oleuropein and ethyl-acetate

The separation and purification of hydroxytysol and oleuropein from Olea europaea L. (olive) using a macroporous resin with a novel solvent system was systematically investigated. Static adsorption experiments with BMKX-4 resin revealed that the experimental data of both hydroxytysol and oleuropein fitted best to the pseudo-second-order kinetic and Freundlich isotherm models. The thermodynamic parameters indicated spontaneous and exothermic adsorption processes. The novel solvent system, composed of n-hexane:ethyl acetate:methanol:water in a (v/v/v/v) ratio of 1:9:1:9, had two phases (upper and lower). The separation and purification parameters of hydroxytysol and oleuropein were optimized using dynamic adsorption/desorption on a column packed with BMKX-4 resin. The effects of flow rates and volumes of the upper and lower phases on the separation efficiency were systematically studied. Under optimal conditions, the fraction of hydroxytysol in the final product increased by 6.34-fold from 0.46 to 2.96%, with a yield rate of 88.58% w/w, while that of oleuropein increased 4.17-fold from 11.40 to 47.59%, with a 93.31% w/w yield rate. These results may be help in selecting a suitable eluent for improved separation of macroporous adsorption resins.

Topics: Acetates; Adsorption; Hexanes; Iridoid Glucosides; Iridoids; Methanol; Olea; Particle Size; Porosity; Resins, Plant; Solvents; Surface Properties; Thermodynamics; Water

A highly sensitive, specific and simple LC-MS/MS method was developed to investigate in vivo bio-transformation of oleuropein in rat. Rat urine samples collected after the intravenous administrations were determined using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the negative-ion mode. The assay procedure involves a simple liquid-liquid extraction of parent oleuropein and the metabolite from rat urine with ethyl acetate. Chromatographic separation was operated with 0.1% formic acid aqueous and methanol in gradient program at a flow rate of 0.80 mL/min on an RP-C(18) column with a total run time of 30 min. This method has been successfully applied to simultaneous determination of oleuropein and its metabolite in rat urine. Oxygenation was found to be the major metabolic pathway of the oleuropein in rat after intravenous administration.

Topics: Acetates; Animals; Chromatography, Liquid; Formates; Injections, Intravenous; Iridoid Glucosides; Iridoids; Liquid-Liquid Extraction; Male; Methanol; Pyrans; Rats; Rats, Sprague-Dawley; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

In this article, an efficient method was developed to screen, isolate and identify the major radical scavengers in the leaves of Olea europaea L. by DPPH-HPLC-DAD, HSCCC and NMR. The method of DPPH-HPLC-DAD was used to screen the major radical scavengers. It was found that three major constituents (A, B, C) in the extract of the leaves of O. europaea L. possessed potential antioxidant activities. In order to identify the chemical structures of those compounds, the HSCCC method with a two-phase solvent system composed of petroleum ether-ethyl acetate-water at an optimized volume ratio of 6:600:700 (v/v/v) together with column chromatography was developed to isolate and purify the active compounds. Pure compounds A (225 mg), B (10 mg) and C (12 mg) with purities 92.6, 95.1 and 96.4%, respectively, were obtained from the crude sample (500 mg). Their structures were identified as oleuropein (A), luteolin-7-O-glucoside (B) and verbascoside (C) by (1) H-NMR and (13) C-NMR.

Topics: Acetates; Chromatography, High Pressure Liquid; Flavones; Free Radical Scavengers; Glucosides; Iridoid Glucosides; Iridoids; Olea; Phenols; Plant Extracts; Plant Leaves; Pyrans