Saint John's wort (Hypericum perforatum L.) is a herbal remedy that is effective in the treatment of mild to moderate depression. In traditional
folk medicine, oily extracts of St. John's wort are used for topical treatment of
wounds,
burns and
myalgia. The lipophilic phloroglucin-derivative
hyperforin has antibacterial and antiinflammatory effects. These effects could be of relevance in topical treatment of infected
wounds and other
dermatoses, but no studies have been conducted so far. The naphtodianthrone
hypericin is a photodtodynamic active substance that kills
tumor cells via the induction of apoptosis.
Hypericin also displays
antiviral activity in vitro. In vivo, intravenous or oral treatment with
hypericin of HIV-infected subjects did not result in a reduction of the virus load. Most of the patients treated with
hypericin experienced
phototoxicity. Similar phototoxic symptoms ("hypericism") have been observed in grazing animals ingesting large amounts of St. John's wort. In contrast,
antidepressant medication with St. John's wort usually does not produce phototoxic symptoms. Recent pharmacokinetic studies suggest that the phototoxic threshold level of
hypericin is not reached with dosages used for the oral treatment of depression. However, very recent reports demonstrated interactions of St. John's wort with other drugs such as
digoxin,
indinavir and
cyclosporin. Blood levels of these drugs were dramatically decreased by St. John's wort. This should be considered in the treatment of skin conditions with
antiviral drugs or
cyclosporin.