title: A possible general mechanism for ultrasound-assisted extraction (UAE) suggested from the results of UAE of chlorogenic acid from Cynara scolymus L. (artichoke) leaves.
abstract: The use of ultrasound-assisted extraction (UAE) for the extraction of chlorogenic acid (CA) from Cynara scolymus L., (artichoke) leaves using 80% methanol at room temperature over 15 min gave a significant increase in yield (up to a 50%) compared with maceration at room temperature and close to that obtained by boiling over the same time period. A note of caution is introduced when comparing UAE with Soxhlet extraction because, in the latter case, the liquid entering the Soxhlet extractor is more concentrated in methanol (nearly 100%) that the solvent in the reservoir (80% methanol) due to fractionation during distillation. The mechanism of UAE is discussed in terms of the effects of cavitation on the swelling index, solvent diffusion and the removal of a stagnant layer of solvent surrounding the plant material.
authors.affiliation: Phytochemistry Department, National Research Centre (NRC), 33 El Bohouth St. (former El Tahrir St.), P.O. 12622 Dokki, Giza, Egypt. Electronic address: brahim82@hotmail.com.
authors.forename: I A
authors.initials: IA
authors.lastname: Saleh
authors.affiliation: Sonochemistry Centre, Faculty of Health and Life Sciences, Coventry University, Coventry CV1 5FB, UK. Electronic address: m.vinatoru@coventry.ac.uk.
authors.forename: M
authors.initials: M
authors.lastname: Vinatoru
authors.affiliation: Sonochemistry Centre, Faculty of Health and Life Sciences, Coventry University, Coventry CV1 5FB, UK.
authors.forename: T J
authors.initials: TJ
authors.lastname: Mason
authors.affiliation: Phytochemistry Department, National Research Centre (NRC), 33 El Bohouth St. (former El Tahrir St.), P.O. 12622 Dokki, Giza, Egypt.
authors.forename: N S
authors.initials: NS
authors.lastname: Abdel-Azim
authors.affiliation: Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr-el-Aini Street, 11562 Cairo, Egypt.
authors.forename: E A
authors.initials: EA
authors.lastname: Aboutabl
authors.affiliation: Phytochemistry Department, National Research Centre (NRC), 33 El Bohouth St. (former El Tahrir St.), P.O. 12622 Dokki, Giza, Egypt.
authors.forename: F M
authors.initials: FM
authors.lastname: Hammouda
mesh_terms: D002726:Chlorogenic Acid / Q000302:isolation & purification*; D031943:Cynara scolymus / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D014465:Ultrasonics
chemical_list: D002726:Chlorogenic Acid
keywords: Chlorogenic acid; Cynara scolymus L.; General extraction mechanism; Ultrasound-assisted extraction