Biotransformation of hydroxycoumarins by the cultured cells of Nicotiana tabacum

Administration of hydroxycoumarins to the cultured cells of Nicotiana tabac um caused the ladder fragmentation of genomic DNA of the cells and the secr etion of the intracellular phytoalexin, scopoletin, into the culture medium , and also the exogenous hydroxycoumarins were transformed into their corre sponding beta-D-glucosides. The glucosylation seems to be a defense reactio n of the cells for detoxification of toxic hydroxycoumarins, because their glucosides did not cause the DNA fragmentation. (C) 2000 Elsevier Science B .V. All rights reserved.