Coumarin inhibits the growth of carrot (Daucus carota L. cv. Saint Valery) cells in suspension culture.
We used a carrot (Daucus carota L. cv. Saint Valery) cell suspension culture as a simplified model system to study the effects of the allelochemical compound coumarin (1,2 benzopyrone) on cell growth and utilisation of exogenous nitrate, ammonium and carbohydrates. Exposure to micromolar levels of coumarin caused severe inhibition of cell growth starting from the second day of culture onwards. At the same time, the presence of 50 mumol/L coumarin caused accumulation of free amino acids and of ammonium in the cultured cells, and stimulated their glutamine synthetase, glutamate dehydrogenase, glucose-6-phosphate dehydrogenase and phosphoenolpyruvate carboxylase activities. Malate dehydrogenase, on the other hand, was inhibited under the same conditions. These effects were interpreted in terms of the stimulation of protein catabolism and/or interference with protein biosynthesis induced by coumarin. This could have led to a series of compensatory changes in the activities of enzymes linking nitrogen and carbon metabolism. Because coumarin seemed to abolish the exponential phase and to accelerate the onset of the stationary phase of cell growth, we hypothesise that such allelochemical compounds may act in nature as an inhibitor of the cell cycle and/or as a senescence-promoting substance.
Dipartimento di Biotecnologie per il Monitoraggio Agroalimentare ed Ambientale, Università Mediterranea di Reggio Calabria, Feo di Vito, I-89125 Reggio Calabria, Italy. mrabenavoli@unirc.it
Maria Rosa
MR
Abenavoli
Agostino
A
Sorgonà
Maria
M
Sidari
Maurizio
M
Badiani
Amodio
A
Fuggi
D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D000596:Amino Acids / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003374:Coumarins / Q000494:pharmacology*; D018552:Daucus carota / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism; D005632:Fructose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D007210:Indoleacetic Acids / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism
D000596:Amino Acids; D003374:Coumarins; D004798:Enzymes; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D015084:2,4-Dichlorophenoxyacetic Acid; D005632:Fructose; D013395:Sucrose; C030737:indoleacetic acid; C030123:coumarin; D005947:Glucose