Dynamic ultrasound-assisted extraction of oleuropein and related biophenols from olive leaves.
A continuous approach for the ultrasound-assisted extraction of olive biophenols (OBPs) from olive leaves is proposed. Multivariate methodology was used to carry out a detailed optimisation of extraction. Under the optimal working conditions, complete extraction of the target analytes (namely, oleuropein, verbacoside, apigenin-7-glucoside and luteolin-7-glucoside with LODs 11.04, 2.68, 1.49 and 3.91 mg/kg, respectively) was achieved in 25 min. The extract was injected into a chromatograph-photodiode array detector assembly (HPLC-DAD) for individual separation-quantification. No clean-up or preconcentration steps were required. Gas chromatography-mass spectrometry (without derivatization of the analytes) was used to identify OBPs at concentrations below the LODs obtained by HPLC-DAD. The efficacy of ethanol-water mixtures to extract OBPs from olive leaves has been demonstrated and compared with that of a conventional method which requires 24h for complete extraction; so these mixtures can substitute toxic extractants used to date.
Japón-Luján
R
R
Department of Analytical Chemistry, Annex Marie Curie Building, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
Luque-Rodríguez
J M
JM
Luque de Castro
M D
MD
D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D057888:Iridoid Glucosides; D039823:Iridoids; D031658:Olea / Q000737:chemistry*; D010636:Phenols / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry*; D011714:Pyrans / Q000302:isolation & purification*; D015203:Reproducibility of Results; D014465:Ultrasonics
D057888:Iridoid Glucosides; D039823:Iridoids; D010636:Phenols; D011714:Pyrans; C002769:oleuropein