Pilot continuous centrifugal liquid-liquid extraction of extra virgin olive oil biophenols and gram-scale recovery of pure oleocanthal, oleacein, MFOA, MFLA and hydroxytyrosol

Abstract

This study provides an efficient pilot-scale liquid-liquid extraction process for the recovery of total phenolic fraction (TPF) from extra virgin olive oil (EVOO) and the further purification of the major TPF constituents (oleocanthal, oleacein, monoaldehydic form of oleuropein aglycone, monoaldehydic form of ligstroside aglycone and hydroxytyrosol) using successively centrifugal partition chromatography and reversed phase high pressure liquid chromatography. Special attention was paid for the selection of the appropriate raw material, which should be rich in the targeted highvalue compounds. For the extraction of the selected EVOOs, a green technique based on liquid-liquid partitioning using the biphasic system n-Hept/EVOO/EtOH/H2O 3:2:3:2 v/v was carried out, first on pioneering laboratory-scale annular centrifugal extractor (ACE) and then on pilot device. 240 L from three different EVOOs (3x80 L of each EVOO) were extracted yielding 285 g of TPF in approximately 2 hours. The second step of this procedure was the purification of the target compounds. A preparative centrifugal partition chromatography (CPC) process was firstly applied for the initial TPF fractionation using a step gradient elution extrusion method with a series of 4 biphasic systems composed of n-Hept/EtOAc/EtOH/H2O in ratios 4:1:3:2, 3:2:3:2, 2:3:3:2 and 1:4:3:2 (v/v/v/v). Preparative reversed phase high performance liquid chromatography (prep-RP-HPLC) was then carried out to polish the target compounds from the enriched CPC fractions resulting in purity higher than 97%. In parallel, the above purification analysis led to the isolation of four minor TPF constituents of which three are new natural products (EDA lactone, (1R, 8E)-1-ethoxy-ligstroside aglycon and (1S, 8E)-1-ethoxy-ligstroside aglycon) and one ((9E, 11E)-13-oxotrideca-9,11diencoic acid) is described for the first time as EVOO constituent.

(−)-Methyl-Oleocanthal, a New Oleocanthal Metabolite Reduces LPS-Induced Inflammatory and Oxidative Response: Molecular Signaling Pathways and Histones Epigenetic Modulation

“…This allowed us to obtain pure met-OLE with the same success as when we previously purified OLE from an olive oil phenolic extract [ 18 ]. This silica-free chromatographic technique has shown to be a good option to isolate these compounds [ 28 ] and consequently improve the yield of the reaction step. Thus, we have performed the conversion of methyl-ligustroside into met-OLE in a 64% yield, which is the best yield reported to date for the Krapcho conversion of ligustroside/oleuropein or their derivatives into the corresponding dialdehydes.…”

Oxidized Forms of Olive Oil Secoiridoids: Semisynthesis, Identification and Correlation with Quality Parameters

“…The purification of the major secoiridoids from EVOO has occurred by following a well-established isolation process of our group with some modifications 23 , 24 . For this procedure, an EVOO rich in all target compounds was selected.…”

“…The enriched fractions were subjected to Prep-HPLC for further purification of target compound. Each of the five enriched CPC fractions was analyzed with a slightly modified elution method using H 2 O and ACN 23 , 24 . All analyses were run on the same chromatographic column at flow rate of 15 mL/min.…”

Potential Uses of Olive Oil Secoiridoids for the Prevention and Treatment of Cancer: A Narrative Review of Preclinical Studies

“…This highly productive method, with the advantage of industrial scale potential, provides huge amounts of high value-added compounds, such as oleocanthal, in their pure forms in a short period of time. This method allows the isolation of biophenols in quantity to meet the needs of in vivo experiments [ 32 ].…”