THE PHOTOTOXICITY OF NITRO POLYCYCLIC AROMATIC-HYDROCARBONS OF ENVIRONMENTAL IMPORTANCE

Polycyclic aromatic hydrocarbons substituted with nitro groups (nitro-PAHs) are important environmental pollutants. They comprise many direct-acting mutagens and are easily transformed into other derivatives by metabolism or irradiation. A new property of nitro-PAHs is documented: they are phototoxic. Irradiation of human eythrocytes with 1-nitropyrene, 2-nitropyrene, 1,3-dinitropyrene and 1,6-dinitropyrene led to hemolysis. Erythrocytes treated in the dark with the sensitizers, or with previously irradiated sensitizers, did not hemolyze. 1-Nitropyrene was also studied with a series of Escherichia coli strains. The phototoxicity was largely oxygen dependent, and the photodynamic effect combined Type I and Type II mechanisms. Light-dependent inactivation of Haemophilus influenzae DNA transforming activity by 1-nitropyrene was partially oxygen dependent, but the photosensitized nicking of pBR322 supercoiled DNA occurred more readily anaerobically. © 1990.