Photodegradation of Environmental Mutagens by Visible Irradiation in the Presence of Xanthene Dyes as Photosensitizers

抄録

The photodegradation of environmental mutagens, such as 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC), and 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), was investigated by visible irradiation in the presence of xanthene dyes as photosensitizers. Although the environmental mutagens themselves were very stable during visible irradiation under the conditions in this study, they were effectively photodegraded in the presence of the xanthene dyes (erythrosine, rose bengal, and phloxine). Moreover, photodegradation of the mutagens was further enhanced for xanthene dyes loaded onto a water-soluble diethylaminoethyl (DEAE)-dextran anion-exchanger via ionic interactions (xanthene-dye_DEX). Photodegradation was inhibited by O₂ removal from the reaction solution. In ESR spin-trapping experiments using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a trapping reagent, signals characteristic of DMPO-^•OH (hydroxyl radical) were observed in the presence of xanthene-dye_DEX. These results suggest that reactive oxygen species derived from O₂, such as singlet molecular oxygen (¹O₂) and/or ^•OH, were active participants in photodegradation of the mutagens in the presence of xanthene dyes or xanthene-dye_DEX.