Phototoxic potential of afloqualone, a quinazolinone derivative, as determined by photosensitized inactivation of bacteriophage.
Effect of UV-A irradiation on bacteriophage lambda in the presence of afloqualone (AQ) was examined to obtain in vitro evidence for phototoxic potential of AQ, a centrally acting muscle relaxant. Neither AQ itself nor the long-lived photoproducts affected viability of the phage, but the phage was inactivated when it was irradiated in the presence of the drug. Photosensitized inactivation was efficiently repressed by the presence of radical scavengers such as hydroquinone, cysteamine and cystein but not by D-mannitol, benzoate, formate and dimethyl sulfoxide (.OH scavengers). Methionine also inhibited inactivation as well. Sodium azide and tryptophan followed them, but 1,4-diazabicyclo[2.2.2]octaine (DABCO) did not reduce the inactivation rate. Deuterium effect was not observed. AQ-sensitized photoinactivation occurred even under anoxic conditions although the rate was lower than under aerobic conditions. In view of these results, Type I process is more suitable for explanation of AQ-sensitized photoinactivation than Type II process.
Fujita
H
H
Department of Molecular Biology, Tokai University School of Medicine, Kanagawa-ken, Japan.
Matsuo
I
I
D000596:Amino Acids / Q000494:pharmacology; D001435:Bacteriophages / Q000187:drug effects* / Q000528:radiation effects; D006878:Hydroxides; D017665:Hydroxyl Radical; D009125:Muscle Relaxants, Central / Q000633:toxicity*; D010100:Oxygen / Q000494:pharmacology; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D010879:Piperazines / Q000494:pharmacology; D011799:Quinazolines / Q000633:toxicity*
D000596:Amino Acids; D006878:Hydroxides; D009125:Muscle Relaxants, Central; D010879:Piperazines; D011799:Quinazolines; D017665:Hydroxyl Radical; C033541:afloqualone; D010100:Oxygen; C007306:triethylenediamine