Furanocoumarins on the surface of callus cultures from species of the Rutaceae and Umbelliferae

Abstract

Four linear furanocoumarins (psoralen, xanthotoxin, isopimpinellin, and bergapten) were identified on the surfaces of callus cells of Ruta graveolens, Ruta pinnata, Daucus carota, and Pastinaca sativa in the concentration range of 0.055 – 1.1 μg total/g fresh weight. In some cases these surface deposits amounted to a substantial percentage of the total, with the highest (67%) in Daucus, but they were not always proportional to the total concentrations in the cells. Variation in the ratios of concentrations of the individual coumarins indicated selective extrusion. An unresolved mixture of isopimpinellin and bergapten, with the former predominating in the proportion of ca. 7:1, was extruded in the highest concentrations on brown callus. Shake cultures produced up to two orders of magnitude more furanocoumarins than callus cells and extrusion was accelerated, but the concentrations of particular exported furanocoumarins varied, again pointing to selective extrusion. Key words: callus, cell surface, furanocoumarins, Ruta, Daucus, Pastinaca.