title: Monitoring the oleuropein content of olive leaves and fruits using ultrasound- and salt-assisted liquid-liquid extraction optimized by response surface methodology and high-performance liquid chromatography.
abstract: A novel and rapid ultrasound- and salt-assisted liquid-liquid extraction coupled with high-performance liquid chromatography has been optimized by response surface methodology for the determination of oleuropein from olive leaves. Box-Behnken design was used for optimizing the main parameters including ultrasound time (A), pH (B), salt concentration (C), and volume of miscible organic solvent (D). In this technique, a mixture of plant sample and extraction solvent was subjected to ultrasound waves. After ultrasound-assisted extraction, phase separation was performed by the addition of salt to the liquid phase. The optimal conditions for the highest extraction yield of oleuropein were ultrasound time, 30 min; volume of organic solvent, 2.5 mL; salt concentration, 25% w/v; and sample pH, 4. Experimental data were fitted with a quadratic model. Analysis of variance results show that BC interaction, A(2) , B(2) , C(2) , and D(2) are significant model terms. Unlike the conventional extraction methods for plant extracts, no evaporation and reconstitution operations were needed in the proposed technique.
authors.affiliation: Department of Agronomy and Plant Breeding, Faculty of Agriculture, Lorestan University, Khorramabad, Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Ismaili
authors.affiliation: Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran.
authors.forename: Rouhollah
authors.initials: R
authors.lastname: Heydari
authors.affiliation: Department of Chemistry, Islamic Azad University, Borujerd, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Rezaeepour
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005638:Fruit / Q000737:chemistry; D057888:Iridoid Glucosides; D039823:Iridoids / Q000032:analysis* / Q000302:isolation & purification; D059625:Liquid-Liquid Extraction / Q000379:methods*; D031658:Olea / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis* / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry; D014465:Ultrasonics / Q000379:methods*
chemical_list: D057888:Iridoid Glucosides; D039823:Iridoids; D010936:Plant Extracts; C002769:oleuropein
keywords: Liquid chromatography; Liquid-liquid extraction; Oleuropein; Olive; Salt-assisted extraction; Ultrasound