Photodynamic action of some sensitizers by photooxidation of luminol.
We report the development of a novel simple experimental method which allows the comparison of new photosensitizers based on their production of reactive oxygen species. A high-performance liquid chromatography (HPLC) assay permits the monitoring of several substances (sensitizer, reactant and oxidized end product) simultaneously on a single chromatogram. Photoreactions were monitored throughout their course by the HPLC assay surveying the sensitizers' efficiency of singlet oxygen production by the oxidative decomposition of luminol. Several photosensitizers were tested: Rose Bengal, Methylene Blue, Protoporphyrin IX, Photosan III, Photofrin, Hypericin and Pseudohypericin. Additionally, photoreactions were monitored by a standard pO(2) detection system. The measurements of the two detection methods were strongly correlated. Rose Bengal proved to be the most efficient photosensitizer, clearly decreasing the luminol concentration and causing a corresponding increase in aminophthalic acid. Our experiments show that when factors necessary for photochemical reactions are absent or are blocked (antioxidants), no reaction can be detected.
Wierrani
Franz
F
Viennese Society for Photophysical Diagnosis and Photodynamic Therapy, Juchgasse 25, 1030 Vienna, Austria.
Kubin
Andreas
A
Loew
Hans Günter
HG
Henry
Michael
M
Spängler
Babette
B
Bodner
Klaus
K
Grünberger
Werner
W
Ebermann
Robert
R
Alth
Gerhart
G
D017323:Dihematoporphyrin Ether / Q000737:chemistry; D004355:Drug Stability; D008165:Luminol / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D010084:Oxidation-Reduction; D017319:Photosensitizing Agents / Q000737:chemistry*; D012395:Rose Bengal / Q000737:chemistry; D012997:Solvents
D017319:Photosensitizing Agents; D012997:Solvents; D012395:Rose Bengal; D008165:Luminol; D017323:Dihematoporphyrin Ether; D008751:Methylene Blue