An update procedure for an effective and simultaneous extraction of sesquiterpene lactones and phenolics from chicory

A new method for recovering and purifying sesquiterpene lactones (SLs) and optimise the solvent system for their extraction from freeze-dried chicory leaves was studied. Catalogna (leafy chicory) and Head Radicchio types were used as test samples. Solid phase extraction (SPE) employing silica-based cartridges allowed a fast and straightforward purification of SL from interfering phenolics, before HPLC determination. Under these conditions, SL were eluted during loading and washing steps whereas polar phenolic compounds were retained on silica stationary phase. Hydrophilic mixtures methanol/water acidified by small percentages of formic acid led to consistently higher SL recoveries in comparison to organic solvents and enabled the simultaneous extraction of phenolics. Phenolic recovery in crude extracts was assessed at levels higher than 95% for both Catalogna and Head Radicchio. Total, free and bound SL amounts detected in extract obtained by 2% (v/v) formic acid in methanol/water 4/1 (v/v) were 2223.4, 778.5 and 1444.9 mg/kg of dried product in Catalogna, and 401.2, 105.1 and 296.0 in Head Radicchio. In both cases, recoveries were consistently higher than those obtained with methanol alone.