Photosensitization by hypericin: Electron spin resonance (ESR) evidence for the formation of singlet oxygen and superoxide anion radicals in an in vitro model
1994; Elsevier BV; Volume: 26; Issue: 1 Linguagem: Inglês
10.1016/1011-1344(94)85037-2
ISSN1873-2682
AutoresChristophe Hadjur, A. Jeunet, Pierre Jardon,
Tópico(s)Porphyrin and Phthalocyanine Chemistry
ResumoThe ability of hypericin (HYP) to photoreact by type I and type II mechanisms was investigated in egg yolk lecithin (EYL) liposomes as a model membrane system. On visible irradiation in aerobic conditions at pH 7, the formation of singlet oxygen and superoxide anion radicals was demonstrated unequivocally using electron spin resonance (ESR) spectrometry with the spin traps 2,2,6,6-tetramethyl-4-piperidone (TEMP) and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO). We conclude from our results that HYP in EYL liposome membranes appears to act through both singlet oxygen and electron transfer mechanisms.
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