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PHOTOACTIVATION OF HYPERICIN GENERATES SINGLET OXYGEN IN MITOCHONDRIA AND INHIBITS SUCCINOXIDASE
Author(s) -
Thomas Carin,
MacGill Randall S.,
Miller Glenn C.,
Pardini Ronald S.
Publication year - 1992
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1992.tb04208.x
Subject(s) - singlet oxygen , hypericin , action spectrum , oxygen , photochemistry , chemistry , photosensitizer , visible spectrum , biophysics , materials science , organic chemistry , biology , pharmacology , optoelectronics
— Photosensitized inhibition of mitochondrial succinoxidase by hypericin was measured in vitro and found to be drug‐dose, light‐dose, and wavelength dependent. Singlet oxygen generation, monitored using the singlet oxygen trap tetramethylethylene, and oxygen consumption in isolated mitochondria sensitized by hypericin were also light‐dose and wavelength dependent. Unequivocal evidence for the generation of singlet oxygen was obtained using kinetic isotope ratios of products from the reaction between singlet oxygen and geminally deuterated tetramethylethylene. An action spectrum for the inhibition of succinoxidase was measured at wavelengths between 400 and 700 nm and found to parallel the recorded visible absorption spectrum of hypericin in isolated mitochondria. The greatest singlet oxygen generation, oxygen consumption, and succinoxidase inhibition occurred with white light or 600 nm irradiation. These data are consistent with a type II singlet‐oxygen‐mediated mechanism for hypericin induced photosensitized inhibition of mitochondrial succinoxidase.