Overpressured Layer Chromatographic (OPLC) Separation of Closely Related Furocoumarins

In this paper, an OPLC method for the analytical separation of eight furocoumarins is described. Of the eight compounds investigated, four are linear furocoumarins (psoralen, bergapten, 8-methoxypsoralen, iso-pimpinellin) and four are angular furocoumarins (angelicin, sphondin, iso-bergapten, pimpinellin). In preliminary experiments, optimization of the mobile phase was made using the “PRISMA” model on TLC plates in unsaturated chambers. Evaluation of the final optimization steps for OPLC separations on HPTLC plates was done densitometrically. With the elaborated OPLC system, seven compounds could be baseline separated, and the resolution between iso-bergapten and angelicin was better than 1.3. Application of the method is demonstrated with the analysis of furocoumarin-containing root extracts from Heracleum sphondylium, H. mantegazzianum and Pastinaca sativa.