Bioprospecting bioactive polar lipids from olive (Olea europaea cv. Galega vulgar) fruit seeds: LC-HR-MS/MS fingerprinting and sub-geographic comparison

Abstract

Olive seeds have been considered as a new nutritionally healthy food supplement. They are rich in monounsaturated n-9 and essential polyunsaturated n-6 lipids. However, little is known about their polar lipids, potentially bioactive and chemical identity markers for olive pulp and oil. This work aimed to identify the polar lipidome of olive seeds to find possible bioactive compounds and markers of geographic origin, by studying samples from six Portuguese sub-regions. Polar lipids were obtained by solid/liquid extraction, NH2-solid-phase extraction, and identified by hydrophilic interaction liquid chromatography (HILIC)-HR-ESI-MS and MS/MS. Ninety-four compounds were identified, including phospholipids, glycolipids, sphingolipids, and acyl sterol glycosides, several of which bear polyunsaturated fatty acids. Multivariate statistical analysis found unique profiles within each sub-region and markers of geographic identity, primarily phosphatidylcholines, phosphatidylethanolamines, and lysophosphatidylethanolamines. Therefore, polar lipid signatures should be further investigated, to assess their bioactivity, nutritional value, and chemical identity for valuing olive seeds and their oil.