Efficient separation and quantitative sleep evaluation of phospholipids and glycerides of Antarctic krill

Glycerides and phospholipids are the primary constituents of Antarctic krill lipids. This study aimed to efficiently separate these components using ethanol, water and n-hexane, and further evaluated the effects on sleep-improvement. Based on hydrophilic-lipophilic balance differences and solvent phase equilibria, the extraction process yielded two distinct layers. The ethanol-water (E-W) layer was rich in phospholipids (92 %), while the n-hexane (NH) layer primarily consisted of glycerides (74 %). Lipidomics analysis identified 995 lipids across five major classes, including glycerides, phospholipids, free fatty acids, ceramides and cholesterol esters. Drosophila activity monitoring revealed that NH and E-W layers improved sleep parameters in insomnia flies, with E-W exhibiting more significant effects. This difference in efficacy can be attributed to E-W's regulation of both nicotinic cholinergic and dopaminergic activity, while NH only regulated nicotinic cholinergic activity. This study elucidated the distinct composition and bioactivity during the extraction of Antarctic krill lipids, providing a scientific basis for their high-value applications in functional foods.