EPR studies of singlet oxygen (1O2) and free radicals (O2.-, .OH, HB.-) generated during photosensitization of hypocrellin B.
Hypocrellin B(HB), a peryloquinone derivative, is one of the main photosensitive agents, hypocrellin. This pigment, in combination with phototherapy, has been used in human medicine to cure various skin diseases. The photochemistry (Type I and II) of HB has been studied using spin-trapping and spin-counteraction techniques. The results show that the active oxygen (1O2, O2.-, .OH) mechanism of HB photosensitization can be converted into nonoxygen free radical (HB.-) mechanism completely when oxygen is exhausted in the experimental system. Under anaerobic conditions, HB only undergoes Type I reaction, generating nonoxygen free radical (HB.-).
Institute of Biophysics, Academia Sinica, Beijing, China.
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Zhiyi
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Nenghui
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Qian
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Meifan
D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000032:analysis; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000528:radiation effects; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000737:chemistry / Q000528:radiation effects*; D011809:Quinones / Q000737:chemistry / Q000528:radiation effects*; D017382:Reactive Oxygen Species / Q000032:analysis; D013113:Spin Labels
D005609:Free Radicals; D017319:Photosensitizing Agents; D011809:Quinones; D017382:Reactive Oxygen Species; D013113:Spin Labels; D010569:Perylene; C064522:hypocrellin B