Microwave-assisted extraction of coumarin and related compounds from Melilotus officinalis (L.) Pallas as an alternative to Soxhlet and ultrasound-assisted extraction.
Soxhlet extraction, ultrasound-assisted extraction (USAE) and microwaves-assisted extraction (MAE) in closed system have been investigated to determine the content of coumarin, o-coumaric and melilotic acids in flowering tops of Melilotus officinalis. The extracts were analyzed with an appropriate HPLC procedure. The reproducibility of extraction and of chromatographic analysis was proved. Taking into account the extraction yield, the cost and the time, we studied the effects of extraction variables on the yield of the above-mentioned compounds. Better results were obtained with MAE (50% v/v aqueous ethanol, two heating cycles of 5 min, 50 degrees C). On the basis of the ratio extraction yield/extraction time, we therefore propose MAE as the most efficient method.
Martino
Emanuela
E
Department of Territorial Ecology and Enviroment University of Pavia, Via S. Epifanio, 14-27100 Pavia, Italy.
Ramaiola
Ilaria
I
Urbano
Mariangela
M
Bracco
Francesco
F
Collina
Simona
S
D002851:Chromatography, High Pressure Liquid; D003374:Coumarins / Q000032:analysis / Q000302:isolation & purification*; D035264:Flowers / Q000737:chemistry; D029903:Melilotus / Q000737:chemistry*; D008872:Microwaves; D010936:Plant Extracts / Q000032:analysis / Q000302:isolation & purification; D014465:Ultrasonics
D003374:Coumarins; D010936:Plant Extracts; C030123:coumarin