Effect on Chromosomes by Coumarin Derivatives in the Dark

Effects on chromosomes were studied in human lymphocytes in vitro as a result of treatment by coumarin derivatives in the dark. This paper presents investigations with the linear furocoumarins 8-methoxypsoralen (8-MOP; xanthotoxin) and 8-isoamylenoxypsoralen (8-IOP; imperatorin), the angular furocoumarin 5′-methylangelicin (5′-MA), and, in addition, the simple coumarin 5,7-dimethoxycoumarin (5,7-DMC). 8-MOP and 8-IOP influenced the growth of lymphocytes basically in the same way, different from that of the angular derivative; 5,7-DMC had no effect compared to the control. We found a slight but reproducible increase in sister chromatid exchange (SCE) frequency equivalent to 3,7 induced SCE/metaphase with 8-MOP in the dark. 5′-MA and 8-IOP had no significant effect on SCE frequency under these conditions. 5,7-DMC resulted in 1,9 induced SCE/metaphase. 8-MOP also revealed a slight clastogenic activity as 8-IOP does. The chromosome damaging effect was expressed mainly in a doubling of the break rate. Relations between structure and activity of the tested compounds as between both types of cytogenetic effects, SCE and chromosome aberrations, are discussed. Key Word Index Coumarins - Psoralens - Angelicins - Sister Chromatid Exchange