Extraction of Coumarins from Plant Material (Leguminosae)

Seven different methods for the extraction of coumarin and corresponding glycosides from Melilotus officinalis L. and furanocoumarins (psoralen and angelicin)from Psoralea cinerea Lindl. were compared. In the case of coumarins, extraction with polar solvents (water, ethanol, methanol)was shown to be the most eflicient: water extraction gave the highest total coumarin concentration, especially for the major component fJ-D-glucosylcis O-hydroxycinnamic acid. Free coumarin could also be recovered in large quantity when the extraction was peñormed with water at room temperature instead of at 100°C. Ethyl acetate, diethyl ether and chloroform extracted the free coumarin poorly and the glycosides hardly at all. In the case of furanocoumarins, the best results were obtained with bolling methanol using either Soxhlet extraction or relluxed solvent. Other extraction methods involving water, methanol at room temperature, ethyl acetate or chloroform gave essentially similar results. Diethyl ether was the least satisfactory in terms of furanocoumarin concentration, whilst water extraction of furanocoumarins is of particular interest because the extracted quantities can be easily correlated with the methanol method.