And doubt continues over which active ingredient is responsible for the potential benefits of the high street remedy known technically as Hypericum perforatum.

Gerlie De Los Reyes and colleagues at the University of Southern California draw attention to research suggesting that hyperforin, rather than hypericin, may be the active component of the medication.

“Hypericins isolated from the extract have been shown to be virtually inactive as psychotropic agents in animal models,” say the researchers.

The team looked at eight commercial brands of St John’s wort and found wide variations in the amount of hyperforin that they contained.

Only two of the products tested contained enough to be clinically therapeutic, they concluded.

And although recent literature suggests that hyperforin is an active anti-depressant, it is not routinely used to standardize St John’s wort products because it degrades under ambient conditions.

Gerlie De Los Reyes said, “It’s essential that manufacturers standardize and list the content of hyperforin on St John’s wort labels.

“Consumers must have this information to make informed decisions about the medications they are taking.”

Reference: De Los Reyes et al, American Journal of Health-System Pharmacy 2002;59:545-547

© Health Media Ltd 2002
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