Toward Hypericin-derived Potential Photodynamic Therapy Agents

To optimize a hypericin derivative as a potential photodynamic therapy agent its light-induced singlet oxygen/superoxide radical formation capability should be enhanced and its long-wavelength absorption band should be bathochromically shifted to better match medicinal lasers. A heavy-atom–substitut...

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Veröffentlicht in:Photochemistry and photobiology 2001-08, Vol.74 (2), p.211-215
Hauptverfasser: Obermüller, Roland A., Hohenthanner, Karin, Falk, Heinz
Format: Artikel
Sprache:eng
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Zusammenfassung:To optimize a hypericin derivative as a potential photodynamic therapy agent its light-induced singlet oxygen/superoxide radical formation capability should be enhanced and its long-wavelength absorption band should be bathochromically shifted to better match medicinal lasers. A heavy-atom–substituted derivative was realized by electrophilic iodination of hypericin to yield 2,5-diiodo-hypericin. Using photodestruction of bilirubin IXα this derivative was demonstrated to exhibit an enhanced light-induced singlet oxygen/superoxide radical formation capability as compared to hypericin. With respect to a bathochromically shifted derivative styryl residues were attached to the methyl groups of hypericin by de novo ring synthesis. Although the long-wavelength absorption band of this derivative displayed a bathochromic shift of nearly 40 nm it unfortunately immediately underwent an intramolecular [2 + 2] cycloaddition to yield the corresponding cyclobutane derivative in which the added conjugation system became interrupted.
ISSN:0031-8655
1751-1097
DOI:10.1562/0031-8655(2001)074<0211:THDPPT>2.0.CO;2