of altered lipid species and pathways in luteolin- treated M1 macrophages

Luteolin is a natural flavonoid derived from vegetables, fruits, and herbs and inhibits the inflammatory response in macrophages. However, there are few reports indicating that luteolin can inhibit inflammation by modulating lipid metabolism disorders. Non-targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)coupled with univariate and multivariate statistical analyses were employed to identify the differences of lipid class and molecular species in LPS plus IFN-γ activated RAW264.7 macrophages (M1 macrophages), accompanied with luteolin at non- cytotoxic doses. Differentially expressed lipids have been further analyzed using the MetaboAnalyst 5.0 software. As a result, 32 lipid classes were effectively down- regulated in M1 macrophages after treatment with luteolin. 85 lipid species showed significant differences in their levels between M1 macrophages group and luteolin- treated group,which involved in glycerophospholipid and sphingolipid metabolic pathways. Our study shows that luteolin altered lipid metabolism in M1 macrophages, which provide additional insight into the underlying mechanisms of luteolin on the inflammatory polarization of macrophages.