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Introduction: Gynura procumbens (Lorr.) Merr. (GP) displays cardio-protective effect, which may hinder atherogenesis induced by oxidized low-density lipoprotein (oxLDL) and leukocytes. The current study was undertaken to elucidate the chemical constituents of GP ethanol extract and its aqueous, chloroform, ethyl acetate, and hexane fractions, and their effects on CD4+ T cell differentiation during atherogenesis. Methods: Initially, the bioactive constituents in GP ethanol extract and its fractions were analyzed using gas chromatography-mass spectrometry (GC-MS). Generated mouse bone marrow dendritic cells (BMDC) were loaded with oxLDL and GP ethanol extract and its fractions for 24 hours and co-cultured with mouse CD4+ T cells for 72 hours. For the determination of T-bet, GATA-3, RORγt, Foxp3, DLL-3, and Jagged-1 mRNA gene expression, the floating cells (CD4+ T cells) and adherence cells (BMDC) were isolated from their total RNAs and reverse transcribed into cDNA.Results: GC-MS analysis showed that GP ethanol extract and its fractions contained various volatile compounds. GP ethanol extract and its fractions also increased the DLL-3 gene but suppressed Jagged-1 gene expression in oxLDL-treated BMDC. Furthermore, GP ethanol extract and its fractions suppressed T-bet, GATA-3, and RORγt gene expression but increased the expression of the Foxp3 gene in differentiated CD4 + T cells. Conclusion: GP ethanol extract and its fractions are composed of various bioactive chemical components that can induce anti-atherogenic effects by inhibiting pro-atherogenic cells such as Th1, Th2, and Th17 cells while increasing anti-atherogenic cells, Treg cells.

Ethnopharmacology relevance Gynura procumbens (Lour.) Merr. displayed cardio-protective effect that may prevent atherogenesis. The primary underlying pathological process of cardiovascular disease is atherosclerosis. Atherosclerotic lesion composed of macrophages, T cells and other immune cells which incorporated with cholesterol that infiltrates from the blood. Aim of the study: The present study was performed to determine underlying mechanism of G. procumbens ethanol extract and its fractions such as aqueous, chloroform, ethyl acetate and hexane affect macrophage derived foam cell formation. Materials and methods Lipid droplets accumulation in treated macrophages were visualized by Oil Red O staining while the total cholesterol present in the treated macrophages were measured using Cholestryl Ester quantification assay kit. Enzyme-Linked Immunosorbent Assay (ELISA) were used to detect TNF-α and IL-1β secretion in the supernatant of treated macrophages. Gene expression of Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and ATP-binding cassette transporter A-1 (ABCA-1) in treated macrophages were analyzed using Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR). Results G. procumbens ethanol extract and its fractions reduced lipid droplet accumulation and total cholesterol in oxLDL-treated macrophages together with significantly reduction of TNF-α and IL-1β secretions in supernatant oxLDL-treated macrophages. LOX-1 gene expression was significantly reduced when G. procumbens ethanol extract and its fractions were added in oxDL-treated macrophages. In contrast, G. procumbens ethanol extract and its fractions significantly increased the expression of ABCA-1 gene in oxLDL-treated macrophages. Conclusion In conclusion, G. procumbens ethanol extract and its fractions inhibit the formation of macrophage derived foam cell by reducing TNF-α and IL-1β expression, which usually highly expressed in atherosclerotic plaques, suppressing scavenger receptor LOX-1 gene that binds oxLDL but induced ABCA-1 gene that mediate lipid efflux from macrophages.