Photoreactivity (365 nm) of some coumarins and 4',5'-dihydro-furocoumarins with nucleic acids.

The Authors have studied the capacity to photoreact with native DNA and r-RNA using six coumarins and four 4′,5′-dihydro-furo-coumarins. Six of these substances have shown a definite photoreactivity both with DNA and r-RNA, even if in a very much lower extent in respect to that of skin-photosensitizing furocoumarins. The low capacity to photoreact with nucleic acids of these substances is discussed, also in connection with the absence of skin-photosensitizing activity.