Comparative mutagenicity of linear and angular furocoumarins in Escherichia coli strains deficient in known repair functions.

Four furocoumarins, two having a linear molecule, psoralen and 8-methyl-psoralen and two having an angular molecule, angelicin and 4,5'-dimethyl-angelicin were tested for mutagenesis in Escherichia coli B wild type and in various strains deficient in known repair systems. The results indicate that both monoadducts and crosslinks are mutagenic. The mutagenic efficiency of the furocourmarins ranks in the following order 8-methylpsoralen psoralen greater than angelicin greater than 4,5'-dimethylangelicin.