Thienocoumarin derivatives: interaction with nucleic acids and synthetic polydeoxyribonucleotides

This paper reports the photobiological properties of two new thienocoumarin s, 4,6,9-trimethyl-2H-thieno[3,2-g]-1-benzopyran-2-one (compound I) and the 6,9-dimethyl-4-methoxymethyl-2H-thieno[3,2-g]-1-benzopyran-2-one (compound II). Cell growth inhibition studies have revealed significant antiprolifer ative potency on human tumor cell lines. The photoaddition process of these tritium-labeled derivatives was investigated using various nucleic acid st ructures (calf thymus DNA, bacterial DNA, and synthetic polydeoxyribonucleo tides). The results obtained show that both compounds photobind to DNA to a higher extent than 8-MOP, taken as the reference drug. The capacity to for m interstrand crosslinks into DNA helix was also evaluated. interestingly, notwithstanding the lack of cutaneous phototoxicity, II revealed a good abi lity to induce diadduct formation. (C) 2000 Elsevier Science S.A. All right s reserved.