Benzo- and tetrahydrobenzo-furocoumarins: new potential photochemotherapeutic drugs.

The synthesis and photobiological activity of new benzo- and tetrahydrobenzo-furocoumarins are described. In order to evaluate the biological activity of these compounds, inhibition of growth assay was performed on human neoplastic cell lines (HL-60 and HeLa), in the dark and after UV irradiation. Some of the new structures revealed strong photobiological activity, so that their affinity for the macromolecule in vitro was studied. DNA binding was evaluated using various techniques, such as flow linear dichroism, fluorimetric titration and thermal transition experiments. The capacity of the various benzo- and tetrahydrobenzo-furocoumarins to photoreact with DNA was studied following photoadduct formation by means of spectrophotometric measurements