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St. John's wort An herbal extract prepared from the plant Hypericum perforatum (St. John's wort) with photodynamic, antineoplastic, and antidepressant activities. Hypericin, one of the active compounds found in Hypericum perforatum, is a photosensitizer that, when exposed to a particular wavelength and intensity of light, may induce tumor cell apoptosis. Another compound, hyperforin, induces caspase-dependent apoptosis in certain tumor cell lines. Hypericum perforatum preparations may also stimulate the activity of cytochrome P450 enzymes and P-glycoprotein drug transporters, resulting in increased metabolism and decreased efficacy of various chemotherapeutic agents and other drugs. Check for active clinical trials or closed clinical trials using this agent. (NCI Thesaurus)
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Synonyms: | ![](https://webarchive.library.unt.edu/eot2008/20090509175825im_/http://www.cancer.gov/images/spacer.gif) | Hypericum perforatum extract St. John's wort extract | | ![](https://webarchive.library.unt.edu/eot2008/20090509175825im_/http://www.cancer.gov/images/spacer.gif) |
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