Dark and Photochemical Interactions of Dimethyltetrahydrobenzoangelicin with DNA |
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| Authors: | Giorgia Miolo Vittorio Lucchini Daniela Vedaldi Adriano Guiotto Sergio Caffieri |
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| Institution: | Department of Pharmaceutical Sciences, University of Padova, Centro di Studio sulla Chimica del Farmaco e dei Prodotti Biologicamenta Attivi dei CNR, Padova, Italy;Department of Environmental Sciences, University of Venezia, Italy |
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| Abstract: | A study of dark interaction and photoreaction between 4,6-dimethyltetrahydrobenzoangelicin (THBA) and DNA is described. 4,6-Dimethyltetrahydrobenzoangelicin is a furocoumarin derivative in which 4'and 5'carbons are linked by a four-methylene bridge. In spite of the bulky aliphatic ring, THBA forms a complex with DNA in the dark and, on UVA irradiation, reacts with pyrimidine bases of DNA yielding monoadducts only involving its furan side double bond. Two main photoproducts form: they derive from a C4-cycloaddition to thymine and cytosine, respectively, and account for 56% and 39% of the total photoreaction yield. Both show cis-syn configuration. Two other isomers, one with thymine and one with cytosine, formed with so much lower yield ( ca 3 and 1%, respectively) that their structure could not be assigned. Furthermore, in spite of its angular structure, THBA induces a small number of crosslinks in DNA. |
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