title: Microwave-assisted extraction of coumarin and related compounds from Melilotus officinalis (L.) Pallas as an alternative to Soxhlet and ultrasound-assisted extraction.
abstract: 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.
authors.affiliation: Department of Territorial Ecology and Enviroment University of Pavia, Via S. Epifanio, 14-27100 Pavia, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Martino
authors.forename: Ilaria
authors.initials: I
authors.lastname: Ramaiola
authors.forename: Mariangela
authors.initials: M
authors.lastname: Urbano
authors.forename: Francesco
authors.initials: F
authors.lastname: Bracco
authors.forename: Simona
authors.initials: S
authors.lastname: Collina
mesh_terms: 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
chemical_list: D003374:Coumarins; D010936:Plant Extracts; C030123:coumarin