Photodynamic reaction of riboflavin and deoxyguanosine.

Previous studies have demonstrated that phototherapy depresses serum riboflavin in jaundiced infants. The potential long-term hazards of this in vivo reaction may be significant in view of the in vitro reaction of riboflavin which modifies intracellular DNA in eukaryotic and prokaryotic cells. Previous investigations have suggested that the DNA-modifying activity of riboflavin results from the generation of singlet oxygen and photooxidation of the guanine moieties of the DNA. In the present study, we demonstrate that singlet oxygen is not involved in the photodynamic reaction of riboflavin and deoxyguanosine.