Correlation of the chemical structure of 4‐nitroquinolines inactivating human cytomegalovirus and established in vivo carcinogenicity tests

Inactivation of the infectivity of human cytomegalovirus (CMV) and herpes simplex virus type 1 (HSV‐1) and type 2 (HSV‐2) has been observed following exposure to 4‐nitroquinoline 1‐oxide (NQO) or its metabolite, 4‐hydroxyaminoquinoline 1‐oxide (HAQO). The present study of the specificity of the chemical structure of 4‐nitroquinolines demonstrated that both the 4‐nitro and 1‐oxide groups were required for inactivation of virus infectivity. Reduction of the 4‐nitro group to a 4‐hydroxyamino group enhanced activity, while further reduction to an amino group resulted in loss of activity against virus infectivity. The capacity to inactivate virus was also lost by substitution of the pyridine ring for the quinoline nucleus of NQO. The relationship between the chemical structure and the ability to inactivate viruses studied here correlates well with earlier in vivo carcinogenicity studies of the same group of chemicals.