Photogenotoxicity of hypericin in HaCaT keratinocytes: implications for St. John's Wort supplements and high dose UVA-1 therapy

N. J. Traynor, P. E. Beattie, S. H. Ibbotson, H. Moseley, J. Ferguson, J. A. Woods

    Research output: Contribution to journalArticlepeer-review

    24 Citations (Scopus)

    Abstract

    Extract of St. John's Wort (Hypericum perforatum) is commonly used as natural remedy for treatment of mild to moderate depression. However, it contains a powerful photoactive component, hypericin, which can cause a severe photodermatitis when eaten by grazing animals (hypericism). In humans, there is evidence that supplementation with St. John's Wort can reduce the minimal erythemal dose (MED) in patients undergoing high dose UVA-1 phototherapy. This is a recent development in phototherapy where the most erythemogenic parts of the UVA spectrum are filtered out, allowing delivery of higher doses of the longer wavelengths of UVA. Although current published evidence suggests that the plasma levels of hypericin are unlikely to cause clinical phototoxicity, it has been established that photoactive Compounds can cause DNA damage at sub-toxic and sub-erythemal doses, the effects of which might not be apparent for many years after the event. The present study used HaCaT keratinocytes to investigate the photoclastogenic ability of hypericin on irradiation with UVA. The results show that although the combination of hypericin and UVA light increased the genotoxic burden, when all factors are taken into account, the risk of significant photogenotoxic damage incurred by the combination of Hypericum extracts and UVA phototherapy may be low in the majority of individuals. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

    Original languageEnglish
    Pages (from-to)220-224
    Number of pages5
    JournalToxicology Letters
    Volume158
    Issue number3
    DOIs
    Publication statusPublished - 15 Sep 2005

    Keywords

    • Hypericin
    • Comet assay
    • Photogenotoxicity
    • UVA-1
    • Photobiology
    • Phototoxicity

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