Microalgae as a New Source of Oxylipins: A Comprehensive LC-MS-Based Analysis Using Conventional and Green Extraction Methods.

Microalgae are promising sources of essential lipids, including omega-3 and omega-6 polyunsaturated fatty acids (n-3 and n-6 PUFA) and novel lipid metabolites like oxylipins. However, limited data exist on the oxylipin profile, its characterization, and the potential impact of the extraction process on these metabolites in microalgae. Thus, our study aimed to investigate the fatty acid and oxylipin profile of four microalgal species of interest ( Microchloropsis gaditana , Tisochrysis lutea , Phaeodactylum tricornutum , and Porphyridium cruentum ) while also examining the impact of the extraction method, with a focus on developing a greener process using ultrasound-assisted extraction (UAE) and ethanol. The UAE method showed similar oxylipin profiles, generally yielding concentrations comparable to those of the conventional Folch method. In total, 68 oxylipins derived from n-3 and n-6 PUFA were detected, with the highest concentrations of n-3 oxylipins found in P. tricornutum and T. lutea and of n-6 oxylipins in P. cruentum . This study provides the most extensive oxylipin characterization of these microalgae species to date, offering insights into alternative extraction methods and opening new avenues for further investigation of the significance of oxylipins in microalgae.