Loic Rene

3‐CARBETHOXYPYRANOCOUMARIN, A PHOTOREACTIVE DERIVATIVE OF XANTHYLETIN WITH INTERESTING PHOTOBIOLOGICAL PROPERTIES

Abstract— The photobiological activity of the newly synthesized pyranocoumarin derivative 3‐carbethoxypyranocoumarin, so‐called 3‐carbethoxyhomopsoralen (3‐CHPs) was studied in comparison to the known bifunctional furocoumarin 8‐methoxypsoralen {8‐MOP) and to the monofunctional furocoumarin 3‐carbethoxypsoralen (3‐CPs) in the presence of 365 nm irradiation using two eukaryotic cell systems, the yeast Saccharomyces cerevisiae and cultured normal human skin fibroblasts. 3‐Carbethoxyhomopsoralen is shown to be a photobiologically active compound capable of effectively photoinducing cytoplasmic “petite” mutants (mitochondrial damage), nuclear reversions and mitotic gene conversion in the diploid yeast strain D7. Per unit dose it is more effective than 8‐MOP and 3‐CPs for the induction of cytoplasmic “petite” mutants but less effective than 8‐MOP for the induction of nuclear reversions and mitotic gene conversion. A very moderate effect on cell survival is accompanied by a relatively strong genetic activity per viable cell. In human fibroblasts 3‐CHPs produces a stronger inhibition of DNA synthesis than 8‐MOP and 3‐CPs at low doses of 365 nm radiation. During post‐treatment incubation human fibroblasts recovered more easily from DNA synthesis and growth inhibitions photoinduced by 3‐CHPs than from those photoinduced by 8‐MOP. The results are in accord with the notion that 3‐CHPs is a highly photoreactive monofunctional compound inducing easily repairable lesions with a low lethal but significant mutagenic potential.