Long-Term Propolis\nIntake-Induced Liver Lipid Remodeling\nin Mice: Effects on Phospholipid-to-Glycerolipid Metabolism and Free\nFatty Acid-Mediated Thermogenesis

Research on the patterns and mechanisms of liver lipid\nremodeling\nregulated by propolis is limited. In the present study, the nine-month\nexperimental duration has shed light on the positive influences of\npropolis on lipid metabolism and thermogenesis capacity in the livers\nof mice. Eight major compounds in propolis were characterized using\nUPLC-QTOF-MS technology. Propolis significantly lowered serum triglycerides\n(TGs) and low-density lipoprotein cholesterol (LDL-C), but it also\nled to increased insulin (INS) levels. Lipidomics change trend analysis\nof 1671 lipid components across 42 categories revealed that the level\nof glycerophospholipids (GPs) decreased while glycerolipids (GLs)\nand fatty acids (FAs) increased in the liver. The expression levels\nof eight key genes involved in the conversion of GP to GL pathways\nin the liver were enhanced in the propolis group. Molecular docking\nresults elucidated the high binding affinities between the eight components\nof propolis and eight receptors involved in lipid metabolism, indicating\nthat primary compounds of propolis possess potent capabilities for\nphospholipid remodeling and lipolysis. These results imply that propolis\ncould facilitate the browning of the liver adipose tissue, promote\nthe conversion of GPs to DGs and FFAs, enhance the consumption of\nFFAs through thermogenic pathways, and thereby exert lipolytic and\nhepatoprotective functions.