Studies on the chelation of hypocrellin A with aluminium ion and the photodynamic action of the resulting complex.
Hypocrellin A (HA), a perylenoquinone derivative, is an efficient phototherapeutic agent. The chelation of HA with aluminium ion (Al3+) results in the formation of a 1:1 complex (Al(3+)-HA). The probable structure for this complex has been proposed. Compared with HA, this complex has a much higher solubility in water. In addition, Al(3+)-HA preserves the 1O2-generating function of HA as demonstrated by diphenylanthracene photo-bleaching experiments. In irradiated oxygen-saturated solutions of Al(3+)-HA superoxide radical anion and hydroxyl radical are formed as verified using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the electron spin resonance (ESR) spin trapping agent. The production of superoxide radical anion is enhanced significantly in the presence of electron donors such as 1-benzyl-1,4-dihydronicotinamide (BNAH). These results suggest that the photodynamic action of Al(3+)-HA proceeds via both type 1 and type 2 reactions.
Institute of Photographic Chemistry, Academia Sinica, Beijing, China.
Y Z
YZ
Hu
J Y
JY
An
L J
LJ
Jiang
D000535:Aluminum / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry*; D004365:Drugs, Chinese Herbal; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D008027:Light; D015394:Molecular Structure; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000528:radiation effects; D019800:Phenol; D010778:Photochemotherapy; D011809:Quinones / Q000737:chemistry* / Q000528:radiation effects; D011838:Radiation-Sensitizing Agents / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013481:Superoxides / Q000032:analysis; D013997:Time Factors
D002614:Chelating Agents; D004365:Drugs, Chinese Herbal; D011809:Quinones; D011838:Radiation-Sensitizing Agents; D013481:Superoxides; D019800:Phenol; D010569:Perylene; D000535:Aluminum; C048388:hypocrellin A