HYPOCRELLIN-A SENSITIZED PHOTOOXIDATION OF BILIRUBIN |
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| Authors: | Jin-Shi Ma Fang Yan Chang-Qi Wang Jing-Yi An |
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| Institution: | Institute of Photographic Chemistry, Academic Sinica, Beijing 100012, China |
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| Abstract: | Hypocrellin A (HA) extracted from Hypocrellia bambusae (b.et Br.) sace, a derivative of 3,10-dihydroxy-4,9-perylenequinone, is a highly effective photosensitizer. Kinetic studies of the HA-sensitized photooxidation of bilirubin IX alpha (BR) in different solvents in the presence of various active oxygen quenchers indicate that in aprotic solvents the photooxidation goes via a Type II (1O2) mechanism, whereas in alkaline protic solvents Type I (electron transfer from an excited state of HA to the ground state of oxygen or the BR substrate). Type II and probably free radical reactions may occur simultaneously. |
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