ICCAS OpenIR
Photobleaching of hypocrellin B and its butylamino-substituted derivative in solutions
Xu, SJ; Tian, CH; Chen, S; Zhang, MH; Shen, T
2001-08-01
Source PublicationPHOTOCHEMISTRY AND PHOTOBIOLOGY
ISSN0031-8655
Volume74Issue:2Pages:184-190
AbstractThe photobleaching of hypocrellin B (HB) and its derivative butylamino-substituted hypocrellin B (BAHB), both of which are potent sensitizers for photodynamic therapy (PDT), were investigated by studies of absorption spectra and quenching experiments and by the determination of photoproducts. Control experiments indicated that the sensitizer, oxygen and light were essential for the photobleaching of HB and BAHB, which suggested that it was a photodynamic process, e.g. the photobleaching processes of both HB and BAHB were mainly self-sensitized photooxidations. The illumination of HB with visible light in oxygenated nonpolar solvents generated singlet oxygen efficiently [Phi(O-1(2)) = 0.76] which in turn attacked the sensitizer HB with the subsequent formation of an endoperoxide product. The endoperoxide of HB is unstable at room temperature and undergoes loss of singlet oxygen with regeneration of the parent HB. The singlet oxygen released from the endoperoxide of HB was detected with chemical trapping experiments. The quenching experiments indicated that in increasingly polar solvents the superoxide anion mechanism (type I) as well as the singlet oxygen mechanism (type II) contributed to the photobleaching of HB. The introduction of the electron-donating butylamino group not only enhanced the yield of the superoxide anion generation but also altered the position of attack in the BAHB molecule by the activated oxygen species. No endoperoxide product was observed, and no singlet oxygen released from the photobleaching process of BAHB was detected. The photobleaching process of BAHB was more complex. Both the singlet oxygen and superoxide anion mechanism played important roles in the photobleaching of BAHB in all organic solvent used here, even in aerobic nonpolar solvents such as CHCl3.
Indexed BySCI
Language英语
WOS IDWOS:000170619600010
PublisherAMER SOC PHOTOBIOLOGY
Citation statistics
Cited Times:4[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.iccas.ac.cn/handle/121111/77510
Collection中国科学院化学研究所
Corresponding AuthorZhang, MH
AffiliationChinese Acad Sci, Inst Chem, Ctr Mol Sci, Beijing 100080, Peoples R China
Recommended Citation
GB/T 7714
Xu, SJ,Tian, CH,Chen, S,et al. Photobleaching of hypocrellin B and its butylamino-substituted derivative in solutions[J]. PHOTOCHEMISTRY AND PHOTOBIOLOGY,2001,74(2):184-190.
APA Xu, SJ,Tian, CH,Chen, S,Zhang, MH,&Shen, T.(2001).Photobleaching of hypocrellin B and its butylamino-substituted derivative in solutions.PHOTOCHEMISTRY AND PHOTOBIOLOGY,74(2),184-190.
MLA Xu, SJ,et al."Photobleaching of hypocrellin B and its butylamino-substituted derivative in solutions".PHOTOCHEMISTRY AND PHOTOBIOLOGY 74.2(2001):184-190.
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