title: Photosensitization mechanism of active species by the complex of hypocrellin B with aluminum ion.
abstract: To improve the water solubility and red absorption of the parent hypocrellin B (HB), the complex of HB with aluminum ion has been first synthesized in high yield. The photodynamic action of Al(3+)-HB, especially the generation mechanism of active species, ([Al(3+)-HB].-, O2.- and 1O2) was studied using electron paramagnetic resonance (EPR) and spectrophotometric methods. In the deoxygenated DMSO solution of Al(3+)-HB, the semiquinone anion radical of Al(3+)-HB is photogenerated via the self-electron transfer between the excited and ground state species. The presence of electron donor significantly promotes the reduction of Al(3+)-HB. When oxygen is present, superoxide anion radical (O2.-) is formed via the electron transfer from [Al(3+)-HB].- to the ground state molecular oxygen. Singlet oxygen (1O2) can be produced via the energy transfer from triplet Al(3+)-HB to ground state oxygen molecules. Furthermore, it is very significant that the accumulation of [Al(3+)-HB].- would replace that of O2.- or 1O2 with the consumption of oxygen in the sealed system.
authors.affiliation: Center for Molecular Science, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: J H
authors.initials: JH
authors.lastname: Ma
authors.forename: J Q
authors.initials: JQ
authors.lastname: Zhao
authors.forename: L J
authors.initials: LJ
authors.lastname: Jiang
mesh_terms: D000535:Aluminum / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D002412:Cations; D003574:Cytochrome c Group / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D066298:In Vitro Techniques; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000494:pharmacology*; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000494:pharmacology*; D011809:Quinones / Q000737:chemistry* / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000737:chemistry; D026082:Singlet Oxygen / Q000737:chemistry; D013053:Spectrophotometry; D019097:Spin Trapping; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors
chemical_list: D002412:Cations; D003574:Cytochrome c Group; D005609:Free Radicals; D017319:Photosensitizing Agents; D011809:Quinones; D017382:Reactive Oxygen Species; D026082:Singlet Oxygen; D010569:Perylene; D000535:Aluminum; D013482:Superoxide Dismutase; C064522:hypocrellin B