Insights into the pineal and related bio-chemistry

Cheer up

A safer form of St Johns wort is on its way

A natural remedy is about to get a revamp. Researchers in the US and Britain are trying to develop a form of the popular antidepressant St Johns wort that has fewer adverse effects. Known as natures Prozac, the extract of the plant Hypericum perforatum is the second most popular herbal supplement in the US, and in Europe it has long been prescribed by doctors to combat depression. The herb has few side effects although in strong sunlight it can cause cataracts (New Scientist, 24 July 1999, p24) and some studies have suggested it is as least as effective as other antidepressants. But earlier this year, doctors warned that St Johns wort which contains more than two dozen active ingredients most of which haven't been studied decreases the effectiveness of a wide range of drugs including birth control pills and anti-biotics. The discovery by Steven Piscitelli of the US National Institute of Mental Health in Maryland that it even interferes with anti-HIV drugs led the Federal Food and Drug Administration too put out a warning advising against its use without consulting a doctor.

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(Cocoa 'Theobroma cacoa ' was considered a food of the gods used in vision quest etc note similar tetrahydro-beta-carbolines in fruit, powerful steroid inhibitors and neurotransmitter enhancers. ECR)

Choc Shock

Chocoholics beware: your favourite food contains substances that help produce alcoholic's cravings for booze. These "neuroactive" alkaloids, known as tetrahydro-beta-carbolines, are produced when our bodies metabolise beer, wine or spirits.

To find out how the herbal supplement interferes with these drugs, two independent studied the commercially available extracts of St John's wort. They discovered that hyperforin a component responsible for much of the antidepressant activity also stimulates the production of a liver enzyme called CY3PA (Journal of Endocrinology, vol. 166, pR11). "Its crucial for the proper metabolism of the body's hormones, synthetic steroids and many drugs," says Krishna Chatterjee of Cambridge University. But if levels of the enzyme are too high, drugs are broken down too fast to be effective. Production of CYP3A is boosted when substances binds to the so-called steroid X receptor in liver cells. Various hormones bind to this receptor, so the higher their concentrations, the faster they are broken down-a negative feedback loop that regulates their levels. But Chatterjee's group hyperforin also binds strongly to the receptor. "It can out compete other drugs that normally bind to the steroid X receptor," he says. Steven Kliewer of Glaxo-Wellcome in North Carolina and his colleagues got similar results (Proceedings of the National Academy of Sciences, vol97, p7500). Both Chatterjees group at Cambridge and Glax-Wellcome now plan to make a synthetic version of hyperforin that wont bind to the steroid X receptor but retains its antidepressant activity. "But it won't be easy," says Kliewer, "because we first need a better understanding of St Johns wort."

Diane Martindale
 
The New Scientist     Aug 19 2000 page 20

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Now researchers at the Spanish Council for Scientific Research in Madrid have found these alkaloids in chocolate in concentrations as high as 7 micrograms per gram (Journal of Agricultural and Food Chemistry, vol. 48, p4900). "I don't know if chocolate is really addictive," says Tomas Herraiz "but the cravings are real." This might explain why rate drink less alcohol if given chocolate, he adds. On the other hand some of the same alkaloids can be found in fruit, which doesn't seem to be addictive.

New Scientist Nov 11 2000 page 31