A three-tier screening strategy-based targeted UPLC-ESI-MS/MS platform delineates the FAHFA landscape in lipid extracts of fruit seeds and pits

A 3-tier screening strategy-based LC-MS/MS profiles FAHFAs in fruit seeds and pits. • Fruit seed oils contain significantly higher total FAHFA levels than pit oils. • Bayberry seed oil is the richest FAHFA source (168 ng/g) among all samples. • OAHOA and PAHOA are identified as predominant FAHFA species in fruit seeds. Fatty acid esters of hydroxy fatty acids (FAHFAs) are bioactive lipids with anti-inflammatory and antidiabetic properties, but their occurrence in fruit seeds and pits remain largely unexplored. Here, untargeted lipidomics and fatty acid profiling were firstly employed to characterize the overall lipid landscape and precursor pools. Subsequently, a targeted platform was established by integrating solid-phase extraction (SPE) enrichment, N , N -dimethylethylenediamine (DMED) derivatization, and UPLC-ESI-MS/MS in multiple reaction monitoring (MRM) mode. Using a predictive MRM database covering 2116 theoretical FAHFA species and a three-tier screening strategy (two MRM filtering rounds followed by retention time and signal-to-noise evaluation), 49 endogenous species were identified in 17 fruit seeds and 4 fruit pits. It was found that fruit seed oils contained significantly higher total FAHFA levels than pit oils (3–168 vs. 1–35 ng/g), with bayberry seed oil showing the highest content (168 ng/g). Predominant species included OAHOA, LAHLA, PAHOA, and OAHSA. This first comprehensive FAHFA profile, achieved via the three-tier strategy, establishes seed oils as notable dietary sources of these lipids and offers a robust platform for discovering bioactive lipids in complex plant matrices. Download: Download high-res image (113KB) Download: Download full-size image