Psoralens on the surface of seeds of Rutaceae and fruits of Umbelliferae and Leguminosae

Linear furanocoumarins (psoralens) were present both inside and on the surface of dry fruits of seven species of Umbelliferae and one species of the Leguminosae and on seeds of three of Rutaceae examined. Surface concentrations varied between traces and 40-mu-g/g of the mature fruits or seeds, amounting to 0.38-43% of the total. In the whole fruits concentrations were very high in Angelica archangelica, Heraceleum lanatum, Pastinaca sativa, and Psoralea bituminosa, reaching levels of milligrams per gram fresh weight of fruits. This high concentration inside the fruit may be the cause of poor germination of embryos in A. archangelica and H. lanatum. Seeds of the Rutaceae had much smaller concentrations of furanocoumarins both on the surface and within the seed.