Phototoxicity and mutagenicity of 4,5'-dimethylangelicin and long-wave ultraviolet irradiation in Chinese hamster cells and human skin fibroblasts.

The phototoxicity and mutagenicity of 4,5'-dimethylangelicin (Ang) were assessed in cultures of hamster cells and human skin fibroblasts after long-wave ultraviolet irradiation. To obtain an impression of the clinical usefulness of Ang, we compared the phototoxicity and mutagenicity of this compound with those of 8-methoxypsoralen (8-MOP). To reach the same cell-killing rate in hamster cells and human skin fibroblasts, the concentration of Ang had to be 15 times higher than that of 8-MOP at comparable doses of radiation. Whether we used the same concentrations and an adjusted radiation dose or adjusted concentrations of Ang and 8-MOP at a constant radiation dose, the mutation induction in hamster cells and human skin fibroblasts was much higher after incubation with Ang than with 8-MOP.