title: Phototoxic and apoptosis-inducing capacity of pseudohypericin.
abstract: Pseudohypericin (PH) and hypericin (H) are photosensitizing plant pigments from Hypericum perforatum. H displays cytotoxic and apoptosis-inducing effects in neoplastic cell lines. Here, we have assessed the phototoxic and apoptosis-inducing capacity of PH compared to H in a cell culture model with human leukemic lymphoma cells (Jurkat). Treatment with both photoactivated H and PH resulted in a dose-dependent inhibition of cell proliferation, whereas not photoactivated H and PH had no effect at the concentrations tested. The half-maximal inhibitory concentration (IC50) of H was lower (100 ng/mL) as compared to PH (200 ng/mL) (p < 0.05). In an apoptosis assay we found a dose-dependent increase of DNA fragmentation after treatment with both photoactivated H and PH. The cytotoxic potential of PH should be taken into account during systemic therapy with Hypericum extracts, since PH is about two times more abundant than H in Hypericum perforatum.
authors.forename: Christoph M
authors.initials: CM
authors.lastname: Schempp
authors.forename: Birgit
authors.initials: B
authors.lastname: Simon-Haarhaus
authors.forename: Jan C
authors.initials: JC
authors.lastname: Simon
mesh_terms: D000873:Anthracenes; D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020902:Hypericum; D019169:Jurkat Cells; D015394:Molecular Structure; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000873:Anthracenes; D010569:Perylene; C004965:hypericin; C056602:pseudohypericin