NON-ANTHOCYANIN POLYPHENOLS QUANTIFICATION IN EUTERPE OLERACEA FRUITS BY A UHPLC−LTQ-ORBITRAP MS METHOD

High antioxidant and anti-inflammatory activities have been observed from non-anthocyanin polyphenols of E. oleracea fruits [1-2]. The aim of this work was to quantify major non-anthocyanin polyphenols by an accurate UHPLC−LTQ-Orbitrap MS method. Fruits were harvested in Pará state (Brazil), processed to pulp and lyophilised. 0.5g of dry pulp powder was defatted by sonication with petroleum ether. The residue was then extracted five times with 5mL MeOH each time for 30 min (optimized conditions giving recovery rates > 90%). The extract was evaporated to dryness with a RapidVap® evaporator at 35°C. Solubilization of the dried extract was realised using 40% MeOH. For the UHPLC quantification, a HSS C18 column (1.8µm) was used with a gradient elution of MeOH and H2O both with 0.1% HCOOH and the ionisation source (ESI) was operated in NI mode. 26 compounds were identified, among them 7 identified for the first time in this fruit. Total error and accuracy profiles were used as validation criteria. Calibration in the matrix was found to be more accurate than calibration without matrix. Trueness, repeatability, intermediate precision, selectivity, response function, linearity and LOD/LOQ for 12 non-anthocyanin phenolic compounds were evaluated and the quantification method validated.
[1] J. Kang et al., Food Chem. 122 (2010) 610–617. [2] J. Kang et al., Food Chem. 128 (2011) 152–157.