepsy, but also viral infections, including AIDS (news - web sites).
Manfredini's group focused on the ascorbic acid SVCT2 transporter, which is believed
to play a major role in regulating the transport of vitamin C into the brain.
In the past, glucose and amino acid units have already shown an ability to cross the
blood-brain barrier, Manfredini explained. ``But they do not guarantee a selective
target, while the SVCT2 transporter can get directly to the central nervous system.''
In the laboratory, the researchers evaluated the effect of adding vitamin C to drugs
known to have difficulty crossing the blood-brain barrier--namely diclophenamic
acid, nipecotic acid and kynurenic acid.
Adding a vitamin C component to each of these three compounds greatly improved their
ability to interact with the SVCT2 transporter, the researchers report in the
January issue of the Journal of Medicinal Chemistry.
The effect of modifying drugs was also tested in animals. Injections of nipecotic
acid linked to ascorbic acid lessened the occurrence of chemically induced
convulsions in mice, while nipecotic acid alone, as expected, was ineffective. Side
effects in the mice were very limited and no lethality was observed, the authors note.
Manfredini told Reuters Health that further tests and additional animal studies of
vitamin C-modified drugs were planned. He has filed a patent for the discovery.
SOURCE: Journal of Medicinal Chemistry 2002 January.
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