Untargeted metabolomics reveals nomilin-induced changes in glycerophospholipid composition associated with delayed senescence of ‘Zhangji’ strawberry fruits

Strawberry is highly perishable, and postharvest senescence involves membrane lipid changes. Nomilin, a citrus triterpenoid, is bioactive in mammals, but its effects on fruit lipids are unknown. This study evaluated nomilin effects on the glycerophospholipid profile of ‘Zhangji’ strawberry using untargeted liquid chromatography-mass spectrometry metabolomics. Fruits were treated with 0, 0.1, 1, 10, and 20 μM nomilin and stored at 25 °C for 8 days. Among the concentrations tested, 10 μM nomilin most effectively delayed senescence. After 8 days, 10 μM nomilin reduced weight loss from 49.70% to 25.10%, maintained firmness at 1.55 N versus 1.02 N in controls, and decreased decay index from 25.71% to 14.00%. It also reduced malondialdehyde content, relative electrolyte leakage, and lipoxygenase activity. Metabolomic analysis identified 173 and 98 differentially accumulated metabolites in positive and negative ion modes, respectively. Pathway enrichment analysis revealed significant enrichment in glycerophospholipid metabolism. Relative quantification showed that nomilin notably induced six lysophospholipid species: lysophosphatidic acid (LPA) 18:2, 18:3, 16:0, and lysophosphatidylcholine (LPC) 18:2, 18:3, 14:0. These findings provide relative compositional information on nomilin-induced glycerophospholipid changes, which may serve as quality markers for postharvest senescence and support natural preservation strategies.