Premium
SELECTIVE TYPE I PHOTOOXIDATIONS IN MIXTURES OF PORPHYRINS AND ELECTROPHILIC NITROIMIDAZOLES
Author(s) -
Bazin M.,
Santus R.
Publication year - 1986
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1986.tb05599.x
Subject(s) - porphyrin , chemistry , electrophile , quantum yield , photochemistry , yield (engineering) , biphenyl , organic chemistry , fluorescence , catalysis , physics , materials science , quantum mechanics , metallurgy
— Electrophilic compounds metronidazole (METRO) and misonidazole (MISO), considerably enhance the photooxidation quantum yield of Type I photodynamic substrates such as Trp, Tyr and Cys. For the latter, the quantum yield of photooxidation which can be much greater than one, suggests radical chain reactions. On the other hand, METRO and MISO inhibit 1 O 2 formation because they react at diffusion controlled rate (∼10 9 M −1 S −1 ) with porphyrin triplets forming, porphyrin radical cations. As a result, the porphyrins are still able to photosensitize the destruction of Type I substrates even in the absence of O 2 . These results are discussed with respect to the possibility of increasing the sensitivity of hypoxic cells to porphyrin photosensitization.