Ceramides from Urtica dioica roots

In methanolic extracts of stinging nettle roots (Urtica dioica) a special class of ceramides was detected. These ceramides contain a double bond in position 8 of the sphingoid base. With the typical amidic linkage the amino group of the sphingoid base (2-amino-1,3,4-trihydroxy-8-octadecene) is either connected to an unbranched fatty acid with 20 – 25 carbon atoms or to a 2-hydroxy fatty acid with the same chain length. Both classes of ceramides were separated from each other by thinlayer chromatoraphy. The members of each class were further separated as trimethylsilyl derivatives by gas chromatography. The structures of the ceramides were determined by mass, NMR and IR spectroscopy combined with hydrolysis experiments.